로즈마리 복합 추출물 처리가 fresh-cut 양상추의 저장 중 품질 변화에 미치는 영향

이현정,최지영,허수현,배수인,김지윤,문광덕 한국식품저장유통학회 2019 한국식품저장유통학회지 Vol.26 No.1

The purpose of this study was to evaluate the quality of fresh-cut lettuce after a washing treatment with differing concentrations of mixed natural extract. Five different treatments were employed: distilled water, sodium hypochlorite (Cl), 20% mixed natural extract (Na-1), 60% mixed natural extract (Na-3), and 100% mixed natural extract (Na-5). Measurements of carbon dioxide concentration, enzymatic activities, total aerobic bacteria, and sensory evaluation were investigated on day 1, 2, 3, and 5 at 5℃. The CO2 concentration in lettuce treated with Cl was significantly higher than that in other samples on day 5, and it remained generally low during the storage period in that treated with Na-5. The enzymatic activities (POD (peroxidase) and PAL (phenylalanine ammonia lyase) activities) in lettuce treated with Na-5 and Na-3 were low during the storage, and were significantly higher in lettuce treated with Cl than that in other samples on day 5. Total aerobic microbial count increased during storage, specifically on day 5, and was 6.53±0.08 log CFU/g in lettuce treated with Cl, while those in lettuce treated with Na-5 was 6.22±0.18 log CFU/g and significantly different. In case of sensory evaluation, there was no significant difference between the washing treatments in off flavor and smell. Color and overall acceptability in Na-5 was higher than that treated with Cl. The results revealed that the washing treatment of mixed natural extracts primarily containing rosemary extracts could be used to wash fresh-cut lettuce.

Rapid Detection of Escherichia coli in Fresh Foods Using a Combination of Enrichment and PCR Analysis

Yukyung Choi,Sujung Lee,Heeyoung Lee,Soomin Lee,Sejeong Kim,Jeeyeon Lee,Jimyeong Ha,Hyemin Oh,Yewon Lee,Yujin Kim,Yohan Yoon 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.4

The objective of this study was to determine the minimum enrichment time for different types of food matrix (pork, beef, and fresh-cut lettuce) in an effort to improve Escherichia coli detection efficiency. Fresh pork (20 g), beef (20 g), and freshcut lettuce (20 g) were inoculated at 1, 2, and 3 Log CFU/g of Escherichia coli. Samples were enriched in filter bags for 3 or 5 h at 44.5℃, depending on sample type. E. coli cell counts in the samples were enriched in E. coli (EC) broth at 3 or 5 h. One milliliter of the enriched culture medium was used for DNA extraction, and PCR assays were performed using primers specific for uidA gene. To detect E. coli (uidA) in the samples, a 3–4 Log CFU/mL cell concentration was required. However, E. coli was detected at 1 Log CFU/g in fresh pork, beef, and fresh-cut lettuce after 5, 5, and 3-h enrichment, respectively. In conclusion, 5-h enrichment for fresh meats and 3-h enrichment for fresh-cut lettuce in EC broth at 44.5℃, and PCR analysis using uidA gene-specific primers were appropriate to detect E. coli rapidly in food samples.

절단방법이 신선절단 사과와 엽채류의 품질에 미치는 영향

정헌식 ( Hun Sik Chung ),정문철 ( Moon Cheol Jeong ),문광덕 ( Kwang Deog Moon ) 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2012 한국식품저장유통학회지 Vol.19 No.2

Whole apples were cut with a sharp or dull knife, and whole cabbages and crisp lettuce heads were cut into salad or thin strips with a knife or by hand. The fresh-cut apples, cabbages, and lettuce were packed in low-density polyethylene bags and kept at 4°C, and their qualities were investigated. Browning and softening of the apples that were cut with a sharp knife were more delayed than those of the apples that were cut with a dull knife. The soluble solids and pH of the fresh-cut apples were not affected by the sharpness of the cutting blade. The browning indexes of the fresh-cut cabbages and lettuce were significantly lower in the samples that were cut with a knife than by hand and in the samples that were cut into large pieces. The results suggest that the cutting blade sharpness, cutting tools, and cut types affected the quality of the fresh-cut apples and leafy vegetables, and that the cutting methods which minimized the cutting damage should be used to retard the browning and softening of the produce.

