降解苯丙氨酸益生菌的筛选及其在酸奶发酵中的应用

Screening of phenylalanine-degrading probiotics and its application in yogurt fermentation

苯丙酮尿症是一种因体内缺乏苯丙氨酸羟化酶而导致苯丙氨酸过度积累的氨基酸代谢病,研究与开发苯丙氨酸限制的低蛋白特殊膳食对这类疾病患者的营养补给具有重要意义。该研究筛选具有苯丙氨酸降解活性的益生菌,并评价其生产低苯丙胺酸发酵乳的潜力。结果表明:植物乳杆菌(Lactobacillus plantarum)YZX21和动物双歧杆菌(Bifidobacterium animalis)F1-7具有降解苯丙氨酸的能力,降解率分别为12.43%和10.09%。菌株的胃肠环境耐受实验显示,L.plantarum YZX21和B.animalis F1-7均具有良好的胃肠道耐受性、自聚集和黏附能力。与B.animali F1-7相比,L.plantarum YZX21具有优良发酵特性,可作为发酵乳生产的辅助发酵菌株。与市售发酵乳相比,添加L.plantarum YZX21使发酵乳中的游离苯丙氨酸含量降低13.10%。此外,添加L.plantarum YZX21发酵乳的感官评价优于商业发酵乳。筛选得到的L.plantarum YZX21具有明显的苯丙氨酸降解活性,而且具有优良的发酵特性与益生特性,为研究与开发针对苯丙酮尿症的特医食品奠定了基础。

Phenylketonuria is an amino acid metabolic disorder caused by the deficiency of phenylalanine hydroxylase,which leads to the over-accumulation of phenylalanine in body.The phenylalanine-restricted low-protein diet plays a significant role of nutrition supply to phenylketonuria patients.The aim of this study was to screen the probiotics with phenylalanine-degrading activity and evaluate the potential application of fermented milk production.The results showed that Lactobacillus plantarum YZX21 and Bifidobacterium animalis F1-7 exhibited high phenylalanine degradation ability.The degradation rates were 12.43%and 10.09%respectively.Moreover,L.plantarum YZX21 and B.animalis F1-7 had good gastrointestinal tolerance,self-aggregation and adhesion ability.Compared with B.animalis F1-7,L.plantarum YZX21 showed better fermentation properties and could be used as an auxiliary starter strain to produce fermented milk.As well as compared with the commercially fermented milk,the content of phenylalanine in fermented milk inoculated with L.plantarum YZX21 was decreased by 13.10%.In addition,the sensory characteristics of the fermented milk with L.plantarum YZX21 was better than that of commercially fermented milk.These findings indicated that L.plantarum YZX21 had high phenylalanine degradation ability,excellent fermentation and probiotic properties,which laid the foundation for the development of foods for special medical purpose to phenylketonuria patients.