• 한국식품저장유통학회지
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• 제20권2호
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• pp.151-157
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• 2013

본 연구에서는 수확시 숙성 정도가 토마토의 저장 중 품질변화에 미치는 영향을 구명하고자 하였다. 그린하우스에서 재배된 'Rafito' 품종을 각각 turning, pink, red 단계에 수확한 후 $30{\mu}m$ PE 필름으로 포장한 후 $5^{\circ}C$와 $10^{\circ}C$에 두어 1주일 간격으로 경도, 가용성 고형분 함량, 적정산도, 색, 라이코펜 함량, 부패율, 저온장해율을 조사하였다. 저장 3주 이후에 $5^{\circ}C$에서는 저온장해가 $10^{\circ}C$에서는 부패가 높게 발생되었다. $5^{\circ}C$에서는 수확 후 품질변화가 거의 없으므로 완숙과인 red 토마토의 품질 유지에 적합하였나, turning과 pink 토마토는 수확후 숙성과정이 억제되어 저장 2주 후에도 미숙한 상태에 머물렀다. Turning과 pink 토마토를 수확 후 $10^{\circ}C$에 저장하면 수확기에 비해 품질이 향상되었다. 특히, turning 토마토는 $10^{\circ}C$에 2주간 저장할 경우 연화는 억제되어 경도가 높게 유지되면서도, 착색이 완성되고 SSC/TA가 증가하며 라이코펜 함량이 완숙과 수준으로 증가되어 내 외부 품질이 가장 우수하였다. 따라서 red 단계에서 수확된 'Rafito' 토마토의 경우 부패를 억제할 수 있는 $5^{\circ}C$ 저장이 바람직하며, red 단계보다 미숙한 상태에서 수확할 경우 저온에서는 후숙에 의한 품질형성이 억제되므로 $10^{\circ}C$가 적정 온도인 것으로 판단된다.

• 원예과학기술지
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• 제28권3호
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• pp.429-433
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• 2010

본 연구는 1-MCP가 'Formosa' 자두의 저장 중 품질 변화와 유통기간 연장에 미치는 효과를 밝히고자 수행하였다. 수확한 'Formosa' 자두를 균일한 크기와 색깔로 선별한 후 수확 당일 그리고 수확 후 1일 후에 걸쳐서 각각 1-MCP를 $1{\mu}L{\cdot}L^{-1}$ 농도로 $20^{\circ}C$에서 16시간 동안 처리하여 대조구(무처리)와 비교하였다. 1-MCP를 처리한 후 14일 동안 상온에서 자두의 연화도, 과중감소율, 가용성고형물 함량 변화, 산도, 그리고 과실의 색깔 변화를 측정하였다. 과중감소율과 과실연화도는 1-MCP 처리구가 무처리구에 비해서 적은 변화폭을 보여주었다. 1-MCP 처리 시기(수확당일 그리고 수확 후 1일) 간에는 따른 큰 차이는 없었다. 가용성고형물 함량에는 통계적 유의성은 없었으나, 1-MCP처리구의 과실에서는 산도와 과실의 색깔 변화가 무처리구에 비해서 적게 나타났다. 또한 1-MCP는 저장 중에 발생하는 과실의 부패병 억제효과를 나타내었다. 따라서 본 연구결과, 1-MCP 처리시기(${\geq}1$일) 연장은 상온저장시 과실의 경도, 산도, 과일 색깔 변화에 큰 영향을 미치지 않았으며, 또한 과실품질 유지에 실용성이 있는 결과를 보여주었다.

• 원예과학기술지
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• 제28권6호
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• pp.954-958
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• 2010

포도 '거봉' 품종의 적정 착과량 설정을 위한 기초자료를 마련하고자 신초당 착립수를 조절하여 변색기 이후의 과실의 품질변화를 조사하였다. 과실의 당도는 변색기 이후 30일까지 급격히 증가하였으며, 신초당 착립수가 적을수록 빠르게 증가하였다. 신초당 10립과 20립 처리구의 당도는 변색기 이후 4주까지 $18.0^{\circ}Bx$ 이상 급격히 상승한 다음, 완만하게 증가하였다. 신초당 30립 처리구의 당도는 변색초기에는 느리게 상승하였으나, 수확기까지 지속적으로 상승하여 $18.0^{\circ}Bx$에 도달하였다. 그러나 신초당 40립과 50립 처리구는 변색기 이후 4주까지도 당도의 상승폭이 현저히 적었고, 성숙기에 도달해도 $15.0^{\circ}Bx$에 그쳤다. 과즙의 산 함량은 모든 처리구에서 변색기 이후 30일까지 빠르게 감소하였고, 그 이후에는 완만하게 감소하였으며, 신초당 50립 처리구를 제외한 모든 처리구의 산 함량은 0.4-0.6%에 도달하였다. 과피색은 변색기 이후 모든 처리구에서 성숙이 진행됨에 따라 녹색에서 자흑색으로 변화하면서 L, b값은 감소하였고, a값은 증가하였다. 총 안토시아닌 함량은 신초당 10립과 20립 처리구의 경우 변색기 이후 2주까지 완만히 증가한 후 변색기 이후 6주까지 급격히 증가하였고, 그 후에는 감소하는 양상을 나타내었으며, 신초당 30, 40 및 50개의 착립구는 정상적인 착색을 나타내지 못하였다. 따라서 본 연구결과 과실품질을 고려할 때 거봉 포도의 착립 정도는 신초당 20립 내외가 적당한 것으로 나타났다.

