Fruit juice processing - FOODZAQ

Hello friends, Welcome back to my blog FOODZAQ. Today we are discuss about processing of fruit juice. Fruit juices is one of man's most popular and healthful beverage. Fruit juice are consumed because of their refreshing and nutritional qualities. It shall be the un concentrate or unfermented but fermentable juices obtained from clean, sound, fresh, ripe named fruit.

Fruit juice shall contain all the constituents naturally present in the juice of the fruit from which it has been prepared. It shall have a total soluble solid content that of the natural juice. It shall show a sign of deterioration. It may be prepared by reconstituting the particular concentrate.

Nutritional qualities of Fruit Juice

• Excellent source of vitamins and minerals.
• Mild laxative.
• Lower the blood pressure.
• Good source of quick energy.
• Helpful in resisting respiratory infection.
• Help digestion of milk in infants.

Types of Fruit Juices

Natural fruit juice are extracted from ripe fruits and contain only natural sugars. sweetened juice is a liquid product which contain at least 85% juice  and 10% TSS.

Classification of Fruit Juices

1. Clear fruit juices : As those prepared from cherries and apple.
2. Cloudy fruit juices : It contain a quantity of insoluble matter such as those of pineapple, orange juices,..
3. Pulps containing fibrous and other insoluble matters such as those obtained from mangoes and guava.

PREPARATION OF FRUIT JUICES

 The preparation and extraction of fruit juice consist of primarily of removing all or part of insoluble solids from whole fruits. The various steps involved in processing of fruit juices are :

1. Selection of suitable varieties.
2. Washing.
3. Inspection and grading.
4. Extraction of juice.
5. Pre treatment of juices.
6. Pasteurization.
7. Filling.
8. Processing.
9. Cooling.
10. Storage. 

Selection of suitable variety

All fruits are do not suitable for making fruit juice either because of difficulties in extraction of juice or because of juice obtained is of  poor quality. The best juice extracted from specially picked sound suitable varieties when they are at optimum stage of maturity.

Stage of maturity varies with varieties. For example : berries should be picked when they are soft ripe for optimum color and flavor. Apple should not be allowed to become over ripe and mealy texture before crushing. Delayed and damaged fruits do not yield good juice. Over sized or under sized fruits which is of good quality can be used.

Washing

Fruit should be thoroughly washed water to remove dust and external matters. Tender fruits like berries, tomato are washed with fine over head sprays of water. Residue of sprays of arsenic and lead should be removed with dilute HCl. Oranges sometimes develop mold deposit on surface which can only removed by scrubbing and washing.

Inspection and grading

In large factories, a continuous broad belt is employed for sorting the fruits.

Extraction of juice

 Generally juice from fresh fruit is extracted by crushing and pressing them except apricots, peaches and citrus fruits. The method of will differ with structure and composition of fruit. In fruits like apple and grapes juice is located through out the fruit and recovered by crushing and pressing. In citrus fruits, the juice containing tissue which is surrounded by a thick skin that contain soluble substance of objectionable color and flavor. So juice must be extracted by avoiding undesirable substances from skin. 

After extraction of juice it is not exposed to air as oxygen of air will adversely effect color, texture and aroma and also reduce vitamin content of juice. Air is also present in surface of fruit particle and dissolve in juice. In the case of citrus juice, particularly in orange juices.

De-aeration is carried out by spraying the juice in to a vacuum chamber, or by allowing it to vacuum chamber as  a thin film travelling over baffles. a vacuum of 70 cm removes 95% of dissolved air and is effective to prevent oxidation.

Straining / Filtration / Clarification

Fruit juice after extraction, always contain varying amount of suspended matters. It consist of broken fruit tissues, seed and skin. it also various gums, pectic substance and protein in colloidal suspensions. Usually coarse particles of pulp, seed and pieces of skin are removed by means of screens in case of almost all fruit juices.

Some juices like grape juice, apple juice, lime juice, cordials are packed brilliantly clear by enzyme clarifying agents and fining agents. Coarse particles of suspension in juice  are removed by straining or by sedimentation. A chemical preservative is added to juice stored in barrels to ensure that juice does not deteriorate. 

Preservation

1. Pasteurization

The method consist essentially in heating juice to 100C or slightly below for a sufficient time to kill micro organisms which cause spoilage and process of heating is called pasteurization. The juice is hermetically sealed in containers before being pasteurized. Usually juices are pasteurized at about 85C for 25-30 minutes.

2. Preservation by chemicals

• according to FSSAI, chemical preservatives permitted are benzoic acid and sulphur dioxide.
• Sodium benzoate is used for preservation. It is a salt of benzoic acid and it is moere readily soluble than acid.
• Sulphur dioxide is also used for preservation. It is fairly stable in neutral or alkaline media. SO2 retards the development of yeast. It can not arrest yeast multiplication
• the chemical preservative should be dissolved a small quantity of juice or water and then added to bulk of juice.
• In recent years, sorbic acid is used an account of its fungi static property.

3. Preservation by addition of sugar

Juice contain 66% or more sugar do not ordinarily fermented. Sugar absorb available water and it is not available for growth of micro organisms.

4. Preservation by freezing

The best way to preserve pure fruit juice is by freezing. properly frozen juice retains its freshness and aroma for long time. apples and berry juices stored in sealed container for 2 years at a temperature of -12 to -10C.

5. Preservation by drying

It is a method of concentrated juice can be sprayed in to a evaporating chamber through which hot air it passed. Freeze drying, foam mat drying are other methods.

6. Carbonation

Mold and yeast require oxygen for their growth. They become inactive in presence of CO2. The yeast cells are filtered out and then juices is carbonated under aseptic condition. The juice will keep without fermenting. Absence of air and presence of CO2 prevent the growth of mold and yeasts in carbonate beverages.

Production of Orange juice

1. Receiving fruits.
2. Washing by agitation or spraying.
3. Inspection.
4. Grading.
5. Extraction of juice.
6. Finishing.
7. Blending.
8. De-aeration.
9. Pasteurization.
10. Filling in to cans.
11. Sealing.
12. Inverting.
13. Processing.
14. Cooling.
15. Storage.

Guys, Thank you for reading my blog FOODZAQ. I hopes you should understands about fruit juice processing. If you have any doubts regarding this blog, please feel free to comment below. If you like this blog, you can also read my previous blogs on food science as well. Thank you again. Have a great day.