Commercial Processing of Mangoes
Processing
Essentially a prime table fruit, mango pulp is perfectly suited for conversion to juices, nectars, drinks, jams, fruit cheese or to be had by itself or with cream as a superb dessert. It can also be used in puddings, bakery fillings, and fruit meals for children, flavours for food industry, and also to make the most delicious ice cream and yoghurt. While the raw fruits are utilized for products like chutney, pickle, amchoor (mango powder), green mango beverage, etc. ripe ones are used in making pulp, juice, nectar, squash, leather, slices, etc. Major export products include dried and preserved vegetables, mango and other fruit pulp, jams, fruit jellies, canned fruits and vegetables, dehydrated vegetables, frozen fruits, vegetables and pulp, freeze dried products and traditional Indian products like pickles and chutneys.
Processed mangoes enable exporters to serve their markets even during off-season period for fresh mangoes. Ripe mangoes may be frozen whole or peeled, sliced and packed in sugar (1 part sugar to 10 parts mango by weight) and quick-frozen in moisture-proof containers. The diced flesh of ripe mangoes, bathed in sweetened or unsweetened lime juice, to prevent discoloration, can be quick-frozen, as can sweetened ripe or green mango puree. Immature mangoes are often blown down by spring winds. Half-ripe or green mangoes are peeled and sliced as filling for pie, used for jelly, or made into sauce, which, with added milk and egg whites, can be converted into mango sherbet. Green mangoes are peeled, sliced, parboiled, then combined with sugar, salt, various spices and cooked, sometimes with raisins or other fruits, to make chutney; or they may be salted, sun-dried and kept for use in chutney and pickles. Thin slices, seasoned with turmeric, are dried, and sometimes powdered, and used to impart an acid flavour to chutneys, vegetables and soup. Green or ripe mangoes may be used to make relish (Morton, 1987).
Industrial Processing Possibilities
Several options have become available for large scale processing of mango products.
1. Mango pulp
2. Juice (See Figure 36 Mango Juice)
3. Nectar
4. Fruit sauces
5. Fruit cocktails
6. Dried mango slices
7. Mango wine
8. Glazings
9. Flavoured yoghurt (See Figure 37 Mango yoghurt)
10. Ice cream
Pulping and juicing
A key step for preparation of the above products is pulping, as described below. Flowcharts are included which depict the manufacturing steps for mango products.
1. Fruit selection. Several requirements need to be met:
- Lack of insect infestation
- Lack of mechanical injuries
- Stage of maturity
- Uniform colour and texture
- Minimum soluble solids of 13 ° Brix
- pH value of 3.5 to 4.0
The receiving area must be clean, well ventilated, and free of insects, rodents or other animals. It is not advisable to hold the fruits too long before processing to avoid spoilage.
2. Washing
The washing pit should be filled with water containing 15 ppm chlorine in order to reduce microbial load and impurities from the fruit. A second washing with clean water is made to eliminate residual chlorine.
3. Blanching
This operation is done to inactivate enzymes, eliminate air inside the fruit tissues, remove off-flavours and aromas, fix fruit colour and soften the tissues for further pulping.
Two methods are currently used to effect blanching: dip in boiling water or direct steam injection. The thermal treatment is applied such that internal fruit temperature reaches 75°C. This usually requires 10 minutes in boiling water, or 6 minutes with steam. Fruit is blanched unpeeled.
4. Peeling and cutting
Pulp is separated from the seed manually with knives made of stainless steel, on a working bench. Mango pieces are placed in clean plastic containers and taken to the pulping machine.
5. Pulping
Mesocarp pieces are passed through a fine mesh to remove undesirable particles. After pulping, a smooth puree is obtained. Recommended mesh size is 0.5 mm. coarser material is separated in the process and disposed properly. The pulp is transferred in containers to the kettle.
6. Thermal treatment
A heat treatment is applied in the kettle to prevent chemical and microbial spoilage. In this treatment the pulp reaches 95 ° C and is held for 10 min. with continuous stirring.
7. Additives
The use of additives is recommended to extend the pulp shelf life. Commonly used additives include 0.39 percent citric acid to decrease pH and prevent microbial growth and enhance effectiveness of preservatives as sodium benzoate (0.5 percent).
To prevent discoloration 0.1 percent ascorbic acid is used as antioxidant. Additives are incorporated to the pulp right before the thermal treatment is finished (ca. 5 min before) by dispersing in hot water or pulp and proper stirring. Final product should have 13 °Brix and pH values between 3.4 to 3.5.
