• Journal of Environmental Science International
• /
• v.21 no.10
• /
• pp.1255-1263
• /
• 2012

Batch cultivations were performed to evaluate the influences of the initial pH condition on mesophilic and thermophilic acidogenic fermentation with food waste recycling wastewater. In both conditions of mesophilic and thermophilic fermentation, TVFAs production rates were maximized at the initial pH 7 condition as 0.15 and 0.23 g TVFAs/L hr, respectively. And pH was also maintained stably between 6 and 7 during 72hr acidogenic cultivation at both conditions. However, predominant VFA components were different according to reaction temperature conditions. In mesophilic condition, propionic acid which has low conversion efficiency to methane was accumulated up to 1,348 mg/L while acetic and butyric acid were predominant in thermophilic condition. Therefore, thermophilic acidogenic fermentation was superior for the effective VFAs production than mesophilic condition. From the DGGE analysis, the band patterns were different according to the initial pH conditions but the correlations of the each band were increased in similar pH conditions. These results mean that microbial communities were certainly affected by the initial pH condition. Consequently, the adjustment of the initial pH to neutral region and thermophilic operation are needed to enhance acidogenic fermentation of food waste recycling wastewater.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.6
• /
• pp.1077-1085
• /
• 1998

The effects of yeast on the fermentation of kimchi were investigated. The treatments were divided into two groups; yeast treatment during salting of Chinese cabbage(YS) and yeast treatment added in kimchi preparation(YF kimchi). The edible periods of the kimchi after yeast treatment during salting (YS kimchi) was extended 4~5 days by the results of pH, acidity, sensory quality. The activities of amylase, polygalacturonase and galactosidase of YS kimchi were retained at low levels compared to non treated condition throughout all fermentation periods, whereas protease activity was not significant different from the non treated condition. In addition, the contents of total hexose and uronic acid did not show remarkable change throughout fermentation, but total pentose was decreased by more than 7% at the early middle stage of fermentation(7~14 day after soaking). The change of free amino acid content was decreased by 16~44% than the non treated condition. In contrast, in the YF kimchi, the sensory quality was not good. The activities of amylase, protease, polygalacturonase and gal actosidase were appreciably higher than that of the non treated condition. Meanwhile, the contents of total hexose, total pentose and uronic acid, as products of degradation of cell wall constituents by the above enzymes, were decreased by 18~68% throughout fermentation than the non treated con dition, and total free amino acids were higher than the YS kimchi. Thus, yeast treatment during salting was found to be more effective to extend the edible periods of the kimchi.

• Food Science and Preservation
• /
• v.9 no.2
• /
• pp.179-183
• /
• 2002

This study was carried out to set up alcohol fermentation condition for uncooked corn. Response surface methodology(RSM) was applied to optimize and monitor the alcohol fermentation condition with uncooked corn. The optimal yeast strain for fermentation of uncooked corn was Saccharomyces cerevisiae GRJ. The polynomial equation for alcohol contents, brix, pH and total acidity showed 0.8852, 0.9202, 0.8806 and 0.9940 of R$^2$, respectively. The optimal rendition for maximum alcohol contents were 0.18%(w/w) of enzyme concentration and 180%(v/w) of added water content. Predicted values at optimum alcohol fermentation condition agreed with experimental value.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.5
• /
• pp.845-848
• /
• 1994

The fermenting conditions for acetic acid production with Acetobacter sp. FM-10 which could grow in the medium containing 10% ehtanol were investigated. Initial concentration of acetic acid in broth medium affected greatly to the fermentation speed. For example , the acetic acid production increased proportionally by the increasing of initial concentration was higher that 1.0%. When the cultivation was started with broth medium containing 5% ethanol, the additional adding ethanol during the fermentation was not significantly increased the acidity of the medium. The acidity of the medium containing 10% ethanol was reached to 8.3% after shaking than static cultivation by about 10 days with 150 rpm shaking speed. Acetic acid production with shaking cultivation was faster the static cultivation by abot 10 days under the same condition except shaking. In acetic acid fermentation with the batch style fermentor , the optimum fermentation condition was 700 rpm of agitation speed and 5L/min air flow rate in 3L culture medium .

