• 한국식품조리과학회지
• /
• 제24권5호
• /
• pp.617-625
• /
• 2008

In this study, we evaluated changes in the quality characteristics of Godulbaegi kimchi during storage at $20^{\circ}C$ and $5^{\circ}C$. The pH and reducing sugar of Godulbaegi kimchi decreased, and the total acidity and color differences increased with increasing storage time at both temperatures. The vitamin C contents of the Godulbaegi kimchi decreased during the first 15 days of storage at $20^{\circ}C$, then increased for 18 days. The total dietary fiber contents were significantly higher in the fresh Godulbaegi kimchi than in the fermented Godulbaegi kimchi samples. Antioxidative activity was significantly higher in the fresh Godulbaegi kimchi than in the fermented kimchi.

• 한국식품조리과학회지
• /
• 제21권2호
• /
• pp.195-200
• /
• 2005

시판김치의 위생 실태를 확인하기 위해 포장 김치 3종, 백화점 김치 3종, 재래시장 김치 3종을 각각 $2^{\circ}C$와 $20^{\circ}C$ incubator에서 숙성시키면서 pH, 산도, E. coli, Salmonella sp., Staphylococcus sp. yeast균수의 경시적 변화를 측정하였다. 백화점 김치의 구입 당일 pH는 5.85로 가장 높았고, 재래시장 김치는 4.47로 가장 낮았다. $2^{\circ}C$저장에서 숙성시킨 김치의 pH는 완만하게 감소되었으나, $20^{\circ}C$에 저장한 김치는 저장 첫날 pH가 가장 급격히 감소되었다. 산도는 이와는 반대 경향을 나타내었다. E. coli 균수는 포장 김치에서는 낮게 검출되었으나 백화점 김치와 시장 김치 같은 비포장 김치에서는 $1\;{\times}\;10^1cfu/mL$ 부근으로 검출되었으며 $2^{\circ}C$저장에서 백화점 김치와 재래시장김치는 저장 2일째까지도 균이 생존하였으나 저장 5일째에는 더 이상 검출되지 않았다. $20^{\circ}C$ 저장의 경우 저장 $1\~2$일 동안 균이 더 이상 검출되지 않았다. Salmonella sp.은 구입 당일 시료 모두에서 약간이 검출되었으나 발효와 더불어 $1\~2$ 일 동안에 감소되었다. 그러나 구입 당일 포장 김치 $7.73\times10^2cfu/mL$, 백화점 김치 $2.87\times10^3cfu/mL$, 재래시장 김치에서 $7.89\times10^2cfu/mL$의 비교적 높은 수의 Staphylococcus sp.가 검출되었고, $2^{\circ}C$ 저장에서 각 시료의 균수는 거의 감소하지 않았으며, $20^{\circ}C$ 저장의 경우에도 감소율은 낮았다. Yeast수는 재래시장 김치가 구입 당일 $2.12\times10^2cfu/mL$의 수를 나타내었고, 발효 숙성전 기간에 걸쳐서 계속 증가하는 경향을 보였다. 이상과 같이 김치가 가장 맛이 있는 시기로 알려져 있는 pH 4.2부근, 산도 $0.4\~0.8\%^{(10)}$에서도 식품 유해가능성을 가진 균이 상당수 검출되므로 원료의 수송, 김치의 제조 및 유통과정에서 병원균에 대한 오염방지에 유의하여야 할 것이다.

• 한국식품조리과학회지
• /
• 제22권6호통권96호
• /
• pp.832-839
• /
• 2006

Kugija was added to Nabak kimchi to improve the quality and preservation and the optimum addition level was assessed. Kugija extract was prepared by boiling kugija fruits, at different ratios (0, 1, 3, 5, 7%; w/v) in water for 30 minutes. The changes in the physicochemical properties of the Nabak kimchi were measured during storage for 25 days at 10?, and compared to a control (without kugija). The pH was decreased in all treatments. Following the fermentation of Nabak kimchi, the total acidity values were inversely proportional the pH changes according to the nature of mutual dependence. However, in short term, during the initial 7 days of fermentation, the total acidity values decreased with increasing concentrations of kugija extract, whereas the trend was reversed after day 10. Total vitamin C content was directly proportional to the concentration of kugija extract and was decreased with the laps of fermentation. Up to day 25, 7% treatment showed the highest vitamin C content, but at 25 days 1% and 3% treatments ranked the first. The mont of reducing sugar was proportional to the concentration of kugija extract however, the difference of values between all treatments became almost indiscernible after day 25. Turbidity values were generally increased in all samples during fermentation period, although only to a limited extent. The lowest turbidity was shown at 3% treatment up to day 16. Total color difference values were increased up to day 16, but then decreased. The optimum level of kugija extract in Nabak kimchi, as determined through these experiments, was between 1 to 3% per added water content, and was preferably 3% for color and fermentation-retarding effect of the product. Kugija extract could be applied for improving the quality and preservation of traditionally prepared Nabak kimchi.

