Processing of Horticultural Crops (1+2)

Introduction

Introduction
Fruit juice and beverages generally comprise of naturally extracted juices, drinks, ready to serve (RTS) beverages, nectars, squashes, cordials and appetizers etc. These products are highly refreshing, thirst quenching, appetizing and nutritionally superior to many synthetic and aerated drinks. Fruit juice is the natural liquid expressed by pressure or other mechanical means from the edible portion of the fruit. Fruit juices are generally extracted from fruits in a number of ways, depending on their structure and composition.

The composition of juice is unaltered during preparation and preservation while for fruit beverages like drinks, squashes, cordial etc the fruit juice or pulp, sugar, acid, colour, flavour etc are mixed in appropriate proportions to a desirable taste. Apple juice, orange juice, mango squash, guava drink, pineapple juice and squash, mixed fruit drink, mango nectar etc are the commercial products available in the market.

Types of fruit juice and beverages

a) Unfermented beverages
Fruit juices which do not undergo alcoholic fermentation are termed as unfermented beverages. They include natural fruit juices, sweetened, ready to serve drinks, nectar, cordial, squash, crush, syrup, fruit juice concentrate and fruit juice powder. They are prepared by following minimum standards as prescribed under Food Safety and Standards Regulation, 2011 and Fruit Products order (Table 8.1) and discussed as under:

Table 8.1: Fruit Products Order (FPO) specifications for fruit beverages

Product	Minimum % of total soluble solids in final product (w/w)	Minimum % of fruit juice in final product (w/w)	Maximum acidity expressed as citric acid (%)
Unsweetened juice	Natural	100	3.5
Fruit syrup	65	25	3.5
Crush	55	25	3.5
Squash	40	25	1.5
Fruit nectar (excluding orange and pineapple)	15	20	1.5
Orange and pineapple nectars	15	40	1.5
Cordial	30	25	3.5
Sweetened juice	10	85	-
Lime/lemon Ready to serve beverage	10	5	-
Ready-to-serve beverage/drink	10	10	-
Fruit juice concentrate	32	100	-
Synthetic syrup/sherbet	65	-	-

Preservative SO₂/BA ppm specified by Food Safety and Standards Regulation, 2011. SO₂- sulphur dioxide; BA- benzoic acid

• Fruit juice: It is a natural juice pressed out of the fruit and remains practically unaltered in its composition during processing and preservation. It is also called as unfermented fruit juice or pure fruit juice, for example apple juice.
• Fruit juice beverage: It is fruit juice which is considerably altered in composition during preparation. It may or may not be diluted before consumption. Ready to serve (RTS) drinks, nectar, squash, cordial, appetizer are all fruit juice beverages.
• Synthetic drinks: Synthetic drinks are prepared by using sugar, water, flavourants, acidulents, colour etc. These drinks do not contain any fruit juice or pulp.
• Ready to serve (RTS) drink: This is a type of fruit beverage which contains atleast 10% fruit juice (for lime drink 5% juice) and not less than 10% total soluble solids. The acidity in these drinks shall not exceed 3.5% as citric acid. RTS beverages are preserved by using class II preservatives not exceeding 70 ppm SO2 or 120 ppm benzoic acid. It is not diluted before serving hence it is known as ready to serve drink for example mango drink, guava drink, pineapple drink etc.
• Fruit nectar: This type of fruit beverage contains atleast 20% fruit juice or pulp and 15% total soluble solids and is preserved by heat processing. The acidity in fruit nectars shall not exceed 1.5% as citric acid. No class II preservative like SO2 or benzoic acid is permitted in fruit nectar as per Indian Food Laws. It is not diluted before serving.
• Squash: Fruit squash consists of fruit juice or pulp to which cane sugar is added for sweetening. According to Indian Food Laws, the fruit squash shall contain atleast 25% fruit juice or pulp and not less than 40% TSS. It shall not contain class II preservative in excess of 350 ppm SO2 or 600 ppm benzoic acid. Acid content in squashes generally remain between 1-1.5% but shall not exceed 3.5% as citric acid. Squash is generally diluted with water in 1:3 ratio before serving. Lime, lemon, mango, orange, guava and pineapple squashes are commercially manufactured.
• Fruit juice cordial: It is a sparkling, clear, sweetened fruit juice from which pulp and other suspended substances have been completely removed. It contains atleast 25% juice, 30% total soluble solids and not exceeding 350 ppm SO2 or 600 ppm benzoic acid as preservative. It is also used for mixing with alcoholic drinks for example lime juice cordial.
• Fruit Appetizer: Fruit appetizer is similar to fruit squash but also contains spices, condiments and herb extract. Spices like black pepper, cumin, large cardamom, ginger along with mentha extract and salt are used for manufacture of appetizer. They are also called as spiced fruit squash. Plum and apricot appetizers are quite common.
• Fruit crush: Fruit crush contains minimum of 25% fruit juice or pulp, 55% total soluble solids (TSS) and not exceeding 350 ppm of SO2 or 600 ppm of benzoic acid. It is diluted before serving.
• Fruit syrup: It is prepared by using minimum of 25% fruit juice or pulp and sweetened by using cane sugar. It shall contain not less than 65% total soluble solids and not exceeding 350 ppm SO2 or 600 ppm benzoic acid as class II preservative.
• Synthetic syrup: Heavy sugar syrup of 70-75 percent strength is used as the base of all synthetic syrups, which are flavoured and coloured with artificial flavour and colours. They may or may not contain fruit pulp or juice. Rose, sandal, almond, khuskhus, kewra sherbets/syrups are quite common.
• Carbonated fruit beverages: It is a ready to serve fruit juice beverage which contains variable amount of fruit juice, sugar, acid etc and impregnated with carbon dioxide gas. Apple juice, lime, lemon and grape juice can be used for the preparation of carbonated fruit juice beverages. They are prepared either by pre mix or post mix method.
• Fruit juice concentrate: It is a fruit juice, which has been concentrated by removal of water either by evaporation, freezing or reverse osmosis. Several products can be made from fruit juice concentrate. Apple juice concentrate, orange juice concentrate etc are commercially prepared in the industry.
• Fruit juice powder: This is a fruit juice which has been converted into a free flowing powder. They can be prepared either by freeze drying, foam mat drying or spray drying processes. They are readily reconstituted to yield full strength fruit juice drinks.