• The Korean Journal of Food And Nutrition
• /
• v.10 no.3
• /
• pp.287-294
• /
• 1997

When bread making, the condition of thawing-fermentation for frozen dough were tested in variable temperature, and measured thawing-fermentation time and volume of frozen dough. L-Ascorbic acid (L-Aa) was added in frozen dough for the comparison test of develop volume in bread staling degree of baking bread were measured additive frozen dough which was stoppages in freezing, staling degrees were tested hardness with Rheometer. The test for comparison of thawing-fermentation time in variable temperature was shown the condition of dough conditioner at 3$0^{\circ}C$ was most effective for bread making, Because That condition was required very short time(74 min) But, in this comparison of volume in final products was shown the products in the condition of thawing-fermentation at 3$0^{\circ}C$ was smaller than the products at 5$^{\circ}C$(418 ml). The baking volume of L-Aa additive frozen dough which has under gone thawing-fermentation at 3$0^{\circ}C$, were shown baking volume of 420 ml in 2 weeks storage terms to 100 mg/kg L-Aa additive dough and shown baking volume of 454 ml in 4 weeks storage terms to dough of 200 mg/kg additive weight. Staling degrees of L-Aa additive frozen bread were measured with Rheometer. The hardness of 100 mg/kg L-Aa additive frozen bread was sown low level hardness in 1~2 weeks freezing term, 150 mg/kg L-Aa additive frozen bread was shown low level hardness in 3 weeks freezing term. In 4 weeks freezing term, 200 mg/kg L-Aa additive frozen bread was shown low level hardness compared with non-additive L-Aa frozen bread. In comparison of frozen bread quality, non-additive L-Aa products was better than additive L-Aa products in equality of baking shape and external apparence. But in total quality in external and internal apparence, additive L-Aa products was better than non-additive L-Aa products.

• Journal of the East Asian Society of Dietary Life
• /
• v.11 no.2
• /
• pp.121-130
• /
• 2001

Jeung-Pyun Is a traditional fermented Korean food made with rice flour, water, sugar salt and unrefined rice wine(Tak-ju). In order to investigate how the addition of soybean and dextran have an influence on Jeung-Pyun fermentation and forming structure of Jeun-Pyun, adding soybean 20% and dextran 1%based on rice weight, we measured physicochemical properties. Also we measured dextran content of Jeung-Pyun batter according to the fermentation time and observed the inside of Jeung-Pyun by SEM in order to find out air pore condition. The dextran content of rice Jeung-Pyun and Jeung-Pyun adding soybean 20% was gradually increased as fermentation time was longer and Jeung-Pyun adding soybean 20% was higher than rice Jeung-Pyun. The specific volume of rice Jeung-Pyun and Jeung-Pyun adding soybean 20% was increased up to a fermentation time of 7~ 10 hours but it was decreased as fermentation time was longer. In the inside structure of Jeung-Pyun observed by SEM, the fermentation condition of Jeung-Pyun fermented for 3 and 7 hour was better and air pore size became larger, the number of it was decreased as fermentation time was longer. The air pore size of soybean 20% Jeung-Pyun is smaller more uniform than that of rice Jeung-Pyun. In conclusion. it can be suggested that the audition of soybean improves the quality of Jeung-Pyun and dextran has an influence on fermentation and forming structure of Jeung-Pyun.

• Food Science and Preservation
• /
• v.8 no.4
• /
• pp.412-418
• /
• 2001

This study was carried out to set up alcohol fermentation condition for uncooked brown rice. Response surface methodology(RSM) was applied to optimize and monitor of the alcohol fermentation condition with uncooked brown rice. The optimal yeast strain for fermentation of uncooked brown rice was S. cerevisiae GRJ. The polynomial equation for alcohol contents, brix pH and total acditiy showed 0.8828, 0.8409, 0.9431 and 0.9280 of R$^2$, respectively. Optimum range of uncooked alcohol fermentation for maximum alcohol contents were 0.34%(w/w) of enzyme concentration and 350%(w/w) of added water content, respectively. Predicted values at optimum alcohol fermentation condition agreed with experimental values.

