Experimental Food Study Laboratory Notebook

Jennifer Hamilton

DFM 357 – PM Lab

November 14, 2014

2

Table of Contents

Lab # Page #

Lab #1: Basic Measuring Techniques 3

Lab #2: Sensory Evaluation 7

Lab #3: Crystallization 17

Lab #4: Starch and Thickening Agents 29

Lab #5: Fiber 37

Lab #6: Fats and Oils 43

Lab #7: Milk Proteins 48

3

Lab#1: Basic Measuring Techniques

Date: September 5, 2014

Conditions: Warm

Purpose:

The purpose of the lab was to explore different measurement techniques and to observe

the difference in weights of the products it produced.

Experimental Procedures:

The instructions were given for Lab #1 by instructor Maryann Smitt and they were listed

in Table’s #1-3 included below. Students measured an assortment of common household baking

goods, three times.

Results:

For data and results, please refer to Table #1-3 attached.

Discussion:

In the basic measurement technique lab, different measuring techniques were used to

measure out an assortment of household products. The way items were measured differed by

sifting vs not sifting, packed vs unpacked, liquid vs solid and coarse vs fine. The texture of a

product or type of product and how it was measured affected the weighed outcome of the

product. For example, in measuring different types of flour in Table #1, sifting and packing

affected the average weight of all purpose flour with an average weight of 179.4g. While sifted

all-purpose flour that was not packed had an average weight of 100.7g. This is a difference of

almost 79g.

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In Table #2, brown sugar that was packed vs not packed also showed a difference in

average weight. The packed brown sugar average weight was 49.3g, while the brown sugar not

packed weighed on average 27.4g. It became evident that how a substance was measured, would

affect the actual quantity of the product produced.

According to Better Homes and Gardens Cook Book, getting consistent successful results

from your product begins with measuring the ingredients with the correct tools. Therefore it is

important to use dry measuring cups for household items like flour, sugar and solid fats, and to

use a liquid measuring cup for household items such as water and oil.

While conducting the experiments with the sugar and fats there were several notable

possible errors that occurred. First, the bowl that was used to place the powdered sugar in was

slightly wet. Even though the scale was zeroed before weighing anything, some powdered sugar

would stick to the bowl. Also the powder sugar stuck in the measuring cup. So the weight may

be slightly underrepresented as a result of residual in the measuring cup. Second, while

measuring hydrogenated oil, some of the hydrogenated oil remained in the measuring cup.

Another notable error is a dry measuring cup was used instead of a liquid measuring cup while

measuring the vegetable oil. This could place more oil in the cup due to surface tension as

opposed to using the meniscus of a liquid measuring method. The vegetable oil we used also

contained remnants of hydrogenated oil. This could alter the weight by having a lower volume

than what might otherwise be. Lastly, while measuring the butter, there was residual butter in the

measuring cup. Thus the results of the average weight of butter could be lower than what it might

otherwise be. These are examples of measurement bias that were discussed in the Research

Process lecture by Christine Batten on August 27, 2014. Ideally you would like to remove bias to

make sure results are consistent and accurate.

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It was observed that the types of fat weighed had considerably different average weights.

The average weight for hydrogenated fat was 46.2g, vegetable oil was 49.6g and butter was

53.1g. Butter was the heaviest possibly due to the milk solids, while hydrogenated fat is the

lightest due to water being removed from the product.

In Table #3, different types of salts were measured ranging from fine to coarse. Table salt

was the heaviest with an average weight of 6.4g while Kosher salt was the lightest with an

average weight of 3.3g. The size of Kosher salt granules took up more room in the measuring

spoon and thus potentially account for why the weight was almost half the weight of table salt,

which was finer and more compact. Coarse vs fine texture seemed to impact amount of product

delivered and must be kept in mind when preparing dishes.

The objective evaluation of the data has shown that measurement technique can and will

alter the desired amount of product. Therefore, in order to reduce measurement bias, it is

important to be aware of the proper technique and tools to use.

References

Batten, C. (2014). DFM 357 – Research Process [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

Darling, J.D. (Ed.). (2012). Better Homes and Gardens Cook Book (12th

ed.). Des Moines, Iowa:

Better Homes and Gardens Books.

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DFM 357 Lab 1 – Basic Measuring Techniques

1 Cup

Table #1

Trial 1

Trial 2

Trial 3

Average

1 a-1 Bread flour, unsifted, fill cup by a spoon 126.5g 125.8g 119.7g 124.0g

2 a-2 Bread flour, unsifted, minus 2 tablespoons 110.7g 109.9g 109.1g 109.9g

3 a-3 Bread flour, sifted, lightly fill cup by a spoon, no

packing or shaking. Level top with edge of a straight

knife or spatula

114.4g 111.9g 115.5g 113.9g

4 a-4 All purpose flour, sifted, packed and tapped into a cup

with a spoon 180.0g 176.6g 181.7g 179.4g

5 a-5 All purpose flour, sifted, lightly fill cup by spoon, no

packing or shaking. Level top with edge of a straight

knife or spatula, then minus 2 tablespoons, level top

with edge of a straight knife carefully.

9.5g 102.4g 100.3g 100.7g

6

b-1

Water 232.7g 229.1g 231.5g 231.1g

1/4 Cup

Table #2

Trial 1

Trial 2

Trial 3

Average

7 c-1 Brown sugar, packed and tapped into a cup with a

spoon. 50.9g 50.1g 46.8g 49.3g

8 c-2 Brown sugar, lightly fill cup by a spoon, no packing or

shaking. Shake and level top with edge of a straight

knife or spatula 27.8g 27.2g 27.1g 27.4g

9

c-3

Granulated sugar or powder sugar, fill cup by a spoon. 26.9g 26.8g 27.8g 27.7g

10

d-1

Hydrogenated fat 45.8g 45.1g 47.7g 46.2g

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d-2

Oil 49.2g 48.7g 50.8g 49.6g

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d-3

Butter 52.3g 54.1g 53.0g 53.1g

1 teaspoon

Table #3

Trial 1

Trial 2

Trial 3

Average

13

e-1

Table salt 6.5g 6.4g 6.4g 6.4g

14

e-2

Kosher salt 3.2g 3.4g 3.3g 3.3g

15

e-3

Sea salt 6.0g 6.2g 5.9g 6.0g

7

Lab #2: Sensory Evaluation

Date: September 12, 2014

Conditions: Noisy, busy, warm

Purpose:

The purpose of the lab was to explore how appearance, odor, taste and texture impact our

experience with food.

Experimental Procedures:

A sequence of exercises was given to experience tasting through a series of solutions that

were coded. The instructions for each station within Lab #2 were given by instructor Maryann

Smitt and were listed in Series A-L of the attached. Students tasted in silence the assortment of

solutions that were sweet, salty, sour, bitter or umami and recorded results in Series A-L. We

used three different types of test: descriptive, affective and difference tests.

Results:

For data and results, please refer to Series A-L, attached.

Discussion:

In the sensory lab, different solutions were evaluated by using difference tests as well as

incorporating different flavor enhancers and inhibitors to solutions. In Series A, Identification of

the Primary Tastes, we had to taste five different solutions and match them to either bitter, sour,

salty, sweet or umami the fifth taste. My four taste receptors were able to identify the five

different solutions very distinctly and easily with bitter on the back of the tongue, sour on the

sides of my tongue, and sweet & salty on the tip of the tongue.

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In series B, Effect of Acid on Sweetness: Paired Comparison Sensory Test, several

different applications were occurring. First, we used the paired comparison test. McWilliams

(2012) defines it as a test of difference in which a specific characteristic is designated. Then the

taster is given two samples to compare and they must identify the sample with the greater

amount of the characteristic being measured. The other application was the addition of citric acid

to the solution. Per Christine Batten lecture on September 3, 2014, we learned that acid increased

the saltiness of a solution. When tasting samples #142 and #293, #142 was less sweet and was a

little salty compared to #293. Per the key attached, #142 was confirmed to be less sweet.

Series C, Effect of Salt on Sweetness: Triangle Sensory Test, used two different

applications. First, it used the triangle sensory test which is defined by McWilliams (2012) as a

test given with three samples presented simultaneously. The taster must identify the sample that

is different from the other two samples presented, which are the same. Tasting three samples

became a little more challenging to identify which sample was different. However, the solution

with the salt tasted slightly sweeter and was ultimately the different sample. This leads to the

other application used, using salt as flavor enhancer. As learned in lecture, salt enhances

sweetness, which was evidenced in sample #256.

Series D, Effect of Sugar on Saltiness: Paired Comparison Sensory Test, used sugar as a

flavor inhibitor along with the paired comparison test. When comparing solution #876 to #190,

#876 was less salty than #190. Solution #876 had salt and sugar added to the solution, thus

blocking taste sites, preventing the normal taste response in the solution (McWilliams 2012).

Therefore, sugar decreased the saltiness. One notable event was other tasters were reacting to the

saltiness of the solution. Even though the lab was supposed to be conducted in silence,

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participants were making faces and sounds to what they tasted. It gave other tasters a perception

the solution was unpalatable, but in reality it was just very salty, thus creating bias.

Series E, Effect of Sugar on Sourness (Acidity): Paired Comparison Sensory Test, used

sugar as a flavor inhibitor in a paired comparison test. In the presence of sugar, the sourness of

the solution was decreased. Solution #186 was very sour tasting, while #453 was less so.

Series F, Effect of Sugar on Bitterness: Paired Comparison Sensory Test, paired two

solutions one of which was sweet and the other bitter. Solution was #468 had sugar added to tea,

while #739 was tea that had been over steeped and was extremely bitter. The addition of sugar to

compensate for the bitterness of the tea, made it taste less bitter, but the amount of sugar added

made it almost too sweet and unpalatable.

Series G, Effect of Different Type of Sugar: Duo-Trio Test, was a test that used the duo-

trio test. This is a test where a taster is given one sample, the control, and then given two more

samples, and then they have to determine which the control is. This test was particularly

challenging to determine which solutions were similar. It was not clear at first which was the

control, thus making it difficult to compare. In addition, the sweetness of the solutions were very

similar, which made it hard to tell them apart. At the point in time when series G was tested, the

taster was getting saturated by the tastes of the previous solutions, to the point where all

solutions started to taste the same. This contributed to possible bias.

