• Korean Journal of Food Science and Technology
• /
• v.17 no.6
• /
• pp.447-453
• /
• 1985

The effects of preheating and calcium chloride on prevention of tissue softening was examined during fermentation and storage of radish root kimchi. In order to find the optimum condition of preheating treatment, activities of pectinesterase (PE) and polygalacturonase (PG) in radish root were measured with respect to $CaCl_2$ concentration and temperature. A maximum firmness was obtained with treatment in 0.05M $CaCl_2$ at $55^{\circ}C$ for 2hr which was optimum conditions for PE activity, while PG was inhibited at the $CaCl_2$ concentration of 0.05M. Firmness of radish root kimchi prepared by preheating treatment was decreased little during fermentation and storage for 25 days.

• Food Science and Preservation
• /
• v.22 no.4
• /
• pp.512-519
• /
• 2015

In this study, the effects of gamma-radiation treatment on cell wall composition and physiological characteristics of astringent persimmon fruit were investigated. The soluble tannin contents of gamma-radiated samples were reduced by the radiation treatment. The hardness of the radiated fruit was decreased when compared to non-radiated fruit. Alcohol-insoluble component of the cell wall in the radiated fruit was decreased from 39.3 mg/g to 37.2 mg/g. The water-soluble content of the radiated fruit was increased from 11.4 mg/g to 13.9 mg/g. The cell wall content of the non-radiated fruit was 26.6 mg/g whereas the cell wall content of radiated fruit was decreased to 23.1 mg/g. Due to the maturation of astringent persimmon fruit by gamma-radiation, water-soluble compounds were increased whereas decreasing in cell wall compounds. The contents of lignin, pectin, and cell wall were decreased from 0.82 mg/g and 3.56 mg/g to 0.77 mg/g and 3.14 mg/g, respectively. Acid-soluble hemicellulose content was decreased by gamma-radiation, while alkali-soluble hemicellulose and cellulose contents were increased. Activities of sotening enzyme as polygalacturonase, pectinesterase and $\beta$-galactosidase existed in persimmon fruit were increased by gamma-radiation. In the sensory evaluation, gamma-radition treated persimmon showed very low astringent taste when compared to the non-radiated fruit. In hardness test, the non-radiated persimmon maintained the hardness while gamma-treated persimmon showed softened outer layer due to the condensation of tannin during radiation treatment. Therefore, gamma-radiation treatment will be used for the removal of its astringency of persimmon fruit and for enhancement of its maturation.

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

• Applied Biological Chemistry
• /
• v.43 no.3
• /
• pp.179-183
• /
• 2000

Satsuma mandarin(Citrus unshiu Marc. var. miyagawa) was stored at $3^{\circ}C$ and 85% relative humidity, and then the changes of firmness, pectin- degrading enzymes activity and other physicochemical properties of citrus fruits during storage were investigated. Firmness of fruits with 2 m probe was decreased quickly from 1,176.8 g-force to 503.6 g-force, and moisture of peel and flesh were decreased from 75.3% to 74.9%, and from 91.8% to 90.7% during maturation, respectively. Decay ratio was increased to 18.75% after 90 days' storage, and after then it was increased rapidly. Weight loss was increased gradually to 24.5% during long-term storage. Firmness with 2 mm probe were decreased from 538.9 g-force to 336.9 g-force gradually during storage. Peel moisture was decreased from 75.8% to 72.6%, and flesh moisture was also decreased gradually from 90.3% to 88.3% during storage. Exopoly-galacturonase activity of peel and flesh were increased from 326.0 units/100 g to 534.9 units/100 g, and from 63.1 units/100 g to 81.0 units/100 g at 90 day's storage, respectively. After then, He enzyme activities were decreased from 394.0 units/100 g and 38.0 units/100 g, respectively. Pectinesterase activity of peel and flesh were increased from $14.4\;{\mu}mol$ to $38.8{\mu}mol$, and from $26.0{\mu}mol$ to $39.0{\mu}mol$ at 60 days' storage, respectively. After then, the enzyme activities were decreased to $6.0{\mu}mol$ and $8.2{\mu}mol$, respectively.

• Korean Journal of Food Science and Technology
• /
• v.31 no.1
• /
• pp.91-98
• /
• 1999

Plums (Prunus salicina L.) were coated with calcium-treated methylcellulose (CaMC) and hydroxypropylmethylcellulose-15 (CaHPMC-15). Respiration rate, weight loss, pH and titratable acidity, texture, and sensory characteristics were compared during 8-day storage period at $30^{\circ}C$. Weight loss and respiration rate of plums coated with CaMC and CaHPMC-15 were lower than those of control plums during storage while pH increased and titratable acidity slowly deceased during storage. Mechanical firmness was significantly deceased during storage, in which CaMC and CaHPMC-15-coated plums were harder than the control. Amount of soluble pectin, and pectin esterase and polygalacturonase activities as the markers of softening commonly increased with storage, but both CaMC and CaHPMC-15-coated plums were not found those increases. Sensory evaluation showed that the flesh softening of plums decreased during storage, and that in the coated plums exhibited the harder flesh. In conclusion, introduction of CaMC and CaHPMC-15 coatings on plums decreased respiration rate and contributed to delay of flesh softening, and the significant difference in postharvest storage quality of the both plums were not found between CaMC and CaHPMC-15 coatings.

