Abstract:The different black beans from Chaoyang, Liaoning Province (HD1), Linyi, Shandong Province (HD2), Harbin, Heilongjiang Province (HD3), and Yanchuan, Shaanxi Province (HD4) were used as raw materials. Various nutritional components were determined by the direct drying method, ignition method, and Kjeldahl method. The moisture, ash, total protein, crude fat, reducing sugar, crude fiber, amino acid composition, fatty acid composition, and anthocyanin content of the different samples were analyzed by combining the amino acid and chemical scores. The results showed that the nutritional composition of the four types of black soybean was similar; total protein was proportionally the greatest component and reducing sugar the lowest. However, there were clear differences between the sample groups in terms of content of individual nutrients. Soluble protein content was greatest in the HD4 group, and HD2 showed the highest level of crude fat, suggesting that black soybean from these two growing areas are the most suitable for the development of protein and oil products, respectively. Altogether, 16 types of amino acids were detected in the samples from the four groups; essential amino acids were the most abundant (37%~38% of total amino acid content). Methionine and threonine are the limiting amino acids, requiring nutrition fortification or raw material matching to guarantee the nutritional quality during the process of product development. Five fatty acids were detected in the four groups, and the unsaturated fatty acid content reached 85.62%~87.1%. The anthocyanidin content, which was found to range from 2.14% to 2.26%, indicates that these black soybeans are optimal raw material for the development of functional (nutritional) foods. These results provide a reference for further refinement of processing methods for black soybeans, with the goal of extracting functional components for the development of useful products.