Series H, Effect of Above Threshold Levels of Salt on Sweetness: Triangle Test,

compared three samples to determine which was the sweetest sample. The standard provided was

#129, which was salty and sample #253 matched the standard. The application of large amounts

of salt decreased the sweetness of the solution. Sample #308 was found to be the sweetest, yet

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was only made with sucrose per the sensory lab key. Samples #129 and #253 had more of a salty

taste and were less sweet. They were made with sucrose and salt.

Series I, Effect of Processing Method on the Flavor of Lemonade: Consumer Preferences

Hedonic Scale Sensory Test, used an affective testing method. The hedonic scale sensory test is

defined as a rating scale used to measure the degree of pleasure experienced with each sample

(McWilliams 2012). Affective testing method evaluates acceptability of the samples

(McWilliams, 2012). Sample #598, dried lemonade mix, was preferred over frozen lemonade

and fresh lemonade with a rating of neither like nor dislike. Sample #470 was disliked very

much, because it was extremely sweet, off putting and had a chemical taste. Sample #229, fresh

lemonade, was disliked moderately due to the sour acidic nature of the solution. Therefore the

dried lemonade was more acceptable out of the three samples. It was not overly sweet, nor was it

overly tart, it was just ok.

Series J, Effect of Color on Flavor, used appearance/color as a test measure to see if the

taster would perceive a different flavor based on color. There were four different color samples:

blue, green, red and yellow. Color somewhat influenced perception of flavor. For example, blue

tasted sweet while green was tart. Overall, the samples tasted sweet and tart/sour. Per the sensory

lab key, the samples were all the same with the exception of color.

Series K, Effect of Genetic Predisposition on Tasting Phenylthiocarbamide (PTC), was a

test to see if the taster was a supertaster. After placing the PTC taste paper on the tongue there

was a metallic, acidic and tin like taste.

Series L, Perception of Flavor Without Visual Cues, explored flavor without sight.

Without sight other senses like taste and smell became more dominant in the flavor experience.

With eyes closed, jelly bean placed on the tongue and chewing begun, sweetness was the initial

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flavor of the candy. But as the jelly bean dissolved further, the tartness became more prominent

and taste was like lemon. However, the sweetness made it hard to decipher exactly what the

flavor was so it could have been pear. Later I found out the actual jelly bean was lemon and lime.

The sensory evaluation lab demonstrated the role different foods have to either enhance

or inhibit flavor. Salt is a flavor inhibitor and enhancer, while sugar reduces saltiness and

bitterness, and acid enhances saltiness. Flavor is made of four components: 1 taste, 2 odor, 3

mouth feel and 4 trigeminal perception. To explore flavor further a variety of tasting methods

from affective to difference testing can be used. Taste is a subjective measure because it will be

unique for each person. This was evident in the Series I test where the hedonic scale was used.

References:

Batten, C. (2014). DFM 357 – Sensory Evaluation [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

McWilliams, M. (2012). Foods Experimental Perspectives (7th

ed.). Upper Saddle River, NJ:

Prentice Hall.

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DFM 357 Lab 2 – Sensory Evaluation

The sensory quality of food encompasses many complex factors: appearance, odor, taste, and texture

(mouthfeel). The flavor of food is derived from a combination of odors and tastes and is influenced by

its temperature and texture. The primary tastes are generally considered to be bitter, salt, sour, sweet,

and umami. Substances that contribute to taste must be in solution before they can be detected.

Individuals vary in their ability to identify specific tastes.

Goal: To experience sensory evaluation of primary tastes and the effect of color on flavor using sensory evaluation

methods.

Outcomes: o To recognize the basic tastes and to identify the effect that one has on the others.

o To recognize the effects of color on taste.

o To use a variety of sensory evaluation tests: specifically the paired comparison, triangle, duo-

trio, and the hedonic scale.

o To increase sensitivity to taste.

Questions for study: How does one taste affect another?

What characteristics of a food are important to your ability to taste?

Procedure: Preparation: Solutions are prepared according to directions in Appendix A.

Experiment: Below are a series of exercises that will give you some experience in tasting. A series of solutions

have been made and coded so that you will not know what they are. You will rotate through each series.

For each series, pour a one-teaspoon sample into a clean cup, taste, and evaluate according to the testing

method indicated. Following each taste, rinse your mouth with water. When you have finished, you can

compare your results with the composition of each solution. Note: this experiment must be conducted in

silence.

Series A: Identification of the Primary Tastes

Taste each of the labeled solutions and place the number in the column that corresponds to the taste sensation

you received from the solution.

Identification Bitter Sour Salt Sweet Umami

Individual 372 798 569 825 281

Correct key # 372 798 569 825 281

Series B: Effect of Acid on Sweetness: Paired Comparison Sensory Test

Place the code under the correct category.

Identification Less Sweet More Sweet No Difference

Individual 142 293

Correct key #

Conclusion:

How did acid affect sweetness?

Acid increased the saltiness of the solution and made it sweeter.

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Describe a paired comparison sensory test.

A paired comparison is when a specific characteristic is designated. The person judging then has to test

the two samples to identify the sample with the greater amount of the specified characteristic.

Series C: Effect of Salt on Sweetness: Triangle Sensory Test

Choose the sample that is different from the other two. Is it sweeter or less sweet?

Identification Two of the Same Different Sample Different Sample:

Less Sweet

Individual 621, 879 256 (more sweet) 879

Correct key #

Conclusion:

How did salt affect sweetness?

Salt enhances sweetness

Describe a triangle sensory test.

A triangle test is when you are given three samples and you have to identify the sample that is different.

Two will be the same.

Series D: Effect of sugar on saltiness: Paired Comparison Sensory Test

Place the code under the correct category.

Identification Less Salty More Salty No Difference

Individual 876 190

Correct key #

Conclusion:

Sugar (decreases/increases) saltiness.

Series E: Effect of Sugar on Sourness (Acidity): Paired Comparison Sensory Test

Place the code under the correct category.

Identification Less Sour More Sour No Difference

Individual 453 186

Correct key #

Conclusion:

Sugar (decreases/increases) sourness.

Series F: Effect of Sugar on Bitterness: Paired Comparison Sensory Test

Place code under the correct category.

Identification Less Bitter More Bitter No Difference

Individual 468 – sweet 739 - bitter

Correct key #

Conclusion: Sugar (decreases/increases) bitterness.

Series G: Effect of a different type of sugar: Duo-Trio Test

Identification Different

Individual 438,724,222 724

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Correct key #

Conclusion:

Describe the duo-trio test.

In the duo-trio test the control is presented first, followed by two other samples, one of which is the same as the

control. The person judging must identify which of the two samples are different from the control.

Series H: Effect of Above Threshold Levels of Salt on Sweetness: Triangle Test

Choose the sample that is different from the standard. Is it sweeter or less sweet?

Identification Identical to Standard Sweeter/Less Sweet

Individual Standard:129-salt &

sweet, 308-Sweet

253 – sweet & salt Less Sweet & Salty

Correct key #

Conclusion:

Salt in larger amounts (decreases/increases) sweetness.

Describe the triangle test.

The triangle test is when you are given three samples and you have to identify the sample that is different. Two

will be the same.

Series I: Effect of Processing Method on the Flavor of Lemonade:

Consumer Preference Hedonic Scale Sensory Test

Rate the 3 lemonade samples from “dislike extremely” to “like extremely” by checking the appropriate box.

Sample #470

☐ ☐ ☐ ☐ ☐ ☐ ☐ ☐ ☐

Dislike

Extremely

Dislike

Very

Much

Dislike

Moderately

Dislike

Slightly

Neither

Like nor

Dislike

Like

Slightly

Like

Moderately

Like

Very

Much

Like

Extremely

Sample #598

☐ ☐ ☐ ☐ ☐ ☐ ☐ ☐ ☐

Dislike

Extremely

Dislike

Very

Much

Dislike

Moderately

Dislike

Slightly

Neither

Like nor

Dislike

Like

Slightly

Like

Moderately

Like

Very

Much

Like

Extremely

Sample #229

☐ ☐ ☐ ☐ ☐ ☐ ☐ ☐ ☐

Dislike

Extremely

Dislike

Very

Much

Dislike

Moderately

Dislike

Slightly

Neither

Like nor

Dislike

Like

Slightly

Like

Moderately

Like

Very

Much

Like

Extremely

Conclusion:

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How do frozen lemonade, a dried lemonade mix, and lemonade made from fresh lemons compare?

For my experience, I preferred the dried lemonade mix to the frozen and fresh lemonade. I really did not care

for the frozen because it was extremely sweet and off putting. It had a chemically taste. For the fresh

lemonade it was a little more tart than I would have cared to have it. Therefore the dried lemonade was

ok. It was not overly sweet, nor was it overly tart, it was just ok.

Describe the consumer preference hedonic scale sensory test.

The hedonic scale is a pleasure scale where samples are ranked in order of preference.

Series J: Effect of Color on Flavor

Identify the flavor of each solution.

Code Flavor 382 blue- Sweet

296 green - tart

432 red – sweet, tart

871 yellow – sour, sweet

Conclusion: Did color affect your perceived flavor?

Color somewhat influenced my perception of flavor. However, I found that most of the samples to be sweet and

tart/sour tasting.

Series K: Effect of Genetic Predisposition on Tasting Phenylthiocarbamide (PTC) Taste a PTC taste paper. Do you taste anything, and if you do, what is the quality?

What I tasted was tin like, metallic, acidic.

Series L: Perception of flavor without visual cues: Have your lab partner choose a jellybean flavor for you. With your eyes closed, have your partner place the

jellybean in your palm. Eat the jellybean. Guess what flavor it is and compare it to the actual flavor.

Describe what happened.

When I closed my eyes and placed the jelly bean on my tongue and began to chew I initially got the

sweetness of the candy, but then I started to taste tartness like a lemon. But the sweetness was throwing

me so I thought it could have been pear. It was hard to identify without seeing the sample, but the other

senses like taste and smell became more dominant.

In actuality the jelly bean that I was given was lemon & lime. So I was close to the flavor profile.

