Investigação das propriedades prebióticas do subproduto do processamento da jabuticaba (Myrciaria jaboticaba (Vell) Berg)

Abstract

Industrial fruit processing generates high amounts of by-products, consisting mainly of husks and seeds. The by-product of the processing of jabuticaba (Myrciaria jaboticaba (Vell) Berg) has a remarkable nutritional value and a high concentration of dietary fibers and phenolic compounds, which can act modulating the intestinal microbiota, stimulating an increase in the population of beneficial bacteria and production of different metabolites. In this context, this study aimed to evaluate the prebiotic potential of the jabuticaba by-product (JB) using in vitro fermentation systems. Initially, the lyophilization of JB and characterization of its nutritional composition and physicochemical parameters was performed. Then, the lyophilized JB was subjected to in vitro gastrointestinal digestion, which was used as the only source of carbon in the culture medium to evaluate the ability to stimulate the growth and metabolic activity of probiotic strains (Lactobacillus acidophilus LA-05, Lacticaseibacillus casei L-26 and Bifidobacterium animalis subsp. lactis BB-12). The effect of SJ on the relative abundance of selected intestinal bacterial groups was also evaluated using the fluorescence in situ hybridization technique coupled with multiparametric flow cytometry during 48 hours of in vitro of colonic fermentation, with the determination of prebiotic indices. The metabolic activity of the colonic microbiota was also monitored for 48 hours by determining pH values, sugar consumption, production of organic acids and profile of phenolic compounds during colonic fermentation. The lyophilized JB showed a high concentration of dietary fiber, mainly soluble fiber, presence of sugars and a variety of phenolic compounds. After 48 hours of cultivation in medium with digested JB (20 g/L), the probiotic strains had counts >8 log CFU/mL, which were similar to those found in the culture medium with fructooligosaccharides. Cultivation of probiotics in the medium with JB resulted in a decrease in pH, increased production of lactic acid and short-chain fatty acids, and consumption of glucose and fructose over time, indicating intense metabolic activity. JB increased the relative abundance of Bifdobacterium spp. and Lactobacillus spp./Enterococcus spp. during the 48 hours of colonic fermentation, in addition to decreasing the relative abundance of Bacteroides spp./Prevotella spp., Eubacterium rectale/Clostridium coccoides and C. histolyticum, resulting in positive prebiotic indexes. The increased metabolic activity of the microbiota was evidenced by a reduction in pH and succinic acid production, an increase in the production of short-chain fatty acids and consumption of medium sugars during colonic fermentation with JB. The phenolic compounds available in JB were extensively metabolized differently during the colonic fermentation period, even with a possible synergistic effect with the SJ fibers in the modulation of the intestinal microbiota. The results showed that JB can contribute to the positive modulation of bacterial groups that form the human intestinal microbiota, with the production of metabolites related to the improvement of intestinal health, which can be explored as an ingredient with prebiotic properties in functional food product formulations.