Contribution of lactic acid fermentation to improved nutritive quality vegetable juices enriched with brewer’s yeast autolysate

Vegetables are rich sources of the biologically active compounds which have beneficial effects in prevention of some diseases and certain types of cancer. From the point of view of protection and health, the objective of this paper was to optimize food content in order to obtain a functional food. In order to improve the nutritive and protective properties of the product, the beetroot and carrot juices enriched with brewer’s yeast autolysate were subjected to lactic-acid fermentation with Lactobacillus acidophilus NCDO1748.Chemical compositions of produced fermented bioproducts showed that fermented carrot juice with brewer’s yeast autolysate had higher contents of some minerals (Ca, P, Fe) and β-carotene than had beetroot juice with brewer’s yeast autolysate. Higher mineral content in the carrot juice better affected production of lactic acid in that sample. Fermented beetroot juice with brewer’s yeast autolysate had higher contents of betanin and vitamin C, which were in accordance with the contents of these components in raw beetroot that did not significantly vary during the processing of the material (pasteurization, fermentation). Thus the fermented bioproduct 3, which is a mixture of beetroot and carrot juices with brewer’s yeast autolysate, represents the product with optimum proportions of pigments, vitamins and minerals.