A Panorama of lactic acid bacterial fermentation of vegetables
Vegetables occupy a prominent position in our diet and form the most nourishing diet.Preservation of vegetables is carried out to prevent their postharvest losses of functional quality whilst providing safe and stable products. In general, preservation process consists of a combination of mild heat stress and low concentration of chemical preservatives to control the food spoilage and the growth of pathogenic spore- forming bacteria. But, consumer demand today is for natural and minimally processed foods, with a fresh like appearance and taste, easy-to-eat and with high level of safety.It is also dependent on a wide range of technologies to ensure that food is maintained at an acceptable level of quality from the time of manufacture till the time of consumption. As a result, research and development of new products is leading to the reduction or even replacement of heat treatments and encouraging the use of traditional preservatives as these are capable of assuring the sensory and nutritional properties of the product without reducing food safety. Non-thermal preservation methods are thus gaining interest as alternative treatments in the food industry due to their capability of assuring the quality and safety of foods. Among them, use of natural antimicrobials from plants (essential oil) and microorganisms (LAB and Bacteriocins) have gained wide range of popularity as bio-preservatives. Traditionally, microorganisms have been used in fermentation from ages but now modern large scale production of foods exploits use of defined strains to ensure consistency and quality in the final product. The biopreservation offer potential application in food preservation and helps in reducing the addition of chemical preservatives as well as the intensity of heat treatment, resulting in foods which are more naturally preserved and richer in sensory and nutritional qualities. Beside this, biopreservation also provides health benefits such as reduction in cardiovascular diseases, improving gastro intestinal microorganisms and immune system, helps in curing diarrhea and lowering cholesterol in the consumers of lactic acid fermented foods. The preservation is accomplished through the production of antimicrobial substances such as lactic acid, diacetyl, hydrogen peroxide, ethanol reutrin and bacteriocin. The bacteria from the genera Lactobacillus, Leuconostoc, Pediococcus and Streptococcus are the main species involved in the lactic acid fermentation. Thus, the lactic acid fermentation of vegetables is an important method of bio-preservation and providing healthful foods to the consumers.
Vegetables, Lactic acid bacteria, LAB fermentation, Biopreservation, Bacteriocin.