Comparative evaluation of physicochemical and fermentative responses of three sorghum varieties from dryland and irrigated land and the properties of proteins from distillers’ grains

Three sorghum varieties [waxy sorghum (WS), high protein sorghum (HPS), and normal sorghum (NS)] grown under dryland and irrigated conditions were evaluated with respect to the physicochemical and fermentative properties. The proteins were extracted from wet distillers' grains with solubles (WDGS) and characterized in terms of purity and in vitro digestibility. Starch, crude protein, crude fat, and fiber contents of the sorghums ranged from 64.16 to 68.05 g/100 g, 11.49–13.54 g/100 g, 2.45–2.98 g/100 g, and 1.62–1.80 g/100 g, respectively. For the same variety, the sorghums grown under dryland conditions had higher protein (0.33–0.91 g/100 g) and lower starch contents (0.74–1.72 g/100 g) than those grown under irrigation conditions. The highest ethanol concentration (85.15 g/L) and yield (41.64 mL/100 g sorghum) were obtained from the NS under dryland conditions and HPS under irrigation conditions, respectively. Sorghums from irrigated land displayed 0.56–8.23 mL/100 g sorghum of ethanol yield higher than those from dryland. Protein (40.21–45.13 g/100 g), crude fat (11.54–13.95 g/100 g), and crude fiber (7.13–9.29 g/100 g) contents in dried distillers' grains with solubles (DDGS) were increased approximately four times compared to the raw sorghum flour. The purity and digestibility in terms of the degree of hydrolysis of the proteins isolated from different sorghum sources ranged from 88.82 to 94.22% and 33.35 to 37.29%, respectively. In addition, the effects of sorghum variety, treatment (dryland and irrigated land), and their interaction on the chemical composition of sorghum and DDGS, ethanol concentration and yield, as well as the purity and digestibility of WDGS proteins were elucidated with a set of correlation coefficients among parameters associated with sorghum.

对在旱地和灌溉条件下种植的三个高粱品种[糯高粱（WS）、高蛋白高粱（HPS）和普通高粱（NS）]的理化和发酵特性进行了评估。从含可溶物的湿酒糟（WDGS）中提取蛋白质，并对其纯度和体外消化率进行了表征。高粱的淀粉、粗蛋白、粗脂肪和纤维含量分别在64.16 - 68.05克/100克、11.49 - 13.54克/100克、2.45 - 2.98克/100克和1.62 - 1.80克/100克之间。对于同一品种，旱地条件下种植的高粱比灌溉条件下种植的高粱蛋白质含量高（0.33 - 0.91克/100克），淀粉含量低（0.74 - 1.72克/100克）。旱地条件下的普通高粱和灌溉条件下的高蛋白高粱分别获得了最高的乙醇浓度（85.15克/升）和产量（41.64毫升/100克高粱）。灌溉地高粱的乙醇产量比旱地高粱高0.56 - 8.23毫升/100克。含可溶物的干酒糟（DDGS）中的蛋白质（40.21 - 45.13克/100克）、粗脂肪（11.54 - 13.95克/100克）和粗纤维（7.13 - 9.29克/100克）含量比原高粱粉大约增加了四倍。从不同高粱来源分离的蛋白质的纯度和水解度方面的消化率分别在88.82% - 94.22%和33.35% - 37.29%之间。此外，通过高粱相关参数之间的一组相关系数，阐明了高粱品种、处理方式（旱地和灌溉地）及其相互作用对高粱和DDGS的化学成分、乙醇浓度和产量以及WDGS蛋白质的纯度和消化率的影响。