• Food Science and Preservation
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• v.22 no.3
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• pp.443-451
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• 2015

This study was carried out to investigate the quality characteristics and identification of acetic acid bacteria for black waxy rice vinegar. Eight (8) strains of acetic acid bacteria were isolated for the production of acetic acid and their acidities were then compared with commercial acetic acid bacteria. Among them, F1, H4, and two types of commercial bacteria (four best strains by vinegar zymogen) were selected. After analyzing the 16S rRNA sequence, both F1 and H4 strains were identified as acetobacter genus. Therefore, the F-1 and H-4 strains were named as Acetobacter sp. F-1 and Acetobacter sp. H-4, respectively. Acidity of black waxy rice vinegar during fermentation was steadily increased up to 16 days and the acidity was then constant. Total acidity content was higher when used FV-1 strain. In the results of Hunter's color value of black waxy vinegar, L value was at 75.01 to 80.11, while (+a) value was at 3.34 to 3.92, and (+b) value was at 12.84 to 18.09. The major organic acid of the black waxy vinegar was acetic acid. The total organic acid content was high when used H-4, F-1, C-2 and C-1 strains. The total free amino acid content of the black waxy vinegar by strain was the highest (351.43 mg%) of F-1 vinegar strain, and the lowest (247.74 mg%) of C-2 vinegar strain. A sensory evaluation of black waxy vinegar indicated that F-1 vinegar strain was better than the other samples in aspect of flavor, color, and overall preference.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.316-323
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• 1996

Flavor components in mash of Takju prepared by different raw materials such as nonglutinous rice, glutinous rice, barley and wheat flour were detected by GC and GC-MS method using non-polar column. Seven alcohols, 15 esters, 10 organic acids, 1 aldehyde, 4 benzenes, 3 phenols, 8 alkans, 2 ketones and 5 others were found in takju after 16 day of fermentation. takju by wheat flour had the most various components of volatile flavor. Treatment with addition starter had less flavor component than that without addition starter in takju by nonglutinous rice. Nine kinds of flavor components including acetic acid ethyl ester, 3- methyl-1-butanol, acetic acid, ethyl benzene, acetic acid 3-methyl butyl ester, 2-phenylethanol, 2,6-di-tert-butyl-4-methyl phenol. plumbagic acid and 1,2-benzenedicarboxylic acid dibutyl ester were commonly detected in all the treatments. Especially, 2,4,0-trimethyl-1,3-benzenediamine was isolated in takju that was made of nonglutinous rice without addition starter. Diethyl sulfide, 4-methoxy benzaldehyde, docosane and 2-methyl propyl octadecanoic acid were isolated from takju by nonglutinous rice with addition starter. Propionic acid ethyl ester, acetic acid butyl ester, 2-methyl butane and 3-methyl pentane were isolated from takju glutinous rice. 2-Hydroxy-4-methyl pentanoic acid and 2-methyl tridecane were isolated from akju by barley 3-(Methylthio)-1-propanol. hexanoic acid ethyl ester, butanoic acid monomethyl ester, tridecanoic acid, ethyl tetramethyl cyclopentadiene and 1,5-diaza-2,9-diketocyclotetradecane were isolated from takju by wheat flour. Major volatile flavor components were acetic acid ethyl ester, 3-methyl-1-butanol, acetic acid and 2-phenylethanol.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.227-232
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• 2014

In this study, Gluconacetobacter sp. gel_SEA623-2 isolated from citrus that produces bacterial cellulose was used to examine the effect of initial concentration of acetic acid and mixed culture inoculated with Lactobacillus plantarum KCCM 80077 on productivity of bacterial cellulose. In mixed culture added with 0.5% acetic acid, the viable cell count increased from $2.4{\times}10^6CFU/ml$ to $1.1{\times}10^7CFU/ml$ after 14 days of culture, and total acidity was about 0.3% higher than single culture added with 0.5% acetic acid, which implies that additional lactic acid was produced by L. plantarum KCCM 80077. In single culture, although bacterial cellulose productivity was higher when the initial concentrations of acetic acid were 0.0% and 0.5%, than when it was 1.0%, there was no significant difference. However, in mixed culture, adding 0.5% acetic acid resulted in dry weight of $37.83{\pm}6.81g/L$ and thickness of $10.33{\pm}0.58mm$, showing a significant difference from that of single culture added with 1% acetic acid, $28.40{\pm}1.23g/L$ and $7.50{\pm}0.50mm$ (P<0.05).

• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.911-917
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• 2011

This study was to investigate the characteristics of the Yakju fermented with differently-processed lotus leaves such as blanching, steaming, roasting, and drying, and fresh one for control. The total acid content was high (0.82~1.22%) in the lotus leaf Yakju, and lactic acid was the main compound among organic acids. Volatile acid content was high (200~500 mg/L) compared to the results of organic acid composition, and the main volatile acid in lotus leaf Yakju was acetic acid. Though the polyphenol content (616.5~693.1 mg/L) was similar among the Yakju, the Hunter's color value of those were quite different and also had a big impact on the sensory evaluation of color. Therefore, it seems that the enzyme activity of polyphenol oxidase in differently-processed lotus leaves may have an influence on the color of lotus leaf Yakju. In a sensory evaluation of color and aroma, lotus leaf Yakju fermentaed with fresh leaves and roasted ones were preferred to the others, and steamed leaves and roasted ones were the best in taste and overall acceptability.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1278-1284
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• 2017

Objective: To assess the potency of calcium propionate (CAP) used as silage additive, an experiment was carried out to evaluate the effect of CAP on the nitrogen transformation, fermentation quality and aerobic stability of alfalfa silages. Methods: Alfalfa was ensiled with four levels of CAP (5, 10, 15, and 20 g/kg of fresh weight [FW]) in laboratory silos for 30 days. After opening, the silages were analyzed for the chemical and microbiological characteristics, and subjected to an aerobic stability test. Results: The increasing proportion of CAP did not affect pH, lactic acid (LA) concentrations and yeast counts, while linearly decreased counts of enterobacteria (p = 0.029), molds (p<0.001) and clostridia (p<0.001), and concentrations of acetic acid (p<0.001), propionic acid (p<0.001), butyric acid (p<0.001), and ethanol (p = 0.007), and quadratically (p = 0.001) increased lactic acid bacteria counts. With increasing the proportion of CAP, the dry matter (DM) loss (p<0.001), free amino acid N (p<0.001), ammonia N (p = 0.004), and non-protein N (p<0.001) contents were linearly reduced, whereas DM (p = 0.048), water soluble carbohydrate (p<0.001) and peptide N (p<0.001) contents were linearly increased. The highest Flieg's point was found in CAP10 (75.9), represented the best fermentation quality. All silages treated with CAP improved aerobic stability as indicated by increased stable hours compared with control. Conclusion: The addition of CAP can suppress the undesirable microorganisms during ensiling and exposure to air, thereby improving the fermentation quality and aerobic stability as well as retarding the proteolysis of alfalfa silage. It is suggested that CAP used as an additive is recommended at a level of 10 g/kg FW.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1136-1144
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• 2016

Leucaena silage was supplemented with different levels of molasses and urea to study its nutritive value and in vitro rumen fermentation efficiency. The ensiling study was randomly assigned according to a $3{\times}3$ factorial arrangement in which the first factor was molasses (M) supplement at 0%, 1%, and 2% of crop dry matter (DM) and the second was urea (U) supplement as 0%, 0.5%, and 1% of the crop DM, respectively. After 28 days of ensiling, the silage samples were collected and analyzed for chemical composition. All the nine Leucaena silages were kept for study of rumen fermentation efficiency using in vitro gas production techniques. The present result shows that supplementation of U or M did not affect DM, organic matter, neutral detergent fiber, and acid detergent fiber content in the silage. However, increasing level of U supplementation increased crude protein content while M level did not show any effect. Moreover, the combination of U and M supplement decreased the content of mimosine concentration especially with M2U1 (molasses 2% and urea 1%) silage. The result of the in vitro study shows that gas production kinetics, cumulation gas at 96 h and in vitro true digestibility increased with the increasing level of U and M supplementation especially in the combination treatments. Supplementation of M and U resulted in increasing propionic acid and total volatile fatty acid whereas, acetic acid, butyric acid concentrations and methane production were not changed. In addition, increasing U level supplementation increased $NH_3$-N concentration. Result from real-time polymerase chain reaction revealed a significant effect on total bacteria, whereas F. succinogenes and R. flavefaciens population while R. albus was not affected by the M and U supplementation. Based on this study, it could be concluded that M and urea U supplementation could improve the nutritive value of Leucaena silage and enhance in vitro rumen fermentation efficiency. This study also suggested that the combination use of M and U supplementation level was at 2% and 1%, respectively.

