脱酰胺对葵花籽蛋白酶解肽的钙结合量及体外消化性的影响

摘要

通过谷氨酰胺酶对葵花籽蛋白酶解肽进行脱酰胺,得到脱酰胺的葵花籽蛋白酶解肽,以此为试样,研究脱酰胺对葵花籽蛋白酶解肽的钙结合能力的影响.结果发现,脱酰胺的葵花籽蛋白酶解肽的钙结合量由72.97 mg/g显著增加到98.20 mg/g,说明脱酰胺可以显著提高葵花籽蛋白酶解肽的钙结合量;通过傅立叶红外光谱对脱酰胺前后葵花籽蛋白酶解肽的钙结合位点进行分析,发现葵花籽蛋白酶解肽与钙结合后,氨基的特征吸收峰均发生移动,N-H的伸缩振动带由3 323 cm-1移动至3 340 cm-1,酰胺Ⅱ带由1 160 cm-1移动至1 656 cm-1,酰胺Ⅲ带由1 241 cm-1移动至1 246 cm-1,同时脱酰胺使其酰胺Ⅰ带由1 660 cm-1移动至1 656 cm-1,说明葵花籽蛋白酶解物肽链上的氨基及羧基是钙的主要结合位点,且脱酰胺后C=O伸缩振动引起的酰胺Ⅰ带进一步向低频移动,表明脱酰胺后羧基上的氧原子与钙的配位作用得到增强,促进了葵花籽蛋白酶解肽钙结合量的提高;另一方面研究还发现体外消化后脱酰胺的葵花籽蛋白酶解肽钙复合物的钙结合量能保持86％以上,与未脱酰胺的花籽肽钙复合物相比消化后的钙结合量提高24％以上.表明脱酰胺能够显著提高葵花籽蛋白酶解肽钙复合物的消化稳定性,即提高葵花籽蛋白酶解肽的钙结合稳定性.%Sunflower seed protein peptide of deamidation,which is prepared by deamidation of sunflower seed protein peptide using glutaminase,was the objects of research on effect of deamidation of sunflower seed protein peptide on Amount of Calcium.The results showed that the amount of calcium of deamidation of sunflower seed protein peptide increased from 72.97 mg/g to 98.20 mg/g significantly.The deamidation of the sunflower tryptic peptide samples was analyzed by Fourier infrared spectrum.Amino characteristic absorption peaks were moved.The N—H stretching vibration band were moved from 332 3 cm-1 to 334 0 cm-1.The amide Ⅱ band were moved from 116 0 cm-1 to 165 6 cm-1.The amide Ⅲ band were moved from 124 1 cm-1 to 124 6 cm-1.The deamidation cause the amide Ⅰ band were moved from 166 0 cm-1to 165 6 cm-1.The results showed that the Amino and carboxyl groups on the peptide chain of Sunflower seed protein peptide were mainly calcium binding sites.The C =O stretching vibration caused by the amide Ⅰ band further to the low frequency shift after deamidation.It showed that the coordination of oxygen atoms and calcium in the carboxyl group was enhanced,which promoted the increase of the calcium binding capacity of the sunflower seed protein.On the other hands,the study also found that deamidation of sunflower seed protein peptide calcium complexes had high maintain ability to calcium binding amount more than 86％ which was increased more than 24％ obviously compared with sunflower seed protein peptide calcium complexes.The results showed that the digestion stability of sunflower seed peptide calcium complex substance was enhanced by deamidation and the calcium binding stability of sunflower seed peptide was increased.