• Korean Journal of Food Science and Technology
• /
• v.28 no.4
• /
• pp.750-755
• /
• 1996

Citrus juice was treated with supercritical carbon dioxide $(SC-CO_{2})$ and the effect of temperature and pressure on quality of citrus juice was determined. Pectinesterase (PE) was inactivated by $(SC-CO_{2})$ below temperatures necessary for thermal inactivation. There was no significant change in the pH, Brix and total acidity of citrus juice before and after $(SC-CO_{2})$ treatment, but brightness was improved. More ascorbic acid was retained during $(SC-CO_{2})$ treatment of citrus juice than thermal treatment $(93^{\circ}C/0.66\;min)$.During storage of supercritically treated citrus juice at $4^{\circ}C$, activity of PE was reversible. Sensory evaluation showed that color, flavor, taste and overall acceptance of $(SC-CO_{2})$ treated juice were not significantly different from untreated juice. This method offers potentially beneficial processing avenues for citrus juice and other juices, especially in the area of minimally processed products.

• Korean journal of food and cookery science
• /
• v.7 no.4
• /
• pp.1-7
• /
• 1991

The object of this study was to investigate the enzyme system in kimchi during fermentation. The results were as follows; 1. Pectinesterase (PE) activity initially increased, following a decrease in kimchi juice but progressively decreased in kimchi solid. 2. Polygalacturonase(PG) activity in kimchi juice initially increased following a decrease near to absence and then increased again. PG activity in kimchi solid, initially decreased following a increase. 3. Peroxidase (POD) activity in kimchi juice initially increased, following a decrease and that in kimchi solid progressively decreased. 4. The activity of ascorbic acid oxidase(AAO) in kimchi juice slightly decreased, following a increase but decreased again. The activity of AAO in kimchi solid, progressively decreased. The cause for the slight increase of the activities of enzymes in kimchi juice after kimchi making was thought to be the extracting effects from kimchi solid. The disappearance of all enzyme activities in fermentation was due to the decrease of pH and the inactivation of enzymes owing to prolongation of fermentation. The cause of increase of PG activity in late fermentation, may be the proliferation of aerobic organisms.

• Journal of the East Asian Society of Dietary Life
• /
• v.22 no.2
• /
• pp.264-270
• /
• 2012

The effect of pectinase on wine production and quality during wine fermentation was investigated in an experiment a laboratory scale (2 kg grape/5 L tank). Experimental results show that the enzyme-treated sample displayed a 13% higher rate of grape juice production compared to control (enzyme-untreated). In the case of color analysis, the addition of pectinase improved the color quality of wine in terms of both color intensity and hue values. The results show that pectinase enhanced both dark-red color and clarity of wine during the fermentation period. Further, the methanol concentration of the wine sample treated with pectinase reached 225.32 mg/L (control: 100.72 mg/L) due to hydrolysis of pectin. Sensory analysis after fermentation showed that pectinase significantly increased the color, smell, taste, and touch intensity scores of wines compared to control.

• Food Science and Preservation
• /
• v.18 no.5
• /
• pp.661-668
• /
• 2011

This study was conducted to devise appropriate blanching-process conditions as a means to convert Doraji, which is widely used in Korean food due to its unique fragrance and flavor, into frozen food materials for various uses. For the Hunter L values representing the brightness transformation among the surface color and gloss changes that were observed in Doraji before and after freezing, and after Doraji went through a blanching process, the specimen that went through a blanching process at $80^{\circ}C$ showed a significantly higher value compared to another specimen processed at a higher temperature, and the first specimen's value also rose after freezing. Meanwhile, for the hardness values, they declined more as the blanching temperature became higher and as the processing time became longer. For the number of total counts and the number of coliform groups, the number of total counts at $3.75{\times}10^5$ and $1.25{\times}10^5$ cfu/g before the blanching process was reduced into the approximately 2-3 log scale, and no coliform group was detected after the blanching process. As for the peroxidase activity, its activation was decreased by the blanching process, and more than 89% of the peroxidase became inactivated in all the specimens that went through the blanching process. The sensory characteristics of the frozen-thawed Doraji by test group showed the radish leaves blanched at $90^{\circ}C$ for 1 min to be the most highly evaluated in terms of the overall preference level (p<0.05).

• The Korean Journal of Food And Nutrition
• /
• v.16 no.1
• /
• pp.7-14
• /
• 2003

This study mainly focused on to investigate the effects of Schizandra chinensis on the growth of a bacterium, CS6 which was isolated from kimchi. CS6 was final]y identified to lactobacillus plantarum that caused acidification of kimchi. The ethanolic extract of Schizandra chinensis(EES) inhibited the growth of L. plantarum. Minimum inhibition concentration of crude EES on L. plantarum was 62.5mg/$m\ell$. In broth culture, 5$\mu\textrm{g}$/$m\ell$ of EES completely inhibited the growth of L. plantarum during fermentation. The addition of 0.4% of EES has no apparent effect on quality including the taste and color on kimchi. It was expected that EES-containing kimchi could extend the period of preservation. Analysis of organic acids in water fractions of EES was carried out by HPLC. It is apparent that antimicrobial active fractions contained the highest concentration of succinic acid, a little tartaric acid and malic acid. Among these organic acids, succinic acid showed the strong inhibitory effect against L. plantarum CS6 in vitro. Succinic acid-containing kimchi with a concentration of 0.4 and 0.5% had the inhibitory effect on growth of L. plantarum. Inhibitory effect of EES on amylase, cellulase and pectinase was also tested. In conclusion, the present experiment demonstrated that EES inhibited the growth of L. plantarum, and various enzyme activity. EES-containing kimchi was sustained the hardness, and initial acidity during fermentation. EES was considered as the possible additive of kimchi process and EES added in kimchi increase the quality, and storage period of kimchi.