A monthly house bulletin of Defence Research & Development Organisation ■ Vol. 31 No. 7 ■ July 2011

ISSN : 0971-4413BULLETIN OF DEFENCE RESEARCH AND DEVELOPMENT ORGANISATION Vol. 19 No. 5 October 2011

Food Processing TechnologiesFood Processing TechnologiesForces do not require elaborate cooking and have shelf-life of 9-12 months under ambient temperature conditions. The various rations, which have become part and parcel of the Armed Forces, include meal ready-to-eat (MRE) for the Army and Navy; emergency/survival rations for the Army, Navy, and Air Force; submarine crew rations; Main Battlefield Tank (MBT) ration; as well as space food. The spin-off benefits of developed technologies/products have been transferred to 235 firms in the form of 568 technologies. Recently, DFRL has developed various functional and neutraceuticals products suitable for anti-hunger, anti-anxiety, anti-sleep, performance enhancing, etc., to cater to the requirements of the Armed Forces.

The mission of the Laboratory is to design, develop and evaluate safe, nutritious, and convenience foods to meet requirements of the Services and as spin-off for civil applications with a vision to be a technological leader of excellence in food research and product development. DFRL efforts to ultimately hold the adages of the great warriors Napoleon Bonaparte and Frederick, the Great that “An army marches on its stomach” as well as Hippocrates, the father of Medicion, ”Let food be thy medicine.” This issue of Technology Focus highlights some of the technologies developed by DFRL.

Defence Food Research Laboratory (DFRL), Mysore, an establishment

of Defence Research and Development Organisation (DRDO), was established in December 1961 to meet the challenges with respect to food requirements of the Armed Forces and in the process, design and develop rations for special operational situations, peacetime garrison ration, emergency/survival ration, etc. Indian troops often operate in far-flung inhospitable terrain under inclement and hostile weather conditions ranging from sub-zero to

50 oC, and hot and humid areas.

The food requirements for these conditions are entirely different requiring special functional ingredients. DFRL with its strong R&D efforts has not only developed various types of lightweight convenience foods suitable for pack rations for the Army, Navy, Air Force, and the Paramilitary Forces but also developed indigenous low-cost processing equipment to achieve the same. The various processed

foods developed for the Armed

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NutrItIouS Food BarS

Demand for the processed and convenience foods is increasing rapidly due to the increasing awareness about the health, changing socio-economic needs, and insufficient time to cook food with the correct/ balanced amount of nutrition.

One such nutritionally balanced convenience food is the nutritious energy bars, which are gaining popularity in the global market after 1980s. Earlier, these energy bars were used by the sport persons who were involved in strong physical activities and therefore, needed greater source of energy during peak performance. But today, due to the increasing focus on the nutrition and healthy food habits and an increasing number of people involved in greater physical activities, energy bars have become a perfect choice as a quality source of energy.

These energy bars are prepared in the form of tablets either using compression technology or using different binders of choice. The bars contain wide range of

nutrients as well as sufficient amount of proteins, fats, and carbohydrates and are available in smaller packets or pouches, light in weight, very convenient to carry and can be eaten at any point of time.

There are different types of energy bars referred by different names such as protein bars, meal replacement bars, granola bars, neutraceutical bars, breakfast bars, health bars and so on. Each bar has different characteristic with a different purpose.

DFRL has developed different types of nutritious energy bars such as compressed tasty bar, composite cereal bar (protein rich), sweet and sour tasty bar, flaxoat tasty bar (rich in soluble fibre), soya-fortified oat bar, ergogenic bar (energy dense), barley bar (rich in soluble fibre β-glucan), omega-3-rich bar (rich in omega-3-fatty acids), fibre enriched bar, coco-cocoa delight bar (antioxidant and fibre rich), and bars for desert and high altitude to cater to the requirements of the Armed Forces. Each bar, targeted with a specific

Omega-3-rich bar.

Fibre-enriched bar. Ergogenic bar.

Desert bar. High altitude bar.

Flaxoat tasty bar.

