• Applied Biological Chemistry
• /
• v.51 no.1
• /
• pp.24-37
• /
• 2008

Yeast with excellent ferment ability was isolated and selected from wild grape to manufacture wild grape wine. Wild grape wine by SMR-3 isolated from wild grape was better than other strains in quality, such as high alcohol content and low acidity, residual sugar, organic acid and fusel oil content. Fermentation condition was optimized to manufacture wild grape wine with response surface methodology using isolated SMR-3 as an alcohol fermentation strain. As a result of culture conditions, 10.61% of alcohol content was expected under the conditions of $21.91^{\circ}C$ fermenting temperature, $21.48^{\circ}brix$ of initial sugar content, and 14.65 day of fermentation time. Residual sugar content showed the lowest value at $24.48^{\circ}C$ fermentation temperature, $12.78^{\circ}brix$ of initial sugar content, and 9.02 day fermentation time. The highest level of sensory evaluation was found at $20.23^{\circ}C$ fermentation temperature, $25.30^{\circ}brix$ of initial sugar content, and 5.94 day fermentation time. Ethyl alcohol was the main alcohol component in wild grape wine and fusel oil in wild grape wine was hardly detected; thus, the quality of wild grape wine was considered excellent. The optimal fermentation conditions of wild grape wine was superimposed by deriving a regression equation for alcohol content, fusel oil, ethyl alcohol content, and overall palatability for each variable of wild grape wine. Hence, the optimal fermentation conditions are estimated to be: fermentation temperature $24{\sim}28^{\circ}C$, initial sugar content $20{\sim}24^{\circ}brix$, and fermenting time $12{\sim}14$ days.

• Microbiology and Biotechnology Letters
• /
• v.15 no.2
• /
• pp.75-79
• /
• 1987

The conventional alcohol fermentation method requires a large amount of energy for cooking the starchy raw materials prior to saccharification. The aim of this study was to compare the possibility of large scale alcohol fermentation from cassava slices were compared in low and high temperature cooking systems. The same amount of saccharifying and liquefying enzymes were used for cooking at low and high temperature. At low temperature cooking, conversion of glucose consumed in fermented mash to alcohol was 0.468g alcohol per g glucose of which was higher yield than that obtained at high temperature.

• Journal of the Korean Society of Food Culture
• /
• v.35 no.5
• /
• pp.450-458
• /
• 2020

This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5℃), medium (10 and 15℃), and high (20℃) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer's preference test enrolling five consumers, Dongchimi fermented at 15℃ until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (-1, 2, 5℃) for four weeks after fermenting at 15℃ for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5℃ groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15℃ and storage at -1℃ for Dongchimi enables it to maintain the best quality for a long time.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.6
• /
• pp.689-695
• /
• 2013

Flounder Verasper moseri Jordan et Gilberu sikhae is a traditional salt-fermented food in Korea. We investigated the optimal processing conditions for desirable quality-controlled flounder sikhae by analyzing the physiochemical properties, microbiological species, and organoleptic properties. The optimal fermentation temperature, salt concentration, and fermentation period for preparing flounder sikhae of acceptable quality were $10^{\circ}C$, 4%, and 14 days, respectively. The amino-N and volatile basic nitrogen (VBN) contents of rhe acceptable quality flounder sikhae were 243.65 mg/100 g and 44.25 mg/100 g, respectively.

• KSBB Journal
• /
• v.30 no.3
• /
• pp.125-131
• /
• 2015

Kluyveromyces marxianus is a well-known thermotolerant yeast. Although Saccharomyces cerevisiae is the most commonly used yeast species for ethanol production, the thermotolerant K. marxianus is more suitable for simultaneous saccharification and fermentation (SSF) processes. This is because enzymatic saccharification usually requires a higher temperature than that needed for the optimum growth of S. cerevisiae. In this study, we compared the fermentation patterns of S. cerevisiae and K. marxianus under various temperatures of fermentation. The results show that at a fermentation temperature of $45^{\circ}C$, K. marxianus exhibited more than two fold higher growth rate and ethanol production rate in comparison to S. cerevisiae. For SSF using starch or corn stover as the sole carbon source by K. marxianus, the high temperature ($45^{\circ}C$) fermentations showed higher enzymatic activities and ethanol production compared to SSF at $30^{\circ}C$. These results demonstrate the potential of the thermotolerant yeast K. marxianus for SSF in the industrial production of biofuels.

