• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.501-510
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• 1992

Lipid prooxidants in sardine skin was characterized. Prooxidants in the sardine skin extract with 0.05M phosphate buffer was purified by successive chromatography on Sephadex G-200, DEAE-Sephadex A-50 and CM-Sephadex A-50. Prooxidants of sardine skin exist mainly in the intermediate molecular weight fractions. Observations of the thermounstability and optimum pH(pH 7.0) suggest that the major prooxidants are enzymes and hemoproteins. They can oxidize well both free and esterified linoleic acid and form conjugated hydroperoxides. From these results, the major prooxidants in sardine skin are assumed to be lipoxygenase-like enzymes.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.7-12
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• 1990

The effect of $Fe^{2+}$ and myoglobin on the oxidative stability of triglyceride molecular species was investigated at $25^{\circ}C$. The molecular species of soybean oil triglycerides were analyzed by capillary column gas chromatography and electron impact ionization mass spectrometry utilizing selected ion monitoring. When $Fe^{2+}$ and myoglobin were added to soybean oil triglycerides, the oxidative stability of each molecular species of triglycerides appeared to decrease in proportion to the increase in the number of double bonds present in the acyl residues, and it was affected by degree of unsaturation of fatty acid when the total degree of unsaturation of triglyceride was the same. But the length of the saturated acyl chain had no influence on the stabilization of unsaturated fatty acid present in the same glyceride when prooxidants were added.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1997.11a
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• pp.143-143
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• 1997

• The Korean Journal of Food And Nutrition
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• v.37 no.1
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• pp.48-56
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• 2024

Effects of glutamic acid (Glu) and monosodium glutamate (MSG) on oxidative stability of oil-in-water (O/W) emulsions with different emulsifier charges during riboflavin (RF) photosensitization were evaluated by analyzing headspace oxygen content and conjugated dienes. Cetyltrimethylammonium bromide (CTAB), Tween 20, and sodium dodecyl sulfate (SDS) were used as cationic, neutral, and anionic emulsifiers, respectively. Glu acted as an antioxidant in CTAB- and Tween-20-stabilized O/W emulsions during RF sensitization, whereas Glu acted as prooxidants in SDS-stabilized O/W emulsions in the dark. However, adding MSG did not have a constant impact on the degree of oxidation in O/W emulsions irrespective of the emulsifier charge. In RF-photosensitized O/W emulsions, the emulsifier charge had a greater influence on antioxidant properties of Glu than on those of MSG.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.33-40
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• 2011

Ionizing radiation can be used to improve the color of green tea extract to brighter. As a result, the irradiated green tea extract can be applied easier and broader in food or cosmetic industry. To confirm the retention of the biological activities of the cosmetic products added with green tea polyphenols (PPs), the real cosmetic products including a skin lotion (PS) and an essence (PE) cream were manufactured. Irradiation also applied to the manufactured cosmetic products to see their improvement of color and changes of biological activity. The PP showed 72% of electron donating ability (EDA) at a 5 ppm concentration and the PS and PE containing 2% PP showed higher than 60%, which was similar inhibition activity to vitamin C. The inhibition of superoxide dismutase (SOD)-like activity of PP, PS, and PE were higher than 55% at a 500 ppm concentration and the inhibition of xanthine oxidase (XOase) were also higher than 65% at a 200 ppm concentration. The measurement of lipid oxidation by addition of $Cu^{2+}$ and $Fe^{2+}$ as prooxidants showed that PP and PS had higher metal chelating ability for $Fe^{2+}$ than that of PE and the ability increased by increase of polyphenol concentration isolated from green tea. The $Cu^{2+}$ chelating ability of PP and PS showed higher than 90% at a 200 ppm concentration. Therefore, it is concluded that addition of PP in manufacturing PS and PE retains its biological activities including EDA, inhibition of XOase and SOD-like activity, and metal chelating ability in the manufactured cosmetic products. In addition, irradiation of PS and PE improved color of the products containing PP brighter without any adverse changes in biological activity of the products.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.492-497
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• 1989

The antioxidant effects against linoleic acid of various protein hydrolysates from fish protein, defatted soybean cake, egg albumin and casein were investigated. Each protein hydrolysate by enzyme hydrolysis exhibited the antioxidative effects by addition of 5mg and 10mg per 1g linoleic arid. Especially, egg albumin and fish protein hydrolysates had a great antioxidative effects. The protein hydrolysates indicated the synergitic effects with ${\alpha}-tocopherol$, and indicated scavenging effects toward metal ion $(Fe^{3+},\;Cu^{2+})$ as prooxidants.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.699-704
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• 2010

Rapeseed oil was stored under different conditions such as in the dark, with UV treatment, and with prooxidantscytochrome C and copper ion. The rapeseed oils stored at different temperatures were analyzed by a mass spectrometrybased electronic nose and discriminant function analysis (DFA). Volatile components in the rapeseed oil increased with storage time, and the discriminant function first score (DF1) moved from a positive position to a negative position as storage time increased. Changes in DF1 were higher under UV treatment than under the dark condition (DF1: $r^2$=0.9481, F=307.03). The different DF1 values (F1) under the dark condition were 0.099, 0.187, and 0.278 as storage temperature increased. The different values under UV treatment were 0.554, 0.588, and 0.542, as storage temperature increased from 4 to $26^{\circ}C$. As concentrations of prooxidants copper ion and cytochrome C increased, amounts of volatile components also increased. These were confirmed by DFA. Furthermore, changes in responses at each ion fragment agreed with reported results for GC/MS, which formed after rancidity of the oil, including pentane, pentanal, 1-pentanol, hexanal, n-octane, 2-hexenal, heptanal, 2-heptenal, decane, 2-octenal, undecane, and dodecane.