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Vol. 9 No.1&2 February-April 2001 

Food Technologies

Several innovative state-of-the-art food process technologies have been developed keeping in view the strategic operational requirements of our Defence forces. These include:

*     Retort processing of foods in flexible pouches
*     Food additives technology
*     Cold shock dehydration technology
*     High temperature short time (HTST) pneumatic drying
*     Flaking technology
*     Fluidized beds for drying of cereals, pulses and vegetables
*     Spray drying
*     Technology of hurdle processing and preservation
*     IntermeDIATe moisture (IM) foods technology
*     Microencapsulation technology
*     High temperature short time extrusion technology
*     Compressed foods technology
*     Thermal processing of foods in aluminium containers
*     Reverse osmosis and ultrafiltration technology
*     Combination dehydration technology
*     Stack encapsulation technology
*     Technology for the extension of shelf-life of fresh fruits and vegetables.
    Some of these technologies have become commercial. Some recently developed technologies with vast potential in both defence and civil sectors are briefly discussed here.

Minimally Processed Vegetables

Minimally processed vegetablesMinimal processing of vegetables is a state-of-the-art technology by which a variety of tropical, sub-tropical, and temperate vegetables can be made available in trimmed and cut forms prepackaged with fresh/fresh-like sensory attributes. Minimum processing protocols have been developed for 14 types of vegetables, viz., cauliflower, cabbage, carrot, beetroot, potato, sweet potato, sponge gourd, ridge gourd, radish, knol-khol, papaya raw, mango raw, yam and  french beans. Permissible additives and preservatives with restricted levels were used so that the sensory attributes did not suffer adversely. Minimum processing protocols are generally without thermal treatments, excepting French beans which requires very short thermal treatment. This additives-based non- thermal process is helpful in retaining the freshness of the produce to a longer period. The minimally processed vegetables are microbiologically safe, besides being rich in ascorbic acid. The process condition and additive treatments vary depending on the nature of commodities, viz. whether they are of white flesh, non-green or green colour. The minimally processed products exhibit a shelf-life of 14-28 days under room temperature (6 1 oC). The technology of minimal processing pertaining to 12 select vegetables has been transferred to a firm of   Maharashtra.

Active Packaging for Extension of Shelf-Life of Fresh Fruits & Vegetables

Flexible packaging materials such as low density polyethylene (LDPE) and linear low density polyethylene when impregnated with potassium permanganate and cinnamic acid, respectively become ethylene scavengers. Fresh fruits and vegetables, such as mango, tomato, banana, and papaya exhibit more shelf-life of two to three weeks when packed in such ethylene scavenging films. The incorporation of ethylene scavengers improve the physico-mechanical properties of the packaging materials considerably- The technology has been perfected in the laboratory and large scale production of such active packaging materials and their evaluation are currently underway.

Process for Freeze-Thaw Dehydration for Instantisation of Cereals & Pulses

An innovative method of processing instant pulses, whole legumes and cereals by freeze-thaw dehydration method has been developed and standardised. The aim of this process is to make cooked and dehydrated pulses, whole legumes and cereals that are instantly reconstitutable in less than 8 minutes by mere mixing in hot water. In this process, the rheological traits, viz, shape and size characteristics are retained to a better definition compared to those in flaking and other processes. Giving cold shock to the cooked mass prior to its dehydration in fluidised bed dryer is the key to this novel freeze-thaw dehydration technique. This process has been utilised for the development of various instant cooking pulses, i.e., Bengal gram, green gram, black gram, red gram, lentils and whole legumes (whole green gram, whole kabuli channa and rajma). These products have been found to be highly acceptable and can be reconstituted within 2-5 minutes by mere mixing with hot water. The shelf-life of these instant foods ranges from 12 to18 months.

The technology was put into good use by DRDO to prepare 6.25 tons of instant khichidi (rice and daal mixed) for supply to Gujarat earthquake victims. Efforts are on to develop snacks items using this technology.

Processed Food Products

By making use of the above technologies, the following ready-to-eat, quick cooking and instant foods have been developed. The shelf-life of each food product is given in parenthesis. Also, some devices and food processing technologies are listed.

Ready-to-Eat Products

Long keeping chapaties ( 6 months)
Preserved chapaties (7 days)
Compressed cereal bar (1year)
Nutribar(1 year)
High protein snacks (9 months)
Composite breakfast cereal bar ( 1 year)
Besan and cashew burfi (6months)
Compo pack ration Spiced potato parothas (6months)
Puff and serve chapaties (5 days)
Stabilised chikki ( 1 year)
Fruit bars (9 months)
Sorghum snacks Sorghum flakes ( 1 year)
Holige and Modaka (4 months)
Emergency survival bar (3 years)
Mutton pickle (6 month/s)

Freeze-Dehydrated (FD) Foods

Fruit juice powders
(Mango,Pineapple, Mosumbi (1 year)
FD shrimp (1 year)
FD meat (6 months)
Chicken pulav(1 year)
Mushroom soup powder (1 year)
FD fruit slices (1 year)
Smart Additives & Devices
Stay-fresh chemicals for fruits and vegetables
Leg-operated chapati rolling machine
Keep fresh salt
Quick Cooking Foods  
Insta nutro cereal mix (bisibele bath) (1 year)
Pre-cooked dehydrated (PD) pulav mix (1 year)
Micro-encapsulation of flavours and food Ingredients
PD dal/curries (1 year)
PD rice (1 year),
PD potato peas curry (1 year)
Instantised Foods
Instant pulav mix (1 year)
Instant curries dal(1 year)
Instant kadhi mix (1 year)
Instant avial mix (1year)
Instant vermicelli kheer mix(1 year)
Instant coconut chutney mix (6 months)
Instant carrot halwa mix (9 months)
Instant dried curried mutton mince (1 year) Hurdle-stabilised cooked capsicum and french beans
Tender Coconut water Instant khichidi mix (1 year)
Instant basmati rice(1 year)
Instant vegetable wadi (1 year)
Instant halwa mix (1 year)
Instant upma mix (1 year)
Instant rava idli mix (9 months )
Scrambled egg mix (1 year)
Instant mutton soup powder,
Instant legumes (Kabuli Chana, Rajma, dry peas) (1 year)
Ration Packs
Emergency flying ration for air crew
Full meal compo pack ration
Supplementary compo pack ration
Survival ration for Army

  DRDO has unique distinction of designing and developing foods for Indian space expeditions, mountaineering and Antarctic expeditions, convenience foods for victims of natural disasters and calamities, using its different food technologies. The Indian ready-to-eat and convenience foods developed by DRDO are regularly being used in Indian Antarctic expeditions. These processed foods were also picked up for use during natural calamities/disasters in Latur and Gujarat earthquakes, Malpa and Chamoli landslides and Orissa cyclone.