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aPPEtISErS For HIGH aLtItudE

Appetisers solve the problems of lack of appetite faced at high altitude and are one of the essential items to be included in the ration of Defence Forces, specifically those deployed at high altitude. DFRL has developed several hot water reconstitutable appetiser (soup) mixes without preservatives having a shelf-life of 6 months in trilaminate pouches at ambient conditions. There are varieties of soup mixes commercially available with shelf stability. These mixes generally contain preservatives and very low levels of appetising agents for imparting flavour. However, to provide more convenience and keeping in view the conditions prevailing at high altitude and the areas where Defence Forces are deployed, an excellent idea of spiced-based appetisers has been conceptualised.

The formulation and pre-processing techniques adopted for development of appetisers by DFRL are unique and specific for each product. The development of ready-to-eat (RTE) appetisers with a shelf-life of more than 8 months, is a unique contribution to the field of food technology and for the Defence requirements. The appetisers have been developed using statistical designs and processed by concentration-dehydration technique. These are chewy, sweet and sour in taste with tolerable but effective pungency levels, and rich in carbohydrate keeping in view the requirements at high altitude. These RTE appetisers include: Ginger munch, fruit munch, jeera munch, pepper munch, lemon munch, and ajwain munch.

The animal studies and human trials have found these appetisers beneficial in terms of enhancing the appetite with increased food consumption/weight gain. The research on physiological action of appetisers has clearly brought out the mechanism of action of decreased levels of appetiser-regulating harmone leptin on consumption of appetiser.

The large scale acceptance trials of these appetisers, both at laboratory and in field areas of base and high altitude (Leh) have been conducted and found successful. The ginger munch and fruit munch are being supplied to several Army units for extended acceptance trials.

functional ingredient, provides maximum health benefits with a calorific value ranging from 400-540 kCal with shelf-life of 6-15 months with good organoleptic acceptance as compared to the bars available in the market, which usually have limited shelf-life of 4-6

months, are either soggy or chewy in nature and not liked by the Indians. Limited trial studies have been conducted for the bars prepared at DFRL for the Army, Navy, Air Force, and paramilitary forces. All the bars were liked by the Indian troops.

PErFormaNcE ENHaNcEmENt drINk

Aloe Vera is known since ages for its health benefits. It is known to increase the blood circulation helping

supply of nutrients to cells, and thus enhances the nutrient absorption across the endothelial cells to

Appetisers for high altitude.

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blood stream. These two properties have been utilised for developing Aloe Vera-based pomegranate drink to enhance the physical performance. The product has been tested for its performance-enhancing

Indian population is growing rapidly prone to diabetic due to increase in unhealthy lifestyle. Spiced Aloe Vera low-calorie beverage developed by DFRL aims to reduce the blood sugar levels in the type II diabetes. The beverage was evaluated for its efficacy in the chemically-induced diabetes in rats. Diabetic rats after consuming the spiced low calorie Aloe Vera juice showed significant reduction in blood glucose levels, extra food intake, water consumption and urine output with no body weight loss associated with reduction in

blood glucose levels and blood lipids. The overall effect of the juice showed anti-diabetic property. After establishing the anti-diabetic benefits of the spiced low-calorie Aloe Vera beverage in experimental animals, it is now being tested in human diabetic patients in different phases.

aNtI-uLcEratIvE FruIt SPrEad aNd Bar

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon and rectum. The possible etiological factors that may play a key role in the development of UC are genetic, immunological and environmental. The Aloe Vera gel has been found capable of reducing the marker enzyme activities related to acetic, acid-induced colonic ulcer in rats. A fruit spread, based

properties in rats, which were allowed to swim until exhaustion.

The results of the tests were compared with commercially available performance enhancers (sports drink). The results indicated a significant increase in swimming time when compared to commercial drink. The product has a shelf-life of minimum 3 months and is under user trials.

SPIcEd Low caLorIE aLoE vEra BEvEraGE

on a blend of Aloe Vera gel, and mango fruit and food bar, have been developed for UC subjects. The phytochemicals responsible for the demonstrated health effect could be the rich content of glucomannans and C-glucosyl chromone,

a novel anti-inflammatory compound present in the fruit spread.

Anti-ulcerative Aloe Vera bar.Aloe Vera fruit spread.

