• 원예과학기술지
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• 제35권1호
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• pp.88-97
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• 2017

This study explored the physicochemical and nutritional changes associated with storage duration of fresh tomatoes. Fruits of the 'TY Megaton' and 'Yureka' tomato cultivars were harvested at the pink stage and stored at $12^{\circ}C$ for 20 days. During storage, firmness, weight loss, skin color (Hunter L, a, b, a / b values), soluble solids content (SSC), titratable acidity (TA), pH, antioxidant contents (lycopene, ascorbic acid, and total phenolics) and antioxidant activity were evaluated. Firmness was above the minimum marketable limit and fresh weight loss was below maximum acceptable weight loss after 3 weeks of storage, and no deleterious effect on antioxidant contents or activities were observed. Significant differences in SSC, TA, and pH were seen between varieties, but not between fruits stored for different durations. In both varieties, Hunter a values increased more than five-fold after 8 days of storage; this correlated with a more than four-fold accumulation of lycopene after two weeks of storage. The antioxidant activity of tomatoes was highest at the beginning of the storage period, likely because of the effective DPPH - reducing power of ascorbic acid and total phenolics. Antioxidant activity increased after 12 days of storage because of increasing lycopene content. Hence, this study indicates that pink - stage tomatoes may be stored at $12^{\circ}C$ for up to 3 weeks without affecting marketability or nutritional value.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1180-1185
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• 2009

This study was aimed to investigate the effect of glycine supplementation on the growth of Leuconostoc mesenteroides and Lactobacillus plantarum during kimchi fermentation. As preliminary experiment, the effect of supplementation of glycine (0-2.0%, w/v) to MRS medium on the growth of Leuc. mesenteroides and L. plantarum was evaluated. At 2.0% glycine in the MRS medium, cell growth rate was inhibited by 79% for L. plantarum and 27% for Leuc. mesenteroides. Subsequently, different concentrations of glycine (0, 0.5, and 2.0%, w/v) were applied for kimchi fermentation for 21 days, at $5^{\circ}C$. At day 14, the pH and titratable acidity (TA) of kimchi supplemented with 2.0% glycine were 4.83 and 0.38%, respectively, whilst the control kimchi had a pH of 4.49 and TA of 0.44%, respectively. The ratio of Leuconostoc/ Lactobacillus in kimchi increased as the concentration of glycine increased. The results show that the presence of glycine affected the growth of the 2 lactic acid bacteria, particularly of L. plantarum.

• Food Science and Biotechnology
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• 제15권1호
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• pp.13-18
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• 2006

Mandarin juice was processed using a continuous high pressure $CO_2$ system. Response surface methodology was used to investigate the effects of the processing parameters such as temperature, pressure, residence time, and %(w/w) ratio of $CO_2$ to juice on total aerobic count (TAC), pectinesterase (PE) activity, cloud level, $^{\circ}Brix$, pH, and titratable acidity (TA) of the juices. Maximum log reduction (3.47) of TAC was observed at $35^{\circ}C$, 41.1 MPa, 9 min residence time, and 7% $CO_2$. PE was inactivated by 7-51%. The cloud was not only retained but was also enhanced by 38%. Lightness and yellowness increased, and redness decreased. The processing temperature and % $CO_2$/juice ratio significantly affected high pressure $CO_2$ processing of the juice in terms of pasteurization, PE inactivation, cloud increase, and color change. The $^{\circ}Brix$, pH, and TA before and after treatment remained unchanged.

• Journal of Dairy Science and Biotechnology
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• 제30권2호
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• pp.69-74
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• 2012

This study was performed to determine by the ability of the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus to ferment Dioscorea opposita Thunb. (yam) and to evaluate the nutraceutical value of fermented yam. The titratable acidity (TA) value increased from 2 to 6% with increased concentrations in both raw yam and extracted lactic acid bacteria (LAB) fermented yam (LFY). The viable cell counts and the allantoin and diosgenin contents were higher in raw LFY at large concentrations (6%) than in extracted LFY samples at all fermentation periods up to 32 h. Based on these data, it confirmed that raw yam fermented by the combination culture of L. bulgaricus and S. thermophilus for various fermentation periods favors the symbiotic growth of LAB and results in higher nutraceutical content.

