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Promising methods in food technology
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Saturday, 18 November, 2006, 08 : 00 AM [IST]
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Premavalli KS & Bawa AS
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assing the traditional technologies like dehydration, salting, sugaring, baking, frying etc. Over the decades, the technological advancements have resulted in several innovative technologies for various applications. Among the dehydration techniques freeze-drying maintains the quality of products which is quite close to that of fresh product. During freeze-drying the thermal / evaporation of moisture is through nonlimation at low temperatures under vacuum. Hurdle technology helps preserve the foods for a period of 2-4 months and is applicable to fruits, vegetables and their products, meat and fish products and sparingly used for cereal products preservation. Hurdle technology is an intelligent combination of hurdles such as pH, temperature, water activity, redox potential, preservative etc., to ensure the microbial safety as well as sensory and nutritional acceptance. Membrane technology is used in the manufacture of clarified juices, for initial concentration through ultra filtration, nano-filtration and reverse osmosis processes. These processes save a lot of energy as well as gives better quality product.
Thermal treatment is the most widely used technology for preservation of foods. Thus retort processing of foods is the most promising technology for both vegetarian and non-vegetarian foods in the ready-to-eat form. Sterilisation temperatures in the range of 110-125oC are used for low acid foods with the main objective of inactivating the undesirable micro-organisms. Commercial sterility refers to the Fo value i.e., the duration of processing at a constant temperature indicating the extent of reduction in population of micro-organisms. The Defence Food Research Laboratory has made a breakthrough in this field, which paved the way for supplying rations to Defence Forces. High pressure technology is a novel non-thermal processing method of food preservation where the food is subjected to high hydrostatic pressure in the range of 100-600 Mpa at room temperature. Though high pressure processing equipment is very costly, it is a promising technology for stabilisation of food against spoilage and helps to improve rheological and functional properties of foods (1). The retention of natural colour and flavour as well as nutrients is better, thus enabling the food industry to manufacture high quality product. Japan is the first country to manufacture high pressure processed fruit juices, jams, fish, meat, yoghurt etc. Asceptic processing is the method of choice for getting sterile quality product where the multilayer laminate packs are used and the sterile product is filled under sterile conditions. Presently, this method is used under the name tetrapak for fruit juices, nectars and milk while its extension to the particulate products is still open for research.
At the advent of consumers demand for nutritious foods, health consciousness, the recent strategy in the field is the development of functional foods with specific health benefits, to counter/replace the medicines or modulate some of the physiological actions. The functional foods is a three-way concept wherein the agricultural or animal origin serves as raw material, specific ingredient components exert functionality and functional component imparts physiological action. The scientific basis of claims for functional foods is a part of the research (2) and the functionalities cover the aspects of reduction in cholesterol and hypertension as well as being anticorcinogenic, antidiabetic, tumor suppressors, from the diseases prevention angle, while, from nutritional supply or value addition angle they covers the supply of dietary fibre, vitamins, minerals, functional fibre, essential fatty acids etc., and in turn good health to the consumers (3). In this direction, the functional properties of raw materials as well as their fat during various processing methods need to be understood well. The Biotechnology is a new born baby, which operates on prebiotics and probiotics for management of gastro-intestinal acting as appetising agents while the enzymes act as anti-stress agents. The probiotics involving Lactobacillus, Leuconstoc, Saccharomyces species can impart several physiological functions for the good health in humans (4).
In the application of functional foods, Nanotechnology is the emerging technique with a great potential for delivering bioactive compounds. Nanotechnology deals with the capability to image, measure, control and manipulate matter at dimensions of 1-100 nanometres through which novel interfacial phenomena introduce new functionalities. In the functional food formulation nanoscale phenomena can be utilised to improve the product functionality and delivery efficiency. Especially in the areas of emulsion, dispersion, biostructured fluids nanoscale operations will emanate better visualisation, resolution and understanding of their functionality (5, 6). The application of nanotechnology in the polymeric field can help to incorporate the nanoparticles for the manufacture of biodegradable packaging materials. Besides the functional foods, nanotechnology can be applied for flavour encapsulation, biosensors, filters, electronic noses etc. (7).
Food design through innovative ingredient technology is the present trend which encompasses the use of statistical software for development of processed products. Multidimensional comparison of ingredients as well as responses for optimisation of ingredients composition can be achieved.
To-day consumer awareness raised the demand of the nutritious, healthy foods for which product developers are looking to add health and wellness value to their products. This strategy has led to the development of health foods. Labelling technology has shifted to a broader sphere including informative labelling and nutritional labelling. Today, the food package should have the information on ingredients, manufacturing and shelf-life details as well as the strength or merit of the product in terms of calories, dietary components such as fibre, PUFA, cholesterol, protein, calcium, iron etc., along with the health claims, if any. The regulations on this aspect help for proper health claims with specific nutrition status (8).
The advancement in food science, requirement of processed convenience foods, improved buying status of consumers, have led to the development of technologies in the field and strategic applications of these will provide the consumer a better quality food in his bowl.
References
1. Makhal et al, Indian Food Industry, 2003, 22(1), 38
2. Ovesen, 1999, British Food Journal, 101, 809
3. Premavalli et al, Beverage & Food World, 2004, 30, 37
4. Premavalli et al, Processed Food Industry, 2002, Nov, 26p
5. Tolles W.M & Rath BB, Current science, 2003, 85, 1746
6. Chem et al, Food Technology, 2006, 60(3), 30
7. Mallika Chowdhary et al, Indian Food Industry, 2005, 24(4), 19
8. Aiyar AS, Indian Food Industry, 2002, 21(1), 7
A S Bava is the director and Premavalli KS is head - Technical Information Centre, Defence Food Research Laboratory
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