Lactic acid bacteria in food industry

Abstract

Lactic acid bacteria (LAB) are known through ages for their wide -applications in food, pharmaceutical and chemical industries. But recently LAB have aroused interest for their ability to secrete extracellular polysaccharides or glucans. These glucans have immense commercial value because of their industrially useful physico-chemical properties. The glucans derived from LAB play crucial role in improving rheology, texture, mouth feel of fermented food formulations and conferring beneficial physiological effects on human health, such as antitumour activity, immunomodulating bioactivity and anticarcinogenicity. The modulation of biochemical properties of glucans require a thorough understanding of its biosynthetic pathway and the relation between the structure of glucans and the functional effect provided by them after incorporation into the food matrix. LAB are employed in food industry for making yoghurt, cheese, sourdough bread, sauerkraut, pickles, beer, wine and other fermented foods and animal feeds like silage. LAB can also produce a variety of functional oligosaccharides that have applications as prebiotics, neutraceuticals, sweetners, humectants, drug against colon cancer and as immune stimulator. LAB are gram positive rods or cocci, non spore forming, acid tolerant, low GC containing, anaerobic or micro-aerophilic bacteria characterized by their ability to ferment sugar to lactic acid. The commonly known LAB genera are Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus. Besides prolonging the shelf life, lactic acid enhances the gustatory and nutritional value, imparts appetizing flavour and texture to the food. Some LAB produce proteinaceous antimicrobial compounds called bacteriocins which inhibit the growth of Gram-positive pathogenic and spoilage bacteria and used as food additives. Lactic acid bacteria as probiotics have been proven effective against diarrhoea, irritable bowel disorder, allergies, stimulation of immunity, lactose intolerance.