• Food Science of Animal Resources
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• v.31 no.6
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• pp.928-934
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• 2011

The objective of this study was to characterize the lactate metabolism and lipolysis in Emmental cheese made of Korean raw milk throughout the ripening periods; 14 d at $10^{\circ}C$, 42 d at $23^{\circ}C$, and 30 d at $4^{\circ}C$. Emmental cheese was made using a commercial starter culture with propionic acid bacteria (PAB) and without PAB as a control on the pilot plant scale. Changes in the contents of five organic acids (citric, lactic, formic, acetic, and propionic acid) and individual free fatty acids (FFAs) were measured using HPLC/PDA and GC/FID. As a result of propionic fermentation by PAB, the concentration of acetic acid and propionic acid increased up to 1.5 and 6.1 g/kg, respectively and the most dramatic increased occurred when incubated in the hot room ($23^{\circ}C$). Lactic, citric, and formic acid contents were 2.6, 2.5 and 0.8 g/kg at the end of ripening, respectively. As a result of lipolysis, the amount of total FFAs was 6,628.2 mg/kg. Compared to the control, levels of individual FFAs from butyric (C6:0) to linoleic (C18:2) acids increased significantly (p<0.05) during the ripening period. Especially, 65.1% of total FFAs was released in the $23^{\circ}C$ room and the most abundant FFAs were palmitic (C16:0), stearic (C18:0) and oleic acid (C18:1). These results demonstrated that the lipolysis of Emmental cheese was strongly affected by bacterial lipase from PAB.

• Clean Technology
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• v.16 no.2
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• pp.88-94
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• 2010

The physiological roles of various wavelength of light emitting diode (LED) on ‘Hayward’ kiwifruit experiencing after-ripening were investigated. Various wavelengths from LED light source were irradiated on kiwifruits kept in plastic bags or under open air at $25^{\circ}C$. During two weeks of storage, firmness of Hayward kiwifruits was decreased by $25^{\circ}C$ treatment than by $4^{\circ}C$ treatment. In the $25^{\circ}C$ storage condition, the firmness of kiwifruits was decreased by the treatment of 380 nm UV and 470nm white LED light source. Sweetness of kiwifruits treated with 380 nm UV LED and dark condition at $25^{\circ}C$ increased higher than $15^{\circ}$Brix. The acidity of kiwifruits under open air was decreased 52% by incubating at $25^{\circ}C$ with 660 nm red LED treatment. The acidity of kiwifruits in plastic bags was decreased 52.6, 55.6, 52.8% by the treatment of 440 nm blue, 470 nm white and 660 nm red LED light source, respectively, compared to that of kiwifruits incubated in darkness at $25^{\circ}C$. Decreased acidity irradiated by 660 nm red LED light source can be applied for regulating periods of the kiwifruit after-ripening process. LED light sources emit very narrow wavelength with a power-saving mode, therefore, the usage of these LED light source for regulating the after-ripening process can be classified as a clean biotechnology producing safe and environment-friendly kiwifruits.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.2
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• pp.109-115
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• 2006

In response to the continuous changes in current consumer demands and market trends for postharvest produces, the functional application for agricultural packaging is becoming increasely significant. This paper focuses on the overview of important changes in physical and chemical status related to postharvest physiology and applications of the functional packaging materials for maintaining the freshness of fruits after harvest. During postharvest treatment and storage periods, fresh fruits undergoes the ripening process in quality attributes of the fruit such as major changes of texture, color, and flavor. Major fruit packaging technologies are concerned with correct gas permeable film and functions of ethylene removal, antimicrobial, and antifogging substances to keep the effective freshness. Application guidelines for the functional packaging in fresh produces were studied.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.452-458
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• 1991