계절에 따른 시판 신선 편이 샐러드 제품의 품질 평가

조순덕 ( Sun Duk Cho ),윤수진 ( Soo Jin Youn ),김동만 ( Dong Man Kim ),김건희 ( Gun Hee Kim ) 한국식품영양학회 2007 韓國食品營養學會誌 Vol.20 No.3

As a result of life-style changes, consumer`s concerns of food have shifted from calories and nutrition to health and convenience. Fresh-cut products are one such new direction for fruit and vegetable consumption. In this study, the vitamin C, mineral, and pesticide contents of various fresh-cut products were analyzed. According to sensory evaluations, the key reason for a lower than expected overall acceptability of many fresh-cut products is that they are likely to have browning and can easily lose their freshness. Also, the sensory evaluation showed that shriveling, the degree of browning, softening around the cut edge, and off-flavors were the primary factors affecting the quality of fresh-cut products. As a nutritional factor of quality, vitamin C content was not practical with regard to fresh-cut lettuce because the level was very low. For product safety, residual pesticides were detected in the fresh-cut products, but the results showed that all items were under permitted levels and considered safe. In evaluation of the microbial levels of the fresh-cut market products, the levels of viable cells, mold, yeast, coliform bacteria, and enterobacteriaceae were not significantly different based on the summer and winter seasons. The levels of S. aureus and Listeria spp. in the products were higher during the summer season than the winter.

On-line fresh-cut lettuce quality measurement system using hyperspectral imaging

Mo, Changyeun,Kim, Giyoung,Kim, Moon S.,Lim, Jongguk,Lee, Kangjin,Lee, Wang-Hee,Cho, Byoung-Kwan Elsevier 2017 BIOSYSTEMS ENGINEERING Vol.156 No.-

<P>In this study, an online quality measurement system for detecting foreign substances on fresh-cut lettuce was developed using hyperspectral reflectance imaging. The online detection system with a single hyperspectral camera in the range of 400–1000 nm was able to detect contaminants on both surfaces of fresh-cut lettuce. Algorithms were developed for this system to detect contaminants such as slugs and worms. The optimal wavebands for discriminating between contaminants and sound lettuce as well as between contaminants and the conveyor belt were investigated using the one-way analysis of variance (ANOVA) method. The subtraction imaging (SI) algorithm to classify slugs resulted in a classification accuracy of 97.5%, sensitivity of 98.0%, and specificity of 97.0%. The ratio imaging (RI) algorithm to discriminate worms achieved classification accuracy, sensitivity, and specificity rates of 99.5%, 100.0%, and 99.0%, respectively. The overall results suggest that the online quality measurement system using hyperspectral reflectance imaging can potentially be used to simultaneously discriminate foreign substances on fresh-cut lettuces.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We developed online fresh-cut lettuce quality measurement system. </LI> <LI> The online measurement system was capable to detect defects on both surfaces of fresh-cut lettuce. </LI> <LI> The multispectral imaging algorithms were developed to detect the foreign substances. </LI> <LI> The imaging algorithms for slug and worm achieved the accuracy of 97.5% and 99.5%, respectively. </LI> </UL> </P>

세척용 시판 살균제 종류에 따른 신선편의 양상추의 저장 중 미생물 변화

황태영 한국식품저장유통학회 2017 한국식품저장유통학회지 Vol. No.