8. Packing
The pulp is packed when hot in plastic containers, sealed immediately and flipped over so the internal part of the lid gets in contact with the hot product. All packing materials must be clean before used.
9. Cooling
Hot containers are cooled with fresh water at the lowest temperature attainable. After cooling, lid closings should be inspected. Finally, containers are cleaned and labels affixed to be sent to a fresh, clean storage place.
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Specification of Alphonso Mango Pulp Physical, Chemical and Organoleptic Characteristics. |
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T.S.S. (° Brix)
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Min 16
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Acidity (% as citric acid)
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Min 0.5
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pH
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< 4.00
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° Brix /Acid Ratio
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32
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Ascorbic Acid (ppm)
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Min 200
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Additives
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Nil
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Pesticide residue
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Absent
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Colour
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Golden yellow
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Flavour
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Characteristic
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Taste
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Characteristic
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Microbial Characteristics |
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T.P.C.
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CFU/g
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< 50
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Yeast
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CFU/g
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< 50
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Mould
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CFU/g
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< 10
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Source: Agafruits (2000)
Average composition of pulp (100/g) |
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Edible Portion
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(%)
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74.00
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Moisture
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(g)
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81 .00
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Protein
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(g)
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0.60
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Fat
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(g)
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0.60
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Minerals
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(g)
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0.40
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Fibre
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(g)
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0.30
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Carbohydrates
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(g)
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16.90
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Energy
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(Kcal)
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74.00
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Calcium
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(mg)
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16.00
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Phosphorus
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(mg)
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18.00
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Iron
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(mg)
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1 .60
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Vitamin C
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(mg)
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20.00
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Vitamin B complex
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(mg)
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1.07
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Vitamin A
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(mg)
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2 743
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Source: Agafruits (2000)
Drying
Dryers around the world are using improved methods to make all sorts of new dried fruit products. Many of these make great natural snacks. Mango is delicious as a snack, in a sauce or in a salad. Snacks are packed in transparent plastic bags. (See Figure 38 Tommy Atkins mango stripes) mangoes are dried in the form of pieces, powders, and flakes. Drying procedures such as sun drying, tray drying (See Figure 39 Tray dryer) tunnel dehydration, vacuum drying, osmotic dehydration may be used. Packaged and stored properly, dried mango products are stable and nutritious.
Figure 38. Tommy Atkins mango strips.
One described process involves as pretreatment dipping mango slices for 18 hr (ratio 1:1) in a solution containing 40°Brix sugar, 3 000 ppm SO2, 0.2 percent ascorbic acid and 1 percent citric acid; this method is described as producing the best dehydrated product. Drying is described using an electric cabinet through flow dryer operated at 60°C. The product showed no browning after 1 year of storage.
Drum drying (See Figure 40 Drum dryer) of mango purée is described as an efficient, economical process for producing dried mango powder and flakes. Its major drawback is that the severity of heat pre-processing can produce undesirable cooked flavours and aromas in the dried product. The drum-dried products are also extremely hygroscopic and the use of in-package desiccant is recommended during storage. The stone removed, the fruit is cut in slices, dried and afterwards ground to a pale grey powder. This powder is used frequently instead of tamarind, the other important sour element in Indian cuisine; mango powder is, however, much weaker than tamarind and has a subtle, resin-like taste. It is mainly used when only a hint of tartness is desired or when the dark brown colour of tamarind is to be avoided. Mango powder is generally more popular with vegetables than with meat, but is frequently found in tikka spice mixtures for barbecued meat. To prepare the barbecued meat of Northern Indian cuisine, an Indian clay oven (tandoor) is required, but substitution by a Western baking oven is acceptable. Meat to be grilled is seasoned with a mixture of several spices (cumin, coriander, fresh ginger, garlic and mango powder, but little or no chiles) with red food colouring and plain yoghurt. After a few hours, it is quickly roasted in the very hot tandoor. Mango powder here serves not only as a tart and sour spice, but also as a meat tenderizer.
Ripe mangoes are a popular fruit and may be used for stewed fruits, fruit jam, fruitcakes and many other standard fruit applications; they can, however, even used for savoury dishes. Indonesian fruit salad (rujak) combines fresh fruits (not too ripe mango, pineapple, papaya, in Java frequently cucumber) with a pungent sauce of palm sugar (won from coconut or other palm trees), fresh red chiles and salt; on Bali, a hint of shrimp paste is never omitted. The result tastes even more delicious that the recipe looks strange! Mexicans sometimes use ripe mangoes or other tropical fruits for their fiery salsas (Katzer, 2000).