• 한국식품영양학회지
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• 제23권4호
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• pp.462-469
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• 2010

본 연구에서는 Kefir의 이화학적인 특성을 측정하여 Kefir가 당뇨병 치료 보조식품으로의 가능성을 규명하고자 Kefir의 이화학적인 특성을 조사하였다. 탈지우유(skim milk)와 우유에서 배양한 Kefir의 일반성분은 수분이 각각 90.02, 87.84%, 단백질은 3.23, 3.00%, 지질은 0.45, 0.64%, 유당은 3.96, 4.14% 그리고 회분은 0.77, 0.68%이었다. Kefir의 48시간 배양시 적정 산도는 0.77%였고, pH는 4.55이었다. $CO_2$의 생성량은 62.3%였고, 알코올 함량은 1.4%이었다. 주사현미경상에서 Kefir grain에는 유산균과 효모균이 혼합 공생하고 있는 것으로 관찰되었다.

• 한국미생물·생명공학회지
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• 제46권1호
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• pp.1-8
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• 2018

Gul (oyster) jeotgals (GJs) were prepared using different types of salt (23%, w/v): purified salt, solar salt aged for 3 years, and bamboo salt crystalized 3 times. One set of GJs was fermented with Bacillus subtilis JS2 ($10^6CFU/g$), while the other GJ set was fermented without starter. During fermentation for 24 weeks at $15^{\circ}C$, the starter GJs showed 10-fold higher bacilli counts than the no-starter GJs, where the maximum bacilli count was $8{\times}10^3CFU/g$. All 28 bacilli strains isolated from the 6-week GJs were identified as B. subtilis by using a RAPD-PCR, indicating that some of the B. subtilis JS2 cells remained viable. Lactic acid bacteria (LAB) and yeasts were present at low levels, $10^1-10^2CFU/g$. LAB with protease activities isolated from 10-week samples were identified as Enterococcus species. The isolates obtained at 16 weeks were all Staphylococcus species. The GJs with bamboo salt showed higher pH and lower titratable acidity (TA) values than the other GJs due to the strong alkalinity of bamboo salt. The amino-type nitrogen in the GJs increased slowly during the fermentation. At 24 weeks, the GJs with purified salt showed the highest amino-type nitrogen (412-430 mg%), followed by the GJs with solar salt (397-406 mg%) and GJs with bamboo salt (264-276 mg%). Meanwhile, the GJs with bamboo salt showed the highest ammonia-type N (63.67 mg%), followed by the GJs with purified salt (49 mg%) and solar salt (48 mg%).

• 식품저장과 가공산업
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• 제3권1호
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• pp.42-46
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml h-1 m-2 nun-1 at $5^{\circ}C$ and $99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%$ CO2 + 1 or $20\%\;O_2, \;8\%\;CO_2+1$ or $20\%\;O_2$, or $12\%\; CO_2+\;20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2 +\;1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SCC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene Production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown.

• 한국축산식품학회지
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• 제33권6호
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• pp.744-751
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• 2013

The objective of this study was to assess the physicochemical and sensory changes of a kefir manufactured by a two-step fermentation (MTY, $1^{st}$ step: $37^{\circ}C$ for 9 h; $2^{nd}$ step: $24^{\circ}C$ for 15 h) and compare it with kefirs produced by two conventional methods (GTY, fermentation at $37^{\circ}C$ for 24 h; KEY, $22^{\circ}C$ for 24 h). Rapid changes in pH and titratable acidity (TA) were observed in samples from all three manufacturing methods during fermentation process and storage period. Lactic acid bacteria (LAB) counts of MTY increased gradually up to 12 h of fermentation, reaching 9.28 Log CFU/mL, with maximum value observed in this experiment of 9.48 Log CFU/mL. The LAB counts of all samples decreased significantly during storage. The highest viscosity was observed for MTY (1750-1771 cPs), compared with the lowest viscosity observed for KEY (1250-1277 cPs). The viscosity of all samples increased slightly during storage (1250-1805 cPs, p<0.05), as well as carbon dioxide content (0.01-1.36%, p<0.05), except for GTY. The most significant increase in alcohol concentration during storage period was seen in MTY from 0.01% to 1.36% (p<0.05). MTY scored significantly higher in most items of the sensory analysis, indicating that the product manufactured by the two-step fermentation method is more acceptable compared with conventionally produced kefirs.