16 Series A: Identification of the Primary Tastes

Identification Bitter Sour Salt Sweet Umami

Correct key # 372 798 569 825 281

Series B: Effect of Acid on Sweetness: Paired Comparison Sensory Test

Identification Ingredients

293 Sucrose

142 Sucrose + Citric Acid (less sweet)

Series C: Effect of Salt on Sweetness: Triangle Sensory Test

Identification Ingredients

621 Sucrose (621 & 879 are the same)

256 Sucrose + Salt (more sweet)

879 Sucrose

Series D: Effect of Sugar on Saltiness: Paired Comparison Sensory Test

Identification Ingredients

190 Salt

876 Salt + Sucrose (less salty)

Series E: Effect of Sugar on Sourness (Acidity): Paired Comparison Sensory Test

Identification Ingredients

186 Citric Acid

453 Citric Acid + Sucrose (less sour)

Series F: Effect of Sugar on Bitterness: Paired Comparison Sensory Test

Identification Ingredients

739 Caffeine

468 Caffeine + Sucrose (less bitter)

Series G: Effect of a different type of sugar: Duo-Trio Test

Identification Ingredients

222 & 438 Sucrose – both the same

724 Agave Syrup – sweeter with bitter after taste

Series H: Effect of Above Threshold Levels of Salt on Sweetness: Triangle Test

Identification Ingredients

308 Sucrose (the different sample)

253 Reference Sucrose + Salt

129 Sucrose + Salt

Series I: Effect of Processing Method on the Flavor of Lemonade: Consumer Preference Hedonic Scale

Sensory Test

Identification Ingredients

470 Frozen Lemonade

598 Dried Lemonade Mix

229 Fresh Lemonade

Series J: Effect of Color on Flavor

Identification: 382, 296, 432, 871.

All samples were the same (lemonade), only the colors were different

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Lab #3: Crystallization

Date: September 19, 2014

Conditions: Hot

Purpose:

The purpose of the lab was to understand the process of crystallization in crystalline and

amorphous candies by applying temperature, time and air incorporation as controls.

Experimental Procedures:

The instructions were given for Lab #3, Crystallization by instructor Maryann Smitt and

are listed in the Lab 3 – Crystallization handout, see attached. Students made an assortment of

crystalline candies such as fondants, fudge, divinity, and amorphous candies such as caramels,

lollipops and peanut brittle. Students recorded in designated tables data for cooking temperature,

beating temperature, beating time, color, texture, consistency and flavor.

Results:

For data and results, please refer to Fondant Results, Fudge and Divinity Results and

Caramels, Peanut Brittle & Lollipop Results below.

Discussion:

Crystalline candies come in several forms. They come either saturated, as much as a

solute can hold; or supersaturated, solution containing more than it theoretically can at a specific

temperature. They have an organized crystalline area where some small amount of liquid is

trapped inside the crystals, otherwise known as mother liquor. This provides a smooth texture to

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the candy. There are several well-known candies that are classified as crystalline candies such as

fondant, fudge and divinity.

The function of cream of tartar in crystalline candy is to create invert sugar. Per Christine

Batten (2014) lecture, cream of tartar is a weak acid which hydrolyses sucrose to form equal

portions of glucose and fructose and promote inversion. This process makes invert sugar, which

ultimately makes a sweeter, smoother product. Cream of tartar can be replaced with corn syrup

because corn syrup is mostly glucose. It acts as a buffer between sucrose molecules preventing

them from joining together in one giant mass and ruining the crystalline structure. Also corn

syrup has already been hydrolyzed to glucose and fructose.

Temperature affects crystalline candies quite dramatically. Beating candies at a certain

temperature disrupts the crystals as they attempt to form. The viscosity at a certain temperature

and agitation results in a finished product that is smooth and velvety. However, if crystallization

occurs before the candy has reached super saturation, then beating must begin immediately until

the candy solidifies. The agitation will disrupt the crystals and keep their size small to provide a

texture that is pretty smooth when finished. This was evident in the Fudge & Divinity Results

table. As the cooking temp was increased, the fudge became less smooth and more crumbly.

Several candies in the lab were made using cream, such as fudge and fondant. Cream

affects the crystal size by interfering with the formation of crystals. The cream fondant was

creamy and buttery while the fondant made with water was very sweet and more firm. Some

common ingredients found in fudge are milk, cream, chocolate and egg whites. The reason why

these items are added to crystalline candies is because of they all contain fat. The fat makes a

finer texture by interfering with crystallization and enhancing flavor. The fat will produce a

smooth texture and enhance flavor, which is desirable in crystalline candies (McWilliams 2012).

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We did not have corn syrup as a sample fondant. The group that was making the sample

cooled their fondant below 40ºC unknowingly because their thermometer was placed in their

bowl incorrectly. The tip of the thermometer was touching the bottom of the bowl and gave a

false reading. As result of this error, the fondant was cooled to 35ºC and was unable to be beaten

because it was too rigid. However, color difference of the fondant could be attributed to the

translucency of the item used. For example, cream of tartar is a white powder giving an opaque

white appearance, while corn syrup would make the product a little more clear and glossy.

The temperature at which you beat a candy affects the crystalline nuclei formation. By

cooling a mixture to about 40ºC it will favor the formation of more nuclei and finer crystals. The

thickness of the solution is also greater at lower temperatures. However, if too low of a

temperature is reached it may delay the formation of a lot of nuclei (Srilakshmi, 2003). This is

important because agitation keeps many of the small nuclei in the supersaturated solution and

prevents it from attaching to already developed crystals. This was seen with Fudge 2,

temperature of beating & speed of beating on crystal size in the Fudge & Divinity Results table.

At a low beating speed and cooler temperature, it took longer for the candy to go from glossy to

dull. It also produced a dry fudge. As the beating temperature increased, the time it took to show

a change lessened and the product was grainier. Lastly, as beating speed increased with a low

beating temperature, the beating time decreased making for smoother and thick fudge.

As temperature is increased in a crystalline candy, it will become harder due to the

increased concentration of sugar. If the temperature is decreased and the water vapor evaporates

more slowly, then it yields a softer, more watery candy.

While making fudge in the microwave there are several factors to consider. First, each

microwave has a different power/strength. Some get hotter more quickly while others are not as

20

powerful and thus take longer to heat items. The microwave in lab is quite old and may not be

powerful enough to generate sufficient heat to dissolve the sugar to the desired temperature. Also

you have to keep agitating the substance to make sure the product is heated through correctly

because the outside is usually exposed to more heat than the inside. In addition, the group

making the fudge was not able to get the cooking temperature above 95°C and the beating

temperature was below the suggested 40°C. It was between 32°C and 35°C. As a result, the

fudge was very runny and not very stable.

Non-crystalline candies or amorphous candies, lack organized crystalline structures due

to their very high concentration of interfering substances such as margarine. In addition it takes a

very high temperature for amorphous candies to form as they have a higher sugar concentration

than crystalline candies. However, one has to be careful while making these candies and make

sure not to scorch the viscous substance. In the third table, Caramels, Peanut Brittle, & Lollipop

Results, the lollipops that were made had a burnt taste because they were scorched.

In addition, extreme high temperatures accelerate the chemical breakdown and

caramelization of amorphous candies. Adding cream will contribute to the Maillard reaction and

produce the browning of the sugar at the end stage of boiling (McWilliams, 2012). This could be

seen in particular with the caramels. Using light cream and evaporated milk to make caramels

yielded two different outcomes. With the light cream, caramels had a glossy appearance but had

a very hard chew. With the evaporated milk, caramels were chunky looking with air bubbles and

had a gritty, runny consistency. The reason for this difference is attributed to the percent of milk

fat in the two products. Light cream on average has about 18-30% milk fat while evaporated

milk is about 0.5-8% milk fat (Alden, 2005). The reduction in fat in the evaporated milk made

for less interfering substances and thus a runnier and grittier consistency.

21

Peanut Brittle was the last amorphous candy that was tested. It is made by heating water,

margarine, salt, sugar and corn syrup to a high temperature until it reaches a soft-ball stage. It’s

very malleable and flattens out of its own accord when picked up with fingers (Batten, 2014).

Next peanuts are added and the candy is cooked further until the syrup turns light brown. Then

the mixture is removed from the heat and baking soda is added, which causes a chemical reaction

to occur, releasing CO2, which causes air bubbles. While we were making the peanut brittle we

constantly stirred. However, by constantly stirring it took longer for the mixture to heat and get

to the softball stage. In the instructions it said to go to 112-116°C, but we ended up having to go

to 150°C to reach softball stage. The over agitation could have caused crystals to form.

However, the end product still turned out brittle, crunchy and had a good flavor of salty and

sweet.

Reference:

Batten, C. (2014). DFM 357 – CHO: SUGARS [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

McWilliams, M. (2012). Foods Experimental Perspectives (7th

ed.). Upper Saddle River, NJ:

Prentice Hall.

Srilakshmi, B. (2003). Food Science (3rd

ed.) pp. 219. Daryaganj, New Delhi: New Age

International (P) Limited, Publishers.

Alden, Lori (2005). The Cook’s Thesaurus: Milk & Cream Retrieved October 31, 2014 from

http://www.foodsubs.com/Dairyoth.html

22

DFM 357 Lab 3 – Crystallization

A. Fondant

250 g water 0.4 g cream of tartar or

400 g sugar 41 g light corn syrup

General Directions:

Before beating, rinse plate with cold water. Dry plate. Place thermometer with mercury column up on a

plate (on wire rack), and tape thermometer in position. Pour candy on plate to cool. Leave undisturbed

until desired temperature is reached (don’t move or jar!!). Beat with a heavy spoon or heavy mixer.

Procedure:

Mix ingredients, stir, and heat to boiling point on high heat. Turn heat down to medium. Cook without

stirring to temperature indicated in your variable. Wash crystals from sides of pan as they form, or cover

pan a few minutes while cooking to dissolve them. Pour mixture onto a prepared plate as indicated under

general directions. Cool to temperature indicated in your variable. When cooled appropriately, stir and

work back and forth until mixture is white and creamy. Then knead until smooth.

1. Effect of temperature of beating

Procedure: Prepare 1½ times recipe.