• Korean Journal of Microbiology
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• v.6 no.2
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• pp.41-53
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• 1968

Studies on the carbohydrate metabolism of yeast as influenced by gamma-irradiation from cobalt-60 have been carried, then the mechanisms of radiation effect on respiration and fermentation were discussed under considerations of permeable changes of irradiated cell membrane. The cells of baker's yeast (Saccharomyces cerevisiae) which had been gamma-irradiated of 240 k.r. doses for an hour, then were put into aerobic oxidation and anaerobic fermentation without substrate. Total and fractionated carbohydrates of irradiated yeast cells were determined by calorimetric method with anthrone and orcinol reagents, the amounts of total carbohydrate, trehalose, RNA-ribose, PCA-soluble glycogen, alkali-soluble glycogen, acetic acid-soluble glycogen, mannan and glucan were determined according to the course of aerobic oxidation and anaerobic fermentation. It is found that the carbohydrates of irradiated cells leak out and amount of the losses teaches eleven times more than that of control, the volume of losses are seems to be replaced by water, it can be suggested the damage of gamma-irradiation occurs in the site of passive transport of cell membrane. The endogeneous aerobic respiration of irradiated cells are increased much more than control, the synthesis of reserve glycogen, glucan and RNA-ribose promoted much more than control. The anaerobic fermentation of irradiated cells are also increased than that of control, but the breakdown of carbohydrate is less than endogeneous respiration of irradiated cells. The synthetic rate is also less than that of aerobic oxidation. In irradiated yeast cells, trehalose is revealed to be primary substrate for endogeneous carbohydrate metabolism, so it is proved that the enzymic patterns are not changed but the activities of enzymes relating endogeneous respiration and autofermentation is activated. It is to be considerable to distiguish endogeneous respiration and autofermentation from exogeneous respiration and fermentation on irradiation, for membrane permeability changes and loses out carbohydrate by ionizing radiation.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.418-424
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• 2014

High-acidity vinegar was manufactured using pear concentrate by fed-batch fermentation without additional nutrients, and the physicochemical properties and volatile components were investigated at different fermentation stages (Stages 1-4) and at various initial alcohol concentrations (IAC; 6-9%). The levels of reducing sugar, free amino acids, total phenolic content, total flavonoid content, and radical scavenging ability increased slightly during Stage 4 (high-acidity vinegar), which was affected by alcohol feeding. The contents of approximately 20 types of volatile compounds differed between the moderate- and high-acidity vinegar samples, as determined by solid-phase microextraction/gas chromatography-mass spectroscopy. The level of acetic acid in high-acidity vinegar increased according to the initial alcoholic content applied. The high-acidity vinegar produced by fed-batch culture at an IAC of 6-7% showed improved physicochemical and volatile properties as compared to the moderate-acidity vinegar.

• Journal of the Korean Society of Food Culture
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• v.33 no.6
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• pp.597-607
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• 2018

This study examined the nutrient components and measured the physicochemical properties of 23 Korean sweet potato cultivars. The proximate composition, free sugars, organic acids, and dietary fiber of sweet potato were analyzed and the water binding capacity, oil absorption and pasting characteristics were measured. The proximate composition was the highest in Happymi and was higher in colored sweet potato than in general sweet potato (p<0.05). The sucrose content was the highest among the free sugars in the general cultivars and yellow/orange colored cultivar. The major organic acids were oxalic acid, citric acid, malic acid, succinic acid, fumaric acid, and acetic acid. Oxalic acid and citric acid were high in the purple colored cultivars and malic acid was high in yellow/orange colored cultivars. Each total dietary fiber content of the general and colored cultivars was 7.51-13.94 and 13.04-16.97%, respectively, but there was no significant difference. The water binding capacity and oil absorption of Juhwangmi was high in all cultivars (p<0.05). The peak viscosity of sweet potato powder showed highest a significant difference of 12.50-1342 cP (p<0.05). The breakdown of Sincheonmi was 512, which was the highest value (p<0.05). The setback of Geonpungmi was significantly low, 6.0 (p<0.05).

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.1016-1021
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• 2005

We studied on screening and isolation of dominant bacteria in the food waste fermentation process and on effective production of VFAs by isolated bacteria. In the result of study, bacteria of twelve species were isolated by anaerobic medium. Among the 12 isolated species including Escherichia coli, Clostridium formicoaceticum, C. butyricum, C. acetobutyricum. E. coli and Clostridium spp. were occurred dominantly in the fermentation process and regarded as best VFAs producing bacteria. Acetic acid are produced 287 mg/gTS(8,176 mg/L) by E. coli in concentration of $6{\times}10^8\;cells/gTS$, 551 mg/gTS(15,715 mg/L) by Clostridium formicoaceticum in concentration of $5{\times}10^4\;cells/gTS$. Three times as much acetic acid were produced as blank. Butyric acid are produced 214 mg/gTS(6,106 mg/L) by C. butyricum in concentration of $2.5{\times}10^5\;cells/gTS$ and produced 254 mg/gTS(7,261 mg/L) by C. acetobutyricum of concentration of $1.5{\times}10^5\;cells/gTS$. Two times as much butyric acid were produced as blank.