Parris Nicholas, Dickey Leland C, Powell Michael J, Coffin David R, Moreau Robert A, Craig James C
Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
J Agric Food Chem. 2002 May 22;50(11):3306-8. doi: 10.1021/jf011455q.
Dry-milled yellow corn and freshly ground food and nonfood grade yellow and white hybrid corn kernels were pretreated in a solution of lactic acid and sodium metabisulfite followed by extraction with 70% ethanol. Zein was precipitated from the extract by reducing the ethanol content of the extract to 40%. Lipid associated with the zein isolates was between 15 and 20% and contained mostly endogenous free fatty acids. The effect of the endogenous free fatty acids on zein isolate films, with and without free fatty acids, was determined by measuring various film properties. Stress-strain measurements indicated 40-200% greater elongation for zein films containing endogenous free fatty acids. Films prepared from zein isolated from preground corn stored for approximately 4 months (27 degrees C, 17% relative humidity) had approximately 3 times greater elongation values than zein films prepared from freshly ground corn.
干磨黄玉米以及新磨制的食品级和非食品级黄白杂交玉米粒，先用乳酸和焦亚硫酸钠溶液进行预处理，然后用70%乙醇萃取。通过将提取物中的乙醇含量降至40%，从提取物中沉淀出玉米醇溶蛋白。与玉米醇溶蛋白分离物相关的脂质含量在15%至20%之间，且主要包含内源性游离脂肪酸。通过测量各种薄膜性能，确定了内源性游离脂肪酸对含或不含游离脂肪酸的玉米醇溶蛋白分离物薄膜的影响。应力-应变测量表明，含有内源性游离脂肪酸的玉米醇溶蛋白薄膜的伸长率高40%-200%。由储存约4个月（27摄氏度，相对湿度17%）的预磨玉米中分离出的玉米醇溶蛋白制备的薄膜，其伸长率值约为新磨制玉米制备的玉米醇溶蛋白薄膜的3倍。