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SHELF-StaBLE cHaPatIES

Preservation of chapaties has great importance in operational pack rations of Armed Forces. The freshly prepared chapaties have limited shelf-life of 12-24 h under ambient conditions and become unpalatable due to moisture loss, development of off-flavour, and microbial spoilage. Armed Forces want minimum shelf-life of one year under all ambient conditions. To cater to the requirements of the Armed Forces, attempts were made to preserve chapaties using antimycotic agents like sorbic acid, propionic acid and other ingredients with shelf-life of one year. These chapaties though provide longer stability, were not acceptable by the users due to bitter aftertaste of preservative and brittle/hard texture during storage. To overcome bitter aftertaste, chapaties were prepared by lowering the concentration of sorbic acid along with natural biopreservative nisin. Though the bitter aftertaste of chapaties was reduced but demand still persisted for the development of chapaties without any chemical additive.

As no such product without additives and a shelf-life of one year at ambient temperature was available in the commercial market, the work was started at DFRL to develop chapaties without chemical additivies. After extensive research, chapaties with natural sensory attributes and additives have been successfully developed using thermal processing.

The time-temperature history, during thermal processing, using an Elab Data cum Fo recorder, has been optimised. These chapaties were subjected to large scale users acceptance trials at different Army units like Eastern, Western, and South-Western Commands and have been found acceptable not only by the Indian Army but also by the Paramilitary Forces like ITBP, BSF, and CRPF. The chapaties have been included in the MRE ration for Army. The technology has already been transferred to private entrepreneur for commercialising the product and supply to the Services.

PrESErvatIoN oF Food GraINS aNd tHEIr mILLEd ProductS By mIcrowavE ProcESSING

The Indian Army procures large quantity of food grains to feed their jawans. However, inadequate storage facilities lead to losses, amounting to 10-15 per cent every year due to insects and pests alone. With progressive increase in the quantity of food grains and necessity for longer storage periods, these losses will increase unless measures for disinfestation are improved. Chemical methods for disinfestations, such as fumigation, require repeated applications as these do not eliminate insect eggs and may also leave harmful residues in the treated grains. Though irradiation

process kills or sterilises the common grain pests in the grains, users are reluctant to accept the process due to safety aspects associated with the irradiation.

To overcome these problems, a nontoxic, consumer-friendly process, based on microwave energy treatment, has been developed to kill/eliminate infestation (insects, larvae, eggs) and inactivate enzymes responsible for spoilage without affecting physico–chemical, nutritional, and sensory characteristics of food grains and their milled products

Resort-processed chapaties.

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like whole flour, semolina, and refined flour. In this process, the food grains/products are conditioned to 14-20 per cent moisture content depending on the type of grains/products, which is then packed in suitable plastic packaging material and subjected to microwave energy for 1-5 min and stored at ambient conditions. The process is helpful in extending the shelf-life of the products by three times (from 3-6 months to 9-18 months). The process helps in preserving food grains (wheat, rice, maize), pulses (red gram dhal, green gram dhal, whole pulses), and milled products (wheat flour, semolina and refined wheat flour) for longer periods.

The microwave heating of grains and their products is more efficient as the energy is generated inside the grains compared to conventional heating in which the energy is applied by convection or conduction from

heating medium (air) to the surface of the product and transferred to inner portion of the grains. Heat transfer rate in this process is multifold and effective in killing the infestation and inactivate the enzymes

like lipoxigenage and polyphenol oxidase. Since microwave energy is non-ionizing radiation, it is the most safe process of disinfestations than irradiation or chemical fumigation or use of pesticides.

DFRL has designed and developed a pilot scale continuous-type microwave dryer with 4 kW capacity to treat 50-60 kg/h of food

grain/products. Technical demonstration of the dryer to process wheat, rice, Bengal gram dhal, red gram dhal, green gram dhal, whole green gram, rajmah, chole, whole wheat flour, semolina, etc., has been successfully done.

ZEro-ENErGy cooLING cHamBErS

Zero-energy cooling is an ancient practice in which evaporation of water plays a role in chilling the solid or liquid commodities. Earthen pots were widely used to chill water even during pre-historic times. The mechanism of cooling involves heat transfer due to evaporation of water during which the latent heat of evaporation (540 kCals/g) leads to ultimate cooling of the storage atmosphere within the container. A number of zero-energy cooling systems have been reported earlier in India and several double-walled brick chambers of different dimensions with and without ventilation have been reported. However, the cross-ventilation in these containers needs further

improvements along with measures to minimise the use of water especially in arid and semi-arid zones. The design and the material used for the containers also need to be improved to make these more user-friendly, portable, and suitable for indoor applications without water seepage.