• 한국식품영양과학회지
• /
• 제26권6호
• /
• pp.1006-1012
• /
• 1997

To observe the food quality of Baik-kimchi which is known as a watery Chinese cabbage pickles without fish sauce and red pepper paste, the changes of dietary fibers and pectic substances during fermentation at 5$^{\circ}C$ and $25^{\circ}C$ were studied. Baik-kimchi fermented at $25^{\circ}C$ showed a greater changes in pH and acidity than those of 5$^{\circ}C$ during storage. Ripened Baik-kimchi products fermented at 5$^{\circ}C$ could be prepared on 9~12 days of fermentation, and those had a pH range from 4.25 to 4.40 and acidity of 0.34~0.53. But in the case of $25^{\circ}C$ fermentation, Baik-kimchi ripened for 3 days showed a pH of 4.02 and acidity of 0.54. The pH and acidity of the Baik-kimchi juice changed more rapidly than those of the Baik-kimchi solid regardless of fermentation temperatures. The content of soluble dietary fiber(SDF) was ranged from 3.06 to 4.87% at 5$^{\circ}C$ and a wide variation in SDF was observed in the sample fermented at $25^{\circ}C$(4.15~11.22%). Insoluble dietary fiber(IDF) were increased from 21.66% to 28.42% in solid of Baik-kimchi during fermentation at 5$^{\circ}C$ and ranged from 21.37% to 24.65% for sample fermented at $25^{\circ}C$. A notable amount of pectin had been dissolved in juice of Baik-kimchi till the best ripening time and showed the level of 223.2mg/100ml at 5$^{\circ}C$ on the day of 9 and 207.3mg/100ml at $25^{\circ}C$ on the day of 2. In contrast, the contents of pectin in solid Baik-kimchi decreased, whereas contents of sodium hexametaphosphate soluble pectin(HXSP) and HCl soluble pectin(HClSP) increased with fermentation period.

• Animal Bioscience
• /
• 제34권6호
• /
• pp.1038-1048
• /
• 2021

Objective: The study aimed to evaluate the effect of storage time and formic acid (FA) on fermentation characteristics, epiphytic microflora, carbohydrate components and in vitro digestibility of rice straw silage. Methods: Fresh rice straw was ensiled with four levels of FA (0%, 0.2%, 0.4%, and 0.6% of fresh weight) for 3, 6, 9, 15, 30, and 60 d. At each time point, the silos were opened and sampled for chemical and microbial analyses. Meanwhile, the fresh and 60-d ensiled rice straw were further subjected to in vitro analyses. Results: The results showed that 0.2% and 0.6% FA both produced well-preserved silages with low pH value and undetected butyric acid, whereas it was converse for 0.4% FA. The populations of enterobacteria, yeasts, moulds and aerobic bacteria were suppressed by 0.2% and 0.6% FA, resulting in lower dry matter loss, ammonia nitrogen and ethanol content (p<0.05). The increase of FA linearly (p<0.001) decreased neutral detergent fibre and hemicellulose, linearly (p<0.001) increased residual water soluble carbohydrate, glucose, fructose and xylose. The in vitro gas production of rice straw was decreased by ensilage but the initial gas production rate was increased, and further improved by FA application (p<0.05). No obvious difference of FA application on in vitro digestibility of dry matter, neutral detergent fibre, and acid detergent fibre was observed (p>0.05). Conclusion: The 0.2% FA application level promoted lactic acid fermentation while 0.6% FA restricted all microbial fermentation of rice straw silages. Rice straw ensiled with 0.2% FA or 0.6% FA improved its nutrient preservation without affecting digestion, with the 0.6% FA level best.

• 한국식품조리과학회지
• /
• 제20권6호
• /
• pp.598-606
• /
• 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.

• 한국식품조리과학회지
• /
• 제21권2호
• /
• pp.217-224
• /
• 2005

The storage characteristics of frozen soy yogurt prepared with hydrolyzed soy protein isolates were evaluated. In order to facilitate lactic fermentation bacteria grow and produce lactic acid as fast rate as possible, soy protein isolate(SPI) was hydrolyzed using two kinds of proteases; bromelain and a-chymotrypsin. The cultural systems employed thereafter for lactic fermentations were Bifidobacterium bifidum or B. bifidum and Lactobacillus bulgaricus. The viable cell counts, normal- and bile acid tolerances from the mixed cultures of B. bifidum and L. bulgaricus decreased sharply during the initial first 3 days of frozen storage and then showed a gradual decrease thereafter. Melt-down percent of the all frozen products have been favorably affected as was shown by less melting at raised testing temperature during 28 days of frozen storage except for the initial 3 days during which a minor change has been observed. Among the various volatile flavor components, the contents of acetaldehyde, acetone, diacetyl and methanol generally increased during the frozen storage. In sensory test, the frozen soy yogurt prepared with a-chymotrypsin and mixed culture of B. bifidum and L. bulgaricus was the most desirable, the highest scores in sourness, bitterness and mouthfeel.

