CARBOHYDRATES P o l y s a c c h a r i d

e s

INTRODUCTION

Carbohydrates are organic molecules in which carbon, hydrogen, and oxygen bond together in the ratio: Cx(H2O)y, where x and y are whole numbers that differ depending on the specific carbohydrate to which we are referring.

Synonym of saccharide (sugar)

CHEMICAL GROUPINGS

Monosaccharides Disaccharides Oligosaccharides Polysaccharides

POLYSACCHARIDES

Serve  for the storage of energy (e.g., starch and glycogen) and as structural components (e.g., cellulose in plants and chitin in arthropods).

important ingredients in many food products particularly in wide range of food emulsions such as mayonnaise and ice cream

They can be used in natural form but in many cases the functionality is adapted by chemical

Modification for example to improve the solubility and water-binding capacity

It has a wide range of capacities among the whole group.

Gel formation is often thermo- reversible and it might melt on heating or set on heating.

TYPES OF POLYSACCHARIDES

STRUCTURAL POLYSACCHARIDES Unbranched polymers e.g. Chitin and

Cellulose

STORAGE POLYSACCHARIDES Branched polymers e.g. Glycogen and

Starch

GOALS

To study the physical and chemical properties of polysaccharides

To determine the changes in polysaccharides during processing

METHODS

EXPERIMENT 3.1MICROSCOPE EXAMINATION OF STARCH

GRANULES

To determine the appearance of starch granules from different materials

Place water

dispersion of

samples on slides

Observe under

the microscope

Draw the

starch granul

es

RESULTS

Figure 3.1.a Sago Starch Figure 3.1.b Sago Starch Figure 3.1.c Potato Starch

Figure 3.1.d Rice Starch Figure 3.1.e Corn Starch

RESULTS

Starch Appearance Size, Shape

Rice Transparent, closely packed Irregular

Corn Transparent, closely packed Irregular oblong

Potato Transparent, loosely packed Oval

Sago Transparent, scattered Oval

Cassava Violet, thread-like Thread-like

Table 3.2 Consistency and appearance of starch mixture at different temperatures

DISCUSSION

Q1 How would you be able to identify the type of starch using a microscope?Starch molecules arrange themselves partially crystalline granules in plants. Each plant species has a unique starch granular size and so it is possible to identify the type of starch using a microscope: rice starch is relatively small (about 2μm) while potato starch have larger granules (up to 100μm).

Q2:If you are given a starchy food item and you are asked to develop a similar food product, what basic information do you have to know? The information that we need to know: The molecular weight the type of saccharide units and linkages

between saccharide units The degree of branching

METHODS

Experiment 3.2 Rheological Properties of Polysaccharides (Starch)

To determine the rheological properties of starches To determine the effect of heat on starch

Mix 100ml water and 2g of corn

starch. Examine

under microscope

Heat to 50 degree Celsius

remove and reexamine. Note any changes

Continue heating to 60 and 70 degrees and

observe under the microscope .

Note any changes and difference on

appearance and consistency

RESULTS

Figure 3.2.a Wet Corn Starch (400x) Figure 3.2.b Wet Corn Starch at 500C (400x)

Figure 3.2.b Wet Corn Starch at 600C (400x) Figure 3.2.b Wet Corn Starch at 700C (400x)

RESULTS

Temperature Appearance Consistency

500C White, very

small

Thick

600C White, small Thicker

700C Dirty white,

medium

thickest

Table 3.2 Consistency and appearance of starch mixture at different temperatures

DISCUSSION

Q1: What is gelatinization? Gelatinization is a process that

breaks down the intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water.

Q2: What is a gel?Gel is defined as a substantially dilute cross linked system, which exhibits no flow when in the steady-state.

METHODSEXPERIMENT 3.3: TYPES OF STARCH GELS To compare the characteristics of different starch gels To determine the effect of sugar on starch gels

A. Starch Gels from Various SourcesPlace 15, 5 and 2 g in

individual

beakers add 5ml of cold

water.

Add boiling water

in such an

amount as

to adjust total

weight to

100g

Heat and stir

after comple

tely dispers

ing remove from heat and

place in a

molder

Allow to

cool under

ice bath, once

cooled remove from molde

r

Properly

label then obser

ve consistenc

y, color and

firmness

RESULTS

StarchTransparency Texture

2 g 5 g 15 g 2 g 5 g 15 g

Corn 2 2 3 1 1 3

Rice

C41 2 3 1 2 3

Rice

malagk

it

1 2 3 1 2 3

Sago 2 2 2 1 2 3

Table 3.3.A. Comparison of gels obtained from different starches.

Transparency: transparent – 1; neither – 2; opaque – 3Texture: soft – 1; neither – 2; hard - 3

METHODS

Prepare gels each

with rice C-4 and

malagkit. Add 5g

starch and 40ml water

Add 3 levels of

sugar 3, 6 and 9 g for

each mixture. Cook and

cool

Observe gel for

transparency,

viscosity, and

texture

B. Effect of Sugar on the Characteristic Sugar

RESULTS

StachTransparency viscosity

3 g 6 g 9 g 3 g 6 g 9 g

Rice C4 3 3 3 1 2 3

Rice

malagkit3 3 3 1 2 3

Table 3.3.B. comparison of gel obtained from rice starch cooked with different amount of sugar

Transparency: transparent -1; neither – 2; opaque – 3Texture: soft – 1 ; neither – 2; hard – 3

DISCUSSION

Q1:For each starch, what amount of starch gave a firm moldable gel? As the amount of sugar increases the fluidity of the sample becomes apparent. Thus, the sample with increased amount of sugar is more viscous. As for the ones with low amount of sugar, moldability and firmness is high.

DISCUSSION

Q2: How does sugar affects the physical properties of starch gels?

Therefore the moldable nature of

polysaccharides becomes less when added with sugar as it increase the temperature at which gelatinization occurs, by doing so viscosity is increased while decreasing the firmness of the solution.

DISCUSSION

Q3: How will you use the results in figuring out formulations for sauces, granules and pudding?

If a liquid sauce is needed, addition of high amount of sugar to polysaccharide solution is done. If on the other hand granulated substance is needed, less sugar should be added. For pudding, since it needs a lot of sugar for stability, the sugar content as well as the temperature is increased.

CONCLUSION

The role of polysaccharides in the stabilization of emulsions is very important. In fact it can be said that their main functionality lies in their ability to thicken the emulsion, which is intended to reduce the creaming rate and to improve the texture to the emulsion.

REPORTED BY

FLORES, NOEME MALINAO, MARIELLE PASCUAL, MITCHEL OLIVE