• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1219-1225
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• 2005

This study was carried out to investigate the effects of preheating temperature on the properties of the Korean traditional pepper pickle. In experimental groups, the pepper was heated in the warm water at 40, 60, 80$^{\circ}C$ for 10 minutes while the control group was not heated. The contents of chlorophyll and vitamin C in treated pepper were evaluated. The contents of chlorophyll were 30.96$\∼$31.13 mg$\%$ at the initial stage of 0 day and 0.76$\∼$2.34 mg$\%$ for 60 days of storage. The vitamin C contents were increased until storage 6 days and then were decreased. Pickles treated at 60$^{\circ}C$ showed the highest score on hardness after 60 days of storage followed by 40$^{\circ}C$>no-heat treatment (NH)>80$^{\circ}C$. The yellowness on the surface of brined pepper peels was increased with preheating temperature increased. Activities of pectinesterase were the highest at 60$^{\circ}C$ followed by 40$^{\circ}C$>80$^{\circ}C$>NH treated. Activities of polygalacturonase were lower than that of NH group.

• Food Science and Preservation
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• v.19 no.6
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• pp.818-824
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• 2012

In this study, danmuji samples stored at 5 and $25^{\circ}C$ were examined for three weeks to observe the changes in the color, property of matter, and microorganisms of danmuji, and its sensory properties, during its storage. The difference in the brightness and redness of danmuji and danmuji filtrate as their storage period became longer was not big but was significant, and their yellowness decreased following storage at both 5 and $25^{\circ}C$. The hardness of the danmuji sample stored at $5^{\circ}C$ showed the greatest value at day 7 while that of the danmuji sample stored at $25^{\circ}C$ showed the greatest value at day 14. It was found in the examination of the total cell number of the stored danmuji that the total cell number was $10^5CFU/g$, with almost no change, but in the case of the danmuji filtrate, the cell number increased from the latter part of the storage. The number of yeast fungi increased until storage day 7 for both the danmuji sample stored at $5^{\circ}C$ and that stored at $25^{\circ}C$. The cell number of danmuji did not change since then while the cell number of the danmuji filtrate constantly increased. As for the sensory properties of each stored danmuji, the overall taste preference was highest at storage days 14 and 21 ($5^{\circ}C$), and the overall scent preference was high for the danmuji that had been stored for 7 days ($5^{\circ}C$), but there was no significant difference. The texture and color of and the overall preference for the danmuji stored at $25^{\circ}C$ significantly decreased as the storage period got longer. All in all, the preference for the danmuji stored at $5^{\circ}C$ was higher than that for the danmuji stored at $25^{\circ}C$, although there was no significant difference. Thus, it is thought that $5^{\circ}C$ is more appropriate than $25^{\circ}C$ as the storage temperature of danmuji products.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.378-385
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• 2017

In this study, we evaluated the changes of fruit quality indices during fruit development and ripening in Korean new pear cultivar 'Changjo', developed from a cross between 'Tama' and '81-1-27' ('Danbae' ${\times}$ 'Okusankichi') in 1995 and named in 2009, to determine appropriate harvest time and to enhance the market quality and broaden the cultivation area. The fruits of 'Changjo' pears harvested from 132 days after full bloom (DAFB) to 160 DAFB. Fruit growth and quality indices were monitored at 1 week interval by measuring fruit weight, length, diameter, firmness, and taste related quality indices. The calculated fruit fresh weight increased continuously with fruit development and reached to an average of 594g on Sep. 20 (160 DAFB). The ratio of length to diameter declines as fruit maturation progress, resulting in 0.898 for ripe fruit stage as a round oblate shape. Flesh firmness of 'Changjo' pears showed over 30N until 153 DAFB and then decreased abruptly with fruit ripening, reaching a final level of about 26.44N on 160 DAFB. Starch content of fruit sap was also decreased abruptly after 146 DAFB which decreased almost half of the fruits harvested at 139 DAFB. In parallel with the decrease of flesh firmness, ethanol insoluble solids (EIS) content decreased sharply with fruit ripens, only 50% of EIS was detected on the fruits harvested on 160 DAFB when compared to that of the fruits harvested on 139 DAFB (Aug. 30). The maximum value of soluble solids contents was observed in the fruits harvested on 153 DAFB, resulting in $14.2^{\circ}Brix$. The changes of skin color difference $a^*$ which means loss of green color occurred only after 139 DAFB, coincide with the decrease of SPAD value of the fruit skin. The sugars of the 80% ethanol soluble fraction consisted mainly of fructose, sorbitol, glucose and sucrose, also increased during maturation and ripening. Fructose and sucrose contents were larger than those of glucose and sorbitol in flesh tissues. These results were explained that stored starch is converted to soluble sugars during fruit maturation, mainly in fructose and sucrose increasing the sweetness of this cultivar. Total polyphenols were increased up to middle of fruit maturation (146 DAFB) and then decreased continuously until the end of fruit maturation. Consequently, our results suggested that the commercial harvest time of 'Changjo' pears should not be passed 153 DAFB and late harvest of this cultivar would not good for quality maintenance during shelf-life. As a result of the post-harvest low-temperature acclimation experiment during the short-term transportation period, fruits harvested at 146 DAFB tended to maintain higher firmness after 14 days of simulated marketing at $25^{\circ}C$ compared to fruits harvested at 153 DAFB regardless of temperature set. And, the slower the rate of decrease to the final transport temperature of $5^{\circ}C$, the higher the incidence of internal browning and ethylene production. Therefore, in order to suppress the physiological disorder and to maintain the fruit quality when exporting to Southeast Asia in the 'Chanjo' pears, it is desirable to lower the temperature of the fruits within a short time after harvest and to set the harvest time before 146 days after full bloom.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.665-676
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• 2016

