Volatile components of “kusaya” were studied by GLC and GC-MS analyses. Eight acids (acetic, propionic, isobutyric, n-butyric, isovaleric, n-valeric, isocaproic, and n-caproic acid), three bases (TMA, DMA or MMA, and ammonia) and six carbonyls (acetaldehyde, propion-aldehyde, acetone, n-butyraldehyde, methylethylketone, and caproaldehyde) were identified. The aroma of “kusaya” seems to be due to the volatile acids identified, especially to n-butyric acid.

抄録全体を表示

新島, 大島及び父島の汁を用い, これら汁中のヒスタミン (Hm) 量, Hm生成菌及びHm分解菌の存在並びにその菌種を調べた. その結果, 各汁ともHm生成菌はほとんど検出されなかったこと, Hm分解菌が10⁴～10⁶cells/ml程度存在したこと, 更にpHがHm分解活性至適域であったことから, 汁中ではHmが蓄積されにくい環境であることが分かった. 各汁のHm分解菌として Alcaligenes がいずれの試料からも多数認められた. しかし, 汁中のHm分解菌のほとんどは, 汁の優勢菌種ではなかった.

抄録全体を表示

The preservability of kusaya and salt-dried fish was compared with samples produced in Niijima Island. The results were as follows: 1) As the viable cell count of salt-dried fish immedeately after drying was 10 times large than that of kusaya, so the degree of deterioration by bacteria during drying thought to be different between these samples .The significant increase in TMA concentration and viable cell count with the lapse of storage time at 20°C was observed in salt-dried fish. 2) dominant microflora of salt-dried fish changed after 5 day's storage at 20°C from Vibrionaceae (42%) and Micrococcus (33%) to Micrococcus (88%). In kusaya sample, Micrococcus became dominant after 5 day's storage, while Corynebacterium was dominant at the begining of storage. 3) No significant difference was observed between the dominant strains of Micrococcus isolated from kusaya and salt-dried fish. 4) Corynebacterium which was the dominant strain of kusaya gravy showed antimicrobial activity against 10 among 12 isolates from raw fish, and 6 among 13 isolates from kusaya. 5) From the above results, it was speculated as the reasons shy storage life of kusaya was superior to that of salt-dried fish that the growth of bacteria on fresh fish was inhibited by the antimicrobial activity of Corynebacterium during immersion in kusaya gravy and the growth of spoilage bacteria on kusaya product might also be inhibited by Corynebacterium during drying and early storage period.

抄録全体を表示

新島の3つの汁中の微生物相を解析した.解析には培養法と遺伝子学的なタイピング法であるPCR-RFLP法およびPCR-DGGE法を用いた.平板培地で計測した生菌数はTSA培地,BP₅G培地,およびABCM培地上で1.2×10⁸～1.5×10⁹/gであった.各々の汁より40菌株を分離し,PCR-RFLP法を用いて分離菌株を群分けしたところ,分離菌株はそれぞれ6～9群に分けられた.各群の代表株を16SrDNAの塩基配列より同定した結果,Pseudomonas属,Marinobacter属,Peptostreptococcus属,Enterococcus属などに該当した.
汁よりDNAを直接抽出し,PCR増幅により得られた16SrDNAをDGGE解析に供したところ,3種類の汁に類似したバンドパターンが認められた.ゲル中より主なバンドを回収してクローニングし,塩基配列に基づいて菌を同定した.その結果,Bacteroides属,Flavobacterium属,Fusobacterium属,Eggerthela lenta , Clostridium属に該当した.培養法により分離された菌群とPCR-DGGE法によって解析された菌群には大きな違いがあることが判明し,汁中には培養できない菌群が存在していると考えられた.

抄録全体を表示

市販の低塩分および高塩分イカ塩辛および自家製低塩分イカ塩辛において，腸炎ビブリオの汚染と一般細菌数の変化を検討した．いずれのイカ塩辛においても，腸炎ビブリオの汚染は確認されなかった．市販品および自家製の低塩分イカ塩辛を25℃で培養すると一般細菌数が48時間で1,000倍近くまで増加したが，高塩分のイカ塩辛では一般細菌数は一定に維持されていた．それらのイカ塩辛に腸炎ビブリオを接種して，その増殖を検討したが，どのタイプのイカ塩辛においても，腸炎ビブリオの菌数の増加は見られず死滅した．本研究において低塩分のイカ塩辛でも腸炎ビブリオが死滅したことから，その生育および増殖の要因としてイカ塩辛の塩分濃度だけでなく，水分活性や添加物の影響も検討する必要があると考えられた．