b) Fermented beverages

Fermented fruit beverage is a fruit juice which has undergone alcoholic fermentation by yeast like Saccharomyces cerevisae. The product contains varying amount of ethyl alcohol. Apple cider, plum wine, grape wine, vermouth etc are common fermented beverages.

A). Method for preparation of fruit juice beverages

SELECTION OF FRUITS: All fruits are not suitable because of difficulties in extracting the juices or due to poor quality juice. The variety and maturity of the fruit and locality of cultivation influence the flavour and keeping quality of its juice. Only fully ripe fruits are selected. Over ripe and unripe fruits adversely affects the quality of the juice.

SORTING AND WASHING: Diseased, damaged or decayed fruits are rejected or trimmed off. Dirt and spray residues of arsenic, lead etc are removed by washing with water or by using dilute hydrochloric (HCl) acid solution (0.5%) followed by washing in water.

JUICE EXTRACTION: Generally juice is extracted by crushing or grating the fruit and pressing the crushed mass in a basket or hydraulic press. Juice can also be extracted by using a screw type juice extractor. Common equipment used for juice extraction are fruit grater or mill, basket or hydraulic press, screw type juice extractor, rosing or burring machine, fruit pulper etc. There are two types of extraction methods i.e., single and double operation system.

• Single operation: In single operation, screw type, plunger type or roller type press is generally used to crush and press the prepared fruit to extract the juice. Citrus fruit segments are fed through a hopper, passed through conical screws and the juice flows out through the perforations while the pomace comes out at the end of the conical jacket. The screw type extractor is operated either manually or by using electricity depending upon the requirement. The juice extracted is generally thick and cloudy and contains a considerable amount of macerated pulp. Care should be taken to remove the rind of citrus fruits completely otherwise it makes the juice bitter. Citrus fruits like lemon, kinnow etc can also be extracted by using a rosing or burring machine. Finally, the juice is strained through a thick cloth or a sieve to remove seeds.
• Double operation: In this system, the fruits are crushed and then pressed separately. Fruit like apple, aonla, berries, grapes, jamun, phalsa etc are crushed in fruit grater or crusher and the crushed mass is pressed by means of basket press and hydraulic press.

Process variables for juice extraction for some fruits are:

• Soft fruits such as berries or tomatoes can be pressed through a fruit press or pulped by using a juicer attachment to a food processor.
• Citrus fruits are usually reamed to extract the clear juice.
• Harder fruits like pineapple are peeled, pulped and pressed to extract the juice.
• Apple and pear fruits are crushed in a fruit grater and pressed in a hydraulic/basket press to extract a clear juice.
• Passion fruit juice is prepared by using a pulper-finisher that separates skin and seeds from the pulp.

The fruits like mango, guava, apricot, peach etc from which the clear juice extraction is difficult are passed through the pulper to make pulp and then the pulp is utilized for preparation of juice, fruit drinks and ready to serve beverages.

DEAERATION: Freshly extracted juice contains appreciable quantity of oxygen which may affect the quality of juice if not removed before packing. Air in juice is due to the presence of intra-cellular spaces present in the fruits. Most of the air as well as other gases are removed by subjecting the fresh juice to a high vacuum. This process is called as deaeration and the equipment used for the purpose is known as the deaerator. Heating of juice during heat processing also helps in removal of the air.