Read general directions (use cream of tartar in place of corn syrup)

Cook to soft ball stage: 1140C (237

0F). Divide cooked fondant between three plates:

Variables:

a. Beat immediately

b. Cool to 70 oC (158

0F); beat as indicated above

c. Cool to 40 oC (104

0F); beat as indicated above

A. Fondant

250 g water 0.4 g cream of tartar or

400 g sugar 41 g light corn syrup

General Directions:

Before beating, rinse plate with cold water. Dry plate. Place thermometer with mercury column up on a

plate (on wire rack), and tape thermometer in position. Pour candy on plate to cool. Leave undisturbed

until desired temperature is reached (don’t move or jar!!). Beat with a heavy spoon or heavy mixer.

Procedure:

Mix ingredients, stir, and heat to boiling point on high heat. Turn heat down to medium. Cook without

stirring to temperature indicated in your variable. Wash crystals from sides of pan as they form, or cover

pan a few minutes while cooking to dissolve them. Pour mixture onto a prepared plate as indicated under

general directions. Cool to temperature indicated in your variable. When cooled appropriately, stir and

work back and forth until mixture is white and creamy. Then knead until smooth.

2. Effect of addition of other sugars

Procedure: Prepare ½ recipe

Read general directions (use corn syrup in place of cream of tartar)

Cook to soft ball stage: 114oC (237

0F). Cool to 40

oC (104

0F) before beating

Effect of cream in place of water

23

3. Cream Fondant

245 g half & half cream

400 g sugar

0.4 g cream of tartar

Procedure: Read general directions. Mix ingredients and heat on medium heat, stirring constantly until

mixture boils. Adjust heat so that it continues to boil but does not scorch. Wash crystals from side

of pan. Cook to 114oC (114

0F). Pour onto plate and cool as indicated in general directions. Cool

to 60oC (140

0F). Stir until creamy and knead until smooth.

Fondant Results:

Record cooking temperature, beating temperature, and beating time needed to crystallize.

Rate on a 9-point hedonic scale

Texture

9 = extremely white color and extremely smooth texture to 1 = extremely gray color and extremely course.

Consistency

9 = extremely firm

5 = moldable

1 = extremely runny

Variation Cooking

Temp. o C

Beating

Temp. o C

Beating

Time

Color Texture Consistency Flavor

A. Fondant

1. Beating temp.

a

114

114 3 min egg shell

wht

2 – dull 6

Sweet

b 114 70 1min

30sec Wht

8 –

glossy,

glisten

5

Really

Sweet

c 114 40 3min

8sec Pearl wht

8 –

smooth,

shinny

3

Sweet

Vanilla

2. Corn Syrup 114 40 N/A N/A N/A N/A N/A

3. Cream Fondant

114

60 20 min cream 8 -

polished 4

creamy

butter

Conclusions: What are the functions of cream of tartar in a crystalline candy? The function of cream of tartar in crystalline candy is to create invert sugar. Cream of tartar is

a weak acid which hydrolyses sucrose to form equal portions of glucose and fructose, which

ultimately make a sweeter, smoother product.

Why may cream of tartar be replaced with corn syrup?

Cream of tartar can be replaced with corn syrup because corn syrup is mostly glucose,

and acts as a buffer between sucrose molecules preventing them from joining together in

24

one giant mass and ruining crystalline structure. Also corn syrup has already been

hydrolyzed to glucose and fructose.

How does temperature of beating affect crystal nuclei formation?

Temperature effect crystalline candies quite dramatically. By beating at a certain

temperature it disrupts the crystals as they attempt to form. The viscosity at a certain

temperature and agitation results in a finished product that is smooth and velvety.

However, if crystallization occurs before the candy has reached super saturation, then

beating must begin immediately until the candy solidifies. The agitation will disrupt the

crystals and keep their size small to provide a texture that is pretty smooth when finished.

It still may not be as smooth as when crystallization is avoided.

What is the effect on crystal size of replacing water with cream? Why?

Cream affects the crystal size by interfering with the formation of crystals. The fat will

produce a smooth texture.

Why is there a color difference in fondant made with cream of tartar vs. fondant made with corn

syrup?

We did not have Corn Syrup as a sample fondant, as a result of an error on the group

making. However, the color difference would most likely be attributed to the

translucency of the item used. For example, cream of tartar is a white powder giving an

opaque white appearance, while corn syrup would make the product a little more clear

and glossy.

B. Fudge 70 g evaporated milk 1.5 g salt

225 g sugar 35.5 g baking chocolate (1 sq. = 28 g)

45 g water 19 g margarine

27 g light corn syrup 2.5 g vanilla extract

Procedure: Mix sugar, milk, water, corn syrup, salt, and chocolate. Cook and stir over medium heat until

sugar dissolves and chocolate melts. Cook to temperature indicated in experiment below. Add

vanilla. Add margarine. Remove from heat. Cool as indicated in experiment below. Beat until

candy is creamy and goes from glossy to dull. Pour quickly into oiled pans, making a ¾ to 1-inch

layer.

1. Effect of temperature of cooking: Correlation of end point temperature and concentration

Procedure: Prepare 1 ½ times recipe

a. Pour out ½ recipe at 110oC (230

0F); cool to 40

oC (104

0F); beat with heavy mixer

b. Pour out ½ recipe at 113oC (235

0F); cool to 40

oC (104

0F); beat with heavy mixer

c. Cook ½ recipe at 118oC (244

0F); pour out; cool to 40

oC (104

0F); beat with heavy mixer

B. Fudge

70 g evaporated milk 1.5 g salt

225 g sugar 35.5 g baking chocolate (1 sq. = 28 g)

45 g water 19 g margarine

27 g light corn syrup 2.5 g vanilla extract

25

Procedure: Mix sugar, milk, water, corn syrup, salt, and chocolate. Cook and stir over medium heat until

sugar dissolves and chocolate melts. Cook to temperature indicated in experiment below. Add

vanilla. Add margarine. Remove from heat. Cool as indicated in experiment below. Beat until

candy is creamy and goes from glossy to dull. Pour quickly into oiled pans, making a ¾ to 1-inch

layer.

2. Effect of temperature of beating and speed of beating on crystal size

Procedure: Prepare 1 ½ times recipe. Cook to 113oC (235

0F)

Variables:

a. Beat immediately on low speed

b. Cool to 40oC (104

0F); beat on low speed

c. Cool to 40oC (104

0F); beat on high speed

3. Microwave Fudge

200 g sugar 20.5 g light corn syrup

28.2 g cocoa 60 g margarine

78 g half & half cream 7.5 g vanilla extract

Procedure: Lightly butter plate. Mix sugar and cocoa in 2 qt Pyrex bowl. Add half & half, corn syrup, and

margarine. Cook for time specified below. Remove immediately. Add vanilla, place

thermometer into bowl, and record temperature after 1 ½ min. Pour into mixing bowl of electric

counter-top mixer. Beat on high speed until mixture goes from glossy to dull. Pour onto plate.

Variables: Prepare one recipe for each variable

a. Cook on high 3 minutes, then cook on medium 5 minutes

b. Cook on high 3 minutes, then cook on medium either 4 ½ - 5 ½ minutes

C. Divinity: 255 g sugar 1.5 g salt

61.5 g light corn syrup 6.2 g egg white

75 g water 2.5 g vanilla extract

Effect of protein addition

Procedures: Cook sugar, syrup, water, and salt to hard-ball stage (127oC) (260

0F). Using electric counter-top

mixer, beat egg whites until stiff peak is reached. Pour slightly cooled sugar solution over egg

whites while constantly beating on high speed. Beat until candy holds its shape. Add vanilla. Pour

into oiled pans. Cut into squares when cold. Candy may be formed into irregular pieces by

dropping it from tip of spoon onto wax paper.

Fudge & Divinity Results:

Record end point cooking temperature and beating temperature and time.

Rate color from extremely dark to extremely light.

Rate texture from extremely course to extremely fine.

Rate consistency from extremely firm to extremely runny.

26

Variation Cooking

Temp. o C

Beating

Temp. o C

Beating

Time

Color Texture Consistency Flavor

B. Fudge

1. Cooking temp.

a 110 44 4:46 brown smooth smooth

Choc,

pwdr

sugar

b 113 56 3:09

drk

brown chalky

buttery,

chalk

c 118 67 1:20 lt brown dry chalky

nutty

choc

2. Beating temp.

& speed

a

113 110 7 drk

brown grainy

soft, supple,

light choc

b 113 40 10 lt brown dry sticky choc

c 113 40 5

med

brown smooth thick choc

3. Microwave

a 90.5 32.5 15

drk

brown runny smooth

sweet,

choc

b 94.5 35.4 8:50 brwn smooth thick choc

C. Divinity 127 115 2:03 wht grainy

chalky to

smooth sweet

Conclusions: What functions do milk, cream, chocolate, and egg white serve in crystalline

candies?

Milk, cream, chocolate, and egg whites bring an element of fat to crystalline candies. It

makes for a finer texture by interfering with crystallization and enhances flavor.

How does temperature of beating affect crystalline nuclei formation?

By cooling a mixture to about 40ºC it will favor the formation of more nuclei and finer

crystals. The thickness of the solution is also great at lower temperatures. However, if too

low of a temperature it may delay the formation of a lot of nuclei. Srilakshmi, B. (2003).

Food Science (3rd

ed.) Daryaganj, New Delhi: New Age International (P) Limited,

Publishers. Pg. 219. This is important because agitation keeps many small nuclei in the

supersaturated solution and prevents it from attaching to already developed crystals.

How are the colligative properties of solutions illustrated in these experiments?

The colligative properties have to do with the concentration of sugar. Therefore, by

increasing the concentration of sugar it required a higher boiling point for the water.

How does cooking temperature affect sugar concentration?

As temperature is increased, the candy will become harder due to the increased

concentration of sugar. If the temperature is decreased and the water vapor evaporates

more slowly, then you get a softer, more watery candy.

27

Why may microwave times be difficult to determine when making fudge?

First off, each microwave has a different power/strength. Some get hotter quicker while

others are not as powerful and thus take longer to heat items. The microwave in lab is

quite old and may not be as powerful to generate enough heat to dissolve the sugar to the

desired temperature. Also you have to keep agitating the substance to make sure the

product is heated through correctly because the outside is usually exposed to more heat

than the inside.

A. Vanilla Caramels: Cook to end point temperature of 118

oC (144

0F).

