Aflatoxin is a potent mycotoxin and a common source of grain contamination that leads to great economic losses and health problems. Although distilled baijiu cannot be contaminated by aflatoxin, its presence in the brewing process affects the physiological activities of micro-organisms and reduces product quality. Bacillus cereus XSWW9 capable of degrading aflatoxin B1 (AFB1) was isolated from daqu using coumarin as the sole carbon source. XSWW9 degraded 86.7% of 1 mg/L AFB1 after incubation at 37 °C for 72 h and tolerated up to 1 mg/L AFB1 with no inhibitory effects. Enzymes in the cell-free supernatant of XSSW9 played a significant role in AFB1 degradation. The AFB1-degradation activity was sensitive to protease K and SDS treatment, which indicated that extracellular proteins were responsible for the degradation of AFB1. In order to investigate the AFB1-degradation ability of XSSW9 during the baijiu brewing process, AFB1 and XSWW9 were added to grain fermentation (FG-T) and normal grain fermentation without AFB1, while normal grain fermentation without AFB1 and XSWW9 was used as a control (FG-C). At the end of the fermentation, 99% AFB1 was degraded in the residue of fermented grains. The differences of microbial communities in the fermented grains showed that there were no significant differences between FG-T and FG-C in the relative abundance of dominant genera. The analysis of volatile compounds of their distillation showed that the contents of skeleton flavor components was similar between FG-T and FG-C. These results offer a basis for the development of effective strategies to reduce the effect of AFB1 on the brewing process and ensure that the production of baijiu is stable.
In this study, two fruit processing coproducts, pomegranate peel and dragon fruit peel, were mixed to fabricate a composite film that can be used in food packaging. Therefore, the purpose of this study was to prepare and evaluate a dragon fruit peel polysaccharide film incorporating pomegranate peel polyphenols. The films were evaluated for their morphology, mechanical properties, crystallinity, solubility, UV resistance, oxidation resistance, and bacteriostatic properties. Different concentrations (0, 0.3, 0.5, 0.7%, w/w) of pomegranate peel polyphenols were added to the dragon fruit peel polysaccharide film by casting technology. The results showed that the addition of pomegranate peel polyphenols made the film hydrophobic, decreased the water vapor transmission rate of the film, and reduced the solubility of the film (p<0.05). Furthermore, the UV transmittance decreased with increasing concentration of pomegranate peel polyphenols (p < 0.05). By contrast, the thermal properties were not significantly affected by the concentration of pomegranate peel polyphenols. After the addition of pomegranate peel polyphenols, the surface of the film became rougher while the cross-section became smoother. X-ray diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy showed that the crystalline nature and functional groups of the film did not change significantly. The compatibility of the film-forming substances was good, and the obtained films also exhibited good mechanical properties. Importantly, the addition of pomegranate peel polyphenols endowed the dragon fruit peel polysaccharide film with excellent antibacterial properties, while also significantly improves the antioxidant activity and UV-resistance of the film. The dragon fruit peel polysaccharide film with 0.7% (w/w) pomegranate peel polyphenols showed the best overall performance. This alternative material is a potential substitute for petrochemical packaging, alleviating serious environmental pollution problems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.