This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water (0.2 ml·L-1), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4TM (1,3,4%), Fresh produce washTM (1,3,4%), CleancolTM (1%), ChitocholTM (1%) and Natural CaTM (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

세척용 시판 살균제 종류에 따른 신선편의 양상추의 저장 중 미생물 변화

황태영,Hwang, Tae-Young 한국식품저장유통학회 2017 한국식품저장유통학회지 Vol.24 No.6

시판 살균제의 실제 적용 시 감균 효과를 조사하기 위해 양상추를 신선편의 가공하고, 세척 시 살균제로 이들을 적용한 후 저장 중 pH 및 일반세균, 효모, 곰팡이, 대장균, 대장균군의 변화를 조사하였다. 살균제 스크리닝 결과, 0.02%의 염소수 처리 시 3.1 log 감소를, 1% 농도에서 acetic acid는 2.4 log, ascorbic acid는 1.3, citric acid는 0.7 log의 감균 효과를 나타내었다. 시판 중인 살균제 대부분에서 2 log 의 감균 효과를 나타내어, 이들을 신선편의 양상추에 적용하고 $10^{\circ}C$에 저장하면서 양상추의 pH 변화 및 미생물의 변화를 조사하였다. 저장 초기 양상추의 pH는 살균제 용액의 pH에 따라 변화하고 있었는데, 용액의 pH가 가장 높은 칼슘제제(12.0)가 6.1, 가장 낮은 Formula 4(4%, pH 1.7)에서 가장 낮은 pH(4.7)로 나타났으며 저장일 경과에 따라 pH는 유의적으로 증가하고 있었다. 대장균군을 제외하고 0.02%의 염소수가 가장 높은 수준의 미생물 저해 효과를 나타내었다. 반면 Formula 4, Fresh produce wash 모두 3% 이상에서 미생물 저해 효과가 나타나고 있었다. 특히 Formula 4는 대장균 및 대장균군 저해 효과가 매우 좋았다. 모든 처리구에서 곰팡이는 검출되지 않았으며 효모의 경우 염소수와 Fresh produce wash 및 알코올 살균제 중 키토콜과 칼슘 제제 처리구가 효과적으로 저해하고 있었다. 시판 살균제에 따라 미생물 저해 효과는 다르게 나타나고 있었으나 염소수와 비교했을 때 초기 미생물 저해 효과는 존재하고 있기 때문에 부가적인 hurdle technology 및 공정관리를 통해 저장 중 항미생물 효과를 지속시킨다면 실제 적용이 가능할 것으로 판단된다. This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water ($0.2ml{\cdot}L^{-1}$), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4$^{TM}$ (1,3,4%), Fresh produce wash$^{TM}$ (1,3,4%), Cleancol$^{TM}$ (1%), Chitochol$^{TM}$ (1%) and Natural Ca$^{TM}$ (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

포장 필름의 산소투과율에 따른 신선편의 양상추의 저장 중 품질변화

황태영 ( Tae-young Hwang ) 한국응용생명화학회 2018 Journal of Applied Biological Chemistry (J. Appl. Vol.61 No.1

This study investigated the effect of different O₂ transmission rate (OTR) of films on surface temperature, weight loss, pH, O₂, CO₂ and sensory characteristics, microbial quality, total phenolic contents and 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity of fresh-cut lettuce during storage at 10 ℃ for 7 days. 80±5 g of fresh-cut lettuce were packaged with oriented polypropylene films respectively. The OTR of packaging materials was 5,000, 8,000 and 10,000 cc/㎡·day·atm. Quality characteristics showed significant differences during storage. The surface temperature was averaged 13 and lower in higher OTR of films. The weight loss of lettuce ranged from 2.8 to 5.4% and the highest loss showed in 5,000 cc/㎡·day·atm of film. pH was increased during storage and the highest pH was found in 5,000 cc/㎡·day·atm. The O₂ content in the packaging was decreased with increasing CO₂ content during storage. The lowest CO₂ was found in 10,000 cc/㎡·day·atm. As OTR was decreased, antioxidant profile of lettuce was decreased. Total aerobic bacteria showed from 5.48 to 6.59 log CFU/g. From the result of the overall sensory test, the marketability of fresh-cut lettuce stored at 10 ℃ seemed to be maintained effectively over 5 days.

