• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.431-437
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• 2015

In this study, high-acidity cider vinegar (HACV) was produced by alcoholic and acetic acid fermentation of apple concentrate without any nutrients and then the optimum alcohol concentration was determined through a qualitative study. HACV was fermented with different initial alcohol concentrations (6-9%) during the process of acetic acid fermentation. The highest content of reducing sugar, organic acids, and free amino acids was observed at 6% of initial alcohol concentration. Approximately 20 types of volatile compounds were identified by solid-phase microextraction (SPME) and GC-MS. The total volatile content was the highest at 6% of initial alcohol concentration, and the acid content was the lowest at 9% of the initial alcohol concentration. The HACV produced by a two-stage fermentation process was qualitatively better than commercial HACV presenting the highest value at 6% of initial alcohol concentration. Malic acid, aspartic acid, and hexyl acetate were selected as quality index components of HACV production by two-stage fermentation on the basis of correlation between their physicochemical properties and the sensory attributes of HACV.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.258-263
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• 1993

New type yoghurts were prepared by fermenting milk containing puffed rice flour(PRF) with some commercial lactic acid bacterial starters. The yoghurts were evaluated for pH, tillable acidity, viscosity and color with sensory evaluation for final quality. The optimum moisture content of rice for puffing was over or less 14%. Increasing addition level of PRF, lightness decreased and, redness and yellowness increased with increasing viscosity greatly. There was no quality difference among commercial starters but pH, acidity and viscosity of yoghurt were affected. During the storage at $5^{\circ}C$, pH dropped, acidity and viscosity increased gradually. The number of lactic acid bacteria was increased until 6 days storage to $3{\times}10^8$ and dropped after on. The yoghurt containing PRF was inferior in flavor texture and taste comparing with commercial yoghurt.

• Korean journal of food and cookery science
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• v.27 no.1
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• pp.63-73
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• 2011

Cabbage (Baechu) Kimchi in its truncated form was placed in four different packing materials, Ny/PE/LLDP, OPP/AL/PE, PP and PET, and quality changes were observed during storage. Changes in pH and total acidity showed an x-shaped cross-curve as pH decreased and total acidity increased during storage. PP tray showed the slowest change at $5^{\circ}C$ with time. The pH was initially 6.25, but decreased to 4.12~4.16 at 20 days, and total acidity showed a 4 to 4.8-fold increase after 20 days of storage compared to the initial value. During storage at $5^{\circ}C$, total bacterial count and lactic acid bacterial count rapidly increased after 4 days. The total bacterial quantity decreased after a period of time and there were differences according to packaging material; OPP/AL/PE packaging showed the most dramatic decrease. Change in microbial count mostly followed a similar pattern to that of total acidity for all packaging materials. Changes in the color of Kimchi liquid, when examined by color index in $L{\cdot}b$/a form, rapidly decreased over time, similar to pH. Small Ny/PE/PP and OPP/AL/PE packages of Kimchi were examined for changes in free volume inside the packaging. After 13 days of storage at $5^{\circ}C$, the volume was 243 mL, but storage at $20^{\circ}C$ resulted in a volume of 372 mL, a more than 1.5-fold increase in free volume. There were changes in the quality characteristics of small package Kimchi according to storage temperature and packaging material, and large changes in pH, total acidity, and microbial count were evident upon storage at $5^{\circ}C$ for 8 days, which was the optimum palatability period. Mostly, PP treatment showed the slowest quality changes upon storage at $5^{\circ}C$. However, due to small package Kimchi's fast consumption system, the appropriate choice of packaging material must consider the product's turnover ratio. Further, the varieties of small package Kimchi should be diversified according to different consumer preferences by offering Kimchi with different maturity levels. Further, since the leading consumer base ranges in age from the teens to thirties, the development of various products targeting such consumers is necessary.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.598-606
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• 2004

