Dept. of Cereal and Food Sciences, North Dakota State Univ., Fargo, ND 58105, USA.
J Food Sci. 2010 Jun;75(5):C420-7. doi: 10.1111/j.1750-3841.2010.01651.x.
Large oil-protein particles (2 to 60 microm) were found in raw soymilk (or water extract of soybean), which was prepared in specific conditions. The large particles could be separated by sedimentation by centrifuging raw soymilk for 5 to 30 min at a low gravitational force ranging from 96 to 2410 x g. Chemical analysis showed that 80% to 90% of the total lipids and 30% to 40% of the total proteins were located in the precipitated fraction. The supernatant fraction had a dramatically higher protein-to-lipid ratio than the whole soymilk. The ratio of 11S/7S proteins and the ratio of 11S acidic/basic subunits were significantly (P < 0.05) higher in the precipitate than that either in the whole soymilk or in the supernatant. Besides centrifuging conditions, other factors, including soymilk concentration, grinding method, soybean variety, and soybean storage, also significantly (P < 0.05) affected the centrifugal fractionation. This study showed that low-speed centrifugation facilitated the separation of oil-protein particles from raw soymilk, and can be used as an innovative method for preparing low-fat soymilk and 11S protein-enriched ingredients. The findings also increased our understanding of the association or aggregation between proteins and lipids in raw soymilk after grinding.
在特定条件下制备的生豆浆（或大豆水提取物）中发现了大油蛋白颗粒（2 至 60 微米）。大颗粒可以通过在 96 至 2410 x g 的低重力下离心生豆浆 5 至 30 分钟来沉淀分离。化学分析表明，80%至 90%的总脂质和 30%至 40%的总蛋白质位于沉淀部分。上清部分的蛋白质与脂质的比例明显高于全豆浆。沉淀中 11S/7S 蛋白的比例和 11S 酸性/碱性亚基的比例均明显（P < 0.05）高于全豆浆或上清液中的比例。除了离心条件外，豆浆浓度、研磨方法、大豆品种和大豆储存等其他因素也显著（P < 0.05）影响离心分级。本研究表明，低速离心有利于从生豆浆中分离油蛋白颗粒，可作为制备低脂豆浆和富含 11S 蛋白成分的创新方法。研究结果还增加了我们对研磨后生豆浆中蛋白质和脂质之间的关联或聚集的理解。