• 원예과학기술지
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• 제35권3호
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• pp.300-313
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• 2017

'Unicon' cherry tomato (Solanum lycopersicum) is one of the most highly perishable horticultural crops due to its high water content and respiration rate. This study was carried out to assess the effect of continuous application of $CO_2$ (control [air], 3%, and 5%) on the quality and shelf life of cherry tomato fruits stored at $10^{\circ}C$ and $85{\pm}5%$ relative humidity (RH) at two maturity stages (pink and red). Continuous application of $CO_2$ did not affect the soluble solids content (SSC) or titratable acidity (TA) of the fruit at either maturity stage during storage. However, there was a significant difference among treatments in terms of flesh firmness, cell wall thickness, pectin content, vitamin C content, skin color, lycopene content, weight loss, ethylene production rate, respiration rate, and acetaldehyde and ethanol production. Fruits treated with 5% $CO_2$ maintained their high quality with regards to vitamin C, skin color ($a^*$), lycopene content, weight loss, physiological parameters (ethylene production rate, respiration rate, and volatile compounds), flesh firmness, cell wall thickness, and pectin content at both maturity stages compared with 3% $CO_2$ treatment and the control. Continuous application of $CO_2$ (5%) reduced the ethylene production rate and the production of volatile compounds during storage. Therefore, cherry tomato 'Unicon' fruit can be stored for two weeks without losing fruit quality at both maturity stages under continuous application of 5% $CO_2$ as a postharvest treatment.

• 한국축산식품학회지
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• 제35권5호
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• pp.683-691
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• 2015

The objective of this study was to identify the coccoidal bacteria present in 188 samples of fermented yaks’, mares’ and cows’ milk products collected from 12 different regions in Mongolia. Furthermore, we evaluated the fermentation properties of ten selected isolates of the predominant species, Streptococcus (S.) thermophiles, during the process of milk fermentation and subsequent storage of the resulting yoghurt at 4℃. Overall, 159 isolates were obtained from 188 samples using M17 agar. These isolates were presumed to be lactic acid bacteria based on their gram-positive and catalase-negative properties, and were identified to species level using 16S rRNA gene sequence analysis. These coccoid isolates were distributed in four genera and six species: Enterococcus (E.) durans, Enterococcus (E.) faecalis, Lactococcus (Lac.) subsp. lactis, Leuconostoc (Leuc.) lactis, Leuconostoc (Leuc.) mesenteroides. subsp. mesenteroides and S. thermophilus. Among these S. thermophilus was the most common species in most samples. From evaluation of the fermentation characteristics (viable counts, pH, titratable acidity [TA]) of ten selected S. thermophilus isolates we could identify four isolates (IMAU 20246, IMAU20764, IMAU20729 and IMAU20738) that were fast acid producers. IMAU20246 produced the highest concentrations of lactic acid and formic acid. These isolates have potential as starter cultures for yoghurt production.

• 한국축산식품학회지
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• 제39권5호
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• pp.792-803
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• 2019

The supplementation with natural ingredients that are rich in polyphenols could improve the quality and functionality of yogurt. Lotus leaf (LL) are abundant in phenolic compounds. We aimed to investigate the effects of LL powder on the quality properties, total phenolic content (TPC), and antioxidant activity of yogurt. Yogurt was supplemented with four different concentrations (0%, 0.2%, 0.5%, and 1%) of LL powder and evaluated for 14 d refrigerated storage. During storage, the titratable acidity (TA) of all LL yogurt groups was higher than that of the control (p<0.05). The $L^*$ and $a^*$ values decreased by LL addition to the yogurts, while the $b^*$ values increased. All LL yogurt groups indicated better viscosity than that of control, and among them, 0.2% LL yogurts had the highest viscosity without significant decrease until the end of the storage duration. The addition of LL into yogurt enhanced the water-holding capacity (WHC) by at least 1.5-fold than that of control for the entire storage duration. The TPC of yogurts gradually increased with the addition of LL (p<0.05) and continued to increase during storage; the 1% LL yogurt at 14 d showed the highest value of $61.94{\pm}1.68{\mu}g$ GAE/g. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and reducing power of the yogurts were also significantly enhanced with increasing LL concentrations (p<0.05). These results suggest that lotus leaf may be useful as a natural ingredient for improving the quality and antioxidant activity of yogurt.