The application of Dongchimi liquid to Naengmyon broth to improve its eating quality was scientifically explored by reviewing the quality of the product properties. Primarily, the optimum fermentation conditions for Dongchimi from which the liquid portion was extracted were pursued and the optimum mixing ratio sought on the basis of the product physicochemical properties. The liquid portions, periodically extracted from Dongchimi at intervals of two or five days, during fermentation at $10^{\circ}C$, were added to Naengmyon broth. The treatments were prepared at three levels namely, basic broth only ('A') and with ratios of Dongchimi liquid to basic broth of 3:7 (v/v, 'B') and 5:5 (vfv, 'C'). As a typical phenomenon of kimchi fermentation, a gradual decrease in the pH with increasing total acidity was observed as the fermentation of the Dongchimi progressed. At $10^{\circ}C$, the optimum ripening was obtained from day 8, and continued until day 15, when the pH was maintained at about 3.8 to 4.0. The total vitamin C and reducing sugar contents increased until the 13th-day of fermentation, but then decreased thereafter. The turbidity and solid content of the Dongchimi liquid increased with progression of the fermentation. With respect to the color values, the lightness (L) decreased, with increases in the redness (a), yellowness (b) and total color difference $({\Delta}E)$ during fermentation. Most of these observed phenomena for the Naengmyon broth substituted with $30\%$ (Treatment 'A') and $50\%$ (Treatment 'B') Dongchimi liquid, with different storage periods, confirmed the previous fermentation patterns of Dongchimi. A decrease in the pH with increasing total acidity, as well as gradual increases in the total vitamin C and reducing sugars (glucose and fructose) up to the 13th-day of fermentation were accompanied by subsequent declining patterns. The turbidity and solid content of the mixed broth also increased with increasing Dongchimi liquid fermentation period. With respect to the color of the mixed broth, the lightness was decreased, while the redness, yellowness and total color difference increased with increasing Dongchimi liquid fermentation period. It was also proven that the addition of slightly over-ripened Dongchimi liquid to the Naengmyon broth was more preferable.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.509-515
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• 1996

The effects of sour liquid ferments with lactic acid bacteria on the baking properties and qualities of White Pan Bread were studied. The mixed culture of Lactobacillus brevis and Lactobacillus plantarum had higher acid equivalents and lower pH-values than single or mixed culture of other lactic acid bacteria which had been used for traditional sour dough bread. Optimum conditions of the incubation of lactic acid bacteria, which are incubation temperature time and culture medium compositions for lactic fermentation, were also investigated to find out optimum activity for good bread making. The mixed culture of L. brevis and l. plantarum incubated for 24 hours at 3$0^{\circ}C$ had the most optimum activity for bread manufacturing process and the qualities of the products. The addition of sour liquid ferments to the sponge dough effected on fermentation activity of the sponge dough to lower the level of pH to 4.64 and to produce more total titratable acidity(TTA) of 0.545, whereas conventional sponge dough bread had 0.46% of TTA. On comparison with control bread, the bread made with sour liquid ferments was found to have better specific volume, taste, symmetry, especially, organoleptic characteristics due to lactic acid, acetic acid and amino acid produced by lactic acid bacteria. Sour dough bread with liquid ferment was considered to be more effective to the inhibition of staling during storage for 6 days at $25^{\circ}C$ and to have longer shelf-than control.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.63-69
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• 2008

For the development of mulberry wine, we investigated its optimum fermentation conditions as well as quality changes during fermentation. The physicochemical characteristics of the mulberry fruit used in the study were pH 4.56, 0.50% titratable acidity, and 13.0 $^{circ}Brix$ soluble solids. The mulberry wine fermented with Saccharomyces cerevisiae KCCM 12224 (Sc-24) at 24 $^{circ}Brix$ soluble solids and $26^{circ}C$ showed excellent characteristics in terms of ethanol production, titratable acidity, and redness. The sucrose, fructose, and glucose contents of the mulberry wine drastically decreased with fermentation time. The citric acid content was maintained during the fermentation period, and malic acid decreased, but lactic and succinic acids increased. The cyanidin-3-glucoside content, a major anthocyanin pigment, of the mulberry wine drastically decreased from 195.5 mg% at the initial stage of fermentation to 15.37 mg% at 2 days of fermentation. However, cyanidin-3-rutinoside decreased gradually. In summary, a mulberry wine of high quality was made by fermentation for 8 days at $26^{\circ}C$ using mashed mulberry fruit containing $24^{\circ}Brix$ soluble solids, after adding 200 ppm $K_2S_2O_5$ and inoculating with 3%(v/v) Sc-24.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.46-52
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• 1992

