Abstract：
In this paper, effects of preheating-induced denaturation of proteins and oleosomes on protein structure and soymilk quality were studied. The protein in soybeans baked at 55 °C (B-55) and 85 °C (B-85) showed an increase of β-sheet content by 3.2 % and a decrease of α-helix content by 3.3 %, indicating that proteins were gradually unfolded while oleosomes remained intact. The protein resisted thermal denaturation during secondary heating, and soymilks were stable as reflected by a small d3,2 (0.4 μm). However, raw soymilk from soybeans baked at 115 °C (B-115), steamed for 1 min (ST-1) and 5 min (ST-5) presented oleosomes destruction and lipids aggregates. The proteins were coated around the oil aggregates. The β-turn content from soybeans steamed for 10 min (ST-10) increased by 9.5 %, with a dense network where the OBs were tightly wrapped, indicating the serious protein denaturation. As a result, the soymilks B-115 or steamed ones were unstable as evidenced by the serious protein aggregation and larger d3,2 (5.65-12.48 μm). Furthermore, the soymilks were graininess and the protein digestion was delayed due to the formation of insoluble protein aggregates. The flavor and early-stage lipid digestion of soymilk from steamed soybeans was improved owing to lipid release.
摘要：
在本文中,研究了预热诱导的蛋白质和油质体变性对蛋白质结构和豆浆品质的影响。在55°C（B-55）和85°C（B-85）烘烤的大豆中的蛋白质显示β-折叠含量增加了3.2％，α-螺旋含量减少了3.3％，表明蛋白质逐渐展开，而油质体保持完整。蛋白质在二次加热过程中抵抗热变性，小的d3,2（0.4μm）反映出豆浆是稳定的。然而,在115°C下烘烤的大豆生豆浆（B-115），蒸1分钟（ST-1）和5分钟（ST-5）出现了油质体破坏和脂质聚集。将蛋白质包被在油聚集体周围。蒸10分钟大豆(ST-10)的β-转角含量增加了9.5%,有一个密集的网络，OB被紧紧地包裹着，表明严重的蛋白质变性。因此,豆浆B-115或蒸豆浆不稳定，蛋白质聚集严重，d3,2较大（5.65-12.48μm）。此外，由于不溶性蛋白质聚集体的形成，豆浆呈颗粒状，蛋白质消化被延迟。由于脂质释放，蒸大豆豆浆的风味和早期脂质消化得到了改善。
