• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.291-297
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• 2000

Oleoresin was extracted from fresh garlic by microwave-assisted extraction (MAE) and its functionality and antibrowning effect were investigated at various extraction conditions. The yield and polyphenol contents of the garlic oleoresin were inversely related to extraction time. The highest yield was l2.9% and maximum polyphenol contents was 574.3 mg% when the oleoresin was extracted for 5 min with ethanol. Apparently, the electron donating abilities of garlic oleoresin increased with extraction time, but there were no significant differences among extraction time intervals. The highest nitrite scavenging effect was found at pH 1.2 and decreased as pH increased. Tyrosinase inhibitory effect was less than 30% for most garlic oleoresin but the 15 minute extraction with ethanol resulted in higher inhibitory effect. Angiotensin I-converting enzyme (ACE) inhibitory effect was highest (89.2%) when oleoresin extracted with ethanol for 20 min. The addition of cysteine, ascorbic acid and citric acid to oleoresin extracts retarded browning action of garlic oleoresin during 10 day storage. 0.1 % cysteine retarded browning reaction and some synergistic effect was found in the combination of citric acid and ascorbic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1312-1317
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• 2008

Physicochemical changes were investigated for the shelf-life extension of cultured wild-ginseng roots during storage with various pre-treatments with blanching, CAMICA-SD and DF-100 and treatments with citric acid and vitamin C. The pH of cultured wild-ginseng roots showed the range of $6.06{\sim}6.42$ at $10^{\circ}C$, but showed higher ranges of $6.08{\sim}6.91$ and $6.08{\sim}8.68$ at 20 and $30^{\circ}C$, respectively. Browning index (a/b) was increased with increasing storage temperature, and the index at 10 and $30^{\circ}C$ were 0.405 and 0.469 after 2 weeks, respectively. Browning index and viable cell number of CAMICA-SD pre-treatment showed little changes compared to pre-teatment with blanching or DF-100. When the cultured wild-ginseng roots were treated with 1.0% citric acid and 0.2% DF-100 after pre-treatments with CAMICA-SD, viable cell number was slightly increased to $4.9{\times}10^2CFU/g$ for 3 weeks storage at $10^{\circ}C$. The mixture of citric acid and DF-100 was also used to prevent the growth of microbiology and to reduce browning reaction, especially enzymatic browning reaction. The mixture might effectively extend shelf life of the cultured wild-ginseng roots.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.21-27
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• 1982

A kinetical approach for the non-enzymatic browning reaction of the dried file-fish was studied. The reaction rates revealed a tend to increase with increasing water activity and showed the maximum at $0.75\;a_w$ The activation energies obtained from the Arrhenius plot ranged 12.5 to 16.5 Kcal/mole. From these energies of activation, the $Q_{10}$ values at $45^{\circ}C$ showed 1.9 to 2.3 and both activation energy and $Q_{10}$ values were reduced with increase in $a_w$ Shelf-lives, the time to reach an 0.15 O.D./g solid at which severe brown color change could be de ectable, decreased rapidly as the temperature and water activity increase. A storage study under a square-wave fluctuating temperature condition (at 35 and $55^{\circ}C$ periodically with 7 days interval), the rate constants at all water activities used in the experiments were higher than those at $45^{\circ}C$, the mean temperature of the cycle which affects other kinetic parameters including activation energies, $Q_{10}$ values and finally the shelf-lives. The data obtained from the fluctuating temperaure storage study will be used in prediction of shelf-life. The shelf lives assessed at $25^{\circ}C$ from the accelerated shelf-life tests ranged from 179 daysat $0.75\;a_w$ to 302 days at $0.44\;a_w$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.291-297
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• 1982

In this part of the studies on dielectric dehydration of foamed fish-starch paste, qualify stability and shelf-life of the product of which the preparation formula and processing conditions were described in previous report (Lee et al, 1982) were determined by means of accelerated reaction test. The product was stored for 50 days under the conditions of temperatures at 35, 45, and $55^{\circ}C$ in steady state and various water activities of 0.44, 0.52, 0.65, and 0.75, respectively. The loss of available lysine, extent of TBA value, and development of browning during the storage were measured and reaction kinetically analysed to assess quality stability and shelf-life of the product for the storage at room temperature of $25^{\circ}C$. Extent of browning was accelerated with the increase of water activity and temperature marking the time to reach a limit of color and flavor deterioration, or to reach brown color density of 0.17 O.D./g at 420 nm, 106 days at aw=0.44, $35^{\circ}C$, and 41 days at aw=0,65, $55^{\circ}C$, These reaction rates resulted in a prediction of shelf-life, 130 to 110 days in the storage at aw=0.44 to 0.75, $25^{\circ}C$. The quality limit assessed by TBA values and sensory evaluation of rancidity was 87 days at aw=0.44, $35^{\circ}C$, and 30 days at aw=0.75, $55^{\circ}C$ which gave a predicted shelf-life, 128 to 113 days . at aw=0.44 to 0.75, $25^{\circ}C$ storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.409-414
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• 1995

