浸泡对玉米SOD和醇溶蛋白提取的影响

100g玉米中加入200mL pH7.80·05mol/L的磷酸缓冲液,40℃下浸泡36h后将玉米淋干,将胚芽与胚乳分离、破碎。从胚芽中提取SOD,SOD酶活最高达到371·55U/g玉米,是未浸泡玉米胚芽的15·8倍;破碎的胚乳∶75%(V)酒精=1∶6混合后,60℃下浸提2h,获得醇溶蛋白。一次浸提醇溶蛋白的提取率为78·94%,比对照提高了20·91%,二次浸提提取率达为93·3%。最后,将提取SOD和醇溶蛋白的玉米残渣进行酒精发酵,同时与采用干法粉碎和湿法粉碎的玉米粉进行对比,其淀粉出酒率分别为53·50%、53·56%和53·51%。

Effect of Steeping on Extraction of SOD and Zein from Corn

Steeping greatly impacts the extraction of SOD and zein from corn. The pH 7.8 phosphate buffer was deemed to the best buffer through experiments. It was determined that 100g corn was first steeped with 200 mL 0.05 mol/L phosphate buffer at 40℃ for 36h. The embryo and endosperm were separated. SOD was extracted from smashed embryo, and total SOD activities were 37 155 U/100g corn,which was 15.8-fold more than one from embryo of corn not steeped. Then, zein was extracted from endosperm smashed using 75% ethanol solvent with the solvent-to-corn ratio of 6∶1 at 60℃ for 2h. The yield of zein was 78.94%, which enhanced by 20.91% compared to control. When extracted twice, the yield of zein reached to 93.30%. Furthermore, the ethanol fermentation with corn, steeped corn and corn residuals after extracting SOD and zein was carried out, and their conversion ratio (to 95%(v) ethanol) reached 53.56%,53.50% and 53.51%, respectively.