Mango fruits have been utilized for long time at every stage of growth. While the raw fruits are utilized for products like pickle, amchoor, green mango beverage, etc. ripe ones are used in making pulp, juice, nectar, squash, leather, slices, etc.
Raw mango products
Mango fruits during early stages of growth are commonly used for sweet or sour chutney. As the fruits attain stone hardening stage, they become suitable for some other useful products like amchoor (seasoning made by pulverizing sun-dried, unripe (green) mango into a fine powder. Amchoor has a tart, acidic, fruity flavour that adds character to many dishes including meats, vegetables and curried preparations. It’s also used to tenderize poultry, meat and fish), pickle, etc.
Ripe mango products
Ripe mango fruit has a characteristic blend of taste and flavour. It contains important amounts of sugar, pectin, carotenoids, etc. Due to comparatively shorter storage life of mango fruits, it is essential to prepare their products immediately.
Mango Leather or Aam Papad: Homogenized mango pulp is prepared and potassium metabisulphite is added to it at a rate of 2 g/kg of pulp. The pulp is then spread on trays smeared without and kept for drying in solar dehydrator or sun. After drying of one layer, another layer is spread over it and dried. The process is repeated until the desired thickness is attained. Finally the leather slabs are cut into pieces and wrapped in butter paper or plastic sheets.
Fresh-cut Mangoes
Mangoes could be an attractive addition to the growing market for fresh-cut produce, but browning and drying have prevented such marketing. Researchers at the USDA-ARS Horticultural Crops Quality Laboratory found that fresh-cut mangoes could be preserved by treating the slices with a combination of hexylresorcinol, isoascorbic acid and potassium sorbate (all food-safe compounds derived from natural products) and storing the slices in plastic containers to prevent drying. Treating whole fruits with methyl jasmonate (an inexpensive product derived from plant essential oils) prevented the development of chilling injury during cold storage and hence markedly increased fruit quality after storage. The treatment worked on fruits at various stages of maturity and had no effect on ripening, softening processes or water loss.
Canning
Canned mangoes do not have to meet any specific standards, but CODEX Alimentarius (Latin, meaning Food Law or Code, UN Commission for Food Standards) is developing international standards. In general, mangoes are processed in cans or in glass jars. FDA requires nutritional facts written on containers. Mangoes are the common product name of the canned food that is made from properly prepared fresh mango varieties, that have the peel (rind), stems and pits (stones) removed; shall be packed in a packing medium consisting of water, with or without a sweetening ingredient, or natural reconstituted, concentrated fruit juice or juices, or fruit puree or nectar, with or without a sweetening ingredient; and may contain: pectin, a suitable acid ingredient, calcium-based firming agents, and beta-carotene.
Styles. The styles of mangoes are: halves, if the mango is cut into two approximately equal parts along the pit or stone from stem to apex; slices, if the mango is cut into long, slender pieces either lengthwise or crosswise; diced, if the mango is cut into approximately cube-shaped pieces with at least 12 millimetres on the longest side; and pieces, mixed pieces or irregular pieces, if the mango is cut into pieces of irregular shape and size.
Quality Standards: have a colour that is typical of the variety; have a characteristic flavour and aroma of properly prepared, properly processed canned mangoes; in the case of “slices” style, these shall be reasonably uniform in size, and in the case of “halves” style, have at least 90 per cent by count of the units approximately the same size; in the case of “halves” and “slices” styles, shall not have more than 20 per cent of the units cut other than parallel to the crease, and not have more than half of those units cut horizontally; have units that are reasonably fleshy with little objectionable fibre, and not excessively soft or excessively firm, and in a 500 g sample of the drained product, not contain more than: six square centimetres in the aggregate of rind, one-eighth of a stone equivalent of pit material, and one piece of harmless extraneous plant material not greater than 10 millimetres in any dimension; and not have more than 30 per cent by count of units that: are blemished by discolouration or dark spots on the surface or that penetrate into the flesh, or in the case of “halves” and “slices” styles, have trim damage with gouges in the units serious enough to detract from the appearance of the product, and five per cent by drained weight of units that are crushed and severed into two or more parts or have lost their normal shape. Mangoes, when properly packed, shall have a minimum drained weight that is not less than 55 per cent of the weight of distilled water at 20°C that the sealed container will hold when full. Varieties most suited for canning include Creole, Mora, Filipino, Irwin and Haden.