As high temperature during citrus growing season has caused a serious problems including inferior coloration in production of mandarins in Korea, we were to investigate the expression pattern of several genes related with coloration during the ripening in high temperature condition of citrus fruits. The expression of genes related with sugar metabolism, cell wall degradation, and flavonoid synthesis in high temperature conditions was investigated in fruits of 'Haryejosaeng' (Citrus unshiu) and 'Shiranuhi' mandarin (C. reticulata). While the expression of beta-amylase (BMY), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and flavanone 3-hydroxylase (F3H) was differently induced, expression of polygalacturonase (PG) decreased dependently on temperature conditions. In 'Haryejosaeng' mandarin, while the expression of genes related to the skin coloration, such as CHS and F3H genes increased at $25^{\circ}C$, the expression of PAL and stilbene synthase (STS) genes were induced at $30-35^{\circ}C$ in all ripening stages. In 'Shiranuhi' mandarin, the expression of the BMY gene decreased at early time point in all temperature condition and then increased at $30-35^{\circ}C$ than at $25^{\circ}C$ in the ripening stage 2 to 3 of fruits. F3H and STS genes also showed the tendency to decrease at $30-35^{\circ}C$. Although the expression levels of genes in ripening stage 1 and stage 2 of fruits showed similar patterns in both 'Haryejosaeng' and 'Shiranuhi', the expression levels of genes were down-regulated in late ripening stage of 'Shiranuhi' fruits compared to 'Haryejosaeng'. In general, the mRNA levels of seven tested genes were higher in 'Haryejosaeng' than in 'Shiranuhi' mandarin, and expression of genes by high temperature was regulated sensitively in 'Haryejosaeng' compared to 'Shiranuhi' mandarin. Further investigations of expression of various genes based on transcriptome analysis in early ripening stage can provide valuable information about the responses to climatic changes in ripening citrus fruits.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.851-858
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• 2010

In this study, waste glass and bottom ash were used as basic materials in order to secure a recycling technology of by-products which was mostly discarded and reclaimed. In addition, because softening point of waste glass is less than $700^{\circ}C$ and bottom ash includes combustible material, it was possible to manufacture low-temperature sintering lightweight aggregates for energy saving at $800{\sim}900^{\circ}C$ that it is as much as 20~30% lower than sintering temperature of existing lightweight aggregates. Thermal conductivity of newly-developed lightweight aggregates was 0.056~0.105W/m. K and its porosity was 40.36~84.89%. A coefficient of correlation between thermal conductivity and porosity was -0.97, it showed very high negative correlationship. With this, we were able to verify that porosity is key factor to affect thermal conductivity. Microstructure of lightweight aggregates by $CaCO_3$ content and replacement ratio of bottom ash in the variation of temperature were that $CaCO_3$ content increased along with pore size while replacement ratio of bottom ash increased as pore size decreased. Specially, most pores were open pore instead of closed pore of globular shape when replacement ratio of bottom ash was 30%, and pore size was small about 1/10~1/5 as compared with case in bottom ash 0~20%. In addition, open pore shapes were remarkably more irregular form of open pore in $900^{\circ}C$ than $700^{\circ}C$ or $800^{\circ}C$ when replacement ratio of bottom ash was 30%. We reasoned hereby that these results will influence on absorption increase, strength and thermal conductivity decrease of lightweight aggregates.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.138-145
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• 2007

The effects of amylopectin and hydrocolloid (locust bean gum and guar gum) content on wheat flour dough and noodle properties were investigated. As the amount of amylopectin increased, the water absorption rate (farinograph), the tension (tension test), the gel stability (freeze-thawing treatment), and the springiness and the cohesiveness (TPA) increased, but the pasting temperature (RVA), the lightness and yellowness (color measurement), and the hardness (TPA) tended to decrease. In sensory evaluations, the scores for cohesiveness, springiness, and acceptability of cooked noodle increased as the proportion of amylopectin increased. The proper combination of amylose/amylopectin ratio and hydrocolloids improved the freeze-thaw stability and the sensory acceptability of wheat flour dough and noodle.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.229-237
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• 1975