• 원예과학기술지
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• 제35권2호
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• pp.199-209
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• 2017

This study detailed the effects of 1-methylcyclopropene (1-MCP) on ripening and fruit quality in red-fleshed kiwifruit (Actinidia chinensis) stored at 0 or $10^{\circ}C$ for 20 days, and $20^{\circ}C$ for 13 days. The quality of the fruit was assessed by measuring ethylene production, respiration rate, weight loss, firmness, flesh color, soluble solids content (SSC), and titratable acidity (TA), along with a sensory evaluation. Compared to untreated kiwifruit, fruit treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP for 24h at $20^{\circ}C$ prior to storage showed a delay in ripening and maintained fruit quality during storage. Ethylene production and respiration rate were affected by 1-MCP treatment only in fruit stored at $20^{\circ}C$, where the values were markedly higher compared to kiwifruit stored at 0 and $10^{\circ}C$. 1-MCP treatment resulted in a clear reduction in weight loss due to a delay in fruit ripening. The firmness of kiwifruit stored at 10 and $20^{\circ}C$ decreased significantly compared to fruit stored at $0^{\circ}C$, but 1-MCP treatment led to a reduction in this loss. Upon storage, SSC increased while TA decreased across all treatments. Sensory evaluation scores increased with decreasing firmness and acidity and increasing SSC. The shelf life of kiwifruit stored at $0^{\circ}C$ was extended without any chilling injury or color changes. In summary, the results show that 1-MCP treatment can potentially maintain quality and delay ripening of red-fleshed kiwifruit stored at all storage temperatures.

• 한국식품조리과학회지
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• 제6권2호
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• pp.51-58
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• 1990

Quality deterioration of barley drink during storage was examined by measuring viable count, titratable acidity (TA), turbidity and pH of barley drinks with or without barley particles stored at temperatures of 20, 25, 30, and 35$^{\circ}C$. Qualitative analysis of organic acids in spoiled barley drink was also performed. TA of barley drink during storage increased to 0.009, 0.0095, 0.0097 and 0.020% at 20, 25, 30 and 35$^{\circ}C$, respectively. TA reached the mixima between 7 and 10 days of storage and reduced from then on. pH values followed the exactly reverse trend of TA. The rate of bacterial spoilage of barley drinks was faster when it was stored at higher temperatures. The numbers of bacteria were in the range between 9.0${\times}10^6-8.0{\times}10^8$ cells/ml depending on the storage temperatures and the different brands. Those samples with higher bacterial growths showed higher optical densities. Volatile organic acids such as acetic, formic, propionic, isobutyric, isovaleric acids were detected in addition to ethyl alcohol. Non-volatile organic acids such as pyruvic, lactic, oxalacetic, succinic, fumaric acids were detected. Among them, acetic acids were most important in their quantities. Five different kinds of spoilage bacteria were isolated and identified as Bacillus Licheniformis, Bacillus coagulans, Badillus cirulans, Bacillus stearothermophilus and Bacillus brevis, all of which were found to form endospores.

• 생물환경조절학회지
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• 제22권3호
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• pp.279-283
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• 2013

본 연구는 수확전 수체살포용 1-MCP(Harvista) 처리가 국내 육성품종인 '감홍' 사과의 품질과 저장성에 미치는 영향을 구명하고자 실시하였다. 수체살포용 1-MCP 처리 후 수확시에 과실의 산 함량은 1-MCP 수확 10일전 처리가 무처리에 비하여 높았으나 다른 과실품질 요인들은 차이가 없었다. 그리고 저장동안 '감홍' 사과의 품질변화를 보면 저장기간이 길어질수록 1-MCP 처리 과실들의 경도와 산 함량이 무처리 과실보다 높게 유지되었으나 가용성고형물 함량은 차이가 없었다. 내생 에틸렌 발생량은 수확시에는 처리간 차이가 없이 낮은 에틸렌발생을 보였으나 무처리 과실들은 저장 180일에는 $58.3{\mu}L{\cdot}L^{-1}$로 급격히 증가한 반면 1-MCP 처리 과실들은 $18.24{\sim}25.03{\mu}L{\cdot}L^{-1}$로 현저히 낮은 발생량을 보였다. 따라서 '감홍' 사과에 수확전 수체살포용 1-MCP 처리가 저장기간동안 과실의 품질을 유지하는데 효과적이었다.

