pH值对柞蚕蛹粉凝胶特性及蛋白质热聚集行为的影响

Effects of pH on Gel Properties and Protein Thermal Aggregation Behavior of Antheraea pernyi Pupae Flour

柞蚕蛹富含优质蛋白质,是一种具有很高开发利用价值的食品原料。采用质构仪、流变仪和激光扫描共聚焦显微镜等分析不同pH值对柞蚕蛹粉凝胶特性及蛋白质分子热聚集行为的影响。结果表明:pH值为7时形成的柞蚕蛹粉凝胶网络较为连续和均匀,凝胶保水性最高(51.67%±0.79%,P<0.05);pH值为9时的柞蚕蛹粉有最低的临界凝胶质量分数(8%)、最高的凝胶硬度(41.67 N±3.37 N,P<0.05)和弹性(2.81 mm±0.07 mm,P<0.05)。柞蚕蛹粉凝胶的储能模量与蛋白质的溶解度呈显著正相关(R=0.92,P<0.05),而与蛋白质的凝固率(R=-0.52)和表面疏水性(R=-0.77)呈显著负相关(P<0.05)。pH值为9时,蛋白质溶解度最高(62.13%±0.63%,P<0.05),表面疏水性最低(70.06μg±9.32μg,P<0.05),形成了更多的小尺寸热聚集物并增强了凝胶基质;而在pH值为5时,蛋白质溶解度最低(28.96%±1.13%,P<0.05),表面疏水性最高(195.66μg±1.30μg,P<0.05),促使更多的大尺寸热聚集物形成并无序堆叠而削弱凝胶基质。研究旨在通过调节pH值控制柞蚕蛹粉中蛋白质的热聚集行为,进而获得理想质地和保水性的柞蚕蛹粉凝胶。

Antheraea pernyi(A.pernyi)pupa is rich in high quality protein,which is a kind of food raw material with high development and utilization value.The effects of different pH values on the gel properties of A.pernyi pupae flour and the thermal aggregation of protein molecules were studied by texture analyzer,rheometer and confocal laser scanning microscope.The results showed that the gel network formed at pH 7 was relatively continuous and uniform,and the water retention of gel was the highest(51.67%±0.79%,P<0.05).At pH 9,A.pernyi pupae flour had the least critical gel mass fraction(8%),the highest gel hardness(41.67 N±3.37 N,P<0.05)and elasticity(2.81 mm±0.07 mm,P<0.05).In addition,the storage modulus of A.pernyi pupae flour gel was significantly positively correlated with the solubility(R=0.92)of proteins(P<0.05),but negatively correlated with the proteins coagulate rate(R=-0.52)and surface hydrophobicity(R=-0.77)(P<0.05).At pH 9,the protein solubility was the highest(62.13%±0.63%,P<0.05),and the surface hydrophobicity was the lowest(70.06μg±9.32μg,P<0.05).More small-size thermal aggregates were formed and the gel matrix was enhanced at pH 9.At pH 5,the protein solubility was the lowest(28.96%±1.13%,P<0.05),and the surface hydrophobicity was the highest(195.66μg±1.30μg,P<0.05),which promoted the formation of more large-size thermal aggregates and disorderly stacking,weakening the gel matrix.The purpose of this study was to control the thermal aggregation behavior of protein in A.pernyi pupae flour by adjusting the pH value,and then the gel with ideal texture and water retention could be obtained.