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Changes in fermentative sugar content during storage of citrus molasses
Abstracts of the Articles Printed in Hakkokogaku Kaishi
499
Abstracts of the Articles Printed in Hakkokogaku Kaishi V o l . 65, N o . 4 (1987)
below 1.7 or 10.7 or above 10.7. When slaked lime for the liming of juice wastes was added at a concenYojiRO KOBA*, and RIICHIRO OHBA (Departmentof tration of 0.6% or more than 0.6%, the sugar concenApplied A~fierobial Technology, Faculty of Engineering, tration was almost unchanged, but when the lime was Knmamoto Institute of Technology, Ikeda 4-22, below 0.4%, the decrease was great. Peel juice that Kumamoto 860, Japan; *Department of Food Science was originally from pH 1.9 to 3.5 did not change in & Technology,Facultyof Agriculture, Kyushu University, 3 days. At pH 1.9, the total sugar content was stable, Hakozaki, Higashi-ku, Fukuoka 8 1 2 , Japan) but at pH 10.9, it decreased slightly. The sugar concentration did not decrease when the peel juice was Hakkokogaku 65: 237-241. 1987. A purple pigment was formed from cereals by first sterilized and then covered with toluol, but when fermentation without cooking. The formation of sterilization was not done, there was some inversion of purple pigment from barley was the most suitable of all the sugar. Storage of citrus molasses (Brlx 71.5 °) cereals tested. For the formation of the pigment, a covered with toluol at 30°C for 54 days caused a slight suitable fermentation period was 5 or 6 days at 30°C decrease in the sugar concentration and sucrose and a desirable initial pH of the fermentation was 3.5. inversion. Below Brix 71.5 °, there were large decreases A supernatant separated from fermented broth by in the sugar concentration caused by microbial fermencentrifugation formed larger amounts of the pigment tation with formation of mannitol. precipitate upon storage in a cold room (5°C) than at high temperatures. The purple pigment was soluble Monitoring and Control of Anaerobic FermenMonograph------MAsAmTO TAYA in dilute acid or alkaline solution and HCl-methanol. tation Systems. (Department of Chemical Engineering, Faculty of However, it was insoluble in butyl alcohol, propyl Engineering, Nagoya University, Furo-cho, Chikusa-ku, alcohol, acetone, or ethyl ether. The tint of the Nagoya 464, Japan) Hakkokogaku 65: 249-263. pigment solution showed purple to blue, leek-green, and green according to the change of pH. This 1987. color-change was reversible. This pigment was To extend the range of possible uses of anaerobic presumed to be flavonoids, especially anthocyanins. microorganisms, the following topics are discussed in
Formation of Purple Pigment f r o m Cereals by Fermentation without Cooking. SEINOSUKEUEDA,
this paper.
Changes in Fermentative Sugar Content during 1. Cellulose digestion by cellulolytic anaerobes, Storage of Citrus Molasses. SATORU TAKAHASHI including rumen bacteria and newly isolated thermo-
(Department of Food Scienceand Technology, Faculty of philes, was examined from the viewpoint of biomass Engineering, Toa University, 15-2 Kusuno, Shimonoseki- utilization. Some characteristic cellulase genes of the shi, Yamaguchi 751, Japan) Hakkokogaku 65: anaerobes were cloned and expressed in Escherichiacoll. 243-248. 1987. The changes in fermentative sugar during the storage of peel juice and citrus molasses were studied in relation to microbial contamination by adjustment of the pH and sugar concentration, or by the covering of the surface of the juice with toluol. The bacterial cell number of 105 that originally contaminated the peel juice was decreased to l0 s by centrifugation or by filtration with the filter aid celite. The bacterial contaminants decreased to 102 when the pH was 1.7 or
2. Extractive fermentation systems were developed to overcome the problem of end-product inhibition, which is often observed in anaerobic processes such as acetone-butanol and ethanol fermentation. 3. Anaerobic cultures could be monitored and controlled on the basis of the gas produced by anaerobic bacteria and fluorescence derived from fluorescent components in microbial cells.