Psychrotrophs producing protease were isolated during ripening periods of Cheddar cheese and one of them containing the highest protease activity was identified as Pseudomonas fluorescens 65. The extracelluar proteolytic enzyme was partially purified from P. fluorescens 65 through the Sephadex G-100 gel filtration. The protease was eluted between 190 ml and 230 ml of elution volume of sodium phosphate buffer. The purified protease showed a single band in SDS-PAGE and its molecular weight was 47,000. The composition of amino acid for the protease was determined and the most abundant amino acids were glutamic acid (14.96%) and serine (13.86%). The optimum temperature and pH for the activity was $45{\sim}50^{\circ}C$ and 6.0, respectively.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.746-754
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• 2016

This study was conducted to assess the effect of ethylene producing tablet (patent no.10-1574011) and treatment period on quality and storability of banana (AAA - Cavendish group) fruit imported into Korea from the Philippines. Three and five days of treatment periods, and different concentrations of ethylene tablet (50 ppmv, 100 ppmv) and control (standard ethylene gas treatment at a concentration of 100 ppmv) were used for the study. Slightly higher respiration rate was observed in banana fruits treated with 50 ppmv in both 3 and 5 days after treatments as compared to the control. Better storability was observed with banana fruits treated with 50 ppmv and 100 ppmv as compared to the control. All the treatments were shown a decrease in firmness as the storage days proceeded. The highest firmness was recorded from 50 ppmv on the initial day of storage while the lowest was recorded from 100 ppmv on 9 day storage. It was observed that banana fruits could be stored for up to 12 days without losing their color quality in all treatments except for the control. However, the quality of fruits at the control rapidly decreased (lost marketability) after 9 days of storage. Banana fruits treated with ethylene tablet with 100 ppmv for 5 days recorded the highest soluble solids content (SSC) at the beginning of storage period which was similar with the control. However, banana fruits treated with ethylene tablet with 100 ppmv for 3 days showed better storability than the control. On the other hand, ethylene tablet with 50 ppmv for 5 days of treatment has extended banana shelf life without affecting peel color, firmness and SSC content. Hence, these results indicate that banana fruits treated with ethylene tablet with 100 ppmv for 3 days or /and 50 ppmv for 5 days are an optimum for ripening of banana to be used for market and ultimate consumption.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.210-214
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• 1973

This study analyses and compares the amino acid composition and available lysine content between Korean fermented soybean Meju and its products as well as home-made and commercially made products. The protein quality of the products was evaluated by the result, and the biological value of the proteins was estimated by using the regression equation for chemical score to biological value as calculated by B.O. Eggum. The amino-N content of soybean is found to be 85% of the total nitrogen content and is reduced to approximately 75% in the fermented products except home-made soysauce, where as the content of ammonia-N and other N-compounds is increased. The difference in protein quality between home-made and commercially made products is not found to be significant. The protein quality of soybean is not damaged greatly in the making of Meju but is seriously damaged during the long periods of ripening. After the ripening the chemical score of the products' protein is reduced to approximately one half of the original soybean protein and the available lysine content to $1/3{\sim}1/2$.

• Journal of the Korean Society of Food Culture
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• v.12 no.4
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• pp.383-389
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• 1997

This study was carried out in order to analyze the changes in nitrogen containing taste compounds of traditional Korean soy sauce with varying Meju concentrations (Meju-water ratios of 1:4 and 1.3:4) and ripening periods (up to 2 years), and to investigate correlation between sensory characteristics and taste compound contents via contents assay and sensory evaluation of soy sauce samples. Nitrogen compound contents were higher in 1.3:4 than in 1:4 for all nitrogen compounds. Free amino acid contents were highest in soy sauce ripened for 210 days. Among amino acids, glutamic acid was highest concentration. Nucleotides and their related compound contents did not vary with concentrations and were highest in the sample ripened for 210 days. In direct sensory evaluation of soy sauce, overall taste preference showed positive correlation to sweet taste. Likewise, overall taste preference showed positive correlation to umami, nutty, sweet taste in the sensory evaluation of seaweed soup seasoned with soy sauce. Sensory evaluation score was higher in 1.3:4 than in 1:4. According to the correlation assay of taste compound contents and sensory evaluations, nitrogen compounds (such as amino type nitrogen), amino acids (such as glutamic acid, aspartic acid, and lysine, and etc.), nucleotides (such as AMP, IMP, and etc) had significant influence on the sensory characteristics of soy sauce, and therefore we can conclude that these compounds affect the taste and quality of soy sauce.