• Journal of the Korean Society of Tobacco Science
• /
• v.23 no.2
• /
• pp.156-161
• /
• 2001

This study was carried out to evaluate the effect of bulk fermentation on chemical, chromatic, and organoleptic characteristics of burley leaf tobacco. The pile of ferment processing was taken up 32 days under the conolitions of leaf moisture contents of $28\pm1%$, with a pressure of some 200kg/$m^2$ within a closed room (mean air temperature and relative humidity ; 20.5$^{\circ}C$ and 58.7%). The pile was opened up and reconstructed two times when the maximum inside temperature reached at $45~46^{\circ}C$. The nicotine content was decreased, but amomnia contents and pH were significantly increased by bulk fermentation. Otherwise, the contents of total nitrogen, total volatile base, organic acids, and fatty acids were not affected by same treatment. The value of L(black to white), a(red to green) and b(yellow to blue) in chromatic characteristics were significantly decreased by bulk fermentation. In sensory test of the cigarettes made by addition of the tormented tobacco leaves after toasting in proportion of 19-25%, no negative characteristics in irritation, taste, and preference were detected in comparison with normally processed cigarettes(19%, 2 years fermentation, toasting). The results suggest that bulk fermentation may be useful to increase the proportion of burley leaf tobacco in the cigarettes and to shorten the period of storage for aging.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.3
• /
• pp.293-300
• /
• 2015

We sought to extend the shelf-life of Alaska pollack Theragra chalcogramma sikhae while maintaining quality. We compared the chemical, microbiological, and organoleptic characteristics of sikhae prepared under four different conditions. Control fish were fermented at ambient temperature ($21{\pm}2^{\circ}C$); other samples were stored at $5^{\circ}C$ after fermentation at ambient temperature for 36 h (A1), 60 h (A2), and 84 h (A3). Volatile basic nitrogen and amino-nitrogen levels, and total acidity increased with fermentation time in all samples, but the pH fell, attaining a relatively lower level in the control than in other samples. Over 90% of all viable cells were lactic acid-producing bacteria; this proportion did not change significantly during fermentation. In terms of texture, only hardness was affected by fermentation. The hardness of the control fell more rapidly than did that of the other samples. In terms of sensory evaluation (the acceptance test and quantitative descriptive analysis [QDA]), A2 was superior to other samples after fermentation for different times; A2 maintained limited salability (6 points on the relevant index) for up to 17 days of storage.

• The Korean Journal of Food And Nutrition
• /
• v.17 no.4
• /
• pp.405-411
• /
• 2004

The sensory properties in Alaska pollack sikhae were compared in 3 different temperature conditions, 5$^{\circ}C$, 20$^{\circ}C$ and alternating temperature(stored at 5$^{\circ}C$ after 10 days of fermentation at 20$^{\circ}C$), respectively, during fermentation. The change of instrumental texture including hardness, cohesiveness, adhesiveness and chewiness increased and/or decreased without significant difference in the sikhae fermented at 5$^{\circ}C$ during fermentation. Three profiles, hardness, chewiness and cohesiveness in the sikhae fermented at 20$^{\circ}C$ increased up to 12 day and then decreased, whereas those in alternating temperature decreased significantly. From the acceptance test during fermentation, sikhae products fermented for 14 days at 5$^{\circ}C$, 9 days at 20$^{\circ}C$ and 13 days at alternating temperature were superior in sensory properties. The score more over 5 point in overall acceptance was maintained until 14 days in 5$^{\circ}C$, 9 days in 20$^{\circ}C$ and 13 days in alternating temperature, respectively, and particularly, alternating temperature condition was superior to the different temperature conditions. The sensory texture and overall acceptance had the high positive correlation with chewiness and taste, respectively. From the result of quantitative descriptive analysis, the intensities of acidic odor and taste in alternating temperature maintained and/or increased during 27 days of fermentation, whereas those in sikhae fermented at 5$^{\circ}C$ decreased. These results demonstrated that cold chain system such as alternating temperature was needed for shelf-life extension and producing of marketable Allaska pollack sikhae.

• Journal of Microbiology and Biotechnology
• /
• v.3 no.4
• /
• pp.266-269
• /
• 1993

The production of free non-volatile and volatile organic acids in Kimchi during fermentations at 30, 20 and $5^{\circ}C$, were determined by gas chromatography. The order in the amount of non-volatile organic acid, soon after preparation, was malic, citric, tartaric, pyroglutamic, oxalic, lactic, succinic and ${\alpha}-ketoglutaric$ acids. The major non-volatile acids at the optimum ripening time were malic, tartaric, citric and lactic acids, and as the temperature was lowered, the amount of lactic, succinic, oxalic, pyroglutamic and fumaric acids increased, while that of malic and tartaric acids decreased. The order in the amount of volatile acids at the beginning was acetic, butyric, propionic and formic acids. Among these acids, acetic acid was significantly increased in its amount during fermentation and the Kimchi fermented at low temperature produced more acetic acid than that fermented at high temperature.

• 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.