• 한국식품저장유통학회지
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• 제22권1호
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• pp.100-107
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• 2015

본 연구에서는 수입에 의존하고 있는 고산도 식초 생산 기술을 대체하고자 포도과즙을 이용하여 적정산도 10% 이상의 식초 제조조건 및 품질특성을 조사하였다. 초기 알코올 함량에 따른 고산도 초산발효에서는 초기 알코올 함량 6%에서 적정산도 12%의 고산도 식초 제조가 가능하였으며 초기 알코올 함량이 높을수록 유도기가 길어져 초산수율이 감소하였다. pH는 구간에 따른 큰 차이가 없었고, 당도는 1단계 초산발효(1st AAF)까지 초기 알코올 함량에 비례하여 높게 나타났으나 2단계 초산발효(2nd AAF)기간 동안에는 초기 알코올 6% 첨가구에서 증가율이 가장 높았다. 고산도 포도식초의 주요 유기산은 tartaric, malic 및 citric acid가 검출되었으며, 유가식 첨가량 및 초산 발효수율 차이로 인하여 초기 알코올 함량이 낮을수록 높게 검출되었다. 미량 알코올 중 ethyl alcohol을 제외한 성분은 극소량으로 검출되어 초기 알코올 함량에 따른 큰 차이가 없었고, ethyl alcohol은 364~581 ppm으로 나타났다. 이상의 결과, 포도 알코올 발효액(초기 알코올 함량 6%)를 이용하여 일체의 영양원을 첨가하지 않고 총산도 12%의 고산도 식초 제조가 가능하였다. 그러나 산업적으로 활용하기 위해서는 초산수율 향상 및 유가식 첨가에 의한 발효기간 단축에 관한 보완 연구가 요구되었다.

• 한국자원식물학회지
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• 제28권2호
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• pp.290-295
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• 2015

포도 송이다듬기는 많은 노동력이 필요하므로 노동력을 감소시킬 수 있는 새로운 송이다듬기 기술을 개발하기 위하여 연구를 수행하였다. 포도의 송이다듬기 기술은 지경솎기가 알솎기에 비하여 작업효율성이 6.7배 높은 것으로 나타났다. 과실품질은 지경솎기 및 알솎기가 무처리구보다 과방과 과립수가 적지만 가용성 고형물은 높고, 산도는 낮게 나타났으며 압상률도 적은 것으로 나타났다. 송이다듬기에 의한 포도의 송이 품질 균일도를 조사하기 위해 송이의 기부, 중간 및 선단 부분의 가용성 고형물 함량과 산도를 측정한 결과 350~450 g의 과방중을 가진 포도송이가 송이 내위치에 따른 품질의 차이가 나타나지 않아 적합한 것으로 판단되었다.

• 한국식품저장유통학회지
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• 제16권6호
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• pp.804-809
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• 2009

최근, 저온 장시간 발효된 묵은지에 대한 소비가 증가하고 있다. 본 논문에서는, 저온($5^{\circ}C$)에서 46주 동안 발효된 묵은지의 pH, 산도, 유기산, 생균수, 아미노산, polygalacturonase (PG) 활성 등을 분석하였다. 10주 발효한 김치에서는 pH 4.1, 산도 0.99%를 나타낸 반면, 46주 발효한 김치에서는 pH 3.9, 산도 1.29%를 보였다. 한편, 10주에서 46주로 발효 기간이 증가하면서, 젖산, 젖산/초산비, Lactobacillus species/Leuconostoc species비 등은 증가한 반면, 호기성 세균, 효모, Lactobacillus species, Leuconostoc species, 유리아미노산, PG 효소 활성은 감소하였다.