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PROCESSING OF STRAWBERRY JUICE AND ITS NUTRITIONAL VALUE

Presented by :Syeda Maria MehmoodRoll # 34

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INTRODUCTION

Strawberry (Fragaria sp.) belongs to the family Rosaceae.

Highly perishable ,must be consumed soon after picking.

Consumed as fresh fruit and also used in the form of jam, jelly and juice.

Fruit is small size, red and sweet.

More than 50% of sugar in strawberry is glucose.

Fruit contains citric acid.

Red color of fruit due to the presence of anthocyanin pigment.

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OBJECTIVE It includes the stability of strawberry juice during

storage by using chemical preservatives, pasteurization, high intensity ultrasound and freezing.

It includes the stability of TSS, pH, acidity of juice.

Includes stability of flavor, color and taste during storage of juice.

It includes the maintenance of nutritional value of juice.

Includes stability of vitamins and other minerals of juice during processing.

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PROCESSING STEPS OF STRAWBERRY JUICE

It consists of following steps:-

Preparation

Hammer mill

Enzyme treatment (Optional)

Pressing / centrifugation

Depectinization

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CONT……… Filtration

Pasteurization / High Intensity Ultrasound

Chemical preservation

Hyperbaric storage

Packing

Freezing

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PREPARATION

Fruit is prepared for juice extraction.

Includes removal of unwanted parts.

Also involves washing, grading, sorting and trimming etc.

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HAMMER MILL

Includes crushing of strawberries.

Done with hammer mill.

Purpose is to shred or crush aggregate material into smaller pieces by the repeated blows of little hammers. 

The rotor with fixed blades rotates within a perforated screen.

Hammer mills are more suited for mature or softer fruits, provided speed is properly adjusted.

 

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ENZYME TREATMENT (OPTIONAL)

Enzyme treatment is applied to crushed fruit mass by adding 2-8% pectolitic enzymes at about 50° C for 30 minutes.

This optional step has the some advantages like : extraction yield will be improved juice color is better fixed finished product taste is improved

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PRESSING / CENTRIFUGATION

It is done for juice extraction.

Hydraulic press is used for strawberry juice extraction.

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DEPECTINIZATION

Strawberries contains high amount of pectin.

Remain as colloidally dissolved residues making the juices viscous.

So, production of low viscous juices require depectinization after pressing.

The complete depectinization by using pectinase enzymes e.g., Rapidase BE SUPER provides a good clarification and filteration of juice.

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FILTRATION

Subsequently, a clear juice is obtained through use of membrane separation process.

Ultra filtration resulted in an accelerated loss of

anthocyanins during juice concentration.

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PASTEURIZATION / HIGH INTENSITY ULTRASOUND

Both methods ensure food safety and long preservation due to its destructive effect on enzymes and microorganisms.

Once the juice has been clarified, it is ready to be preserved.

For a single-strength juice packaging line, a typical process is to heat the juice to 88° C (190° F) and then bottle it.

This produces a shelf-stable product.

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CONT…

Ultrasound has been identified as a potential technology to meet the FDA requirement in reduction of microorganisms found in fruit juices.

Anthocyanins are highly unstable and very susceptible to degradation.

Ultrasound processing of juices have a minimal effect on the degradation anthocyanin content in strawberry juice.

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CHEMICAL PRESERVATION

Sugar concentration and combination of preservatives play a positive role in extending the shelf life of strawberry juice.

Potassium sorbate, Sodium benzoate can maintain the good quality of juices during preservation.

They are added in juice to give more stability to juice.

So, strawberry juice (30.5 brix) with 0.05% sodium benzoate + 0.05% potassium sorbate and 0.1% citric acid, Strawberry juice (30.5 brix) with 0.1% sodium benzoate and 0.1% citric acid maintained better quality stored at ambient temperature for three months.

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CONT…. Artificial sweetener used for sugar also.

The most common artificial sweeteners are (aspartame, saccharine, and sucralose) but others such as xylitol and all-natural stevia are other options.

Be aware, however, that the artificial sweeteners will only sweeten. 

They will not contribute any additional preservation effects like sugar will. 

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HYPERBARIC STORAGE

Hyperbaric storage at room temperature evaluated as a new food preservation method.

Strawberry juices maintained at different pressure levels (0.1, 25, 100 or 220 MPa) at 20 ºC.

Hyperbaric storage reduced the initial microbial load of the juices.

Moreover, pressure was effective to attenuate viscosity and color losses in the juice stored.

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PACKING

In some cases large reserves of single-strength juice are kept in juice silos after having been pasteurized.

But usually the juice is immediately processed into retail or institutional packages.

Juices also packed in glass bottles, plastic bottles and tetra packs.

We have a wide range of liquid packaging solutions, formats and volumes includes : Single serve cartons with Straws and Multi-serve cartons with or without a range of different cap closure styles.

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FREEZING

Then freezing of juice is done.

Thus low temperature during manufacture and storage is a valuable hurdle to deterioration.

Put the sealed juice containers in the freezer and freeze.

Mostly freezing is done after packing because commercially processed juice packings in rigid plastics need freezing.

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NUTRITIONAL BENEFITS OF STRAWBERRY JUICE Strawberry is a highly nutrient dense fruit.

Contains great amount of vitamins and minerals.

Packed with a variety of anti-oxidant substances.

Also rich in phenolic compounds such as flavonoids and ellagic acid.

Includes flavonoids, anthocyanidins, vitamin C (112 %), vitamin E (1%).

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CONT…. Also rich in dietary fiber (1 %) , beta-carotene.

Contains potassium (11 %), folate (5 %), thiamine (3 %), riboflavin (8%), niacin (2 %).

Includes biotin, magnesium (6%) , iodine and zinc (2%).

Very low in protein (1.4g), sugar and calories .

Virtually devoid of fat (0.9g) and cholesterol.

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HEALTH BENEFITS OF STRAWBERRY JUICE

Anti-anemic ( due to presence of folate )

Anti-cancer (due to presence of antioxidants e.g., folate, vitamin C, ellagic acid)

Anti-coagulant (due to presence of acetylsalicylic acid)

Anti-inflammatory (due to presence of Anthocyanidin , a unique flavonoid )

Brain and mental health (due to presence of folate )

Digestive health (due to presence of vitamin C ,dietary fiber)

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CONT….. Diuretic (due to presence of potassium)

Heart health (due to presence of antioxidants)

Immune system (due to presence of vitamin C)

Blood Sugar Benefits(due to presence of ellagitanins, polyphenols)

Cardiovascular Benefits (due to presence of antioxidant and anti inflammatory Phytonutrients)

Mood improver

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REFERENCES http://thejuicedietrecipes.blogspot.com/2013/04/ben

efits-of-drinking-strawberry-juice.html http://juicers-best.com/blogs/benefits-of-juicing/6859

618-benefits-of-juicing-strawberries http://digital.csic.es/bitstream/10261/81966/4/HYPER

BARIC%20_STORAGE.pdf http://onlinelibrary.wiley.com/doi/10.1002/jsfa.27406

00411/abstract http://ucanr.edu/datastoreFiles/608-729.pdf http://milnefruit.com/fruit-vegetables-purees.html

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