Discrimination methods for biological contaminants in fresh-cut lettuce based on VNIR and NIR hyperspectral imaging

Mo, Changyeun,Kim, Giyoung,Kim, Moon S.,Lim, Jongguk,Lee, Seung Hyun,Lee, Hong-Seok,Cho, Byoung-Kwan Elsevier 2017 Infrared physics & technology Vol.85 No.-

<P><B>Abstract</B></P> <P>The rapid detection of biological contaminants such as worms in fresh-cut vegetables is necessary to improve the efficiency of visual inspections carried out by workers. Multispectral imaging algorithms were developed using visible-near-infrared (VNIR) and near-infrared (NIR) hyperspectral imaging (HSI) techniques to detect worms in fresh-cut lettuce. The optimal wavebands that can detect worms in fresh-cut lettuce were investigated for each type of HSI using one-way ANOVA. Worm-detection imaging algorithms for VNIR and NIR imaging exhibited prediction accuracies of 97.00% (RI<SUB>547/945</SUB>) and 100.0% (RI<SUB>1064/1176</SUB>, SI<SUB>1064-1176</SUB>, RSI-I<SUB>(1064-1173)/1064</SUB>, and RSI-II<SUB>(1064-1176)/(1064+1176)</SUB>)<SUB>,</SUB> respectively. The two HSI techniques revealed that spectral images with a pixel size of 1×1mm or 2×2mm had the best classification accuracy for worms. The results demonstrate that hyperspectral reflectance imaging techniques have the potential to detect worms in fresh-cut lettuce. Future research relating to this work will focus on a real-time sorting system for lettuce that can simultaneously detect various defects such as browning, worms, and slugs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> VNIR- and NIR- HSI algorithms to detect worm on fresh-cut lettuce were developed. </LI> <LI> The optimal wavebands to discriminate worm were investigated by the one-way ANOVA. </LI> <LI> The worm detection algorithm achieved the accuracy of 100% for NIR-HSI. </LI> <LI> The best pixel size of spectral images to detect worm were 1×1 or 2×2mm. </LI> </UL> </P>

Effect of initial oxygen concentration and film oxygen transmission rate on the quality of fresh-cut romaine lettuce

Kim, Ji Gang,Luo, Yaguang,Tao, Yang,Saftner, Robert A,Gross, Kenneth C John Wiley Sons, Ltd. 2005 Journal of the science of food and agriculture Vol.85 No.10

<P>Modified atmosphere packaging (MAP) is widely used to maintain the quality of fresh-cut produce by matching the oxygen transmission rate (OTR) of the packaging film to the respiration rate of the packaged product. The effect of the interaction between film OTR and the initial headspace O<SUB>2</SUB> on quality of fresh-cut vegetables has not previously been reported. Romaine lettuce leaves were sliced, washed, dried and packaged with film OTRs of 8.0 and 16.6 pmol s<SUP>−1</SUP> m<SUP>−2</SUP> Pa<SUP>−1</SUP>, and with initial headspace O<SUB>2</SUB> of 0, 1, 2.5, 10 and 21 kPa. Packages were hermetically sealed and stored at 5 °C for up to 14 days. For samples packaged in 16.6 OTR film, increasing the initial headspace O<SUB>2</SUB> concentration delayed O<SUB>2</SUB> depletion within the packages, hastened the onset and increased the intensity of discoloration, and inhibited the development of CO<SUB>2</SUB> injury, acetaldehyde and ethanol accumulation, off-odors and electrolyte leakage. With 8.0 OTR-packaged lettuce pieces, ≤1 kPa initial headspace O<SUB>2</SUB> treatments induced an essentially anaerobic environment within the packages and increased acetaldehyde and ethanol accumulation and off-odor development. Increasing the initial O<SUB>2</SUB> concentration above 1 kPa in 8.0 OTR packages transiently increased O<SUB>2</SUB> concentrations and reduced fermentative volatile production, off-odors, electrolyte leakage and CO<SUB>2</SUB> injury. Regardless of initial headspace O<SUB>2</SUB> concentration, all 16.6 OTR-packaged samples had severe discoloration after 14 days of storage. Quality was better maintained in 8.0 OTR-packaged lettuce pieces as the initial headspace O<SUB>2</SUB> concentration was increased. A 21 kPa initial O<SUB>2</SUB> treatment of 8.0 OTR-packaged lettuce maintained good quality throughout storage and had the best overall quality score. Copyright © 2005 Society of Chemical Industry</P>