| 摘要: |
| 【目的】研究热处理对全脂大豆蛋白质分子结构特征、溶解度和体外消化率的影响及三者之间的相关性。【方法】以全脂大豆为样本，对其进行湿热法（120 ℃高压(0.1 MPa)灭菌锅加热7.5 min）和干热法（120 ℃烘箱干燥15 min）处理，同时设膨化全脂大豆粉不作加热处理。使用傅立叶红外光谱（FTIR）技术，定量计算蛋白质分子结构特征（酰胺Ⅰ带、酰胺Ⅱ带、酰胺Ⅰ带/酰胺Ⅱ带、蛋白质二级结构中α-螺旋、β-折叠及α-螺旋与β-折叠的比值），并采用体积分数0.2%KOH溶液定氮法和胃蛋白酶 胰酶制剂两步酶解法，分别对大豆样品蛋白质溶解度和粗蛋白体外消化率进行分析，用Pearson方法分析各指标间的相关性。【结果】不同热处理条件显著影响了3种大豆样品蛋白质的分子结构特征、溶解度和体外消化率，且以对膨化全脂大豆的影响最大。蛋白质酰胺Ⅰ带、酰胺Ⅱ带的峰高和峰面积与其溶解度和体外消化率呈显著正相关关系（P＜0.05）；而蛋白质酰胺Ⅰ带与酰胺Ⅱ带峰高比值与其溶解度和体外消化率呈显著负相关关系（P＜0.05），蛋白质酰胺Ⅰ带与酰胺Ⅱ带的峰面积比值与其溶解度和体外消化率也呈显著负相关关系（P＜0.05）；α螺旋含量、α螺旋/β折叠值与蛋白质溶解度和体外消化率呈极显著正相关关系（P＜0.001）；无规则卷曲含量与蛋白质溶解度和体外消化率呈显著正相关关系（P＜0.05）；而β-折叠含量与蛋白质溶解度和体外消化率呈极显著负相关关系（P=0.002）；并且蛋白质溶解度与体外消化率呈极显著正相关关系（P＜0.001）。【结论】得到了一组新的蛋白质分子结构特征数据，而且蛋白质的分子结构特征、溶解度和体外消化率三者之间存在密切的相关性关系。 |
| 关键词: 热处理 傅立叶红外光谱技术 分子结构特征 溶解度 体外消化 |
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| 基金项目:国家重点基础研究发展计划“973计划”项目（2013CB127306） |
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| Effect of heat-treatment on molecular structure characteristics,solubility and in vitro digestibility of full-fat soybean protein |
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BAI Mingmei,SUN Zewei,LONG Guohui,et al
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| Abstract: |
| 【Objective】This study investigated the effect of heat-treatment on molecular structure characteristics,solubility,in vitro digestibility as well as their relationships of full-fat soybean protein.【Method】In this study,full-fat soybean was treated with moist process (autoclaved (0.1 MPa) at 120 ℃ for 7.5 min) and dry process (heated at 120 ℃ for 15 min).A group of fat full soybean was also extruded without heat treatment.The protein molecular structures (including amide Ⅰ,amide Ⅱ,amide Ⅰ/amide Ⅱ,and ratios of α-helix and β-sheet and α-helix/β-sheet in secondary structure) were quantified using Fourier transform infrared molecular spectroscopy (FTIR).The protein solubility and in vitro digestibility were analyzed by (0.2%)KOH solution kjeldahl and pepsin pancreatin two-step enzymatic methods,respectively.Pearson method was used to calculate correlation coefficients.【Result】Different heat treatments had significant effect on protein molecular structure characteristics,solubility and in vitro digestibility,with the greatest impact on the extruded soybean.Heights and areas of amid Ⅰ and amide Ⅱ had significantly positive correlation with protein solubility and in vitro digestibility (P<0.05).The height ratio of amide Ⅰ to amide Ⅱ was significantly negatively related to solubility and in vitro digestibility (P<0.05),and the area ratio of amide Ⅰ to amide Ⅱ was significantly negatively related to solubility and in vitro digestibility (P<0.05).The contents of α-helix and ratio of α-helix to β-sheet had very significantly positive correlation with solubility and in vitro digestibility (P<0.001).The contents of random coil had significantly positive correlation with solubility and in vitro digestibility (P<0.05).The contents of β-sheet had significantly negative correlation with protein solubility and in vitro digestibility (P=0.002),and significantly positive correlation was found between protein solubility and in vitro digestibility (P<0.001).【Conclusion】Novel molecular structural data was obtained and close correlations were found between molecular structure characteristics,solubility and extracorporeal digestibility. |
| Key words: heat treatment Fourier transform infrared molecular spectroscopy molecular structure protein solubility hydrolysis in vitro |
