Nippon Nōgeikagaku Kaishi

Relationship between pH and Citric Acid Content in Shoyu Koji

Studies on pH of Shoyu Koji. Part I

Shoji SASAKI, Yoshiki KATOH, Kazuo UCHIDA

1986 Volume 60 Issue 1 Pages 1-7
Published: 1986
Released on J-STAGE: February 18, 2009

DOIhttps://doi.org/10.1271/nogeikagaku1924.60.1

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This study examined the influence of citric acid on pH in shoyu koji culture and citric acid metabolism in cultures of Aspergillus oryzae ATCC 48022 and A. sojae Y-291 during the kojimaking process. The pH depended on the amount of citric acid in the koji. The citric acid content was largely influenced by the moisture of the culture medium, culture temperature and strain used. A large amount of citric acid aws found in koji grown in low water content medium under low temperature.
¹⁴C-Citric acid added to the medium was not metabolized by A. oryzae when the koji was grown at 23°C on medium moistened by spraying with water whose weight ratio to soybean was 1:1. Under the same culture conditions, A. sojae metabolized a small amount of ¹⁴C-citric acid. Both Aspergillusstrains synthesized citric acid from ¹⁴C-malic acid and ¹⁴C-pyruvic acid. On the other hand, A. oryzae and A. sojae metabolized a considerable amount of ¹⁴C-citric acid when koji was grown at 33°C on medium moistened by spraying with water whose weight ratio to soybean was 1.8:1.
More citrate synthase _??_EC 4.1.3.7_??_ and less aconitate hydratase _??_EC 4.2.1.3_??_ activity were observed in koji cultures of A. oryzae and A. sojae grown at 23°C on the medium moistened by spraying with water whose weight ratio to soybean was 1:1 than in cultures grown at 33°C on the medium moistened by spraying with water whose weight ratio to soybean was 1.8:1. The amount of citric acid in koji cultures seemed to depend mainly on the enzyme activities of citrate synthase and aconitate hydratase in koji.

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Mechanism of Potentiating Effect of Lysine and Glutamic Acid on Inactivation of Phage J1 by Ascorbic Acid

Akira MURATA, Kanehiro YOKOO, Kazuo OSHIMA, Fumio KATO

1986 Volume 60 Issue 1 Pages 9-14
Published: 1986
Released on J-STAGE: February 18, 2009

DOIhttps://doi.org/10.1271/nogeikagaku1924.60.9

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The mechanism of potentiating effect of glycine on inactivation of phage J1 by ascorbic acid (AsA) was reported earlier. Here we report on the mechanism of potentiating effect of L-lysine and L-glutamic acid on inactivation of phage J1 by AsA. Bubbling oxygen through the reaction mixture and addition of hydrogen peroxide or transition metal ions into the reaction mixture enhanced the inactivation of phage by combining AsA and each amino acid. In contrast, nitrogen bubbling and the addition of reducing agents, chelating agents or general radical scavengers inhibited the inactivation of phage. Experiments using specific radical scavengers, superoxide dismutase or catalase showed that hydroxyl radical (OH••) were mainly responsible for the inactivation of phage. The spectrophotometric study showed that amino acids increased the autoxidation rate of AsA. Essentially the same results were obtained with some other L-amino acids. These findings are similar to those obtained with glycine. The results taken together indicate that amino acids enhance the phage-inactivating effect of AsA by increasing the rate of OH• generation during autoxidation of AsA. In addition, the same potentiating effects on inactivation of phage by AsA were observed with D-amino acids.

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Shoot-Forming Cultures of Pelargonium graveolens by Jar Fermentation

Hiroaki KATAGI, Etsuko TAKAHASHI, Kazuo NAKAO, Masayoshi INUI

1986 Volume 60 Issue 1 Pages 15-17
Published: 1986
Released on J-STAGE: February 18, 2009

DOIhttps://doi.org/10.1271/nogeikagaku1924.60.15

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We were able to develop a shoot-forming culture of Pelargonium graveolens in jar fermentors by a modification of Linsmaier-Skoog's medium with 10^-5M indoleacetic acid and 10^-6M 6-benzyl-adenine. Young adventitious shoots (10g fresh weight) which had been cultured on agar media were inoculated into 5-liter jar fermentors containing 3-liters of medium and cultured under continuous illumination at 25°C with agitation of 3 liters/min (1vvm) aeration through sintered glassfilter. After 3 weeks, the yield was 145g fresh weight. The GC-pattern of volatile compounds in the extract of the shoot-forming culture was similar to that of natural Pelargonium leaf oil, and these volatile compounds in the shoot-forming culture were identified with standard compounds. But the content of citronellol (a major constituent of natural Pelargonium leaf oil) in the culture was less than that in intact leaves. With the use of 10^-5M indolebutyric acid as auxin and reduced concentration of NH₄⁺, the weight of the shoot-forming culture increased to 37.5-fold during 3 weeks of jar culture.

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Studies on Chemistry of Plant Flavor and Biological Activity

Hiroyuki NISHIMURA

1986 Volume 60 Issue 1 Pages 19-29
Published: 1986
Released on J-STAGE: February 18, 2009

DOIhttps://doi.org/10.1271/nogeikagaku1924.60.19

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[title in Japanese]

[in Japanese]

1986 Volume 60 Issue 1 Pages 61-62
Published: 1986
Released on J-STAGE: February 18, 2009

DOIhttps://doi.org/10.1271/nogeikagaku1924.60.61

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[title in Japanese]

[in Japanese]

1986 Volume 60 Issue 1 Pages 62-64
Published: 1986
Released on J-STAGE: February 18, 2009

DOIhttps://doi.org/10.1271/nogeikagaku1924.60.62

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