130 g sugar 14 g margarine

65 g brown sugar 1 g salt

54 g light corn syrup 5 g vanilla extract

149 g light cream

Effect of fat and protein content of milk products on consistency:

Procedure: Mix all ingredients except vanilla. Place on medium high heat initially and lower heat as cooking

continues. Stir occasionally at beginning of cooking and constantly toward end of process. Cook

to firm-ball stage (118oC) (144

0F). Add vanilla. Turn into oiled pan. Cool. This is a soft, rich,

chewy caramel.

A. Vanilla Caramels: Cook to end point temperature of 118oC (144

0F).

130 g sugar 14 g margarine

65 g brown sugar 1 g salt

54 g light corn syrup 5 g vanilla extract

149 g evaporated milk

Effect of fat and protein content of milk products on consistency:

Procedure: Mix all ingredients except vanilla. Place on medium high heat initially and lower heat as cooking

continues. Stir occasionally at beginning of cooking and constantly toward end of process. Cook

to firm-ball stage (118oC) (144

0F). Add vanilla. Turn into oiled pan. Cool. This is a soft, rich,

chewy caramel.

B. Peanut Brittle 200 g sugar 19 g margarine

113 g light corn syrup 190 g raw peanuts

75 g water 5 g vanilla extract

3 g salt 7 g baking soda

Procedure: Cook sugar, syrup, water, salt, and margarine to soft-ball stage (112 – 116oC) (234

0F - 240

0F).

Add peanuts. Continue cooking slowly until syrup is light brown and meets hard-crack test

(152oC) (306

0F). Remove from heat. Add vanilla and soda. Mix ingredients well. Pour onto oiled

baking sheet, spreading as thin as possible. When mixture is nearly cool, wet hands in cold water,

and turn candy over, stretching to desired thinness. Break into pieces.

C. Lollipops

65 g light corn syrup vegetable coloring

75 g water 5 g flavoring

100 g sugar

Procedure: Cook sugar, syrup, and water to 155oC (310

0F). Stir only until sugar is dissolved. Remove any

crystals that form on sides of pan. Cook slowly toward end process so syrup does not scorch. Cook

28

to extreme hard crack stage 155oC (310

0F). Remove from heat and add coloring and flavoring,

stirring only enough to mix.

Drop mixture from tip of a tablespoon onto a smooth, oiled surface, taking care to make drops

round. Press a toothpick or skewer into edge of each before it hardens. Any decorations are

pressed on at same time. Candies should be loosened from slab before they are quite cold to

prevent cracking.

Caramels, Peanut Brittle, & Lollipop Results:

Variation Cooking

Temp. (C°)

Color Texture Consistency Flavor

A. Vanilla caramels

1. Light cream 118 light brown glossy hard chew caramel

2. Evaporated milk 118 light brown chunky, air

bubbles

gritty, chewy light

caramel

B. Peanut brittle 150 tan, light

brown,

peanut

butter

glossy,

smooth

outside with

chunky inside

crunchy,

brittle

salty,

sweet

C. Lollipop 152 amber smooth,

glistens

viscous lemon w/

slight burnt

taste

Conclusions: Why do these candies not crystallize?

Amorphous candies do not have organized structures and do not crystallize due to the

interfering substances used such as margarine. Also it takes a higher heat for amorphous

candies to form.

Why do light cream and evaporated milk cause differing consistencies in caramel?

Light cream has more milk fat while evaporated milk has less fat which will change the

interfering substances in the amorphous candies.

Aeration of peanut brittle mixture is obtained by what process?

After removing the sugar mixture from the heat, we added the baking soda to it. This

caused a chemical reaction to occur and CO2 was released causing air bubbles in the

mixture.

What does the boiling temperature tell you about concentration of these sugar solutions?

A very high temperature is needed in order for amorphous candies to form as they have a

higher sugar concentration than crystalline candies.

29

Lab #4: Thickening Agents

Date: September 26, 2014

Conditions: Warm

Purpose:

The purpose of the lab was to prepare and observe the results of a variety of starch-based

agents in food products after being cooked and after being frozen-thawed.

Experimental Procedures:

The instructions were given for Lab #4 by instructor Maryann Smitt and were listed in

Comparative Thickening Power of Thickening Agents section listed below. Students made an

assortment of thickening agents using collectively 11 different flours/starches.

Results:

For data and results, please refer to Lab 4 – Thickening Agents Evaluation Sheet 1a

through 11c attached.

Discussion:

Starch is made up of two granules, amylose and amylopectin. Amylose is a linear, coiled

chain of glucose molecules that are slightly soluble (McWilliams, 2012). This structure allows

for good gel formations. Amylopectin is a branched, sticky, transparent substance that does not

form gels well, if at all, but is good for sauces (Batten, 2014). Some examples of sources of

amylopectin are tubers and waxy rice.

The process of gelatinization is when a starch granule is heated causing the hydrogen

bonds to break and allowing water to enter and swell the granule (McWilliams, 2012). Pasting is

30

achieved when change takes place in starch granules due to continued heating after gelatinization

has taken place (McWilliams, 2012). Per Christine Batten’s lecture on Starch, you do not want to

over stir the starch granules because this could also lead to pasting. Starches with greater

amounts of amylose present will gelatinize quicker and have better pasting ability. Amylopectin

is usually found in higher proportion in starches, but the starches that contain 17-30% amylose

make better gels (Batten, 2014). Sources of starch containing higher amylose are corn, wheat,

and rice, which are all cereal grains. The data collected and presented in Thickening and

Evaluation Sheet showed that on average soy flour, sweet rice flour, oat flour, buck wheat flour

and semolina flour produced the most consistent products after being cooked.

The addition of sugar to starch delays gelatinization by competing for water, thus

preventing bonding. It also must be cooked at higher temperature and for a longer period of time

for gelatinization to occur. Sugar affects gelatinization by increasing translucency and decreasing

the viscosity and strength of the gel (Batten, 2014). According to McWillams (2012), root

starches see the greatest increase in translucency during gelatinization. In the lab evaluation

sheet, 4a-4c, tapioca was observed to be the most translucent. However, it was hard to have

consistent rating results. It would have been helpful to have a gauge or example of what was

considered transparent and what was considered opaque. This left a lot of room for subjectivity

and interpretation of what could be considered transparent. With methodological bias aside, the

flour/starch that had more sugar added should have yielded a more transparent result.

Heating water and starch is important to swell the granules, but it is also allows for

hydrogen bonds within the granules to break and release some amylose into the surrounding

water (McWilliams 2012). Gel strength is optimal when starch paste has been heated until

31

enough amylose has been released. An example of starches that could withstand higher

temperatures of 95-100°C were oat flour and buckwheat flour with 6 tablespoons of sugar added.

Consistency of the starches was hard to decipher, as my gauge of what was the smoothest

consistency seemed to change. What I thought one starch was would change when I went to the

next starch. As such, my data may not be the most reliable. I based consistency on cohesiveness

and uniformity, even if it was bubbly, it was consistently bubbly. However, with bias aside, data

collected showed there were multiple starches that had the smoothest consistency, such as

semolina flour, buck wheat flour, and sweet rice flour. Tapioca and all purpose flour came in a

close second.

Lastly we looked at the freeze thaw capability of starch; i.e., the ability to freeze starch

and thaw without loss of quality of the starch. One problem with the thawing process was

syneresis or weeping of the starches. This is when liquid is released from the starch. However,

there were several flours that did have good freeze-thaw stability, such as tapioca and sweet rice

flour. Semolina flour and barley flour were a close seconds. Bias still was a problem when trying

to properly rate the consistency of the thawed starches, thus data may not be the most reliable.

The group who had corn starch did not freeze their samples. As a result no data could be

recorded. However, according to McWilliams (2012), cornstarch and wheat starch have the

poorest freeze-thaw stability.

References:

Batten, C. (2014). DFM 357 – STARCH [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

McWilliams, M. (2012). Foods Experimental Perspectives (7th

ed.). Upper Saddle River, NJ:

Prentice Hall.

32 DFM Lab 4 – Thickening Agents

Goal: Prepare and observe the results of a variety of starch-based agents in food products.

Objectives: Compare thickening power of a variety of starches.

Compare freeze/thaw stability of a variety of starches.

Observe the effect of sugar and acid on starch viscosity.

Use modified starches utilized in the food industry and compare characteristics with

traditional starches.

Use starch as a thickener for a variety of food products.

Starches are a major functional component of many foods.

The endosperm of cereals (wheat, corn, rice, oats, barley, and rye) is a major source of starch. In addition,

roots such as cassava also known as tapioca starch and tubers such as potatoes are major sources of starch.

When starches are heated with water, the water migrates into the granule causing swelling. This process is

called gelatinization and increases the viscosity of the starch. Maximum viscosity occurs at different

temperatures depending upon the starch, but wheat and cornstarch both require temperatures of at around

900C (194

0F) for maximum viscosity.

Most natural starches have two fractions: amylose and amylopectin. Some starches are genetically

modified to change the proportion of amylose and amylopectin. Waxy starches have been modified to

contain nearly 100% amylopectin. Amylose is primarily responsible for gel strength in a cooled starch

paste; thus those starches with no amylose do not form gels at commonly used concentrations.

Chemical or physical modification of starch has produced products with unique characteristics for cold-

water swelling, stability in acid, or stability when freezing (an example is polar gel).

Over a period of time a starch gel will retrograde, a process of reforming hydrogen bonds, becoming

rubbery, and losing water. Some of the chemical modifications of starch available to industry minimize

the retrograde process.

33 Comparative thickening Power of Thickening Agents

Procedure: Mix 15 g (2 T) thickening agent with indicated amount of sugar then add 1 cup of water.

Heat until thickened. Turn down the heat to low and cook for 5 minutes, stirring only occasionally. Flour

and cornstarch must reach a near boiling temperature for thickening to occur. Freeze ½ of each product to

thaw and evaluate later.

Conclusions:

1. Which starches are most translucent?

The starches that are most translucent are amylopectin based. Within the 11 starches/flours we used,

tapioca was the most translucent. According to McWillams (2012), root starches see the greatest

increase in translucency during gelatinization.

2. Which starches gelatinize at 95 – 1000C?

Based on the results of the tests done, oat flour and buckwheat flour with 6 tablespoons of sugar

added gelatinized at 95-100°C.