The technology of zero-energy cooling depends on evaporative cooling where cooling effects are maximised under high temperature and low humidity conditions. Zero-energy cooling can be used for the upkeep of perishables such as fruits, vegetables, mushrooms, milk, eggs, etc., by judicious designs in the form of double-walled brick chambers, household

Microwave dryer.

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refrigerator-like metallic containers, and reinforced plastic containers. Controlled dripping of water can minimise the use of water, thereby, facilitating minimal use of water and maximum temperature drop. The water-holding material shall be conducive for capillary action and with lower thermal conductivity. Coarse sand and pine grass, sandwiched between the two walls, are ideal for use as water-holding media inside the container.

DFRL has developed different types, namely, double-walled brick chambers, and metallic and plastic zero-energy cooling chambers wherin 50- 150 kg fresh produce can be stored at low temperature for extended period. These cooling containers can be used by farmers, Army units, households, and commercial centres. Under ideal temperature and humidity conditions, the temperature gradient inside the chambers can be maintained between 6- 9 ˚C , which will reduce the perishability of the items significantly. The containers can be placed under shady and well ventilated conditions. Double-wall brick

chambers are more useful to Army units and farmers. The smaller containers could be used in households. Use of non-conventional energy is the major merit of these devices and areas with energy crunch can make full use of zero-energy cooling to reduce perishability of valuable commodities such as fruits, vegetables, mushrooms, milk, etc.

Zero-cooling devices developed by DFRL have advanced features compared to similar devices available within the country. The variable-drip system and cross-ventilation provided in the double-walled brick chamber is a novelty. Similarly, the refrigerator- like container with metallic grills, and top-opening plastic container are user-friendly and specifically made for household applications and commercial kitchens. The features also include portability and minimium seepage of water. User trials of metallic and plastic transportable containers have been carried out at ASC depot Jodhpur. The trials were highly successful and recommended for induction into the Armed Forces deployed in forward/desert locations.

aNtIFrEEZE coNtaINErS

Freezing of fruits and vegetable is a major problem at high altitude due to extremely low temperature coupled with cold blizzards. Requirement of antifreeze containers has often been felt to prevent freezing of fresh commodities as thawing of such items in hot

water results in loss in flavour and texture. Since the respiratory heat by fresh commodities at low temperature is minimal, chemical heaters are required to compensate the restricted generation of respiratory heat to keep the fruits and vegetables warm within the

Portable zero-energy cooling chamber. Plastic mobile zero-energy cooler. Double-wall brick cooler.

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container. Freezing results in irreversible changes in texture and flavour of fresh produce. The insulated containers therefore should restrict freezing to maintain the quality of fresh produce supplied to the troops deployed in snowbound high altitude locations.

DFRL has designed and developed antifreeze containers with a rated capacity of 30 kg and 80 kg of fresh produce. The containers have high-density polyurethane (1½“) as the insulated material. A secondary insulation provided inside the container and a stainless steel (SS) casing within the container help in maintaining warm water and the temperature within the container. A metallic platform, placed inside the container, keeps the fruits and vegetables away from the chemical heater. Chemical reaction is carried out within a drawer and the heat generated thereby is dissipated inside the chamber in which the fresh commodities are placed.

The chemical heater used in the container has been developed by DFRL using the principle of multi-phase exothermic reaction of potassium permanganate (KMnO4). Each sachet of 25 g of KMnO4 is known to provide heat energy of 220 kCal/sachet.

Such self-heated containers are not available in the country and the technology is restricted to prevention or minimisation of thawing of frozen foods and dairy products using insulated boxes. Use of chemical heaters is practicable even in remote locations such as high altitudes without the use of conventional energy. The chemical heaters

are easy to operate and the periodicity of use can be maintained depending on the ambient temperature. The device can be used for a variety of products such as fruits, vegetables, meat, poultry products in fresh or processed forms to avoid freezing of products under sub-zero temperature.

The antifreeze container with different fruits, vegetables and packaged liquid foods, i.e., juices and milk has been subjected to field trials at 360 Coy ASC (Sup) Type C at Leh, and 5102 Coy ASC Depot at Khalsar, and at Karu, Loma, and Chushul.