• Transactions of the Korean hydrogen and new energy society
• /
• v.16 no.4
• /
• pp.315-323
• /
• 2005

The integrated or the two-stage (dark anaerobic and photosynthetic) fermentation processes were compared for the hydrogen production using purple non-sulfur photosynthetic bacteria, Rhodopseudomonas palustris P4. Cell growth, pH changes and organic acids and bacteriochlorophyll contents were monitored during the processes. Culture broth of Rps. palustris P4 exhibited dark-red during the photosynthetic culture condition, while yellow under the anaerobic condition without light. Rps. palustris P4 grown at the photosynthetic condition evolved 0.38 and 1.33 ml $H_2$/mg-dcw during the dark and the light fermentation, respectively, which were totally 1.71 ml $H_2$/mg-dcw at the two-stage fermentation. The rate of hydrogen production using Rps. palustris P4 grown under the dark anaerobic condition was 2.76 ml $H_2$/mg-dcw which consisted of 0.46 and 2.30 ml $H_2$/mg-dcw from the dark and the photosynthetic fermentation processes, respectively. Rps. palustris P4 grown under dark anaerobic conditions produced $H_2$ 1.6 times higher than that of grown under the photosynthetic condition. However, total fermentation period of the former was 1.5 times slower than that of the latter, because the induced time of hydrogen production during the photosynthetic fermentation was 96 and 24 hours when the seed culture was the dark anaerobic and photosynthetic, respectively. The integrated fermentation process by Rps. palustris P4 produced 0.52 ml $H_2$/mg-dcw(1.01 mol $H_2$/mol glucose), which was 20% of the two-stage fermentation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.5
• /
• pp.679-683
• /
• 2003

Strawberries were fermented for their effective value added product. In alcohol fermentation of strawberries, alcohol content was maximum value (9.22% ) under the condition of 16.32$^{\circ}$Brix of initial sugar concentration, 53.03 hr of fermentation time and 28.8$^{\circ}C$ of fermentation temperature. Acetic acid content revealed minimum value (0.49%) under the condition of 13.18$^{\circ}$Brix of initial sugar concentration, 50.99 hr of fermentation time and 24.96$^{\circ}C$ of fermentation temperature. Residual sugar content revealed minimum value (3.97$^{\circ}$Brix) under the condition of 15.00$^{\circ}$Brix, 52.00 hr and 26.0$0^{\circ}C$. The optimum conditions for each alcohol fermentation were 14$^{\circ}$Brix, 50 hr and 28$^{\circ}C$.

• Journal of Wetlands Research
• /
• v.9 no.1
• /
• pp.123-131
• /
• 2007

Effect of nitrogen-load condition on hydrogen ($H_2$) production and bacterial community in a continuous anaerobic hydrogen fermentation were investigated. The slight $H_2$ production on extremely low nitrogen-load condition (C/N ratio: 180) at the start-up period. The highest $H_2$ production was obtained when the C/N ratio was 36, the $H_2$ production yield ($mol-H_2/mol-glucose$) reached to 1.7, and it was indicated that Clostridium pasteurianum mainly contributed to the $H_2$ production. The $H_2$ production was decreased on both the lower (C/N: 72) and higher (C/N: 18) nitrogen-load conditions. The excess nitrogen-load was not always suitable for the hydrogen production. The fluctuation of $H_2$ production seemed to be caused by a change in the bacterial community according to the nitrogen-load condition, while a recovery of $H_2$ productivity was possible by a control of nitrogen-load condition through the bacterial community change. When the nitrogen-load condition was not suitable for hydrogen production, the lactic acid concentration was increased and also lactic acid bacteria were definitely detected, which suggested that the competition between hydrogen fermentator and lactic acid producer was occurred. These results demonstrated that the nitrogen-load condition affect on the $H_2$ productivity through the change of bacterial community in anaerobic hydrogen fermentation.