The monitoring, via an in vitro digestion system, of the bioactive content of vegetable juice fermented with Saccharomyces cerevisiae and Saccharomyces boulardii

Abstract

In the present study, an in vitro model simulating gastro-intestinal (GI) digestion, was adapted to assess phenolic compounds from watermelon radish (R), red beet (RB) and black carrot (RC) juices fermented using Saccharomyces cerevisiae and Saccharomyces boulardii. The phenolic profiles were analyzed by high pressure liquid chromatography (HPLC) analyses. The total phenolic content, the antioxidant capacity and viability of microbiota was investigated in terms of bioaccessibility, and sensorial evaluation of products were performed. Results indicated that S. cerevisiae (78.10-83.87%) and S. boulardii (78.40-90.25%) showed higher viability compared with lactic acid bacteria, fermented by S. cerevisiae and S. boulardii, respectively. Cyanidin-3-O-glycoside chloride was only present at high concentration (1549.86-1774.86 mg/L) in black carrot juice, whereas vanillic acid was detected in all fermented vegetable juices. The high antioxidant activity of RC juices fermented by S. boulardii were associated with increased concentrations of total phenolic compounds, whereas higher the bioaccesibility of antioxidant activity was measured for fermented RB juices. Practical Applications: To improve the nutritional and functional properties of the products, the radish, red beet and black carrot juices enriched with Saccharomyces cerevisiae and Saccharomyces boulardii were subjected to lactic acid fermentation. Microbial viability and chemical quality were assessed in the fermented vegetable juices. The juices fermented by S. boulardii were rich in phenols and antioxidant capacities. The total phenol was more bioaccessible from black carrot juices fermented by S. boulardii. A higher bioaccessibility of antioxidant activity was measured in the red beet juices. Fermentation of vegetables by S. boulardii could combine the function of vegetables while developing a new product with more healthful benefits.