[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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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.

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We prepared two novel products of miso using sesame flour. The first is sesame flour miso for which 20% of the rice–koji was replaced with sesame flour; the second is sesame flour–koji miso for which 20% of the rice–koji was replaced with sesame flour koji cultured with Asp. niger. The water content of the sesame flour miso was as high as that of rice–koji miso, and the nitrogen content of miso ranked in the order of the sesame flour miso, rice–koji miso, and sesame flour–koji miso. The sesame flour–koji miso was rich in amino acids; particularly, the glutamic acid and aspartic acid showed values double that of other miso. The pH of sesame flour–koji miso indicated the lowest value, and the values of acidity at I,II of the sesame flour–koji miso are about 1.7–1.8 times as high as for other miso. The content of total polyphenols of the sesame flour–koji miso indicated about 1.6 times the value of rice–koji miso. In addition, DPPH redical scavenging activities and SOD activities of the sesame flour–koji miso were high. During fermentation, the miso developed using sesame flour increased its antioxidation activity. Moreover, a high correlation was also observed between the content of the total polyphenols and the radical scavenging activity. Although the color of the sesame flour–koji miso was dark, the sesame flour–koji miso was not judged inferior in sensory evaluation points compared with rice–koji miso. These results suggest the possibility of applying the novel miso products developed using sesame flour.

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