Thursday, December 29, 2011: 08:20:10 PM

Food Processing Guest Column

Bio-process technologies: hope for the future - Dr VH Potty, Diversified Food Technologies

Bio-processing is gaining quick popularity in the food processing sector, thanks to development of science and technology

Two of the most prevalent technological options for the food industry to process raw food materials into preserved or consumable products are chemical conversion or physical methods. Food technologists adapt various chemical engineering unit operations to food processing where generally no deliberate chemical reactions are involved. In contrast, very few chemical reactions are in vogue in processing foods as the intention of processing is to preserve every nutrient, which are all chemicals with different molecular structure, as far as possible for delivery to the consumer. Of course there are unintentional consequences of processing, especially at temperatures above the ambient one and reactions involving amino acids, sugar, vitamins, minerals, fatty acids and the like are unavoidable. Some of these reactions are considered desirable while many others are unacceptable as far as the consumer is concerned. Maillard reaction that progressively yields brown chemical artefacts are liked in products like baked foods while undesirable colour tints imparted due to this reaction is sought to be stopped, especially in products with natural white colour. Use of chemicals like preservatives, emulsifiers, stabilisers, antioxidants and the like, some of which are natural and others synthetic, cannot make these foods chemically processed.

 
Physical processing
 
Physical processes like flour milling, grain polishing, flaking, puffing, popping, sugar recovery from cane, milk pasteurisation, oil seed crushing and many others invariably depend on mechanical operations and temperature rise is very minimal. Of course there are high temperature processes like baking, coffee roasting, coco bean processing, extrusion cooking, canning, frying, cooking, grilling and the like, but temperatures generally do not exceed 200 degree Celsius. One of the unavoidable consequences of food processing or cooking is that there is a loss of nutrients like vitamins and others, thermally unstable, which varies from process to process and product to product. The fortification and enrichment technologies help the industry to make up for the nutrient losses, albeit to a limited extent. Still the consumer is always sceptical about the healthiness of many products going through the industrial manufacturing hubs. Frozen foods are invariably preferred because of the perception that at sub-zero temperatures nutrients are stabilised, reducing the possibility of spoilage considerably. Besides, these foods have relatively long shelf life that enables consumers to store them at home.
 
Fermented foods which are derived by the action of beneficial micro-organisms belong to a group of products evolved historically over centuries of human civilisation. Wines with a history of thousands of years are made from grapes and other high sugar fruits using yeast as the "biological converter". Same is true with regard to beer made by fermentation from grains and hops. Products derived by fermentation of grains, fruits, molasses and the like and after subsequent physical processing yield many established lines of product such as Whiskey, Gin, Rum and Vodka. The simplicity of yeast fermentation lends itself to household preparation of wines, while the flourishing existence of illicit liquor making industry reflects the ease with which yeast fermented products can be made with minimum facilities. Another classic example is bread making, where again yeast is involved under aerobic conditions. Then there are many other products like yogurt, cheese, Indian idli and dosa and a hundred other products made and eaten in over 70 countries of the world. One thing in common with all these products is that all of them involve use of one or more micro-organisms with assured safety.
 
Bio-processing
 
There are many processes employed by the food industry using enzyme preparations derived from micro-organisms, plant and animal sources and by no stretch of imagination the end products can be called fermented foods. Conversion of starch into sugars catalysed by amylase and amylo glucosidase enzymes or manufacture of High Fructose Corn Syrup (HFCS) through Glucose Isomerase or making Pectinase clarified fruit juices or tenderising of meat using Papain and many such enzyme mediated processing cannot be classified as fermentation process. Similarly, there is an important emerging area that has great relevance to food preservation and that is Bacteriocin class of Bio-preservatives obtained from safe bacterial species. Foods which can be preserved by these natural antibiotic substances will have to be considered as partly "Bio-processed". Probably it would be more appropriate, when natural micro-organisms and the derived enzymes from them or plant and animal based enzymes are used in preservation or conversion, if they are called Bio-processed foods. Bio-processing is relevant even to many non-food products also and one of the most promising areas for using this process is in the energy sector where non-food biomass is sought to be converted into readily usable energy forms like alcohol.
 
Dr VH Potty is a renowned food technologist and the chairman of Diversified Food Technologies (Mysore)

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