抄録全体を表示

The salt contents of salmon meat linearly increased from 0.8% raw meat to 4.4% after 14-day's salting process at 15 wt% NaCl addition. From the DSC analysis, it became clear that the denaturation of the meat mainly occurred on myosin by salting. As the denaturation proceeds, the enthalpy change, ΔH (mcal/mg of meat) of 0.999 rapidly decreased to 0.646 for 1-day salting and then gradually decreased to 0.567 for a 14-day salting. Elastic modulus (E), viscosity, and rupture strength of meat decreased by 1-day salting, but they increased during salting. The temperature dependence of dynamic rigidity (G'), of the salmon meat pastes, suggests that the gelation occurred at ca. 58°C. The phenomena of disintegration (“himodori”) were observed on the smples excepts those of 1st day and after 10 days. The reason that has been considered is said to be due to the network structure of salt soluble proteins that were not yet formed in the 1st day's sample, and that polymerization of heavy chains of myosin proceeded in the samples after 10 days.

抄録全体を表示

To clarify the effect of microbes on the formation of amino acids during the ripening of squid shiokara, changes in the viable cell counts in 2.5% and 10% NaCl-BPG medium, 10% NaCl-PDA medium, and 10% NaCl-LBS medium, and amino acid contents etc. during ripening at 20°C were compared to shiokara containing 10% NaCl with and without antibiotics.
Though the viable cell counts in the shiokara without antibiotics markedly increased during the ripening in contrast to those with antibiotics, neither the total nor the individual amounts of amino acids significantly differed between the samples, suggesting that microbes have a slight effect on the formation of amino acids.
The initial bacterial flora of the shiokara without antibiotics were dominated by Staphylococcus, irrespective of the medium used for counting. The dominant flora in the later stage of ripening, however, differed depending on the media: Staphylococcus dominated on the 2.5% NaCl-BPG medium, while Micrococcus dominated and Streptococcus appeared in the deteriorating stage on the 10% NaCl-BPG medium.

抄録全体を表示

の二次加工品から検出された不揮発性アミン及び揮発性塩基窒素の由来について, 製造工程順に試料を採取して調査を行った. その結果, の素焼から検出されたスペルミジンは元来魚体中に含まれる生体アミンであること, プトレシンは汁に含まれていたものであることが判明した. しかし, 味付け品から比較的高濃度に検出されたプトレシン, カダベリン, ヒスタミン, チラミン及びスペルミジンは主として調味液に由来するものであることが判明した. また, 揮発性塩基窒素は汁に由来するものであった.

抄録全体を表示

The experiments were carried out to elucidate the reasons why marked increase in the pH of kusaya gravy after fish immersion occurred only in a beaker and did not in a manufacturer's large tank.
Changes in chemical components such as organic acids, volatile basic nitrogen and polyamines were analysed during storage of kusaya gravy in vitro. Acetic acid showed the most significant decrease by about 0.8% in the gravy of which pH increased from 7.0 to 8.8 after 8 days' storage at 20°C. When acetic acid was added into this gravy to give the concentration of 1%, the high pH recovered to below 7. Spiral bacteria isolated from kusaya gravy consumed acetic acid.
Drastic increase of pH value, accompaninig the growth of spiral bacteria, was observed in the gravy kept in an open beaker and was not observed in a screw-capped bottle. A great increase in the pH value was not observed in the bottom layer of the gravy infused in a long tube during 3 months' storage.
These results suggest that a reason why the pH of the gravy kept in a large tank in situ did not greatly increase is that spiral bacteria can hardly grow to consume organic acids like acetic acid in the inner part of the gravy.

抄録全体を表示

Bacterial flora of Kaburazushi (fermented turnip and yellowtail with malted rice), which is a traditional fermented food in Kanazawa, Japan, was surveyed by a simple method. Samples were obtained from four different factories. Lactobacillus, Streptococcaceae, cocci-other and coliforms were detected in samples. Predominant bacterial groups in Kaburazushi were Lactobacillus, however samples obtained from different factories and/or on different day showed different numbers of Lactobacillus and pH values. In the case of samples having large numbers of Lactobacillus, the pH value was lower. During storage at 4°C, the numbers of Bacillus and pH value did not change. Lactobacillus decreased with days of storage. Streptococcaceae were dominant after storage for 14 days, however Streptococcaceae were not detected after storage for 27 days.

抄録全体を表示