Functional Properties of Triticale Bran Bioactives Using In Vitro and In Vivo Model Systems

Part of the solution to reducing the prevalence of chronic diseases is the employment of food as medicine. Whole grain consumption has been associated with a variety of health benefits owing to their bioactive constituents, namely fibre and phytochemicals. The overall aim of this study was to discover the underlying mechanisms behind the positive physiological effects of whole grains and further elucidate their nutritional value. In particular, the bioactive properties of alkylresorcinols (ARs), phenolic lipids present almost exclusively in cereal grains, and soluble dietary fibre, potential prebiotics, were investigated using triticale bran (TB), an underestimated cereal crop. Specific objectives were met through the following projects. Conditions for large-scale extraction of ARs from cereal grains were optimized using response surface methodology (RSM). Isolation of ARs for 16-24 h at a solid-to-solvent ratio of 1:40 (weight per volume) and temperature of 24 °C produced the highest yield with the least amount of co-extractives/unknowns. The antioxidant and anti-inflammatory activities of ARs were evidenced by in vitro model systems, ORAC, DPPH, and COX assay whereby results were in agreement with ex vivo model systems, RAW 264.7 macrophage cell cultures induced by AAPH or LPS. Subsequently, the in vivo effects of ARs were evaluated and oxidative stress markers in liver and heart tissues of mice supplemented 0.5% ARs and mice fed 10% TB demonstrated antioxidant protection. Additionally, water extractable polysaccharides (WEP) from cereal samples were isolated by varying treatments; the highest yield with the least amount of impurities was achieved by boiling water extraction followed by successive enzyme treatments, dialysis and successive ethanol fractionations. Using yogurt as fermentation model, probiotic yogurt in the presence of TB produced significantly higher TTA values, lower pH levels, and improved microbial viability compared to controls. In addition to the prebiotic potential of TB, likely owing to its high fibre content, isolates of WEP also demonstrated antioxidant activity as measured by ORAC assay. Findings of this study will contribute to a better understanding of the underlying mechanisms behind the health benefitting properties of whole grains.