• Microbiology and Biotechnology Letters
• /
• v.22 no.5
• /
• pp.550-556
• /
• 1994

For an extension of the palatable stage in Kimchi which was limited by further lowering pH as the fermentation proceeds, the starter culture of bacteriocin-producing Enterococcus faecium DU 0267 obtained from Kimchi was added at the preparation time, and pH, bacteriocin activity, growth of lactic acid bacterial group and gas production in Kimchi were examined during the fermentation at 10, 20 and 30$\circ$C . The pH of Kimchi fell rapidly to 4.0~4.2 in the early fermentation stage, and then, has gone down very slowly throughout further fermentation. The lactic acid bacte- ria, particularly lactobacilli and leuconostoc, were remarkably slower in its growth than those in the control. Although the patterns of these change during fermentation at different temperatures were similar, these effects by the addition of starter were enhanced at 10 and 20$\circ$C. The bacteriocin activity was increased rapidly during log phase of the bacteriocin producer strain in the early fermentation stage of Kimchi and reached their maximum after fermentation at 10$\circC, for 8 days and at 20 or 30$\circ$C for 2 days. Thereafter, the activity disappeared quickly. The gas production by fermentation was also suppressed considerably, and their volume produced after fermentation at 20$\circ$C for 14 days corresponded to 60% of those of the control.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.1
• /
• pp.16-23
• /
• 1998

Effect of Fermentation temperature on the changes of chemical components in Kakudgi during fermentation was investigated by measuring free sugar, organic acid and volatile compounds up to 57 days at several temperatures. The mannitol was increased in palatable period in contrast with those of other free sugars. The higher the initial fermentation temperature was and the longer the initial fermentation time at 2$0^{\circ}C$ was, the faster the second increasing period was and the less the initial contents was. Lactic acid was increased 6~31 times from a little amount at the initial period. The higher the initial fermentation temperature was and the more the increasing content was. But malic acid which was abundant(55.1% of total nonvolatile organic acid) in the initial fermentation period was remarkably decreased in the palatable period. The change of the sulfides among the volatile compounds was remarkable. Methyl allyl sulfide which was a little in the initial fermentation period was remarkably increased in the final fermentation period, and the correlation coefficients between the content of methyl allyl sulfide and aroma in sensory evaluation were high. It could be suggested that the fermentation temperature should be set to 4$^{\circ}C$ after fermentating at 2$0^{\circ}C$ for 36 hours in the view point of keeping the Kakdugi taste and quality well because of high content of free sugar and nonvolatile organic acids.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.6
• /
• pp.832-840
• /
• 2014

This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures ($5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$) and four durations (0, 1, 2, and 3 d) were arranged in a $4{\times}4$ factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as $25^{\circ}C$ and $35^{\circ}C$. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds $35^{\circ}C$, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above $35^{\circ}C$ during summer.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.7
• /
• pp.937-945
• /
• 2014

Green and black tea by-products, obtained from ready-made tea industry, were ensiled at $10^{\circ}C$, $20^{\circ}C$, and $30^{\circ}C$. Green tea by-product silage (GTS) and black tea by-product silage (BTS) were opened at 5, 10, 45 days after ensiling. Fermentation characteristics and nutrient composition, including tannins, were monitored and the silages on day 45 were subjected to in vitro ruminal fermentation to assess anti-nutritive effects of tannins using polyethylene glycol (PEG) as a tannin-binding agent. Results showed that the GTS and BTS silages were stable and fermented slightly when ensiled at $10^{\circ}C$. The GTS stored at $20^{\circ}C$ and $30^{\circ}C$ showed rapid pH decline and high acetic acid concentration. The BTS was fermented gradually with moderate change of pH and acid concentration. Acetic acid was the main acid product of fermentation in both GTS and BTS. The contents of total extractable phenolics and total extractable tannins in both silages were unaffected by storage temperatures, but condensed tannins in GTS were less when stored at high temperature. The GTS showed no PEG response on in vitro gas production, and revealed only a small increase by PEG on $NH_3$-N concentration. Storage temperature of GTS did not affect the extent of PEG response to both gas production and $NH_3$-N concentration. On the other hand, addition of PEG on BTS markedly increased both the gas production and $NH_3$-N concentration at any ensiled temperature. It can be concluded that tannins in both GTS and BTS suppressed rumen fermentation, and tannins in GTS did more weakly than that in BTS. Ensiling temperature for both tea by-products did not affect the tannin's activity in the rumen.

• Journal of the East Asian Society of Dietary Life
• /
• v.5 no.2
• /
• pp.39-48
• /
• 1995

The effects of storage containers and storage temperatures on Kimchi quality were investigated. The results were summarized as follows : 1. Pabix, poly ethylene-back+plastic container, tupper-ware were much better than crock, stainless steel, and plastic container in keeping a Kimchi. However, there was no significant differences between containers in the sensory test for Kimchi. 2. Kimchi stored at 18$\pm$2$^{\circ}C$ was the most delicious, which revealed pH 4.30, acidity 0.45-0.50%, and salt concentration 3.10wt% in the 4th days after storage whereas sensory score for Kimchi quality was very low in the 12th days after storage. 3. pH in Kimchi stored at 5$^{\circ}C$ after fermentation at 18$\pm$2$^{\circ}C$ was slowly decreased as compared to the Kimchi stored at 18$\pm$2$^{\circ}C$, but texture score of Kimchi stored at -5$^{\circ}C$ or -8$0^{\circ}C$ after fermentation at 18$\pm$2$^{\circ}C$, but texture score of Kimchi stored at -5$^{\circ}C$ or -8$0^{\circ}C$ were compared to that of the Kimchi stored at 18$\pm$2$^{\circ}C$ after fermentation. 5. In the group of Kimchi stored at 1$0^{\circ}C$, immediately after picking it took 48days until the best conditions which were pH 4.30 and acidity 0.45-0.50% were matched. 6. The most promising method in keeping good taste and good quality of Kimchi was to store Kimchi at 5$^{\circ}C$ after 4days fermentation at 18$\pm$2$^{\circ}C$. And, for long period preservation of Kimchi, it took would be effective to store at -8$0^{\circ}C$ after fermentation at 18$\pm$2$^{\circ}C$.

