A number of traditional fermented products are found in Japan. Lactic acid bacteria are present in most of the fermented products with molds and yeasts and contribute to growth inhibition of spoilage microorganisms and production of aroma compounds. In the article, diversity of lactic acid bacteria in shochu, sake and sunki are reviewed. Fructophilic lactic acid bacteria, recently found in fermented products, are introduced.

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Although there are in excess of 1000 cheese varieties worldwide, each manufacture of cheese varieties involves combining only four ingredients; milk, coagulants (rennet), microorganisms and salt. Especially lactic acid bacteria (LAB) starter is involved in cheese production and contributes to the ripening process. LAB commonly used in cheese manufacture includes mesophilic Lactococcus and Leuconostoc genus, which are produce lactic acid in the cheese production process and promote a decrease pH and coagulation of milk. In the ripening process, LAB provides the enzymes, especially proteinase, involved in the proteolytic conversions that give rise to peptides and amino acids, which contribute to the cheese taste and flavour in semi-hard or hard-type cheese. The amino acid catabolism is initiated by aminotransferase (AT) of Lactococcus lactis strain and contributes to cheese aroma formation during cheese ripening. The enzyme is dimeric or tetrameric with a molecular mass subunit of about 38-43.5kDa. Recent studies have also determined that AT activity is from a strain of Lb. paracasei subsp. paracasei. AT is known to have a significant impact on cheese flavour, and it should therefore be possible to use AT activity profiles as selection criteria of LAB as adjunct cultures for cheese production.

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Extracellular polysaccharides (EPS) produced by Lactobacillus plantarum No.14 (LP14) were fractionated into neutral EPS (NPS), weakly acidic EPS (W-APS) and strongly acidic EPS (S-APS) by anion-exchange chromatography. The NPS was further fractionated into high molecular weight neutral EPS (HNPS) and low molecular weight neutral EPS (L-NPS) by gel filtration chromatography. The W-APS and S-APS contained carboxyl group 0.76% and sulfate group 7.94%, respectively. H-NPS contained galactose (Gal), glucose (Glc) and rhamnose and L-NPS contained mannose (Man) and Glc in the molar ratio of 0.62 : 1.00 : 0.27 and 0.92 : 1.00, respectively. W-APS contained Gal, Man and Glc and S-APS contained Gal, Man and Glc in the ratio of 0.41 : 6.74 : 1.00 and 0.20 : 0.08 : 1.00, respectively. Mitogenic activity of all EPS as well as LP14 to Peyer's patch cells and mesenteric lymph node cells of swine were significantly higher than control. In conclusion, EPS produced by LP14 consisted of two NPS and two APS, and each EPS had a different sugar composition, furthermore all EPS and LP14 exert immunostimulatory activity on both Peyer's patch cells and mesenteric lymph node cells of swine. These findings suggest that EPS from LP14 has the possibility to have new physiological activities.

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Many researches have reported that a wide variety of mutagens was discovered in our surroundings, and we face to the risk of their mutation. It has been pointed that intaking antimutagens such aslactic acid bacteria is effective to reduce mutagens from human intestinal tract. In order to elucidate antimutagenicity of lactic acid bacteria, further studies on the mechanism are necessary. Therefore, we investigated the ability of various cellular components of lactic acid bacteria to adsorb heterocyclic amines. The strains used were five different strains which were isolated from fermented vegetables, and the mutagens examined were four heterocyclic amines which were detected from foods. As the results of adsorbing assay by HPLC, the cell wall fraction showed the highest ability to adsorb PhIP, MeIQx, and MeIQ. The peptidoglycan fraction had the highest ability to adsorb Trp-P-1. Thus different cellular components of lactic acid bacteria adsorbed different heterocyclic amines.

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