• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1477-1483
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• 1999

In order to retain or remove the flavor components of onions, this study was performed to investigate the effect of seaweeds and adsorbents on volatile flavor components of onion juice by testing a sensory evaluation, measuring the amount of pyruvate and thiosulfinate, and investigating the changes of volatile components by SPME/GC. The main flavor compounds in raw onion juice were dipropyl tetrasulfide, 1-propenyl propyl trisulfide, methyl propyl trisulfide, dipropyl trisulfide. Volatile flavor compounds in onion juice treated with tangleweed, brown-seaweed, laver and celite showed a relatively decreasing tendency compared to untreated onion juice, but most of volatile flavor compounds in onion juice treated with activated charcoal and ${\beta}-cyclodextrin$ were removed. The result of the sensory evaluation with various materials for masking onion flavor showed a significant difference at the p<0.05 level. The amount of pyruvate and thiosulfinate treated with tangleweed, brown-seaweed, laver and celite showed little difference compared to untreated onion juice, but the amount of pyruvate and thiosulfinate treated with activated charcoal and ${\beta}-cyclodextrin$ decreased largely compared to untreated onion juice. As a result of the study, onion juice treated with tangleweed, brown-seaweed, laver and celite showed the effect of preserving the pungent taste and masking the onion flavor. Activated charcoal and ${\beta}-cyclodextrin$added to onion juice might have a role in removing the onion flavor by adsorbing volatile flavor compounds in onion.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.355-360
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• 2004

Residual contamination levels of natural microflora in strawberries were evaluated. Approximate counts of total aerobic mesophilic bacteria, total coliforms, and lactic acid bacteria were 8, 2, and 3 log CFU/g, respectively, whereas those of Escherichia coli and yeasts/molds were under the detection limit (<10 cells/g). Growth inhibition degrees of total aerobic mesophilic bacteria, total coliforms, and lactic acid bacteria were also evaluated based on three hurdles of preservative, storage temperature, and pH of strawberry paste prepared as model system. Strawberry paste was stored at low ($4^{\circ}C$), room ($20^{\circ}C$), and high ($37^{\circ}C$) temperatures. Potassium sorbate was added as a preservative up to 0.1%. Acidity of strawberry paste was adjusted to pH 4 or 7. During 7-day storage, inhibitory effects of the hurdles against bacterial groups were: storage temperature > pH of strawberry paste > addition of potassium sorbate. Combination of three hurdles most effectively inhibited growth of residual microflora.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.445-450
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• 2002

This study was performed to evaluate the effect of chitosan addition on shelf life of bread. Four different molecular weights (MW) of chitosan, 1 kDa, 5 kDa, 30 kDa, and 120 kDa were used. The growth of spoilage bacteria was inhibited depending on MW and concentration of chitosan, and most inhibited conditions were 0.1% of 30 kDa and 120 kDa of chitosans. But the growth of yeast and mold showed very weak inhibition. This showed that yeast would grow normaly in the fermentation process of bread. Shelf-life of bread was improved depending on concentration of chitosans at WM 30 kDa and 120 kDa. Antioxidative effect of chitosan was increased with the larger molecular weight and the higher concentration during storage. The preservation of bread by adding chitosan was improved.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.35-41
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• 2006

Possible application of hurdle technology extention of shelf-life of fresh-cut apples was investigated by evaluating various hurdle factors known to be effective microbial growth inhibitors and their synergistic effects. Fresh-cut apples treated with chitooligosaccharide or grapefruit seed extract (GSE) showed higher microbial counts than those treated with distilled water during latter half of storage period, and at high concentrations. Citric and malic acids showed similar results, although microbial counts of fresh-cut apples treated with 0.75% or higher concentration of citric acid increased at 4 days of storage at $18^{\circ}C$, indicating malic acid is more effective than all hurdles tested for controlling microbial growth. Using ascorbic acid and calcium chloride as additional hurdles to control browning and softening, minimum and maximum compositions of dipping solution were: 0.25 : 0.5 : 0.25% and 0.75 : 1.0 : 0.75% malic acid: ascorbic acid: calcium chloride, respectively.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.551-559
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• 2001

Sodium nitrite which is added in processing of meat process product to develope color and to keep bacteria from growing, produces toxic substance after reacting, bring about deterioration by oxidation and toxic substance. So natural material is needed to substitute this sodium nitrite for. Chitosan which is made of chitin by processing of deacetylase, has various function of antibiosis and antimutation. We studied about the substitution effect of chitosan against sodium nitrite in pork sausage. As a result, of storing the sausage, antimicrobial effect of sodium nitrite was detected by 0.35% of chitosan(M.W. 30 kDa). This chitosan had same color developing effect even though addition content of sodium nitrite reduced until 15 ppm which is less than 1/10 of standard level. And chitosan decreased fast a residual nitrite. This result shows that chitosan inhibited a formation of nitrosamine.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.661-665
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• 2002

