Microbial ecology of Narezushi and function of isolated lactic acid bacteria isolated

对米州出产的纳热祖实进行了微生物生态、成熟过程中成分的变化以及乳酸菌分离株(LAB)功能的研究。本研究对传统食品进行了积极的继承，以三马祖士为例，鱼肉和大米的细菌活菌数分别为8.9×10~(-8)个/g和1.8×10~(-8)个/g。根据核苷酸序列，从纳热祖什分离到的3个实验室分别被鉴定为乳杆菌sakei、乳酸明串珠菌和乳酸乳球菌。同时还分离到了几种常见细菌。对三马祖什和萨巴祖什的微生物群进行了分子生态分析。在89个无性系中，共检测到13种。包括五个实验室：Lb.sakei，Leuc.geliumLeuc.mensenteroides，Lc.lactis subsp.lactis MR17，Lc.piscium。根据克隆的丰度，认为Lb.sakei是主要的实验室。在93个无性系中，共发现23种。本研究以乳酸菌、戊糖小球、鱼腥藻、银耳等11个实验室为研究对象，对其成熟过程中化学成分的变化进行了研究。纳氏鱼肉成熟后，水分含量增加。鱼肉灰分含量降低，米饭灰分含量增加。成熟过程中蛋白质含量变化不大。Ayuzushi几乎所有的氨基酸都降低了。萨巴祖什增加了几种氨基酸，桑马祖什增加了许多氨基酸。不同供试品种间游离氨基酸含量的变化不同。成熟过程中氨基酸种类的变化在不同品种之间也不同。乳酸是纳豆中的主要有机酸。对几个实验室分离株进行了耐酸性测试，但没有一个分离株能耐受PH2的处理。

Narezushi produced in Mie Prefecture were investigated for microbial ecology, changes in components during maturing process, and function of isolated lactic acid bacteria(LAB). The study was conducted to inherit the traditional food positively.In the case of Sammazushi, viable counts of bacteria were 8.9X10^8 and 1.8X10^8 cells/g for fish meat and rice, respectively. Three LABs isolated from the Narezushi were identified as Lactobacillus sakei, Leuconostoc lactis, and Lactococcus lactis, respectively, based on nucleotide sequences. Several general bacteria were also isolated.Molecular ecological analyzes of microbiota of Sammazushi and Sabazushi were carried out. For Sammazushi, 13 species were detected from 89 clones. Five LABs,Lb.sakei, Leuc.gelidum Leuc.mensenteroides, Lc.lactis subsp.lactis MR17,Lc.piscium were included. Lb.sakei was considered as major LAB according to abundance of clone. For Sabazushi,23 species were found from 93 clones. Eleven LABs,Lb.sakei, Pediococcus pentosaceus, Lc.piscium, Leuc.gelidum etc.were included.Changes in components during maturing process were investigated. Moisture of fish meat portion was increased after maturation in Narezushis tested. While ash content of fish meat was decreased, that of rice portion was increased. Change in protein content was small during maturing process. Almost all amino acids were decreased in Ayuzushi. Several amino acids were increased in Sabazushi, and many of amino acids were increased in Sammazushi. Changes in contents of free amino acid were varied among Narezushis tested. Kinds of amino acids changed during maturing were also varied among Narezushis. Lactate was major organic acid among Narezushis. Several LAB isolates were tested for tolerance against acid, however, none of the isolate tolerated for treatment at pH2.