• Journal of the Korean Society of Food Culture
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• v.31 no.4
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• pp.348-356
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• 2016

The purpose of this study was to investigate the chemical contents (sugar, nitrogen, and amino acids) and sensory characteristics of traditional soy sauce according to three different methods. The samples were taken from four different periods (0, 20, 40, and 60 days after fermentation). Total sugar contents increased in all groups according to ripening period, and Gyupjang (G) showed the highest sugar content among the groups. Total nitrogen and amino acid contents of all groups increased after 60 days of ripening, and Gyupjang (G) and Gyupjang mixed with salt water (SG) had higher total nitrogen content compared to Chungjang (S) at the same period. The results from the sensory evaluation show that preferable sensory characteristics, such as color preferences, sweetness, umami taste, and overall preference, were significantly higher in Gyupjang (G) and Gyupjang mixed with salt water (SG) than in Chungjang (S). Preferable sensory characteristics had significantly high positive correlation with most amino acids, total nitrogen, and sugar contents, except for glutamine. Based on the significant difference in preferable sensory characteristics between Gyupjang mixed with salt water (SG) and Chungjang (S), Gyupjang mixed with salt water (SG) can be used to improve sensory characteristics. This research implies that adding salt water during the manufacturing Gyupjang process is advisable to yield high quality soy sauce.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.666-672
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• 1997

Twenty years' daily mean air temperature data was used to calculate the critical early seeding date(CESD), the optimum heading date(OHD), the critical late heading date for stable ripening(CHDR) and the critical late ripening date(CLRD) for rice seeded on dry paddy in different agroclimatic zones in Korea. The CESD was defined as the first day with mean air temperature of 13$^{\circ}C$, and the OHD as the first day of the 40 consecutive days with mean air temperature of 22$^{\circ}C$ or above after heading. The CHDR was defined as the date after which the cumulative daily mean air temperature would be at least 76$0^{\circ}C$. Lastly, the CLRD was defined as the last day when daily mean air temperature remains above 15$^{\circ}C$. This information was used for the estimation of periods from the earliest date of seeding to optimum heading date, the latest possible date of heading and the latest possible date of ripening in respective regions. For instance, in Suwon, those respective periods mentioned were found to be 104days, 124days, and 165days.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.302-311
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• 2023

This study aimed to investigate the changes in bioactive compounds across the ripening stages of three pepper cultivars, each characterized by unique skin colors. The samples used in this study consisted of three pepper cultivars distinguished by their skin colors as green, purple, and yellow green at breaker ripening stage. Samples were harvested at each of the four ripening stages, including premature, breaker, turning, and mature, and subjected to analysis for various bioactive compounds, including capsaicin, ascorbic acid, kaempferol, quercetin, and sugars. In all cultivars with varying skin colors, the capsaicin content within green pepper fruits consistently increased as the ripening stages advanced. Ascorbic acid was most abundant during the premature stage of development in purple and green cultivars, subsequently declining as maturation progressed. In the case of the purple cultivar, kaempferol content decreased by approximately 30% at the mature stage, while the green cultivar exhibited a gradual increase in kaempferol content with maturation. Conversely, the kaempferol content of the yellow green cultivar rapidly declined as maturation progressed. Regarding quercetin content, the purple and green cultivars tended to decrease with maturity, while the yellow green cultivar displayed an increasing trend. Furthermore, the accumulation patterns of glucose, fructose, and sucrose, the predominant free sugars in green pepper fruit, demonstrated an inclination to increase as the maturation stage advanced in both purple and green cultivars. In contrast, the yellow green cultivar initially showed an elevation in free sugar content during the immature stage, followed by a minor reduction during maturation and a subsequent rise during the mature stage. Each pepper cultivar, distinguished by its unique skin color, exhibits varying levels of bioactive substances at different ripening stages. Therefore, optimal harvesting and utilization should align with periods when the desired substance content is at its peak.