In order to develop ginseng tea powder with spore forming lactic acid bacteria Lactobacillus sporogenes was used. In the jar fermentor experiment under optimal culture conditions, the number of spore of L. sporogenes reached about $20{\times}10^8\;CFU/mL$ and sporulation rate was 97%. Granulated ginseng tea was made from glucose 7 kg, lactose 2 kg, ginseng extract 1 kg and spores 5 g $(5200{\times}10^8\;CFU/g)$. In the treatment of artificial gastric juice (pH 3.0) for 4 h and artificial bile for 8 h, the survival rate of spores in the granulated ginseng tea was 55.4% and 90.0% respectively. The spores survived 77.6% after incubation for 20 min in boiled water. Its storage stability was about 75% for 12 months at room temperature.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1073-1078
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• 2002

Antimicrobial activities in 70% ethanol extracts of Korean bamboo trees were investigated. Among the antimicrobial activities against ten major strains causing food poisening, Wangdae (Phyllostachys bambusoides S. et Z.) showed the strongest activity among five major bamboo trees cultivated in Korea. Although all extracts showed relatively strong antimicrobial activities against Staphylococcus aureus and Streptoccus mutans, the extracts of bamboo culms showed stronger activities than that of bamboo leaves. MICs (minimal inhibitory concentration) of the extracts of Wangdae culm against Staphylococcus aureus and Streptococcus mutans were over $10\;and\;20\;{\mu}L/disc$, respectively. The extract of Wangdae culm inhibited the growth of Staphylococcus aureus and Streptococcus mutans at over 0.5% concentration, and almost inhibited the growth of these strains at 1% level. The inhibitory effect of the extract of Wangdae culm was not destroyed by heating at 60, 80, and $100^{\circ}C$ for 60 min and at $121^{\circ}C$ for 15 min, suggesting that the component in the bamboo tree was very heat-stable. These results indicate that 70% ethanol extract of Wangdae culm could be useful as a natural antimicrobial agent.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.363-372
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• 2000

Gamma irradiation$(1{\sim}5\;kGy)$ was applied to Korean beef to improve the hygienics and quality preservation. The effective dose of irradiation was 3 kGy for the sterilization of the initially contaminated microorganisms. After 8 weeks of storage at $5^{\circ}C$, no growth of the microorganisms were observed in the samples irradiated above 5 kGy. The pH was slightly increased as storage period increased. However, no significant change in pH was observed by gamma irradiation. The acid value of beef during storage at $5^{\circ}C$ was increased rapidly with the elapse of the storage period in both nonirradiated and irradiated samples, but that of the 3 kGy irradiated samples increased more slowly than the nonirradiated. VBN value increased more rapidly in nonirradiated sample than the irradiated during storage. Especially VBN value of the nonirradiated sample was four fold higher than that of the 3 kGy irradiated sample after 8 weeks of storage at $5^{\circ}C$. No significant differences in the components of fatty acid were observed by gamma irradiation. The amount of released free amino acid was increased during storage and was not significantly affected by gamma irradiation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.368-377
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• 2021

Plum is a typical fruit that is consumed processed rather than raw. In this study, we manufactured one of the processed foods, viz., plum Jangachi. In this process, the manpower-dependent seed separation and flesh cutting operations were automated by mechanizing, thereby altering the manufacturing process. Quality and Safety were assessed through microbial evaluation, analysis of color, and detection of preservatives in the plum Jangachi. Preference factors were identified through sensual evaluation. When compared with other plum Jangachi currently available in the market, our product was determined to contain 2.7±0.1 Log CFU/g total aerobic bacteria, which is slightly higher than the average of other products. This was not surprising, as the figures are due to the inherent characteristics, which were determined to be lower as compared to other commercial plum Jangachi. Other coliforms, tar dyes, and preservatives were undetected, thereby conferring satisfactory Quality and Safety. In general, there was no statistical difference in the sensual evaluation and appearance; overall, our product received better feedbacks than products on the market. Taken together, our results provide a foundation for applying the mechanization of plum-processed foods, thereby promoting the local economy in the main production area, and overall characteristics obtained are regarded sufficient in terms of market competitiveness.

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.121-128
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• 1999

This experiment was carried out to establish effective weed control system in the cultivation of Coix lachryma-jobi L. The effect of annual weeds artificially transplanted on the growth of Coix lachryma-jobi L. were that the higher the density of weeds, the lower the yield considerably by reducing number of grains and tillers per plant. Among four weeds of Echinochloa crusgalli galli P. BEAUV., Digitaria sanguinalis $S_{COPOL}$., Chenopodium album L., and Portulaca oleracea L., weed of Portulaca oleracea L. reduced adlay yield most by 182.6kg/10a and it was judged to be the most injurious weed to adlay production. Among four weed control systems, which are one herbicide treatment, one herbicide treatment + one cultivating work with cultivator, two times cultivating work with cultivator and two times hand-weeding, the control system of 'one herbicide treatment + one cultivating work with cultivator' showed the lowest amount of weed growth by 7.34 weeds per $m^2$ in comparison with control plot of 35.00 weeds per $m^2$. Among four weed control systems, the system of 'two times hand-weeding' had much more amount of light penetration in adlay canopy with 791.9 mol than any other systems.