The feedback has been encouraging. The container prevented the freezing of fresh fruits, vegetables, and packaged liquid foods without the periodic use of the chemical heater.

ENvIroNmENtaLLy dEGradaBLE Food PackaGING matErIaLS

Food packaging is mainly designed to protect food products from outside influences and damages, and also to provide consumers with ingredient and nutritional information. The goal of food packaging is to contain food in a cost-effective way that satisfies industry requirements, consumer desires, food safety,

and to minimise the environmental impacts. In spite of all advantages, biodegradability of these materials is limited and only minimal degradation has been observed even after a long time. Non-degradability of these materials is disturbing and damaging the ecosystem. The environmental impact of the plastic

Antifreeze container.

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waste is of increasing global concern. Incineration of these plastic wastes produces a large amount of CO2 that contributes to the global warming. In some cases toxic chemicals like HCl and HCN are also produced, which cause global pollution as well. On the other hand satisfactory landfilling sites are also limited and rapidly reaching their maximum capacity. Recycling is the next choice. In India, recycling of more than 50 per cent of plastics is being done from both industry as well as urban waste. However, recycling also has its own disadvantages like difficulty in sorting wide variety of plastics and the property changes occurring during recycling, limiting its applications range.

Armed Forces are facing a serious threat of non-degradable plastic waste accumulated in sensitive areas like Siachen glaciers. The present technical expertise available in plastic-waste disposal is inadequate in solving the problem at high altitude. Even though some technologies are available, these are not suitable for high altitude areas because of hilly terrains, low oxygen levels, sub-zero temperature, and limitation of energy. The conditions are so harsh that survival of personnel is the first priority leaving aside the collection of plastic waste for disposal. This has resulted in the accumulation of large quantity of plastic waste contributed mostly by the packaging materials.

The situation called for the development of a technology for making conventional plastics

degradable or for developing an alternate packaging material, which can readily degrade when exposed to such environmental conditions.

DFRL has developed various low-cost bio-degradable films for packaging applications by incorporating rice bran into low-density polyethylene (LDPE), where rice bran acts as a substitute for commonly used starchy materials. The rice bran acts as biodegradable fillers in LDPE. The oil present in rice bran acts as an internal plasticiser and helps in the incorporation of more bran in LDPE. At high altitude, where growth of microorganism is limited and exposure to ultraviolet (UV) radiation is more, certain photosensitising additives have been incorporated at various concentrations to promote photodegardation.

These films have been evaluated for their degradability under various environmental conditions. The aerobic biodegradation of these films was evaluated on exposure to activated municipal sewage sludge inoculum under laboratory conditions. Results indicated that 60 per cent of total rice bran present in these films (LDPE having 20 per cent rice bran) is degraded within 30 days of evaluation. The percentage weight loss in these films also confirmed the biodegradation. These films were also subjected to various environmental conditions like exposure to direct sunlight, UV radiation and also storage under room temperature. The samples were removed periodically and the change

Photodegradable LDPE films after 75 days of direct sunlight exposure.

Photodegradable LDPE films after 100 days of direct sulight exposure.

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was estimated in its physico-mechanical properties. The rate of photodegradation was found to be directly proportional to the amount of photosensitiser added to the film. LDPE films containing higher levels of photodegradable additives disintegrated completely within 100 days of direct sunlight exposure, whereas films with lower concentration of photodegradable additives disintegrated within 180 days. As the percentage of photosensitiser decreased, the time required for complete disintegration increased.

In the case of storage under room temperature,

the degradation was very slow and with a lower concentration of additives, a shelf-stability of more than one year could be achieved. The results showed that by varying the concentration of photosensitiser in the film, shelf-stability of these films can be altered. These films are particularly suitable for preparing environmentally degradable secondary packaging films for food packaging applications. Once the film is discarded after use, it degrades in almost all environmental conditions by a combination of biodegradation and photodegradation processes.

ENtEroBactErIacEaE IdENtIFIcatIoN kIt

The Enterobacteriaceae is a large family of bacteria, including many of the familiar pathogens like Salmonella, Shigella, Escherichia coli, and Proteus. These are highly adapted organisms with the capability to cause serious diseases. like salmonellosis, enteric fever (typhoid), infectious disease, diarrhea, urinary tract infections, etc.