499
Abstracts of the Articles Printed in Hakkokogaku Kaishi V o l . 65, N o . 4 (1987)
below 1.7 or 10.7 or above 10.7. When slaked lime for the liming of juice wastes was added at a concenYojiRO KOBA*, and RIICHIRO OHBA (Departmentof tration of 0.6% or more than 0.6%, the sugar concenApplied A~fierobial Technology, Faculty of Engineering, tration was almost unchanged, but when the lime was Knmamoto Institute of Technology, Ikeda 4-22, below 0.4%, the decrease was great. Peel juice that Kumamoto 860, Japan; *Department of Food Science was originally from pH 1.9 to 3.5 did not change in & Technology,Facultyof Agriculture, Kyushu University, 3 days. At pH 1.9, the total sugar content was stable, Hakozaki, Higashi-ku, Fukuoka 8 1 2 , Japan) but at pH 10.9, it decreased slightly. The sugar concentration did not decrease when the peel juice was Hakkokogaku 65: 237-241. 1987. A purple pigment was formed from cereals by first sterilized and then covered with toluol, but when fermentation without cooking. The formation of sterilization was not done, there was some inversion of purple pigment from barley was the most suitable of all the sugar. Storage of citrus molasses (Brlx 71.5 °) cereals tested. For the formation of the pigment, a covered with toluol at 30°C for 54 days caused a slight suitable fermentation period was 5 or 6 days at 30°C decrease in the sugar concentration and sucrose and a desirable initial pH of the fermentation was 3.5. inversion. Below Brix 71.5 °, there were large decreases A supernatant separated from fermented broth by in the sugar concentration caused by microbial fermencentrifugation formed larger amounts of the pigment tation with formation of mannitol. precipitate upon storage in a cold room (5°C) than at high temperatures. The purple pigment was soluble Monitoring and Control of Anaerobic FermenMonograph------MAsAmTO TAYA in dilute acid or alkaline solution and HCl-methanol. tation Systems. (Department of Chemical Engineering, Faculty of However, it was insoluble in butyl alcohol, propyl Engineering, Nagoya University, Furo-cho, Chikusa-ku, alcohol, acetone, or ethyl ether. The tint of the Nagoya 464, Japan) Hakkokogaku 65: 249-263. pigment solution showed purple to blue, leek-green, and green according to the change of pH. This 1987. color-change was reversible. This pigment was To extend the range of possible uses of anaerobic presumed to be flavonoids, especially anthocyanins. microorganisms, the following topics are discussed in
Formation of Purple Pigment f r o m Cereals by Fermentation without Cooking. SEINOSUKEUEDA,
this paper.
Changes in Fermentative Sugar Content during 1. Cellulose digestion by cellulolytic anaerobes, Storage of Citrus Molasses. SATORU TAKAHASHI including rumen bacteria and newly isolated thermo-
(Department of Food Scienceand Technology, Faculty of philes, was examined from the viewpoint of biomass Engineering, Toa University, 15-2 Kusuno, Shimonoseki- utilization. Some characteristic cellulase genes of the shi, Yamaguchi 751, Japan) Hakkokogaku 65: anaerobes were cloned and expressed in Escherichiacoll. 243-248. 1987. The changes in fermentative sugar during the storage of peel juice and citrus molasses were studied in relation to microbial contamination by adjustment of the pH and sugar concentration, or by the covering of the surface of the juice with toluol. The bacterial cell number of 105 that originally contaminated the peel juice was decreased to l0 s by centrifugation or by filtration with the filter aid celite. The bacterial contaminants decreased to 102 when the pH was 1.7 or
2. Extractive fermentation systems were developed to overcome the problem of end-product inhibition, which is often observed in anaerobic processes such as acetone-butanol and ethanol fermentation. 3. Anaerobic cultures could be monitored and controlled on the basis of the gas produced by anaerobic bacteria and fluorescence derived from fluorescent components in microbial cells.