An attempt was made to utilize the enzyme produced by Asp. oryzae as meat tenderizer. The production, purification, and various properties of proteinase produced by Asp. oryzae were investigated. Results obtained are as follow; 1. A strain which had the highest proteolytic activity was selected among 9 Aspergillus species. 2. Culture medium consisted of wheat bran 10g, 2% glucose, 0.03% urea and 0.1% $MgSO_4$ (pH 6.5). Mold was incubated at $30^{\circ}C$ for 3 days. 3. Enzyme extract from culture medium were fractionated with ammonium sulfate and purified by Sephadex G-75 column chromatography. 4. When pH of reaction mixture was controlled, maximal activity of proteinase by Asp. oryzae was obtained at pH 3, pH 6.6, $8.4{\sim}8.5$ and pH 10.0 to 10.5. Those results were interpreted to show that enzyme consists of acid proteinase, neutral proteinase and alkaline proteinase. Enzyme was stable at pH 6 to 10. 5. Opt. temperature for proteinase activity was $50^{\circ}C$, but enzyme was stable up to $40^{\circ}C$. 6. The proteinase was inhibited by $Ag^+$. It was also inhibited by EDTA. 7. When myofibrillar proteins were treated by proteinase from Asp. oryzae, ATPase activities of myofibrillar proteins changed remarkably. Accordingly, it was concluded that proteinase produced by Asp. oryzae were able to be used as meat tenderizer.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.251-257
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• 2009

The effects of temperature variations during storage on the quality characteristics of muskmelons (Cucumis melo L.) were investigated. In samples stored at $4^{\circ}C$ and $10^{\circ}C$, weight losses were almost 2.9- and 3.4-fold higher, respectively, compared to samples stored at $0^{\circ}C$. Soluble solids slightly increased except in the samples stored at $10^{\circ}C$, but acidity decreased over the entire storage period. Firmness decreased with storage time, but the samples stored at $0^{\circ}C$ had a lesser decrease in firmness than the samples stored at other temperatures. Water loss from the muskmelon stalk was most inhibited, and vitamin C content was maintained for the longest period, with storage at $4^{\circ}C$. Mineral contents (Ca, Na, Fe, Mg, K) were best maintained in muskmelon samples stored at $10^{\circ}C$ for 15 days, but levels had decreased by 30 days. Microbiological quality was not appreciably different at any storage temperature at 18 days; however, samples stored at $4^{\circ}C$ and $10^{\circ}C$ had deteriorated by 25 days. The results of sensory evaluations indicated that taste was best retained in samples stored at $10^{\circ}C$ for 15 days, although changes in taste were evident at all storage temperatures. When the samples were stored over 22 days at $10^{\circ}C$, retention of texture and overall acceptability were more inferior compared to samples stored at $0^{\circ}C$ and $4^{\circ}C$. These results suggest that storage at $4^{\circ}C$ can be used to reduce deterioration in muskmelons without significant loss of their quality attributes.

• Food Science and Preservation
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• v.21 no.6
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• pp.767-775
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• 2014

The shelf-life of fresh mushrooms is notably limited because their browning, texture change, and decay are too fast after immediately harvest. Especially, the best management for extending golden needle mushroom's shelf-life is modified atmosphere packaging under pressure vacuum at cold storage. In this study, three types of films, $20{\mu}m$ polyethylene+polypropylene (PE+PP), oriented polypropylene (OPP), and low density polyethylene (LDPE) were tested to extend the shelf-life of golden needle mushrooms. Mushrooms were packed under pressure vacuum and stored at $10^{\circ}C$ for 2 weeks. The golden mushrooms in LDPE film as a commercial packaging, were highly perishable and immediately proceed deterioration as browning, elongation, fluctuation of respiratory quotient (RQ) and softening within 7 days after packaging. On the other hand, the mushrooms in OPP and PE+PP film shown that shelf-life were extend to 14 days from 7 days, causing delay breakup of vacuum and maintenance of color, length, and RQ during storage. The breakup of vacuum in PE+PP film was faster few days than OPP film packaging. This present study indicated that the golden needle mushrooms by OPP packaging under pressure vacuum treatment might be extended the shelf-life until approximately 14 days during cold storage.

• Korean journal of food and cookery science
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• v.16 no.4
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• pp.363-366
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• 2000

This study was attempted to compare the properties of proteolytic enzymes in fruits(Pear, Kiwifruit, Fig, Pineapple and Papaya) for the application of scientific information to cooking. The results were as follows: 1. The optimum temperature of crude proteolytic enzymes in pear, fig and pineapple is 60$^{\circ}C$ and it was relatively active in 40-70$^{\circ}C$; papaya showed max. activity in 60$^{\circ}C$ and highly stable activity in 40-80$^{\circ}C$, but kiwifruit showed max. activity in 40$^{\circ}C$ and it maintained to 70$^{\circ}C$. 2.. The crude proteolytic enzymes of pear, fig, pineapple and papaya showed opt. pH at pH 7.0 and maintained at pH 5.0-8.0, but max. activity of kiwifruit observed in pH 3.0 and pH 5.0-8.0. 3. As a result of comparison of total activities of fruits per kg unit, the order of activities was pineapple > kiwifruit > papaya > fig > pear.