大豆酱油分子质量超滤分级及抗氧化活性研究

Studies on the Molecular Weight Ultrafiltration of Soybean Soy Sauce and Its Antioxidant Activity

为研究酱油中不同分子质量段酱油肽的抗氧化能力,通过高效液相色谱法测定酱油中蛋白质及多肽的分子质量分布情况,并分别使用截留分子质量为2,5,10 ku的超滤膜进行分级。探究温度、压力和时间对膜渗透通量的影响,结果表明在操作压力为600 kPa、温度35℃下超滤120 min的膜通量较高。超滤分级后得到分子质量分别为>10 ku,5～10 ku,2～5 ku,<2 ku的4个部分。分别研究4个组分的酱油肽对羟自由基、超氧阴离子自由基、ABTS·+自由基的清除能力,研究结果表明:4种酱油组分均具有一定的抗氧化能力,其中分子质量<2 ku和2～5 ku的酱油组分抗氧化能力较强,说明酱油中含有两种分子质量的抗氧化性肽。

The antioxidant activity of different molecular weight segments of peptides derived from soy sauce is studied. The soy sauce was desalted using an electrodialyzer and then filtered with ultrafiltration which equipped with 2, 5 ku and 10 ku ultrafiltration membranes, respectively. The effects of operating pressure, temperature and time on permeate flux was investigated, and the optimum parameters are determined. The experimental results show that operating pressure and temperature of experiment are two very prominent factors influencing flux of permeate. Increasing operating pressure or temperature of experiment, flux of permeate would increase. The optimum operating conditions were an operating pressure of 600 kPa, a temperature of 35 ℃ and performed 120 min. The molecular weights of <2 ku, 2-5 ku, 5-10 ku and>10 ku were obtained by ultrafiltration, different molecular weights of peptides derived from soy sauce were analyzed for the antioxidant activity in different systems including hydroxyl free radical, superoxide anion free radical, and ABTS·+. The results show that the peptide derived from soy sauce with a molecular weight less than 5 ku showed the stronger antioxidant capacity.