• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.123-131
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• 2004

The effect of reactive oxygen species (ROS) on the formation of $N^{\varepsilon}$-(carboxymethly)lysine (CML). one of the endproducts in the Maillard reaction of protein (or glycation), was investigated. Glyoxal, a main precursor of CML formation, was produced from both glucose and fructose during their autoxidation. The transition metal ion showed to involve in the formation of glyoxal by the metal catalyzed oxidation, suggesting that ROS accelerated the reducing sugar autoxidation. The stimulative effect of ROS on the autoxidation was more prominent in glucose than in fructose. Polyunsaturated acids (PUFAs) were shown to form glyoxal by peroxidation in proportion to the degree of unsaturation, but ROS did not affect on PUFA peroxidation. Ascorbic acid also lysine (CMHL) in the model system using hippuryl lysine and glucose had a significant effect on ROS, whereas it had no effect on ROS using glyoxal as a reactant. Almost the same trend was obtained by the analysis of antigen coated indirect noncompetitive ELISA using monoclonal antibody (6D12). These data indicated that ROS affected glucose autoxidation as well as mediated both CML and glyoxal formation, but did not affect the reactive compounds such as fructose, PUFAs and ascorbic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.1009-1015
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• 2000

Fermentative and antioxidative characteristics of red mustard leaf (RML) kimchi, a traditional, fermented Korean vegetable food, were investigated. For the study, RML kimchi was made of RML, with green onion, red pepper, garlic, ginger, and sugar, and fermented at 15$^{\circ}C$. The pH was decreased and total acidity was increased during fermentation. The contents of reducing sugar, total vitamin C, and total Phenol content were 2.36%, 65 mg%, and 59 mg% at the initial stage. Although the content of reducing sugar decreased gradually during fermentation, however, the quantity of ascorbic acid decreased with the tendency of slightly increased at 6 days, and the amount of total phenol was increased. CIE L*, a*, b＊values were increased until 6 days of the fermentation. In order to determine the antioxidative activity of RML kimchi itself, the model systems of RML kimchi were made with cooked beef. TBA values of RML kimchi which was fermented for 6 days showed the lowest level in model systems. Water, n-hexane, methanol extracts of RML kimchi had a considerable antioxidative activity with the inhibition of formation of peroxide during the autoxidation of linoleic acid mixtures in aqueous model systems.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.859-865
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• 2007

The chemical components and antioxidative activity of Korean gold kiwifruit were investigated. The values of pH, soluble solid and total acidity were 4.43${\pm}$0.16, 17.01${\pm}$0.04$^{\circ}Brix$, and 0.082${\pm}$0.02%, respectively. Hunter L, a, and b values were 49.80${\pm}$0.24, -6.79${\pm}$0.02, and 19.72${\pm}$0.18 value, respectively. Proximate compositions were as follows; moisture 78.62${\pm}$2.26%, crude protein 1.34${\pm}$0.25%, crude lipid 0.70${\pm}$0.06%, crude fiber 1.99${\pm}$0.13%, crude ash 0.99${\pm}$0.26%, and carbohydrate 16.36${\pm}$1.23%, respectively. Mineral elements were K 265.86${\pm}$5.00, P 71.82${\pm}$29.18, and Ca 23.84${\pm}$2.10 mg%, respectively. Free sugar compositions were sucrose (1.04${\pm}$0.18%), glucose (2.17${\pm}$0.21%) and fructose (1.86${\pm}$0.11%). Amino acid contents of Korean gold kiwifruit was very rich in glutamic acid 86.51 ${\pm}$5.58 mg/100 g and deficient in tyrosine 15.00${\pm}$4.91 mg/100 g. Organic acid compositions were quinic acid (6.65${\pm}$0.21 mg/g), malic acid (1.62${\pm}$0.13 mg/g) and citric acid (4.82${\pm}$0.21 mg/g). Contents of ascorbic acid and total phenols were 0.27${\pm}$0.06 mg/g and 0.047${\pm}$0.002 mg/g, respectively. The DPPH radical scavenging activity and reducing power of the water extract from Korean gold kiwifruit was 86.87% and 1.96 at a concentration of 25 mg/mL. The water extract showed considerable antioxidative activity against linoleic acid autoxidation in a dose-dependent manner.