RESUMO
Literature reports that ingestion of phytosterols and γ-oryzanol contributes to cholesterol lowering. Despite in vivo observations, thermodynamic phase equilibria could explain phenomena occurring during digestion leading to such effects. To advance the observations made by previous literature, this study was aimed at describing the complete solid-liquid phase equilibrium diagrams of cholesterol + phytosterol and γ-oryzanol systems by DSC, evaluating them by powder X-ray, microscopy, and thermodynamic modeling. Additionally, this study evaluated the phenomena observed by an in vitro digestibility method. Results confirmed the formation of solid solution in the cholesterol + phytosterols system at any concentration and that cholesterol + γ-oryzanol mixtures formed stable liquid crystalline phases with a significant melting temperature depression. The in vitro protocol supported the idea that the same phenomena can occur during digestion in which mechanochemical forces were probably the mechanisms promoting cholesterol solid phase changes in the presence of such phytocompounds. In this case, these changes could alter cholesterol solubility and possibly its absorption in the gastrointestinal lumen.
RESUMO
This study evaluated the resistance of Bacillus coagulans GBI-30, 6086 (BC) spores through the processing and storage of white and whole wheat bread. The physicochemical parameters of the probiotic bread formulations were also characterized. Loaves of bread containing or not BC were prepared. Throughout the processing, samples were collected (after mixture, after fermentation, and after baking) for enumeration of BC. In addition, BC was enumerated in different parts of loaves of bread (crust, crumb, and whole slice) collected after baking (day zero) and at different storage times (3, 7, and 10 days). The incorporation of BC did not affect the moisture, specific volume, texture and color parameters, water activity, and pH of loaves of bread. Mixing and fermentation steps did not reduce the BC survival in white or whole wheat bread. The highest (p < 0.05) number of decimal reductions (γ) was caused by baking in the crust for both loaves of bread. Baking caused around two γ of BC in the crust and 1.5 γ of BC in crumb and a whole slice of white and whole bread. Generally, storage did not increase the γ caused by baking, regardless of the evaluated part or type of bread. Results show the impacts of baking on BC and highlight the formulated white and whole wheat loaves of bread as suitable carriers for delivering the probiotic BC.