清酒醸造において「もろみ」は最後の仕上げの工程であり, それより前の全ての工程を「要因」と考えるならば,「結果」に相当するものである。今回は醸造の基本技術シリーズとして筆者に「もろみをいかに導くか」に的を絞って説明して頂いた。

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米焼酎においても減圧蒸気による製品が主流になってきている。同じ原料を用いた焼酎でも蒸留法によりその香味は大きく異なり, 望ましい香味特性として要求される成分も再検討が必要である。このような視点から, 減圧蒸留の米焼酎の香気成分と官能評価との関係を見直し, さらに好ましい香りを多くし評価を悪くする成分を低減する目的で焼酎酵母の育種を行い, 実用にまで至った研究成果について解説していただいた。

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焼酎製造には様々な原料が使用されており, その原料の違いによる個性が備わっていると考えられる。しかしながら, 芋焼酎でその特徴香が甘藷から由来するモノテルペンアルコール類であることが明らかにされていることなど以外に, 原料由来の香味についての詳細な研究は多くはない。本解説では焼酎, 特に泡盛中のバニリンの由来を探求し, バニリンが植物細胞壁のリグニンから麹菌の酵素, 蒸留中の化学反応, さらには貯蔵中の化学反応を経て生成されることを明らかにし, さらには関与する酵素の遺伝子レベルでの研究も含めて, 一連の研究成果について紹介していただいた。このような研究の積み重ねにより, 焼酎をはじめとする酒類の香味に対する原料の意義や, 貯蔵も含めた製造工程の意義が明らかにされ, 酒類の多様化にも寄与していくことが期待される。

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食品の日付表示が,「製造年月日表示」から「期限表示」と切り替わって丁度1年余, また, 本年4月からは「栄養表示」も新しくなった。味噌は種類が多く, 品質特性を十分に保持し得ると認められる期限 (賞味期限) の設定には慎重を要するものと思われる。味噌の賞味期限設定のための味噌の保存試験も手がけられた筆者に, 最近の市販味噌の「期限表示」,「栄養表示」の調査結果についても解説いただいた。

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N性とは醤油業界で使われる独特の言葉で, 醤油を希釈して加熱した時に白濁を生じることをいい, N性物質を含む醤油は著しく商品価値を損なう。
この現象の起こる原因は, 大豆を蒸煮処理する時の不適切な場合に起きる。起きてしまった醤油の改善方法として幾つか研究されているが, まだまだ難問も多い。著者は通常の火入条件で, 比較的簡単に処理できる方法を確立したので紹介していただいた。

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創業360年の周年行事の一環として設置された四季醸造のミニプラントが, 来訪者の大きな反響を呼んでいると聞く。
そこで, そのミニプラントについて, 図や写真を交えて解説いただいた。

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清酒製造技術者の後継者育成を目的に昭和60年からスタートした, 日本酒造組合中央会の技術幹部養成研修 (通信教育) も13年目を迎えている。その間多くの方々の努力と貢献により, 受講者は基礎過程で約3千名, 上級課程で約千名を数えている。清酒製造技術者の育成は重要度を増しており本研修が担う役割は大きい。
研修に直接携わっておられる筆者に, これまでを振り返っていただくとともに受講者の意見もまとめ, 今後の研修の方向性も示していただいた。

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戦後, ビール造りの伝統的な姿は, 設備の大型化, 自動化, 省力化及び高速化により大きく変わり, 技術の伝承を如何にするのかといった問題も生じてきているという。
この問題を解決するために, サッポロビール株式会社が作られた教育研修機関について, 筆者にご紹介願った。

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To develop a new type of sake having a refreshing sour taste, non-lactic acid assimilating sake yeasts (MLA-12 and MLA-15) that were partially deficienct in malate dehydrogenase (MDH) were isolated from Saccharomyces cerevisiae Kyokai no.901 with treatment of ethyl methanesulfonate.It was found that MDH activities of the mutants were less susceptible to catabolite inactivation by glucose than that of the parental strain Kyokai no.901.The mutants produced a relatively large amount of lactic acid but a small amount of malic acid in static YNB 10 medium.However, the mutant MLA-12 produced large amount of malic acid (90 mg/l) than the parental strain (60 mg/l) and mutant MLA-15 (40 mg/l) in static YNB 10+10% ethanol medium.And malate synthase activity of the mutant MLA-12 was the highest.The result of the sake brewing with mutant MLA-12 on a laboratory-scale (300 g total rice) revealed that the amount of malic acid increased in proportion to the formation of ethanol during the moromi-mashing.The sake made with the mutant MLA-12 contained two times as high concentrations of lactic acid and malic acid as that made with strain Kyokai no.901 and had a refreshing sour and flavorous taste like wine.

