出版社：Japan Science and Technology Information Aggregator, Electronic
摘要：Miki(a traditional beverage in Amami Island) was prepared in a laboratory(Kagoshima University) using boiled rice and raw sweet potato. Simultaneously, miki was prepared in Amami Island and commercial miki made in Amami Island was purchased. Lactic acid bacteria (LAB) in them were identified using a 16S ribosomal DNA analysis. It was shown that LAB in laboratory made miki were Lactococcus lactis subsp. lactis (30/30). However, LAB in miki made in Amami Island were different from the laboratory one, Leuconostoc lactis (3/6), Leuconostoc citreum (2/6), and Lactococcus lactis subsp. lactis (1/6). LAB in the commercial drink was Leuconostoc citreum (5/6) and Leuconostoc mesenteroides (1/6). These results indicated that microflora of LAB differed according to the lot of raw sweet potato and circumstances, the details of which are future problems. Lactococcus lactis subsp. lactis is known as producer of bacteriocin (nisin), so the production of bacteriocin or possession of nisin gene was examined from the halo formation of the sensitive strain or PCR of genomic DNA. The results showed that Lactococcus lactis subsp. lactis in miki produces bacteriocin and they possess nisin–A gene. The succession of bacteria was examined using CaCO3 plates, which showed that non–halo forming bacteria appeared at an early stage (before 3 days) but disappeared at a late stage (after at least 4 days after mashing) along with an increase in halo forming bacteria. We considered that these non–halo forming bacteria were aerobic bacteria which did not produce acid, and halo forming bacteria were LAB which produce acid. Using a starter of LAB, we were able to suppress the appearance of non–halo forming bacteria and make possible the stable production of miki.
