热处理对大豆蛋白分级分离的影响

对大豆粕进行不同热处理(湿热、干热和压热),研究热处理对大豆蛋白分级分离的影响。研究表明未热处理低温豆粕11S与7S分级不完全,高温豆粕蛋白质得率虽不及低温豆粕的1/2,但高温豆粕中11S与7S级分更易于分离。湿热处理对7S级分纯度影响较大,特别是90℃时7S级分纯度仅为(23.5±0.71)%、得率仅为未加热低温豆粕的1/14。干热处理(特别是70℃时)所得11S和7S级分纯度较高且蛋白质得率损失少。压热处理蛋白质得率大大降低。各级分的脂含量分析表明:高温豆粕IM和7S级分脂含量明显高于未加热低温豆粕。未加热低温豆粕的脂类主要集中于11S和IM级分,湿热处理使脂类向7S级分富集,70℃干热处理IM级分的脂含量最高。结果表明:70℃干热处理2 h的低温豆粕对大豆蛋白的分级分离效果较好。

Effects of Thermal Treatment on Fractionation of Soy Protein

Effects of different thermal treatments on the fractionation of soy protein were studied. Results:11S and 7S cannot be fractionated completely in unheating low temperature desolventized soybean meal, and high temperature desolventized soybean meal is favorable for fractionating llS from 7S at expense of half protein recovery loss. The purity and yield of 7S are reduced obviously by moist-heating, merely purity23.5 % and yield1/14 of the control for 90 ℃ moist-heating. Dry-heating, especially 70 ℃ treatment results in higher purity of11S and 7S and less recovery loss. High press heating decreases protein recovery greatly. The lipid analysis for every fraction shows that the lipid concentrations of 7S and IM fractions in high temperature desolventized soybean meal are obviously higher than those in low temperature desolventized soybean meal. Lipid concentrates in11S and IM for low temperature desolventized soybean meal, in 7S for moist-heated soybean meal, and in IM for 70 ℃ dry-heated soybean meal. It is preferable for soy protein fractionation to use low temperature desolventized soybean meal treated with 70 ℃ dry-heating for2 h.