3. Which starches have the smoothest consistency?

This was hard to decipher, as my gauge of what was the smoothest consistency seemed to change.

What I thought one starch was would change when I went to the next starch. As such, my data may

not be the most reliable. I based consistency on cohesiveness and uniformity, even if it was bubbly, it

was consistently bubbly. However, with that said there were multiple starches that had the smoothest

consistency, such as semolina flour, buck wheat and sweet rice flour. Tapioca and all purpose flour

came in a close second.

4. What affect does sugar have on the viscosity of gelatinization?

Sugar affects the viscosity of gelatinization by reducing the paste viscosity and gel strength. It does

this by competing with the starch for the water that is needed for gelatinization and as a result it delays

gelatinization. Also it requires a higher temperature while cooking as the level of sugar increases. This

was seen in the data collected, the flours with more sugar required more heat to reach pasting.

5. Which starches have the greatest freeze-thaw stability?

There were several flours that had good freeze-thaw stability, such as tapioca and sweet rice flour.

Semolina flour and barley flour was a close second. There was still basis on how to properly rate the

consistency, thus the data may not be the most reliable. According to McWilliams (2012), cornstarch

and wheat starch have the poorest freeze-thaw stability.

6. What may you conclude about amylose vs. amylopectin in the various starches; from the

results, which ones have the greatest amount of amylose?

Starches with greater amount of amylose present will gelatinize quicker and have better pasting

ability. Amylopectin is usually found in higher proportion in starches, but the starches that contain 17-

30% amylose make better gels. Sources of starch containing higher amylose are corn, wheat and rice,

which are all cereal grains. The data collected showed that on average soy flour, sweet rice flour, oat

flour, buck wheat flour and semolina flour produced the most consistent products after being cooked.

34 According to McWilliams (2012), tapioca provides the least amount of amylose. However, within the

data collected it provided one of the more consistent outcomes.

35

DFM Lab 4 – Thickening Agents Evaluation Sheet

Rate: Thickness 9 (thickest) – 1 (thinnest); Transparent 9(most transparent) – 1 (opaque); Consistency 9 (most consistent) – 1 (least

consistent) No. Thickening Agent Addition

of Sugar

Gelatiniz-

ation

Temp (C°)

Thickness Transparency Consistency Comments

As Cooked After freezing

1a Corn Starch (15g) No sugar 81.3 7 3 3 Not saved

no sugar – lumpy, looks like Vaseline

6 Tb – looks like jelly 1b Corn Starch (15g) 25g (2 Tb)

82.1 6 3 5 Not saved

1c Corn Starch (15g) 75g (6 Tb) 83.4 7 3 4 Not saved

2a Flour (15g) No sugar 90.9 4 4 8 7

2 Tb – a little lumpy

6 Tb (thawed) – watery and glossy looking 2b Flour (15g) 25g (2 Tb)

91.0 4 4 7 7

2c Flour (15g) 75g (6 Tb) 91.5 3 4 8 8

3a Barley flour (15g) No sugar Not taken 7 2 7 8

no sugar – small lump, but smooth

2 Tb – chunky

6 Tb – smoother w/ big air pockets

thawed 6 Tb – watery and glassy

thawed 2 Tb – dryer

3b Barley flour (15g) 25g (2 Tb) Not taken 8 2 6 8

3c Barley flour (15g) 75g (6 Tb) Not taken 7 2 7 8

4a Tapioca (15g) No sugar 77 6 7 8 8

no sugar – more opaque

6 Tb – sm air bubbles 4b Tapioca (15g) 25g (2 Tb)

78 7 7 7 7

4c Tapioca (15g) 75g (6 Tb) 83 7 8 8 9

5a Potato starch (15g) No sugar 94.8 2 4 2 8

starch remained in chunks

5b Potato starch (15g) 25g (2 Tb) 93.5 4 3 4 7

5c Potato starch (15g) 75g (6 Tb) 93.7 4 3 5 6

6a Millet (15g) No sugar 82.5 4 3 8 8

supper bubble on 2 Tb – Chunky & runny

no sugar – smooth, grainy, fluid, sm granular

6 Tb – smooth, really runny 6b Millet (15g) 25g (2 Tb) 91.8 2 5 4 6

6c Millet (15g) 75g (6 Tb) 91.7 2 4 7 7

36

Rate: Thickness 9 (thickest) – 1 (thinnest); Transparent 9(most transparent) – 1 (opaque); Consistency 9 (most consistent) – 1 (least

consistent) No. Thickening Agent Addition Gelatiniz-

ation

Temp (C°)

Thickness Transparency Consistency Comments

As Cooked After freezing

7a Soy Flour (15g) No sugar 66.3 5 1 7 7

no sugar – lumpy (thawed – dry)

2 Tb – sm lumps, but consistent

6 Tb – very fluid (thawed – sticky) 7b Soy Flour (15g) 25g (2 Tb) 66.8 4 1 7 5

7c Soy Flour (15g) 75g (6 Tb) 8.8 2 1 8 5

8a Sweet Rice Flour (15g) No sugar 89.3 8 2 8 8

clear whitish color, pretty smooth & thick

2 Tb – air bubbles

As sugar increases becomes less white 8b Sweet Rice Flour (15g) 25g (2 Tb) 78.6 8 3 8 7

8c Sweet Rice Flour (15g) 75g (6 Tb) 92.7 7 4 8 9

9a Oat Flour (15g) No sugar 97.6 6 1 7 6

no sugar – sort of chunky, forming skin

thawed no sugar – gritty

thawed 2 Tb – chunky

thawed 6 Tb – lumpy

9b Oat Flour (15g) 25g (2 Tb) 98.4 7 1 7 6

9c Oat Flour (15g) 75g (6 Tb) 100.7 7 1 7 5

10a Buckwheat Flour (15g) No sugar 75.2 4 1 8 8

dark coloring more so.

6 Tb – runny 10b Buckwheat Flour (15g) 25g (2 Tb)

89.5 3 1 8 7

10c Buckwheat Flour (15g) 75g (6 Tb) 97.3 5 1 8 6

11a Semolina Flour (15g) No sugar 88.2 5 3 8 8

no sugar – grainy, but smooth

2 Tb – looks like soup

6 Tb – runny & yellowish 11b Semolina Flour (15g) 25g (2 Tb) 79.2 4 3 8 8

11c Semolina Flour (15g) 75g (6 Tb) 86.5 4 4 8 8

37

Lab #5: Fiber Date: October 3, 2014

Conditions: very warm

Purpose:

The purpose of the lab was to make chocolate chip cookies or muffins using a variety of

mystery fibers and observe the flavor, appearance and texture of each product.

Experimental Procedures:

The instructions were given for Lab #5 by instructor Maryann Smitt and were listed in

DFM 357 Lab 5 – Fiber included below.

Results:

For data and results, please refer to the Evaluation Form attached.

Discussion:

Fiber is an important part of our diet. It comes from the bran portion of a grain kernel.

There are two types of fiber, soluble and insoluble. Soluble fiber has limited digestion, but is

able to bind to cholesterol. The flora will break bonds which will provide a little bit of energy

(Batten, 2014). Insoluble fiber is excreted undigested, thus playing a role in the bulking of our

stool, which increases transit time.

Within lab we made 11 products, six cookies, five muffins and we did not make the oat

bran muffin. The cookie and muffin that I most enjoyed was muffin #374 (made with inulin) and

cookie #346 (made with oat bran). Muffin #374 was very sweet and had a nice crunchy, golden

brown top. Even though it was sweet, it had a nice mouth feel. The reason why I liked cookie

38

#346 was because it had a subtle sweetness, a nice light brown coloring, and a nice crunch and

chew. It made for an enjoyable cookie. There were some products that were too dense, dry or

would stick to the roof of your mouth. This was true for the cookies #576 and #948, psyllium and

oatmeal ground, respectively. The fiber dextrin used in muffin #183 gave an off taste, leaving an

after taste in the mouth.

The mystery fibers made for very distinct products, differing greatly. Per McWilliams

(2012), inulin is a versatile ingredient that lacks flavor and is able to reduce the fat and sugar

content of products, thus lowering the overall calorie content. As such, companies are starting to

use inulin in products. I did enjoy inulin in the muffin, but not in the cookie. The cookie was too

chewy and had a floury taste.

Possible errors in this lab could be due to over saturation of the taste buds. Eating a lot of

sweets overwhelmed the pallet and made it hard to determine true flavor profiles, especially in

the cookies. Inadequate hydration could have also played a role. Lastly, the products could have

been over mixed, thus making a denser product and changing the overall mouth feel.

Reference:

Batten, C. (2014). DFM 357 – Fiber & Plant Food [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

McWilliams, M. (2012). Foods Experimental Perspectives (7th

ed.). Upper Saddle River, NJ:

Prentice Hall.

39

DFM 357 Lab 5 – Fiber

Chocolate Chip Cookies

Recipe 353 923 293 576 346 948

Serving 6 cookies 6 cookies 6 cookies 6 cookies 6 cookies 6 cookies

Butter 1/4 cup 1/4 cup 1/4 cup 1/4 cup 1/4 cup 1/4 cup

Sugar 2 T+ 2 tsp 2 T+ 2 tsp 2 T+ 2 tsp 2 T+ 2 tsp 2 T+ 2 tsp 2 T+ 2 tsp

Egg (L) 0.5 0.5 0.5 0.5 0.5 0.5

Baking Soda 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp

AP Flour 65 g 65 g 65 g 65 g 65 g 65 g

Salt 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp

Vanilla 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp 1/4 tsp

Choc chips 3 oz 3 oz 3 oz 3 oz 3 oz 3 oz

Fiber Add 30g

Fiber F

Add 47g

Fiber A

Add 43g

Fiber B

Add 27g

Fiber C

Add 54g

Fiber D

Add 29g

Fiber E

Cooking Method:

1. Pre-heat oven to 375°F

2. Sift the flour.

3. In a bowl, place butter, sugar, egg, baking soda, salt, and vanilla. Mix together with a

hand mixer for 2 minutes on medium speed.

