Prebiotic potential of gos synthesized from lactose and lactulose by the β-galactosidase of L. bulgaricus CRL 450

CUÑO, GUADALUPE ; FARA AGUSTINA ; ZÁRATE, GABRIELA ; SAÉZ, GABRIEL

Campinhas

Congreso; 12 SLACA Simposio Latinoamenricano de Ciencia de los Alimentos; 2017

Universidad de Campinhas

Recently, an increasing attention has been paid to the development of functional foods by researchers and food industry. Prebiotics are non-digestible carbohydrates that stimulate the specific growth/activity of a restricted number of colonic bacteria resulting in benefits upon host health. Different oligosaccharides (FOS, GOS, lactulose, among others) have been used as prebiotics. GOS are obtained by transgalactosyation activity of microbial β-galactosidases. It has been proposed that GOS synthesized by LAB and Bifidobacteria are more selectively fermented in the gut than the produced by other microbial genera. The aim of the present study was to assess the effect of oligosaccharides synthesized from lactose and lactulose by the β-galactosidase of Lactobacillus bulgaricus CRL 450 on growth of lactobacilli and bifidobacteria and the metabolic fermentation profile of mice colon used as host model. Large bowel contents of Balb/c mice were suspended at 10% (w/v) in PBS, pH 7 and supplemented with lactose, Vivinal® (GOS synthesized B. circulans), Lb450-GOS (GOS synthesized L. bulgaricus CRL 450); lactulose, OSLU (oligosaccharides from lactulose) and Lb450-OSLU. Suspensions were incubated at 37ºC for 15h under anaerobic atmosphere. LAB and bifidobacteria were determined by plate count in Rogosa and HHD agars, respectively, and the main fermentation products (ethanol, lactate and SCFA) were determined by HPLC. As expected, addition of disaccharides increased growth of both microbial groups compared with control homogenate without carbon source. Further increase of LAB was obtained by supplementation with Vivinal®-GOS and OSLU whereas the highest stimulation was obtained by oligosaccharides obtained from lactose and lactulose with L. bulgaricus CRL450 β-galactosidase. Regarding bifidobacteria, disaccharides and GOS-Lb450 showed the best effects. In agreement, lactate production was increased in homogenates supplemented with these carbohydrates whereas SCFA were increased in homogenate supplemented with OSLU+Lb450 β-gal. Further in vivo studies to confirm the prebiotic potential of L. bulgaricus β-galactosidase are ongoing.