屎肠球菌发酵特性及其功能性研究
Study on the fermentation and function characteristics of Enterococcus Faecium
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摘要: 探讨了分离自新疆酸奶疙瘩的一株屎肠球菌在乳制品应用中具有的潜在益生价值。通过测定滴定酸度、丁二酮、乙醛、游离氨基酸等指标,研究了屎肠球菌在脱脂乳中的发酵特性以及发酵乳上清液具有的抗氧化与抑菌功能。结果表明,屎肠球菌产酸、产香和降解酪蛋白能力强,37℃发酵24h,滴定酸度为123.55°T,丁二酮含量为12.31μg/mL,乙醛含量高达90.12μg/mL,游离氨基酸含量为331.92μg/mL,活菌数最高可达1.10×1010cfu/mL。发酵乳上清液对常见病原微生物有抑制作用,且抑菌物质具有热稳定性、较宽的pH范围、对蛋白酶敏感的特点,对羟自由基清除率为96.84%,超氧阴离子自由基清除率为31.33%,具有抗氧化能力。Abstract: The potential application in dairy products of Enterococcus faecium selected from Xinjiang yogurt bumps was discussed.The fermentation characteristics of Enterococcus faecium in the skin milk and the antioxidative and antibacterial activity of fermentation liquid were studied via the determination on titration acidity, diacetyl, acetaldehyde, free amino and so on. The results showed that Enterococcus faecium demonstrated strong acid production, aroma- producing and proteolytic activity, the titration acidity was123.55°T, the characteristic flavor contained 12.31μg/mL of diacetyl, 90.12μg/mL of acetaldehyde, the free amino acids content was 331.92μg/mL and the living cells was up to 1.10×1010cfu/mL after incubation for 24 hours at37℃. Fermented liquid showed inhibitory activity against pathogenic microorganisms and antimicrobial substances were resistant to heating, stable at a wide pH range, sensitive to protease.The scavenging activity on hydroxyl radical and superoxide radical anion of fermented milk were 96.84%, 31.33%.