4. Add flour slowly into bowl and mix with a hand mixer until combined.

5. Use the scale and measure the dough, then divide it into 6 equal portions.

6. Line a baking pan with parchment paper.

7. Place the cookies on the baking pan.

8. Bake for about 8 minutes or until the cookies turn golden brown.

9. Remove cookies from the oven and place the baking sheet/cookies on a cooling rack.

10. Record baking time.

40

Muffins (medium size)

Recipe 583 374 183 658 285 769

Serving 6 muffins 6 muffins 6 muffins 6 muffins 6 muffins 6 muffins

Egg 0.5 0.5 0.5 0.5 0.5 0.5

Milk 1/2 cup 1/2 cup 1/2 cup 1/2 cup 1/2 cup 1/2 cup

Vegetable

Oil

1/8 cup 1/8 cup 1/8 cup 1/8 cup 1/8 cup 1/8 cup

AP flour 1 cup 1 cup 1 cup 1 cup 1 cup 1 cup

Sugar 1/8 cup 1/8 cup 1/8 cup 1/8 cup 1/8 cup 1/8 cup

Baking

Powder

1/2 Tbsp 1/2 Tbsp 1/2 Tbsp 1/2 Tbsp 1/2 Tbsp 1/2 Tbsp

Salt 1/2 tsp 1/2 tsp 1/2 tsp 1/2 tsp 1/2 tsp 1/2 tsp

Fiber Add 30g

Fiber I

Add 47g

Fiber L

Add 43g

Fiber G

Add 27g

Fiber K

Add 54g

Fiber H

Add 29g

Fiber J

Cooking Method:

1. Pre-heat oven to 375°F

2. Butter muffin tins.

3. Sift the flour.

4. In a bowl, beat the eggs, milk, and oil with a wire whisk for 2 minutes by hand.

5. Add salt, sugar, flour, and baking powder to the bowl and combine with a spatula or

wooden spoon until “just mixed” (the batter will not be smooth).

6. Pour dough equally into 6 muffin cups.

7. Bake for about 20 minutes or until the top gets golden brown.

8. Remove muffins from the oven and place the baking tin/muffins on a cooling rack.

9. Record baking time.

41

Evaluation Form

Cooking Time Appearance Texture Flavor

Cookies

353

F

13 min

Mounded, fat, pale

yellow

Dense, dry,

crumbly

Sweet & chocolaty

923

A

14 min

Dark brown,

crackly

Very chewy and

crunchy

Floury, sweet

chocolate

293

B

10.5 min

Flat, lumpy Crunchy & sticks

to the teeth

Sweet, chocolate

hides bitterness

576

C

16 min

Very pale, high

mounded

Dry and gritty. Felt

like chewing on

hay

Very grassy.

346

D

14 min

Glossy chips, light

brown, dense

Nice chew with

crunch

Subtle sweetness,

nice

948

E

13.35 min

Golden brown dry, sticks in throat sweet, with nice

chocolate flavor

Muffins

583

I

24 min

Whitish, yellow

with light brown

flecks

Chewy, sticks to

top of mouth

Floury, granular

374

L

23 min

Golden brown top,

crunchy top, pale

yellow, crumbly

Crunchy top Very sweet

183

G

17 min

Dark golden brown Soft, small

granules

After bite, flour or

fiber

658

K

25 min

Tan, yellow Dry, but dissolves Earthy with slight

sweetness

285

H

Did not make

N/A N/A N/A

769

J

20 min

Pale yellow, air

bubbles, high

peaks

Chewy Slight sweetness,

cornbread

Please answer the following:

1. Which muffins and cookies had the best texture and flavor? I preferred muffin L (made with

inulin) and cookie D (made with oat bran). Muffin L was very sweet and had a nice crunchy

golden brown top. Even though it was sweet, it had a nice mouth feel. The reason why I liked

42

cookie D was because it had a subtle sweetness, a nice light brown coloring, and a nice

crunch and chew. It made for an enjoyable cookie.

2. Which fiber would be the best addition to muffins or cookies to maintain good quality?

Based on the text, inulin is a good fiber addition to muffins and cookies. It is lower in fat and

sugar, thus lowering calories.

3. Were you able to guess any of the fiber substitutes? If so, which one(s). I was not able to

identify any of the fiber substitutes. I narrowed it down to two, but could not decipher

further.

Mystery Fiber Lab – Answers Fiber revealed: COOKIES MUFFINS

Fiber A Inulin Fiber L Fiber B Dextrins Fiber G Fiber C Psyllium Husks, ground Fiber K Fiber D Oat Bran Fiber H Fiber E Oatmeal, ground Fiber J Fiber F Flaxseed meal Fiber I

43

Lab #6: Fats and Oils Date: October 10, 2014

Conditions: Cool at first and then became very warm

Purpose:

The purpose of the lab was to test the plasticity of different types of fat and flours while

making pastry. We were to observe color, flavor and tenderness.

Experimental Procedures:

The instructions were given for Lab #6 by instructor Maryann Smitt and were listed in

DFM 357 Lab 6 – Fats and Oils attached below.

Results:

For data and results, please refer to Table 1, 1a to 2e included below.

Discussion:

Fat has many functional roles in baking such as providing color, flavor, texture,

tenderness and shortening power, to name a few (McWilliams, 2012). Even though color, flavor

and texture are important, they are not as important as tenderness when making pastry. The

tenderness of a pastry is generated by the type of fat and its ability to surround the flour,

preventing water from getting into the flour, and thus limiting gluten formation (Batten, 2014).

This process is known as shortening power. Therefore, it is important to pay attention to the type

of fat being used when making pastry.

In lab #6 we used six different fats to make pastry. The pastry that was most tender was

made using butter. According to McWilliams (2012), butter contains 80 percent fat and about

44

16.5 percent water. This water escapes as steam when baking, thus creating a flakier pastry. The

margarine stick pastry was a little less tender, but similar. McWilliams (2012) notes a stick of

margarine can be substituted for butter because of the fat to water ratio being similar. One would

think using the tub of margarine should then also yield similar results. However, tub margarine

has a lower melting point and has higher water content (McWilliams, 2012). As a result this fat

produced the least tender pastry. The pastry tasted oily, had a hard outside with a somewhat soft

inside, and produced a very light color.

Using different types of flour will change the consistency of the pastry depending on the

amount of gluten present in the flour. Gluten is not naturally occurring in nature, but when two

proteins giladin and glutenin are mixed in equal parts, gluten is formed. To develop gluten you

add water, flour and then agitate the product. The proteins are hydrated, changing their shape and

ability to bind together and trap air (Batten, 2014). Therefore, it is important to make sure when

making pastry to not overwork the dough. It is possible within our experiment that people over

mixed the pastry dough, thus creating a denser product.

The amount of protein in flour differs by which type of flour you use. For example, cake

flour has the least amount of protein at 7.5%, while bread flour has 11.5-12% protein (Batten,

2014). The more protein that is present, the more gluten forms. Due to the variety of protein

levels in the alternative flours used in lab, there was a variety in tenderness of pastry. For the

most part the majority of the pastries were pretty dense, with the exception of oat flour which

disintegrated on contact. It was interesting to note, bread flour produced more of a cracker like

pastry due to the additional protein in the flour, and thus additional gluten development. Soy

flour was omitted, but since it is gluten free and high in protein, it may have had a similar

outcome as oat flour and fallen apart or it could have become super dense due to the additional

45

protein. Either way, when making pastry, it is important to be aware of how you are combining

the flour and fat to make sure not to overwork the dough and thus ensure a flaky pastry when

making pie crust.

Reference:

Batten, C. (2014). Fats and Oils [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

Batten, C. (2014). Gelating, Baking, Leavening Agents [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

McWilliams, M. (2012). Foods Experimental Perspectives (7th

ed.). Upper Saddle River, NJ:

Prentice Hall.

46

DFM 357 – Lab 6 Fats and Oils

Plasticity and types of fat – make pastry using the following recipe and variations:

Pastry ¾ C. AP flour ¼ C. fat 2 T. cold water ¼ t. salt

1. Preheat oven to 425 degrees

2. Add salt to flour and stir to combine well

3. Add fat all at one time; use a pastry blender or two knives to cut the fat into the flour until the size of uncooked rice granules

4. Sprinkle the water over the surface one drop at a time while flipping the mixture upward with a 4-tined fork.

5. Mash the dough together with the fork to form a ball, approximately 10 strokes

6. Turn dough onto a 12” long piece of wax paper; manipulate to form a more cohesive ball; flatten

7. Place a 12# long piece of wax paper on top of the flattened ball; roll out with a rolling pin into a ¼’ oblong piece

8. Cut into strips approximately 2” X 3”; bake in a 425 F oven until light golden brown

9. Note the total baking time required

Types of fat: 1a. Shortening (the control) 1b. Lard 1c. Margarine (stick) 1d. Butter 1e. Vegetable oil 1f. Soft margarine (tub) 1g. Reduced fat margarine Types of flour: 2a. Whole wheat flour 2b. Bread flour 2c. Cake flour 2d. Oat flour 2e. Soy Flour

47

Study Questions: 1. Which fat produced the tenderest pastry? Why? Butter produced the tenderest

pastry due to the fat to water ratio. There was enough water to generate steam while baking and create flakiness in the pastry.

2. Which fat produced the least tender pastry? Why? The fat that produced the least tender pastry was the reduced fat margarine. The lack of fat and increased ratio of water made the product oily and hard.

3. What effect did the various types of flour have on the pastry? Using different types of flour changed the consistency of the pastry due to the amount of gluten present in the flour. Most of the alternative flours to all purpose were pretty dense with the exception of oat flour which dissolved on contact. It was interesting to note bread flour produced more of a cracker like pastry due to the additional gluten in the flour.

