摘要
为防止玉米淀粉食品会因回生而降低品质,该文利用酸性、中性和碱性3种蛋白酶水解小麦面粉中的球蛋白、谷蛋白和醇溶蛋白,研究酶解物中混合多肽对玉米淀粉回生的影响。研究结果表明,酸性蛋白酶水解谷蛋白所得多肽混合液能强烈抑制玉米淀粉回生,使玉米淀粉回生率由14.0%降低到8.0%。其他2种水解物促进玉米淀粉回生,促进最多的是碱性蛋白酶水解醇溶蛋白,使玉米淀粉回生率由14.0%升高到19.5%。通过红外和核磁分析了混合多肽抑制或促进玉米淀粉回生的可能机理。研究成果为控制淀粉回生提供一条全新的途径。
Retrogradation is the molecular interaction that occurs between glucan molecules in gelatinized starch during cooling. It profoundly affects quality, acceptability, and shelf-life of starch-containing foods. Corn starch is cheap and is widely used in foods such as instant noodles, sausages, pastries, etc. But the quality of these foods in hardness, digestion, compatibility, etc, becomes deteriorated during storage due to starch retrogradation. Wheat gluten is a kind of nutritious, high quality, and inexpensive plant-based protein. It is often suggested that gluten has an anti-firming effect in bread, but the reason for this is not clear. There are four kinds of proteins in wheat flour：albumin, globulin, glutenin, and gliadin. In order to find the peptides with the ability of hindering corn starch retrogradation, these proteins were hydrolyzed by acid, neutral, and alkali proteases. The effects of these peptides in hydrolysate of globulin, glutenin, and gliadin on the retrogradation of corn starch were carried out in this paper. The results showed that the peptides from hydrolysis of glutenin by acid protease strongly inhibited retrogradation of corn starch, lowering the retrogradation rate of corn starch from 14.0%to 8.0%. Other hydrolysis promoted the retrogradation of corn starch, in which the largest increase in the retrogradation rate of corn starch was the peptides from the hydrolysis of gliadin by alkaline protease, enhancing the corn starch retrogradation rate from 14.0%to 19.5%. The possible mechanism in enhancing or inhibiting the retrogradation of corn starch was analyzed by IR and nuclear magnetic resonance. The increase in the corn starch retrogradation rate was caused by peptides with hydroxyls in hydrolysate of gliadin that formed glycosidic bonds with hydroxyls on corn starch. These glycosidic bonds were resistant to hydrolysis of starch by α-amylase. The factor that reduced the corn starch retrogradation rate was the presence of hydrophilic peptides in hydrolysate of glutenin that had the ability of forming a double helix with corn starch. This double helix was in favor of gel formation. The gel system hindered the formation and growth of a crystal nucleus of retrograded corn starch, thus reducing the retrogadation rate of corn starch. Sulfdryl groups were absent in the hydrolysate of these proteins, inferring that those groups might only exist in the spatial structure of these proteins. A further study of these peptides on the retrogradation of corn starch should be carried out on the aspect of interaction of peptides and starches in three-dimensional space. The findings in the paper provide a new way to control retrogradation of corn starch.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2014年第12期265-269,共5页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金重点项目(No.31130042)
国家自然科学基金项目(31271935)
天津市应用基础与前沿技术研究计划项目(14JCYBJC30800)资助
关键词
淀粉
水解
蛋白质
回生
蛋白酶
starch
hydrolysis
proteins
retrogradation
protease
