The metabolic profiling of Chinese yam fermented by Saccharomyces boulardii and the biological activities of its ethanol extract in vitro

Chinese yam(Dioscorea opposita Thunb.),as one of the medicinal and edible homologous plants,is rich in various nutrients and functional factors.In this study,Chinese yam fermented by Saccharomyces boulardii was performed to investigate its bioactive components and metabolic profile.And then,the main bioactive components and biological activities of fermented Chinese yam ethanol extract(FCYE)were evaluated.Results showed that there were 49 up-regulated metabolites and 52 down-regulated metabolites in fermented Chinese yam compared to unfermented Chinese yam.Besides,corresponding metabolic pathways analysis initially revealed that the distribution of bioactive substances was concentrated on alcoholsoluble small molecular substances.Ulteriorly,the total polyphenol content and the total flavonoid content in FCYE were significantly increased,and the corresponding antioxidant and immunomodulatory activities in vitro were also significantly enhanced.Our study provided a new reference for the comprehensive utilization of Chinese yam and laid a theoretical foundation for the development and application of natural probiotic-fermented products.

Effects of shading after pollination on kernel filling and physicochemical quality traits of waxy maize

Understanding the effects of shading after pollination on kernel filling and physicochemical properties of waxy maize could improve kernel quality.Experiments were conducted to investigate the effects of shading(30% and 50% light deprivation,taken plants without shading as control) on kernel weight,size,and physicochemical properties during kernel development in 2013 and 2014 using two waxy maize varieties(Suyunuo 5 and Yunuo 7).Results indicated that shading reduced kernel filling rate and decreased kernel size and weight,and the influence was large under severe light deprivation conditions.The large reduction in kernel weight and volume of Suyunuo 5 in response to shading indicated that it was more sensitive to shading than Yunuo 7.Starch content was reduced and protein content was increased by shading,especially under severe shading after 22 days after pollination(DAP).The iodine binding capacity of Yunuo 7 was not affected by shading at fresh and maturity stages but was gradually decreased by shading at the newly formed stage,while the values for Suyunuo 5were decreased at 7 and 40 DAP only by moderate shading and were similar among three treatments at 22 DAP.Severe shading decreased crystallinity at all kernel development stages,whereas moderate shading decreased crystallinity at fresh stage and increased it at mature stage for Suyunuo 5.Crystallinity in Yunuo 7 was increased by shading at 7 DAP and decreased by shading at 40 DAP,whereas the value at 22 DAP was increased by moderate shading and reduced by severe shading,respectively.The average gelatinization temperatures at different stages were decreased by shading and showed no difference between two shading levels.The retrogradation percentage at 7 DAP for both varieties was increased by shading.The value at 22 DAP was increased by moderate shading for Suyunuo 5 and decreased by severe shading for Yunuo 7,respectively.The retrogradation percentage at 40 DAP was decreased by shading treatments for Suyunuo 5 and reduced only by moderate shading for Yunuo 7.Peak viscosity was decreased by shading at fresh stage for Yunuo 7 and at maturity for Suyunuo 5.In conclusion,shading after pollination inhibited kernel filling of waxy maize and reduced paste viscosity quality,but kernel retrograde quality,crystallinity and starch iodine binding capacity in response to shading were dependent on stage and variety.