• Korean Journal of Food Science and Technology
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• v.13 no.1
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• pp.53-56
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• 1981

Several tests were conducted to study lipoxygenase activity and off-flavor developement in frozen sweet corn. Fresh corn contained about 60% of total lipoxygenase activity in the germ section. When non-blanched frozen sweet corn was stored at $-10^{\circ}F$, it developed off-flavor and most significant changes in the flavor profile of off-flavored sweet corn was $4{\sim}5$ times higher hexanal peaks. The high hexanal peaks observed in the sterilized sweet corn with added lipoxygenase, alone and in combination with other enzymes, suggested the fact that high hexanal peaks in off-flavored sweet corn could be due to an oxidative reaction of lionleic acid (and other unsaturated fatty acids) catalyzed by lipoxygenase. Based on lipoxygenase activity and linoleic acid content in sweet corn, this reaction occur most heavily in the germ section of sweet corn. There was a significant relationship between flavor score of frozen stored corn-on-the-cob and hexanal peak in the germ section of corn-on-the-cob. This result indicated that hexanal peak could be used as an objective index of off-flavor development in frozen sweet corn.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.229-234
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• 1991

Attempts were made to improve the textural quality of French-fried potato produced with S potato varieties popular in Korea. The most suitable variety to produce French-fried potato, among 5 varieties tested, was Superior. Texture of French-fried potato was improved by air drying blanched potato strips at room temperature for over 1 hour, immersing potato strips in 6% starch solution at $60^{\circ}C$ for 2 minutes, and immersing in 1.5% hydroxypropyl methyl cellulose(HPMC) solution at $60^{\circ}C$ for 2 minutes. Textural quality of French-fried potato was significantly improved, when blanched potato strips were subjected to air drying at room temperature for 1 hour, followed by immersing them in 1.5% HPMC solution at $60^{\circ}C$ for 2 minutes prior to frying.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.119-124
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• 1987

Combined cryoprotectants (C.C.) were formulated to depress freezing points of strawberry pulp and orange juice concentrate to ${-15}^{\circ}C$, and quality changes in fruit pulps during storage ai ${-15}^{\circ}C$ in the liquid state were investigated. C.C. suitable for strawberry pulp consisted of sucrose (2.5%, w/w), glucose (12.7%), fructose (12.7%), glycerol (1%), propylene glycol (1%) and ascorbic acid (0.1%), and that for orange juice concentrate containing 48% solids glucose (5%), fructose (5%), glycerol (4%) and citric acid (1%). When quality of fruit pulps was compared among control and those with C.C., quality of fruit pulps stored with added C.C. was at least as good as control, except treatment B which had significantly lower overall preference. Strawberry jam prepared from pulp stored for 4 monthes did not show any significant quality differences among control and treated samples. The results of this study indicated that fruit pulps could be stored with added C.C. in the liquid state at the frozen storage temperature, while maintaining qualities at least as good as the conventionally frozen stored products.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.371-379
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• 2015

This paper represents the structural design of the light weight axle beam for medium duty commercial vehicle using hot press. To reduce the weight of the axle, axle beam of solid type was replaced by hollow type which was made by hot press. According to the change of axle beam structure and manufacturing method, we have to investigate the structural strength and fatigue performance. To verify the axle beam performance, the structural analysis was carried out by simplified axle beam model and various design parameters that are axle beam height, thickness and width. From the analysis results, the light weight axle beam structure was founded and applied the full model analysis. This study will be used as a guidance in development of the light weight axle for medium duty commercial vehicle.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.921-927
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• 1995

Peach pulp was separated into serum and insoluble pulp by centrifugation at 11,000 rpm for 10 min. The serum portion was concentrated at $50{\sim}55^{\circ}C$ and $30{\sim}50\;mmHg$ with aroma recovery. Vapor generated at the early stage of vacuum evaporation was condensed and taken as aroma fractions: AR-1($0{\sim}5%$), AR-2($5{\sim}10$), AR-3($10{\sim}15%$), AR-4($15{\sim}20%$). Dynamic headspace concentration method was used to trap volatile compounds in aroma fractions and identification of aroma compounds was made by GC/MS. The yield of serum separated from peach pulp was 70.5% and the serum fraction contained the most of aroma compounds. Thirty-one aroma compounds, including ethylene, benzaldehyde, l-limonene and ${\gamma}-dodecalactone$ were identified. The efficiency of aroma recovery was reduced, as the recovery time was extended, as indicated by less peak numbers and peach areas of aroma fractions.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.391-398
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• 1999

