谷物蛋白肽对大米淀粉理化特性和体外消化特性的影响

Effects of Cereal Protein Peptides on the Physicochemical Properties and in Vitro Digestion Characteristics of Rice Starch

摘要:

本研究以大米淀粉为原料，探讨谷物蛋白肽的添加对大米淀粉理化性质和体外消化性能的影响。结果表明：添加10%的小麦肽对降低体系的峰值黏度、崩解值的效果最好，其值分别降低300 MPa·s；相反，5%的玉米肽使淀粉糊的终值黏度、回升值降低最大，分别降低256 MPa·s、200 MPa·s；谷物蛋白肽可以增大大米淀粉糊的焓变，提高淀粉糊的热稳定性；淀粉溶解度与谷物蛋白肽的添加量成正相关，3种肽对淀粉膨胀度无影响；大米肽能明显改变淀粉冻融稳定性，添加5%、10%可以使淀粉的冻融稳定性增强，析水率降低3%；3种肽可降低大米淀粉中易消化淀粉的含量，综合比较，大米肽对降低淀粉体外消化的效果最好，其中添加5%的玉米肽使易消化淀粉的含量降低值最大，降低25%，其次是添加1%的大米肽。根据谷物蛋白肽的主要氨基酸成分分析，大米肽的碱性氨基酸含量明显要比其他两种肽的含量高，玉米肽中的各氨基酸含量也相应的比小麦肽高；因而，谷物蛋白肽对淀粉的影响主要因素与各自的氨基酸含量以及分子量大小有关。

Abstract:

In this study, rice starch was used as the raw material to investigate the effects of addition of cereal protein peptides on the physicochemical properties and in vitro digestion of rice starch. The results showed that the addition of 10% wheat peptides led to the greatest reduction of the peak viscosity and disintegration value of starch paste (which were respectively reduced by 300 MPa·s); On the contrary, the addition of 5% corn peptide caused the greatest decreases in the final viscosity and recovery value (which were reduced by 256?MPa·s and 200 MPa·s). The cereal protein peptides could increase the enthalpy and improve the thermal stability of the starch paste. The solubility of the starch was positively correlated with the amount of the added cereal protein peptides, although these peptide had no effect on starch swelling. The rice peptide could obviously change the freeze-thaw stability of starch, with its addition at 5% or 10% enhancing the freeze-thaw stability of starch while reducing the syneresis rate by 3%. The three kinds of peptides could reduce the content of the rapidly digestible starch in the rice starch. On the basis of comparisons, the rice peptide lowered the in vitro digestibility of starch the most. Adding 5% corn peptide could cause the greatest decrease (by 25%) in the content of rapidly digestible starch, followed by adding 1% rice peptide. According the analysis of the main amino acid components in the cereal protein peptides, the content of basic amino acids in the rice peptide was significantly higher than those of the other two kinds of peptides, and the contents of amino acids in the corn peptides were correspondingly higher than those of wheat peptides. Thus, the main factors associated with the impact of the cereal peptides on the starch were related to their respective amino acid contents and molecular weights.