红茶菌发酵黄浆水的体外抗氧化活性

Antioxidant Activity of Fermented Soy Whey with Kombucha Consortium

黄浆水是豆制品加工过程中产生的废液,但其中含有丰富的营养物质,且适宜微生物生长。传统的红茶菌由醋酸菌和酵母菌组成的液面生物膜发酵茶糖水得到。本研究利用黄浆水作为红茶菌的新型发酵基质,期望开发出新型功能型饮料。随发酵时间延长至第6天,发酵黄浆水pH值下降至3.24,总酸浓度为0.121 mol/L,还原糖质量浓度下降至1.37 mg/mL。用体积分数80%甲醇溶液对发酵前后黄浆水进行提取并测定总黄酮质量浓度,采用高效液相色谱法对大豆异黄酮进行定性、定量分析。采用1,1-二苯基-2-三硝基苯肼自由基清除能力、2,2’-联氮-二(3-乙基-苯并噻唑-6-磺酸)阳离子自由基清除能力、亚铁离子还原力和还原力4种抗氧化模型对发酵前后黄浆水的抗氧化活性进行分析。结果表明,发酵第6天黄浆水的总黄酮质量浓度为268.45 mg/L,糖苷型大豆异黄酮质量浓度下降至49.76 mg/mL,苷元型大豆异黄酮质量浓度增加至150.95 mg/mL。经发酵后的黄浆水抗氧化活性相比未发酵黄浆水明显提高。本研究为黄浆水的资源利用提供了新的途径。

Soy whey is a major by-product from the soy product industry,which is suitable for the growth of microorganisms due to rich nutrients.Kombucha is a sweet and sour functional beverage made from sweet black tea fermented by a symbiotic consortium of yeasts and acetic acid bacteria.In this study,we used soy whey as a new fermentation substrate for kombucha consortium to develop a novel functional beverage.The results demonstrated that after fermentation for 6 days,pH decreased to 3.24,which corresponded to an increase in total titration acidity up to 0.121 mol/L,and the content of reducing sugar decreased to 1.37 mg/mL.Total flavonoids from unfermented and fermented soy whey were extracted using 80%methanol and were qualitatively and quantitatively determined by high performance liquid chromatography(HPLC).Their antioxidant capacity was evaluated by 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical and 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)(ABTS)cation radical scavenging ability,ferric reducing antioxidant power and reducing power.The results showed that the total flavonoids concentration of 6-day fermented soy whey was up to 268.45 mg/L;the soybean iso flavonoids glycoside concentration was reduced to 49.76 mg/mL,and the soybean iso flavonoids aglycone concentration was increased to 150.95 mg/mL compared with the unfermented one.The fermentation could signi ficantly improve the antioxidant activity of soy whey.This study provides a new way of utilizing soy whey resource.