Pastry Variation

Cooking time

Color

Flavor

Tenderness: Rank 1-10; 1 least tender, 10 most tender

1a. Shortening 15 min Off-white Salt, cracker 3

1b. Lard 9 min Golden Brown Dry, light 8

1c. Margarine, stick

5 min Golden Brown Dry & gritty 7

1d. Butter 13 min Light Golden Brown

Buttery, dry 8 – nice flakes

1e. Vegetable oil

Did not make

N/A N/A N/A

1f. Soft tub margarine

14 min Yellowish brown Cracker like, a little salt

6 – crunchy outside, but soft center

1g. Reduced fat margarine

15 min Very light Oily 3 Hard outside, soft inside

2a. Whole wheat flour

18 min Light brown Earthy, cracker like 4 – dense

2b. Bread flour 12 min Golden brown Cracker like 5 – flaky 2c. Cake flour 14 min Whitish Sweet & dry 4 – dense

2d. Oat flour 14 min Sand/tan Dry, flat 10 – dissolves on touch

2e. Soy flour Did not make

N/A N/A N/A

48

Lab #7: Milk Proteins Date: October 24, 2014

Conditions: Warm

Purpose:

The purpose of the lab was to make basic cottage cheese and basic ricotta cheese by using

four different types of milks: whole milk, 2% milk, non-fat milk and soy milk, while observing

the flavor and tenderness of each product.

Experimental Procedures:

The instructions were given for Lab #7 by instructor Maryann Smitt and were listed in

DFM 357 Lab #7 Milk Proteins attached below.

Results:

For data and results, please refer to Table 1, Cottage Cheese Evaluation and Table 2,

Ricotta Evaluation attached below.

Discussion:

In lab #7 we made cottage cheese and ricotta cheese with an assortment of milks:

whole milk, 2% milk, non-fat milk, and soymilk. With the exception of soymilk, milk contains

two categorizations of milk proteins that are made up of casein and whey. To make cheese you

have to separate the curd from the whey. Curd is the precipitate from casein when the pH of milk

is at 4.6 (McWilliams, 2012). Casein is milk proteins that are sensitive to acidity and are the least

soluble. It is made up of three components: alpha casein (the most abundant), beta casein, and

kappa casein. On the surface of the casein micelle is the kappa casein which coats and protects

49

the alpha casein from precipitating or curdling (Batten, 2014). When casein is precipitated to a

pH of 4.6, it reaches its isoelectric point, or is neutral. Whey is the liquid byproduct that drains

from the curd when milk begins to clot. The nutrients that are found in whey from rennin-

coagulated milk are water soluble B vitamins, proteins, and some minerals (McWilliams, 2012).

Per McWilliams (2012), whey can be concentrated and used in baking products, meats, sauces,

dips and related products to give structure to gels, bind water & promote browning.

In the process of making cottage cheese we used rennin, which is a proteolytic enzyme

found in the stomach lining of calves that is used to cause coagulation (McWilliams, 2012;

Batten, 2014). The enzyme removes the hydrophilic part of the kappa casein of the micelle. In

the presence of calcium, this para-kappa casein becomes hydrophobic, thus drawing the micelles

together to easily form a gel (McWilliams, 2012; Batten, 2014). Rennin also changes the pH of

the protein and the isoelectric point can be reached. In addition, rennin is heat sensitive and thus

while making cottage cheese, precautions must be taken. The temperature must be maintained

between 15 and 60°C to activate the enzyme to remove the hydrophilic part of the kappa casein

and promote curd formation (McWilliams). Once curd is formed it is cut to release the whey and

promote further curd formation.

Out of the four milks used to make cottage cheese: whole, 2%, non-fat and soymilk, the

best milk to use was whole milk. The lower the fat contents, the more chewy and dense the

cottage became. All of the cottage cheeses were relatively bland due to lack of salt. If salt was

added though, it would have affected the electrical charge and pH of the casein and caused

further curdling (Batten, 2014). However, in terms of mouth feel and tenderness, whole milk was

soft yet slightly chewy, thus giving it the most appealing out of the presented options. The

50

soymilk cottage cheese could not form a curd and was considerably runny. This was due to the

fact there was no casein for the rennin to act upon.

When making ricotta cheese we used white vinegar for an acid to yield the curd. By

adding acid it shifts the pH to the isoelectric point of kappa casein and thus removes the

hydrophilic coating of casein. The best ricotta was made from whole milk. It had slightly firm

curds with soft chew. It was moist looking and not crumbly, unlike the 2% milk ricotta cheese.

Both the cottage cheeses and ricotta cheeses were relatively soft and flavorless. With the

ricotta cheeses the whole milk was slightly more tart, yet had a sweetness that was desirable over

the 2%, non-fat, and soymilk ricotta’s. The soy milk ricotta did have a slightly nutty flavor and

was very smooth, almost like a mousse consistency. As the milk fat decreased, the cheese

became more firm and less supple. For example, the 2% ricotta was very crumbly when handled

in comparison to the whole milk, which was firmer.

I made the whole milk cottage cheese and the process was relatively simple with the

exception of time. After the application of the rennin, we had to wait an hour for the curd to

form. However, the curd formed closer to 35 minutes. The fact that we were using only 2 cups of

milk may have been why the time was reduced. When reviewing the directions for ricotta cheese

it seemed to be a little more involved. The directions had increased room for error due to the

possibility of scorching the milk. Whey is heat sensitive and bringing the milk to almost boiling,

83°C, could cause scorching. This could lead to skum, which is a skin on warm milk (Batten,

2014). This is why the directions called for gentle agitation after the vinegar was added to make

sure the skum formation did not occur.

51

References:

Batten, C. (2014). Proteins [PowerPoint Slides]. Retrieved from

https://ilearn.sfsu.edu/ay1415/course/view.php?id=3334

McWilliams, M. (2012). Foods Experimental Perspectives (7th

ed.). Upper Saddle River, NJ:

Prentice Hall.

52

DFM 357 Lab #7 Milk Proteins

Basic Cottage Cheese Formula

Milk 2 cups

Rennet 1 Tablet

Dissolve rennet in 1 tablespoon of lukewarm water while milk is being heated to 370C. Add

dissolved rennet and let stand 1 hour. Use a knife to slice curd into ½ inch cubes. Reheat to

370C and maintain that temperature until whey separates. Carefully transfer the clotted mixture

to a sieve lined with a double layer of cheesecloth. Collect the whey in a bowl below. Measure

the volume of whey in a graduated cylinder. Place the curd on a serving dish for evaluation.

(Optional: If desired salt may be added to the curd for flavor)

Variations:

a. Whole milk

b. 2% milk

c. Non-fat milk

d. Soymilk

53

Basic Ricotta Cheese Formula

Regular Milk Ricotta Formula

Milk 2 cups

White vinegar 1 Tablespoon

Heat the milk in non-reactive pot on medium heat, stirring occasionally until tiny bubbles start

appearing on the milk and temperature is about 830C. It will be close to boiling. When

temperature is reached, remove from heat, add vinegar, and stir gently for 1 minute. Curds will

start to form immediately.

Line a colander with a double layer of cheesecloth and place over a large bowl or sink.

Remove the pan from heat and gently ladle curds into the prepared sieve. Pull up on the sides

of the cheesecloth to drain off any extra liquid, but do NOT press on the curds. Gather the

edges of the cloth, tie into a ball with string, and allow to drain for at least 15 minutes.

Variations:

e. Whole milk

f. 2% milk

g. Non-fat milk

h. Soymilk

54

1. What is rennin? How does it destabilize the protein dispersion in milk and cause

gelation?

Rennin is proteolytic enzyme found in the stomach lining of calves that is used in making

cheese to cause coagulation. The enzyme removes the hydrophilic part of the kappa casein of

the micelle. In the presence of calcium, this para-kappa casein becomes hydrophobic, thus

drawing the micelles together to easily form a gel. Rennin also changes the pH of the protein

and the isoelectric point can be reached.

2. What precautions need to be taken in making cottage cheese with rennin? Why is the

curd cut?

Rennin is heat sensitive and thus while making cottage cheese, precautions must be taken. The

temperature must be maintained between 15 and 60°C to activate the enzyme to remove the

hydrophilic part of the kappa casein and promote curd formation. Curd is cut to release the

whey and promote further curd formation.

3. What nutrients are found in the whey from rennin-coagulated milk? Identify uses for

whey.

The nutrients that are found in whey, a byproduct of cheese making, from rennin-coagulated

milk are water soluble B vitamins, proteins, and some minerals. Per McWilliams (2012), whey

can be concentrated and used in baking products, meats, sauces, dips and related products to

give structure to gels, bind water & promote browning.

4. Which milk(s) made the best cottage cheese? Did the fat content have any effect on flavor

or tenderness?

Out of the four milks used: whole, 2%, non-fat and soymilk, the milk that made the best cottage

cheese was whole milk. All of the cottage cheeses were relatively bland due to lack of salt.

However, in terms of mouth feel and tenderness, whole milk was soft yet slightly chewy, thus

giving it the most appealing out of the presented options. The soymilk cottage cheese could not

form a curd and was considerably runny. This was due to the fact there was no casein for the

rennin to break apart.

5. How did the ricotta cheese compare to the cottage cheese? (Flavor, texture, appearance,

ease/difficulty of production)

Both cheeses were relatively soft and flavorless. With the ricotta cheeses the whole milk was

slightly more tart, yet had a sweetness that was desirable over the 2%, non-fat and soymilk

ricotta’s. The soy milk ricotta did have a slightly nutty flavor and was very smooth and was

almost like a mouse consistency. As the milk fat decreased the cheese became more firm and

less supple. For example, the 2% ricotta was very crumbly when handled in comparison to the

whole milk, which was firmer.

55

I made the whole milk cottage cheese and the process was verily simple with the exception of

time. The directions for ricotta cheese seemed to be a little more involved and more room for

error due to the possibility of scorching.

6. Which milk(s) made the best ricotta cheese? (Flavor, texture, appearance)

Whole milk made best ricotta cheese. It had slightly firm curds with soft chew. It was moist

looking and not crumbly unlike the 2% ricotta cheese.

56

Cottage Cheese Evaluation:

Type of Milk

Whey

Curd

Volume

Flavor

Flavor

Tenderness

a. Whole milk 364 mL Not much flavor Soft, chewy

b. 2% milk 353 mL

Milky bland,

flavorless

Supple, moist

c. Non-fat milk 370 mL

Milky bland Gritty, chewy

d. Soymilk Not available

Did not develop

correctly

Ricotta Evaluation

Type of Whey / Milk

Flavor

Tenderness

e. Whole milk

Slightly tart, yet sweet Soft, but firm

f. 2% milk

Taste cracker more than cheese Soft chew, crumbly

g. Non-fat milk

Bland Very firm

h. Soymilk

Nutty Very smooth, too smooth,

too soft