Enzymatic hydrolysis of crushed ginger was carried out to increase the yield of ginger extract, and the quality of the extract was investigated. The first extract was obtained by pressing crushed ginger, and the second extract by pressing ginger pomace hydrolyzed with $\alpha$-amylase at $90^{\circ}C$ for 1 hr. Oleoresin was extracted from the residue of enzymatic hydrolysis with 90% ethyl alcohol. The first extract, second extract and oleoresin were mixed to obtain the final ginger extract. The yield of final extract was increased by 276% on the solid base of the fresh ginger extract. The final ginger extract contained less crude fiber, starch and free amino acids (62, 48 and 40%, respectively), but contained more free sugar (270%) compared to fresh ginger extract.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.375-379
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• 1999

This study was designed to develop non-thermal pasteurized fresh apple juice by applying pulsed electric field (PEF) treatment. The effect of non-thermal PEF treatment on physicochemical and sensory properties of apple juice was examined by measuring changes in vitamin C contents, colors, flavors and sensory properties. Color of PEF and heat treated apple juices was not significantly different from each other. Vitamin C content of PEF treated apple juice was close to that of fresh apple juice, but was much higher than that of heat treated apple juice. Heat treated apple juice lost 70% of flavor components, whereas PEF-treated apple juice lost only 15%. Sensory scores of PEF treated apple juice were significantly higher than heat-treated one in flavor, taste and overall acceptability. In conclusion, PEF treated apple juice had superior physico-chemical and sensory properties to heat-treated one.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.59-65
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• 1984

Effect of ripening methods and harvesting time on vitamin content of 5 tomato varieties was investigated in 1978 and 1979. Ascorbic acid content in the breaker ripened tomatoes was significantly higher than that in the vine ripened tomatoes, and the result was consistent for two consecutive years. Ascorbic acid content in the vine ripened tomatoes markedly increased as the season progressed, early harvested tomatoes containing significantly less ascorbic acid. Carotene content was not significantly affected by the ripening method. Higher carotene content, however, was observed for tomatoes harvested in the late season. This result could indicate the effect of temperature for carotenogenesis around the harvest time. Thiamin and riboflavin contents in the vine ripened tomatoes were significantly higher than those in the breaker ripened tomatoes in the 1978 season, but these differences were not observed in the 1979 season. Thiamin and riboflavin contents in the vine ripened tomatoes decreased considerably as the season progressed. Thiamin and riboflavin contents in tomatoes harvested in the early season were significantly higher than those in the mid and late seasons.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.536-540
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• 1988

Effects of blanching time, chemical dipping, freezing method and storage period on texture, color and yield of frozen whole and sliced mushrooms were investigated, and the results are summarized as follows; Frozen whole mushrooms blanched for 5min. had markedly tougher texture than mushrooms blanched for 1 or 2 minutes. As the storage time of frozen mushrooms increased from 3 to 6 months, shear press values increased very significantly. The texture of Freon frozen and plate frozen mushrooms was similar after 3 months storage. Blanching time did not affect texture of frozen sliced mushrooms significantly, but storage time did. The results of sensory evaluation for texture were in good agreement with shear press values. Chemical dipping methods were effective in maintaining desirable color of frozen whole and sliced mushrooms stored for 3 months. The yield of frozen whole mushrooms was significantly increased by shortening blanching time in combination with chemical dipping. Sliced mushrooms required at least 2 min. blanching, to avoid excessive breakage in mechanical slicing operation, for better yield.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.1038-1044
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• 1997

The mode of the combined effect of adipic acid and medium chain monoglycerides was investigated by using nine strain. Though monoglycerides alone had little antibacterial activity against gram negative strains, the combined use with adipic acid showed much higher activity against others of gram positive strains as well as gram negative strains. But exceptionally, it seemed difficult practically to prevent the growth of lactic acid bacteria completely by the combined use of adipic acid and monoglyceride. For yeast and mold, monoglycerides alone had a high activity but adipic acid had a little activity. In antibacterial mechanism, we thought that adipic acid acted on the cell envelope and then monoglyceride acted on the altered cell.