The conventional methodology for identifying Enterobacteriaceae is based on isolation in pure cultures, and biochemical and serological tests. These tests are tedious and time-consuming, and need 3-5 days to get the results. Moreover, these procedures are not economical. Immunoassays such as ELISA use polyclonal or monoclonal antibodies or a combination of both. However, the use of polyclonal antibodies in these tests may produce a high number of false positive

results due to cross-reactions of shared epitopes present in other bacteria or even in food components. A few commercial systems, employing antibodies in simple agglutination tests, are expensive and at times may lead to erroneous results. Molecular methods like PCRs and other recently developed commercial cassette kit-based systems are reliable and rapid but are very expensive.

DFRL has developed a testing kit that detects Salmonella genus, Shigella genus, entire E. Coli group along with Proteus Vulgaris/Mirabilis at the same time, employing monoclonal antibody-based simple dot ELISA and a set of four biochemical tests, namely, indole production, KOH string test, urease production, and oxidase. Test system is reliable, inexpensive, simple to perform, and takes only 3 h to produce results. System

Enterobacteriaceae identification kit.

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has been tested at DFRL as well as by third parties, namely, JSS Medical College, Mysore; SDM Medical College, Dharwad; and Kasturaba Medical College, Mangalore, with highly satisfactory results with number of reference strains, isolates, and clinical samples. The

mEat tEStING kItS

Meat quality testing has become important due to public awareness of food safety and the demand for safe and wholesome foods. The conventional methods used to determine the quality of meat are mostly microbiological and chemical. These methods are laborious, time consuming and by the time the results are obtained, the meat becomes unfit for human

consumption. DFRL has designed and developed testing kits for meat as well as processed products. These tests are rapid, simple, and inexpensive and can be adopted under field conditions.

Armed Forces are currently using 30 test kits per month at different Army units.

SyStEm For mIcE SwImmING ENduraNcE tESt

Forced swimming test is a method used for evaluating the endurance capacity of mice treated with various nutraceuticals/functional foods/plant extracts/drugs. Several natural compounds present in various fruits, vegetables, medicinal plants, and herbs increase the physical work capacity/athletic performance of the humans. Supplementation of these compounds has also been shown to increase the endurance capacity during exhaustive exercise in experimental mouse models. Therefore, a most reliable method with high reproducibility is required to screen the myriad of

plants or drugs for its physical performance-enhancing properties in mice.

DFRL has designed and developed a unique system (Patent field) for mice swimming endurance test with online control and monitoring of adjustable features like water flow, temperature, swimming, tracking, and timing, and testing backwater area. In this system, mouse is allowed to swim against surface water current (adjustable) and its swimming capacity is measured until fatigue, defined as the failure to rise to the surface of water to breath, within a 7 s period.

Meat testing kits.

kit can be used in microbiology departments of all medical and veterinary colleges diagnostic laboratories, analytical and quality control food laboratories, CFLs of Armed Forces, Army hospitals, food export inspection agencies, and disease control agencies.

Technology Focus focuses on the technological developments in the Organisation, covering the products, processes and technologies.

Editorial CommitteeCoordinatorDr AL Moorthy, Director, DESIDOC, Metcalfe House, DelhiMembersShri R Shankar, Director of CV&E, DRDO Bhavan, New DelhiCmde PK Mishra, Director of Naval Research & DevelopmentDRDO Bhavan, New DelhiShri Sudhir K Mishra, Director of Missiles, DRDO Bhavan, New DelhiDr K Muraleedharan, Director of Materials, DRDO Bhavan, New DelhiDr Rajeev Varshney, SO to SA to RM, DRDO Bhavan, New Delhi

Editors acknowledge the help provided by Dr GK Sharma, Sc F, DFRL in preparing this issue of Technology Focus.

The swimming tank houses the temperature sensor and especially designed copper cooling coil to accurately condition and monitor the water in the tank. The system comprises especially designed mounting fixture for video camera interfaced with computer to monitor and track the movements of mice. The system is interconnected to the heating coil for regulating required temperature

in the test swimming tank. The water current is generated by circulating conditioned water with a pump connected to the test pool and regulated by a valve in closed loop. The floatation bubble, which functions as water wings and does not interfere with active behaviour in the swim test, enables all mice to swim or float without sinking when they cease active behaviour.Mice swimming endurance testing system.