Chapter 17 - B-group vitamins production by probiotic lactic acid bacteria

Abstract

Lactic acid bacteria (LAB) are a heterogeneous group of microorganisms that have a long history of use as starter cultures for the elaboration of fermented foods because these industrially important bacteria can improve the safety, shelf-life, nutritional value, flavor, and overall quality of fermented products. In addition, LAB have been shown to exert a large range of beneficial properties, which is why they are frequently used as probiotic microorganisms in a variety of novel products. In 2002, the Food Agriculture Organization (FAO) defined probiotics as "live microorganisms which, when administered in adequate amounts, confer a beneficial health effect on the host" The probiotic and beneficial aspects of LAB have been intensely reviewed elsewhere and will not be the subject of this chapter. In addition to their intrinsic beneficial properties, certain strains of LAB have the capability of producing/releasing and/or increasing specific beneficial compounds in foods. These functional ingredients are sometimes referred to as nutraceuticals, a term that was first coined in 1989 to describe "a food (or part of a food) that provides medical or health benefits, including the prevention and/or treatment of a disease". These ingredients can be macronutrients (such as unsaturated fatty acids present in some oils), micronutrients (such as vitamins), or non-nutritive compounds (such as hydrolytic enzymes and flavonoids) and can be naturally present in foods (such as omega-3 fatty acids in fish or vitamin C in citrus fruits, etc.) or added (i.e., milks fortified with calcium and vitamin D, cereals fortified with folic acid, and others). Since LAB are involved in the preparation of a wide range of fermented foods and because of their GRAS (Generally Recognized as Safe) status, the selection of strains delivering nutraceuticals is now the main objective of several research groups. Among these studies, vitamin production by LAB has gained the attention of the scientific community. It has been shown that certain foods fermented with LAB contain high levels of B-group vitamins as a result of microbial biosynthesis. For this reason, LAB (considered food-grade microorganisms) are the ideal candidates to deliver specific compounds such as vitamins into foods.