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In this study, coix seed starch nanoparticles were prepared by nano-precipitation method using three different systems (alkali solution, water-ethanol system and dimethyl sulfoxide (DMSO)-ethanol system). The structures and physicochemical properties of the three nanoparticles were investigated by analysis of their particle characteristics, molecular characteristics, crystallization characteristics and thermal characteristics. The results showed that the nanoparticles prepared using alkaline solution had the highest proportion of nanoparticles (85.65%). Both the nanoparticles prepared using alkaline solution and water-ethanol system had an A-type crystalline structure, while the crystalline structure of the nanoparticles prepared using DMSO-ethanol system changed from A-type to amorphous. The nanoparticles prepared using alkali solution at 45 ℃ had the smallest particle size (348 nm), the highest polydispersity, higher degree of order, relative crystallinity and thermal stability, indicating that alkali solution was the most suitable to prepare coix seed starch nanoparticles. This study may provide a theoretical basis for the preparation of starch nanoparticles and the study of their structural properties as well as the expansion of the application of coix seed starch.

This paper investigated the effects of steam explosion (SE) pretreatment on the structural characteristics and antioxidant activity of Hypsizygus marmoreus polysaccharides (HPS). Hypsizygus marmoreus samples were pretreated at different SE temperatures (120–200 °C) and polysaccharides were extracted using the water extraction and alcohol precipitation method. The results showed that SE pretreatment improved the extraction rate of HPS. Under the conditions of SE treatment time of 60 s and temperature of 160 °C, the extraction rate of HPS was the highest (8.78 ± 0.24%). After SE pretreatment, the structural changes of HPS tended to enhance the antioxidant activity, which showed that the content of Gal and Man in the monosaccharide composition increased and the molecular weight decreased. When testing antioxidant activity in vitro, the ability of SE-pretreated HPS to scavenge DPPH radicals, hydroxyl radicals, and superoxide anion radicals was better than that of HPS without SE pretreatment. Our findings shed light on SE pretreatment as an efficient method for extracting active polysaccharides, providing a new way to improve their extraction rate and biological activity. [ABSTRACT FROM AUTHOR]

In Asia, Monascus has been used in food fermentation for nearly a thousand years. It has attracted increasing attention in recent years due to its ability to produce a variety of important active substances such as monacolin K (MK) and pigments. MK is an effective drug widely used for lowering human blood cholesterol that functions by inhibiting the rate-limiting enzyme in cholesterol biosynthesis. Monascus strains, fermentation methods and fermentation conditions have significant effects on MK yield, and much research has been undertaken to obtain higher MK yields. In this paper, the research progress of Monascus strain breeding for high MK yield, medium optimization for MK production during Monascus fermentation, and optimization of fermentation process conditions are fully reviewed. This provides reference for future research on Monascus fermentation and industrial production for high-yield MK production.