Resistant starch (RS) is widely used in the food industry because of its ability to regulate and protect the small intestine, but their distinct effects on the structural and functional properties of waxy and non-waxy proso millet starches are not completely understood. The crystalline structure and physicochemical properties of waxy and non-waxy proso millets’ starch samples were analyzed after heat-moisture treatment (HMT). The analysis revealed significant differences between the RS of waxy and non-waxy proso millets. The crystal type of proso millets’ starch changed from type A to type B + V. The relative crystallinity of the RS of waxy proso millet was better than that of non-waxy proso millet. The gelatinization temperature and thermal stability of RS significantly increased, and the pasting temperature (PTM) of the RS of waxy proso millet was the highest. The water solubility and swelling power of the RS in proso millet decreased, and the viscoelasticity improved. The correlation between the short-range ordered structure of RS and ΔH, and gelatinization properties has a stronger correlation. This study provides practical information for improving the nutritional benefits of waxy and non-waxy proso millet in food applications.

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Selenium is an important element that affects human growth and development, and also affects the yield and quality of common buckwheat. In our study, two common buckwheat varieties were sprayed with different concentrations (0 g/hm2, 5 g/hm2, 20 g/hm2) of sodium selenite solution at the initial flowering period and the full flowering period, respectively, to determine the effects of selenium solution on the physicochemical properties of common buckwheat starch. With increasing selenium levels, the amylose content, peak viscosity, breakdown, relative crystallinity, pasting temperature and gelatinization enthalpy first decreased and then increased, while the transparency showed a trend of increasing and then decreasing. All samples exhibited a typical A-type pattern, while at high selenium level, the degree of short-range order of common buckwheat starches changed. From the rheological properties, it can be seen that the starch paste is dominated by elastic properties, while the low selenium treatment decreases the viscosity of the starch paste. These results showed that spraying different concentrations of selenium solutions at different periods significantly affected the physicochemical properties of common buckwheat starch.

BACKGROUND: Starch is a major nutrient in the human diet and has been widely used as an ingredient in many food and nonfood applications. However, the research on the quality characteristics of Tartary buckwheat is lagging behind, and there is a lack of high-quality special varieties, which makes it difficult to become a popular food. The physicochemical properties of Tartary buckwheat starch may be affected by different environments and varieties, and the stability of planted varieties in different regions is also an important issue in current research. RESULTS:The average amylose content and pasting properties of Dingxi Tartary buckwheat were lower, while the solubility, transparency, relative crystallinity and gelatinization enthalpy were higher compared with the other two regions, and there were significant differences between different varieties. All samples showed typical A-type structure, and the starch shortrange order structure changed slightly. Amylose content, solubility, transparency, granule size distribution, pasting properties and thermal properties were significantly affected by environment and variety.CONCLUSION: When choosing high-quality special varieties and products for processing, it contributes to select different buckwheat varieties and planting areas based on various objectives by understanding the effects of environment and varieties on the physicochemical properties of Tartary buckwheat starch. In this study, the four varieties planted in Dingxi and the two varieties in Zhaojue were easy to digest, and the differences of pasting properties and thermal properties are helpful to improve the application of Tartary buckwheat starch in the food industry.