• 한국식품과학회지
• /
• 제44권5호
• /
• pp.613-620
• /
• 2012

본 연구는 전복물김치의 국물 주재료로 북어와 감초를 사용한 담금법을 확립하여 제조하고, $4^{\circ}C$에서 김치를 저장하면서 저장기간별로 일반성분, pH, 산도, 젖산균, 구성 및 유리아미노산의 변화를 측정하였다. AMKP와 AMKL의 수분함량은 88.37-90.94%, 조회분 함량은 2%이내였다. AMKP와 AMKL의 조단백질 함량은 저장 21일째까지 감소하다가 저장 28일째 증가하는 경향을 보였고, 조지방 함량은 저장기간 동안 계속해서 감소하는 경향을 보였다. pH의 변화는 저장기간 동안 AMKP 및 AMKL 시료 모두 공통적으로 발효가 진행됨에 따라 감소하였고, 산도는 저장 28일째까지 꾸준히 증가하다가 저장 35일째에는 감소하는 양상을 보였다. AMKP 및 AMKL은 저장 21일째에 산도 0.50-0.54%, pH 4.29-4.30을 나타내어 저장 21일째가 적숙기임을 예측해 볼 수 있었다. 또한 AMKP 및 AMKL는 발효과정 중에 Leuconostoc sp.의 균수가 급격히 증가하여 저장 21일째에 최대값에 도달하였다. 전복물김치 AMKP 및 AMKL의 주요 구성아미노산은 glutamic acid, glycine, aspartic acid 및 arginine 이었고, 그 중에서도 glutamic acid의 함량이 가장 높게 나타났다. 또한 전복물김치 AMKP 및 AMKL의 주요 유리아미노산은 hydroxyproline, taurine 및 arginine이었다. 이상의 결과에서 전복물김치는 저장기간 동안 국물의 종류에 상관없이 동일한 발효양상 및 영양성분의 조성을 보였고, 단백질 급원인 전복의 첨가로 인해 기존에 보고된 일반 물김치의 실험결과에서보다 발효가 지연되고 적숙기가 연장되는 결과를 얻었다. 또한, 전복물김치는 풍부한 아미노산의 용출로 발효에 긍정적인 영향을 주어 맛과 저장성을 향상시켜 줄 것으로 기대되며, 본 연구의 결과는 전복물김치의 상품화 연구의 기초 자료로 활용이 가능 할 것으로 생각된다.

• 한국식품영양학회지
• /
• 제21권1호
• /
• pp.51-55
• /
• 2008

Colour and texture are the most difficult quality aspects of Kimchi to maintain during storage. Therefore, this study investigated how to maintain superior quality Kimchi during fermentation without changes in color and texture. By examining differences between samples covered with vinyl(A group) and not covered with vinyl(B group) and assessing pH, total acidity, total viable cell count, total lactic acid bacteria cell count and sensory characteristics. The results are indicated that pH, total acidity, total viable cell and total lactic acid bacteria were similar between group A and B. Group A showed higher sensory score for colour, taste, texture and acceptability than group B(p<0.001). Covering the Kimchi with vinyl appeared to have a similar effect as when Kimchi is kept in a Kimchi-pot under stones or the outer leaves of vegetables making it possible to maintain good color and texture during storage. In conclusion, even though, it is not practical to use Kimchi-pots within urban settings today, vinyl coverings may offer the same effects.

• 한국식품조리과학회지
• /
• 제17권5호
• /
• pp.431-440
• /
• 2001

This study was carried out to investigate the effects of oligosaccharide addition on Jeung-Pyun fermentation. Fructooligosaccharide (FOS), isomaltooligosaccharide (IMOS), galactooligosaccharide (GOS) were used at the concentration of 15%, 25% or 35% of the rice in Jeung-Pyun ingredients. The physicochemical properties, sensory evaluation and instrumental characteristics were examined. The internal structure of Jeung-Pyun samples was observed by SEM. The pH of Jeung-Pyun batters was decreased as the fermentation progressed. Compared with the control using sucrose, the specific volume of Jeung-Pyun was higher in the 15% and 25% of oligosaccharide-added samples. The degree of gelatinization decreased more slowly than control as the storage time increased both at 20$\^{C}$ and 4$\^{C}$. In sensory evaluation, Jeung-Pyun with FOS and IMOS at the levels of 25∼35% and GOS at the levels of 25% showed the best scores. In instrumental characteristics, springiness, gumminess, hardness and cohesiveness were similar among all samples during storage at 20$\^{C}$ and 4$\^{C}$. In the internal structure of Jeung-Pyun observed by SEM, Jeung-Pyun substituted with oligosaccharide at the levels of 25% for sucrose showed large and regularly distributed air pores. In conclusion, the replacement of sucrose with oligosaccharide in Jeung-Pyun ingredients appeared acceptable in terms of fermentative aspects.