Antioxidative characteristics of dihydroxyphenylalalnine(DOPA), melanin and enzymatic oxidation products of tyrosine(EOPTs) were studied in a model system. EOPTs were prepared by the tyrosine-tyrosinase reaction at pH 6.5 and $25^{\circ}C$ at various time intervals(0~120min). All EOPTs were brown in varied intensities with increased absorption at 200~210, 280, 310~320nm, and 450~490nm. EOPTs obtaiend at the early stage of the reaction(1~3min especially) showed a higher antioxidative activity than those from the later stage on the inhibition of peroxide, conjugated dienoic acid and malonaldehyde formations in linoleic acid autoxidation. Additionally among the substances of tyrosine, DOPA and melanin, DOPA showed the highest antioxidative activity while that of tyrosine was the lowest during the linoleic acid autooxidation. It was observed that DOPA and melanin had the ability of free radical scavenging, which may party contribute to their antioxidative activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1301-1304
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• 2001

Deodorizing activity of polyphenol cxidase (PPO) extracted from apples was investigated by measuring the changes of methyl mercaptan as an indicator of halitosis in human mouths. In the studies of apple extracts on deodorizing activity, the deodorizing activity was increased with the amount of apple extracts. In the cases of adding PPO to the low molecular fraction of apple extracts, the deodorizing activities were increased with the amount of the law molecular fraction of apple extracts and the reaction time of the extracts with PPO. Deodorizing activities of PPO is thought that o-quinone as an intermidiate produced by an oxidative reaction of PPO during enzymatic browning reactions may react with methyl mercaptan to form a non-volatile and sulfur-containing compound .

• Food Science of Animal Resources
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• v.40 no.3
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• pp.350-361
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• 2020

Quality control of meat products is one of the main concerns of consumers, governmental control authorities, and retailers. The purpose of this study was to employ ribose-induced Maillard reaction in detection of meat adulteration and differentiation of fresh-chilled from frozen-thawed minced veal. The browning intensity was assessed through measuring the absorbance at 420 nm with a spectrophotometer as well as the direct analysis of the color and pH. The results showed that CIE b*, CIE a*, and A_420* values in the extract of fresh-chilled veal were significantly (p<0.05) higher than frozen-thawed samples. The extract of frozen meat samples stored at -18℃ became significantly darker and more yellowish compared to -4℃. The results showed that the A_420* value in the frozen-thawed veal stored at -4℃ and -18℃ was reduced by approximately 17.22±3.53% and 11.68±2.49%, respectively, compared with fresh-chilled veal. The findings also showed that the storage temperature of minced veal and the heating time in this reaction had a significant effect on all tested variables (p<0.0001). The proposed method can be considered as an easy, quick, and inexpensive test for differentiating between the fresh-chilled and frozen-thawed minced veal.

• Korean Journal of Food Science and Technology
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• v.12 no.2
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• pp.122-125
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• 1980

The mechanism of cooking barlay (naked and covered barley) was investigated. Cooking properties of both naked and covered barley were similar. At higher cooking temperature of above $110^{\circ}C$, a browning reaction occurred and no terminal point of cooking was observed. The cooking rate followed the equation of a first-order reaction. The activation energies of cooking temperatures below $100^{\circ}C$ and above $100^{\circ}C$ were about 19,500 and 9,500 cal/mole, respectively. The cooking process of barley comprised two mechanisms: At temperatures below $100^{\circ}C$ the cooking rate is controlled by the reaction rate of barley constituents with water, and at temperatures above $100^{\circ}C$, it is controlled by the rate of diffusion of water through the cooked portion toward the interface of uncooked core in which the reaction is occurring.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.294-299
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• 1987

Lipid composition of dried grasshopper which the most significant factor of quality deteriorioration for processing and storage were studied. Also brown pigment formation and its effect of lipid autoxidation were studied. Lipid contents of matured female grasshopper were revealed 5.12% and composed of high content of unsaturated fatty acid. The phospholipid comprised 27.35% of the total lipid. On sun ana hot ai' drying, carbonyl values were greatly increased but peroxide values were not determined. On freeze drying, lipid peroxide and carbonyl compounds in grasshopper lipids were nearly not accumulated. Peroxide values were increased during early stage of storage, but carbonyl values were steadly increased for 98 days. Hydrophilic brown pigments which caused by sugar-amino reaction were higher than that of lipophilic. In the water soluble fraction of the browning products has some autioxidative activity, but in liposoluble fraction has not.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.1-5
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• 1988

Changes in the quality characteristics of three sizes of boiled-dried anchovies packaged in kraft paper laminated with 0.03 mm PE film during storage for six months at $5^{\circ}C$ were studied. In case of Dae-myul (78-80mm), the reaction of thiobarbituric acid, browning rate of lipid oxidation and Hunter-Scale color values. L, a, and b, were higher than those in Joong-myul (45-49 mm) or So-myul (30-34 mm). Organoleptic evaluation suggests that boiled-dried anchovy be good in sequence as So-myul, Joong-myul and Dae-myul. Shelf life of Dae-myul was half times lower than that of Joong-myul or So-myul. Regression equation for the sensory score prediction with lipid oxidative browning was determined.