超声改性蛋白对玉米淀粉凝胶结构及消化特性的影响

Effect of Ultrasonically Modified Protein on Structure and Digestive Properties of Corn Starch Gels

摘要:

为探究超声改性蛋白对玉米淀粉凝胶结构及消化特性的影响规律,将不同超声时间处理的大豆分离蛋白分别添加至玉米淀粉中,利用傅里叶红外光谱仪、差示扫描量热仪、X-射线衍射仪及流变仪等表征超声改性蛋白与玉米淀粉复配凝胶体系结构,并对其体外消化特性进行分析。结果表明:与原玉米淀粉相比,当淀粉中添加不同超声时间处理的大豆分离蛋白后,玉米淀粉的短程有序性、分子内和分子间氢键强度、糊化焓值(ΔH)均降低,且随着超声时间的延长,呈逐渐降低趋势,当超声时间达到30min时,复配体系的ΔH降低了27.27%；超声改性蛋白与玉米淀粉间相互作用主要通过疏水作用力；复合凝胶体系的X-射线衍射图显示出典型Ⅴ型结构特征,说明改性蛋白的加入改善了淀粉消化特性,与原淀粉相比,慢消化淀粉和抗性淀粉含量均随着超声时间的延长逐渐升高,慢消化淀粉和抗性淀粉质量分数分别提升了7.01%和3.41%。研究结果旨在为改性蛋白在淀粉基食品中的应用提供理论依据。

Abstract:

In order to investigate the influence of ultrasonic modified protein on the gel structure and digestive properties of corn starch (CS), soybean isolated protein (SPI) treated with different ultrasonic time was added to corn starch, and the structure of ultrasonic modified protein and CS compound gel system was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry and rheometer, and its in vitro digestive characteristics were analyzed.The results showed that compared with the original CS, the short-range orderliness, intramolecular and intermolecular hydrogen bond strength, and enthalpy (ΔH) of pasting of CS decreased, when soybean isolate protein modified with different ultrasonic time was added to the starch, and the ΔH of pasting tended to decrease gradually with the increase of ultrasonic time, and the ΔH of the compound gel system decreased by 27.27% when the ultrasonic time reached 30min. The interaction between the ultrasonic-modified protein and the CS was mainly through hydrophobic forces. The X-ray diffraction pattern of the compound gel system showed typical V-shaped structure characteristics, suggesting that the addition of the modified protein improved the starch digestion characteristics, and the content of both slow-digesting starch (SDS) and resistant starch (RS) increased gradually with the increase of ultrasonic time compared with the original starch, and the SDS and RS mass fractions increased by 7.01% and 3.41%, respectively.This study might provide a theoretical basis for the application of modified proteins in starch-based foods.