Biochemical Studies on Oxidation of catechin by Pseudomonas cepasia

洋葱假单胞菌氧化儿茶素的生化研究

• 批准号: 09680028
• 负责人: KATO Miyuki
• 金额: $ 2.11万
• 依托单位: Kagawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680028/
• 关键词: Pseudomonas cepasia; catechin; post-heated fermented tea; enzyme; 有機酸; 風味成分

We have clarified flavor components of post heated fermented teas in various are as. Also, we have isolated a number of microorganisms from post-heated fermented teas. By using these microorganisms, effect on flavor components were examined. Among all, Examination was made on Pseudomonas cepasia (P. cepasia) affecting tea catechins. P. cepasia was isolated front a bucket in the process of post-heated fermented tea production . This microorganism was contained in Goishi-cha (GOS3). Laphet-so (PBJ17) and Miang (LAO P.D.R B2TS2). P. cepasia was a grain-negative bactellium. Further, properties of P. cepasia was examined. As a result, the thus isolated P. cepasia showed an S-shape growth curve similar to the type culture . The isolated P. cepasia remained stable even in a heat treatment at 100℃, thus showing a high heat stability. Regarding the optimum pH value, it was found out that this isolated P. cepasia grew in the alkaline region compared with the type culture. In a model experiment . P. cepasia was added in the bucket in the post-heated fermented tea production and changes in the flavor components ware monitored. As a result, the catechin content was decreased. In particular, (-)-epigallocatechin gallate((-)-EGCg) showed a remarkable decrease- Also, examination was made on enzymes seemingly largely affecting the oxidation of catechin- Thus it was found out that (-)-EGCg, etc. were decreased by adding catechin during the culture period. It was also clarified that the capability of degrading catechin appeared not in the P. cepasia culture medium but in the cells. To extract the enzymes from the cells, cell disruption with the use of a French press was an efficacious means . It was also found out that (-)-EGCg, among catechins, served as the major substrate.

澄清了不同种类热后发酵茶的风味成分。此外，我们还从加热后的发酵茶中分离出了一些微生物。利用这些微生物，考察了对风味成分的影响。其中，对影响茶儿茶素的cepasia假单胞菌进行了检测。在热后发酵茶生产过程中，从桶前分离出了cepasia。这种微生物存在于Goishi-cha （GOS3）中。lapet -so （PBJ17）和Miang （LAO p.d.r. B2TS2）。P. cepasia是一种颗粒阴性菌。进一步研究了该植物的特性。结果表明，该菌株的生长曲线与模式培养相似，呈s型。分离得到的cepasia在100℃的热处理条件下仍保持稳定，具有较高的热稳定性。在最佳pH值方面，与模式培养相比，该分离菌株生长在碱性地区。在一个模型实验中。在加热后的发酵茶生产过程中，在桶中加入香豆菌，并对其风味成分的变化进行了监测。结果，儿茶素含量降低。特别是(-)-表没食子儿茶素没食子酸酯（(-)- egcg）有明显的下降。此外，对影响儿茶素氧化的酶进行了检测，发现在培养期间加入儿茶素后，(-)- egcg等都有所下降。同时也澄清了对儿茶素的降解能力不是出现在荠菜培养基中，而是出现在细胞中。为了从细胞中提取酶，使用法式压滤机破坏细胞是一种有效的方法。还发现儿茶素中(-)- egcg是主要的底物。