The optimum condition for the developement of a whey beverage from the concentrated whey was studied. Reverse osmosis system was used to obtain concentrated lactose from cheese whey. The hydrolysis degree of lactose by $\beta$-D-galactosidase was determined using HPLC (high performance liquid chromatography). The order of hydrolysis degree was 1:1, 2:l and 3:l concentrated lactose. It resulted from the concentrated salt which slightly inhibited $\beta$-D-galactosidase with constant enzyme dosage. The optimum condition for enzyme dosage was 2% in non-concentrated lactose, 3% in 2:l and 3% in 3:l concentrated lactose after 4 hours of reaction. When the 3:l concentrated lactose was used, more than 70% was hydrolyzed by 3% enzyme dosage. Furthermore the change of fermented whey by lactic acid bacteria was investigated. Based on the result of sensory test, the most favorable response was obtained at pH 4.2 and titratable acidity of 0.7% about 6 hours of fermentation at $37^{\circ}C$ with 2%: thermophilic starter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.460-465
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• 2001

To prepare vinegar using concentration apple juice, response surface methodology (RSM) was applied to optimize and monitor the vinegar fermentation properties by two stage fermentation. In the first stage, the optimum conditions for maximum alcohol contents were 18.56。Brix of initial sugar concentration, 61.96 rpm of agitation rate and 67.32 hr of fermentation time. The optimum condition for maximum acidity in the second stage (vinegar fermentation) were 201.53 rpm of agitation rate and 179.42 hr of fermentation time. Malic acid content was the highest and its content little changed during acetic acid fermentation. Lactic acid content increased a little during alcohol fermentation. Acetic acid content apparently increased during acetic acid fermentation.

• Korean Journal of Agricultural Science
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• v.38 no.3
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• pp.485-491
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• 2011

Yogurt was prepared from skim milk added with 2, 4 or 6% of green whole grain of barley, wheat, glutinous rice and common rice, respectively. Changes in pH, titratable acidity, viable cell counts and viscosity during fermentation were monitored and its sensory evaluation was also performed. The optimum level of additives such as green whole grain of barley, wheat, glutinous rice and common rice for yogurt manufacture was selected to 2%. The samples added with green whole grain of barley and wheat powders reached pH 4.5 in 12 hours. After 4 hours of fermentation, pH, the viable cell counts and viscosity in samples added with 2% green whole grain of barley, wheat, glutinous rice and common rice powders were the highest. Especially, in overall sensory evaluation using 5 parameters, the sensory scores of glutinous rice and common rice 2% yogurts were significantly high. From this experiment, the additives optimum level of glutinous rice and common rice powders was selected to be 2%.

• Food Science and Preservation
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• v.8 no.1
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• pp.74-78
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• 2001

Instant gruel using pumpkin(Cucurbita maxima Duch var. Evis) was prepared and the optimum mixing ratio of ingredients and cooking method were examined by physicochemical characteristics and sensory tests. The optimum mixing ratio of materials were steamed pumpkin 78.4%, heated com 9.2%, roasted onion 4.6%, boiled redbean 6.9%, sugar 0.6%, salt 0.3% in overall acceptance of instant pumpkin gruel. In order to Felons the shelf-life, instant pumpkin gruel was packed using pouch pack(PE-CPP) and heated under the different conditions. After heat treatment, products were decreased colors value and increased acidity and viscosity The sensory evacuation of heated product after 5 days at 37$^{\circ}C$ was preferable at 120$^{\circ}C$ for 30∼40 min treatments.