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To control moromi-mash fermentation process, rapid measurement of glucose concentration is needed.We made a comparative study on four methods measuring glucose contents.Glucose concentrations determined on-line by the hydrogen peroxide electrode as a sensor showed good correlation (0.977 correlation coefficient) with those determined off-line by the glucostat method, when moromi-mash samples were filtered by a 20μm pore-sized filter and a 0.45 μm pore-sized filter successively.On the other hand, among off-line determinations, 0.986 to 0.972 correlation coefficients were obtained between glucose concentrations determined by the medical instruments with the disposable sensors and those determined by the glucostat method, when moromi-mash samples were filtered, and their glucose concentrations were made to be in the range from 4 mg glucose per ml moromi to 40 mg per ml with water.We think that rapid and easy measurement of glucose concentrations in moromi-mash is possible by use of the medical instruments.

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Instead of the parallel fermentation which is generally practised in sake making, we developed a step-by-step fermentation of moromi where the fermentation took place following a mashing process including steaming of rice and saccharification of the steamed rice
Saccharification of steamed rice results in a sugar-rich solution containing some rice in a semi-solid state.The solution has been called reishu, a sweet drink. Firstly, methods to saccharify steamed rice in various states were compared.When the mixture of steamed rice, rice koji, and water was incubated at 55°C or 15°C, the steamed rice in the crushed state yielded 43 w/w% glucose at 55°C for 20 h incubation the largest amount among the other states of the steamed rice.
After centrifuging of reishu, 9 to 43% of the reishu volume became supernatant (clear liquid). Some contamination problem with wild yeasts in reishu made (at 15°C) from crushed or pounded rice after steaming was solved by addition of ethanol (3% as a final) to the mixture and covering the top of the mixture with a thin plastic film.Tests on sake making with the use of reishu showed that reishu made from brown rice fermented more vigorously than that made from polished rice.
Sake resulted from the fermentation test had higher acidity than that produced by the parallel fermentation.We think that the developed method would lead to make various kinds of sake, for example, sake with low alcohol content.

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Three types of yield-limiting cultivation (ten 7-year old vines per type) were compared at the university vineyard during four years from 1993 to 1996.The average cluster weight from 10 kg of fruit per vine (in the range of 249-334 g for 4 years) was heavier than that from 12 kg (200-275 g) or 20 kg (190-230 g) of fruit per vine.The refractometric degree, titratable acidity of the grape juices at their full maturity and wine quality showed no clear difference among the three types.However, in 1993 of bad meteorological condition (chilly summer) for grapevines, 10 or 12 kg of fruit yield per vine gave better quality musts and wines than 20 kg did.On the other hand, the good meteorological conditions in 1994 to 1996, significantly influenced must composition and wine quality rather than the different types of yield-limiting cultivation did.

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Salt-torelant bacteria inhabiting a soy sauce mash and a fermenting soy paste are classfied into the species, Tetragenococcus halophilus (formerly Pediococcus halophilus). Nevertheless, they have been known to show a wide variety of reducing activity, ability to decompose am ino acids, the metabolism of organic acids, the carbohydrate fermentation and others.The authors collected eight twenty-day aged moromi specimens from eight soy sauce factories.About 100 representatinve strains were isolated from one specimen and grouped on the basis types of the fermentation patterns with five selected carbohydrates. It was found that there were diverse types of the fermentation patterns within the strains isolated from one moromi specimen.Number of the types ranged from 11 to 24, and the frequency of occurrence of each type was widely distributed among the eight apecimens.

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