• Food Science and Biotechnology
• /
• v.16 no.5
• /
• pp.812-816
• /
• 2007

To overcome the problem of ginseng's earthy smell in the manufacture of ginseng wine, we used dried ginseng powder that was extrusion-cooked at $125-168^{\circ}C$ in the wine making process. By using a ginseng powder that was extrusion-cooked at higher temperatures, fermentation by Maillard reaction products (MRPs) was delayed, and the acidic pH that results from extrusion cooking was improved. At $15^{\circ}C$ with glucose instead of sucrose, an addition of 0.5%(w/v) diammonium phosphate (DAP) to the $125^{\circ}C$ extrusion-cooked ginseng powder reduced the primary fermentation time to 11 days versus 33 days without DAP. In the absence of DAP, by increasing the fermentation temperature from 15 to $30^{\circ}C$, increasing the starter yeast inoculate from 0.02 to 1 %, and by increasing the amount of ginseng extrudate from 1 to 2%, fermentation time was effectively reduced more than 10-fold. The results of this study may provide information for the alcohol fermentation of materials containing MRPs as well as for poor nitrogen sources.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.1
• /
• pp.62-67
• /
• 1997

To enhance the hyperproductive and low energy-consuming ethanol fermentation rate, the thermotolerant yeast S. cerevisiae RA-74-2 cells were immobilized. An efficient immobilization condition was proved to be $1.5{\%}$ (w/v) alginate solution, neutral pH and 20 h activation of beads. The fermentation characteristics and stability at various temperatures were examined as compared with free S. cerevisiae RA-74-2 cells. The immobilized cells had excellent fermentation rate at the range of pH 3-7 at 30-$42^{\circ}C$ in 15-$20{\%}$ glucose media. When the seed volume was adjusted to 0.12 (v/v) (6ml bead/50 ml medium), $11{\%}$ (w/v) ethanol was produced during the first 34 hand $12.15{\%}$ (w/v) ethanol [$95{\%}$ (w/v) of theoretical yield] during the first 60 h in $25{\%}$ glucose medium. In repetitive fermentation using a 2 litre fermentor, 5.79-$7.27{\%}$ (w/v) ethanol [76-$95{\%}$ (w/v) of theoretical yield] was produced during the 40-55 h in $15{\%}$ glucose media. These data suggested the fact that alginate beads of thermotolerant S. cerevisiae RA-74-2 cells would contribute to economic and hyperproductive ethanol fermentation at high temperature.

• KSBB Journal
• /
• v.7 no.1
• /
• pp.33-37
• /
• 1992

This study is to investigate the ethanol tolerance of yeast strains related to fatty acid composition and intracellular ethanol concentration for various fermentation temperatures. The maximum accumulation of ethanol in the cells was decreased by lowering the fermentation temperature, while unsaturated fatty acid content was increased by decreasing the fermentation temperature. Thus, we found that the increase of ethanol accumulation in cells resulted in the decrease of unsaturated fatty acid content. Therefore, it was suggested that the composition of unsaturated fatty acids in the cell membrane be strongly related to the diffusion of ethanol from cell to medium.

• Korean Journal of Food Science and Technology
• /
• v.52 no.1
• /
• pp.94-102
• /
• 2020

Brown rice Makgeolli was brewed by using the Saccharomyces cerevisiae strain SRCM102596 under different fermentation conditions: temperatures at 20 and 25℃ and Nuruk ratios of 5, 10, and 15%. There were no significant differences in the pH and total acidity between samples. The alcohol content at the different nuruk ratios varied significantly by the days in the fermentation process. The major free sugars were maltose, glucose, and fructose, and they gradually reduced with fermentation. The major organic acids in the brown rice Makgeolli were oxalic acid, citric acid, malic acid, succinic acid, and acetic acid. The lactic acid content increased with the number of days in the fermentation process. Among the 24 different free amino acid contents identified, the total free amino acid content of, especially, threonine, serine, and alanine were high in the brown rice Makgeolli, at 20℃ and nuruk ratio of 10%.

• The Korean Journal of Food And Nutrition
• /
• v.30 no.6
• /
• pp.1184-1190
• /
• 2017

Baking characteristics of gluten-free rice bread were investigated, when 20, 30, 40, 50 and $60^{\circ}C$ water was added during mixing. The temperature of the dough before fermentation was affected by the temperature of the water and the mixing time. When $60^{\circ}C$ water was added, the specific gravity of the dough was the highest before fermentation (p<0.01). The specific gravity of the dough after fermentation was 32~39% of the specific gravity of the dough before fermentation. When $50^{\circ}C$ water was added, the volume and the specific volume of rice bread were higher than those in addition of water at other temperatures (p<0.001). In case of adding water of $50^{\circ}C$, the shape of the rice bread showed the largest volume, high appearance and a round shape. After storage for 2 and 24 hours, the addition of water of $50^{\circ}C$ resulted in the lowest hardness and chewiness values of rice bread. The sensory descriptive analysis revealed that when $50^{\circ}C$ water was added, the air cell size, springiness and hardness values of gluten-free rice bread were lower than those in addition of water at other temperatures. There was a difference in the appearance and texture of gluten-free rice bread, when 20, 30, 40, 50 and $60^{\circ}C$ water was added during mixing.