Abstract
The composition of the intestinal microbiota (IM) is directly related to the development of several inflammatory and autoimmune diseases. Probiotic microorganisms are able to colonize the gastrointestinal tract (GIT) and, among other health beneficial effects, help in the reduction of inflammatory conditions and promote the normalization of the IM. Fibers are not digested in the small intestine and reach the colon intact, serving as substrate for the local microbiota. In the beer manufacturing, the by-product brewer's spent grain (BSG) is generated, which has around 70% of fibers. It is a low cost ingredient with interesting nutritional properties that is still little explored. Vitamin D has several biological functions through the mediation of the vitamin D receptor (VDR), acting on the antibacterial mechanism of the innate immune system. Furthermore, studies have shown that vitamin D and VDR expression are directly linked to the composition of the IM, as well as the susceptibility to the development of autoimmune diseases and inflammatory bowel diseases. Thus, the present research project aims to: I) Evaluate the fermentability of BSG's flour by starter and probiotic cultures and to select a suitable combination for the application in probiotic fermented milk (FM); II) Incorporate BSG's flour in probiotic FM and evaluate the viability of microorganisms in the FM throughout the storage period and their resistance to the passage of the food product through in vitro simulated conditions of the GIT; III) Study the in vivo effect of the consumption of probiotic FM supplemented with BSG's flour on the VDR expression. A total of 10 probiotic strains (Bifidobacterium animalis, B. longum, Lactobacillus acidophilus, L. fermentum, L. reuteri, L. paracasei and L. rhamnosus) and 2 starter strains (Streptococcus thermophilus) will be evaluated for subsequent selection of 1 probiotic and 1 starter strains for the production of probiotic FM, based on their ability to ferment the BSG's flour. In addition, four FM formulations will be evaluated, in triplicates: FM1 (control; without the addition of probiotic culture or BSG); FM2 (only with BSG); FM3 (with probiotic culture and without BSG); FM4 (with probiotic culture and BSG). The FMs will be stored at 4 ° C for 28 days, during which the viability and resistance of the probiotic bacteria to in vitro simulated passage through the GIT and the characterization of the product in terms of its composition, fiber content, phenolic compounds content, and antioxidant capacity will be evaluated. In addition, in vivo assays with mice will be performed. The animals will be divided into five groups (1 control + 4 treatments) and will receive the FMs or PBS daily during 21 days. The expression of VDR in the epithelial cells of the ileum, short chain fatty acids profile and IM composition in the feces, as well as the recovery of the probiotic strains employed in the FMs after passage through the GIT will be evaluated. This last stage will be conducted at the University of Illinois, Chicago, USA, under the supervision of Prof. Dr. Jun Sun. (AU)
Scientific publications(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)