• Journal of Ginseng Research
• /
• v.22 no.3
• /
• pp.193-199
• /
• 1998

The purpose of this study was to Investigate characteristics of the water soluble browning reaction products (WS-BRPs) from Korean red ginseng by heat treatment. Absorbance of WS- BRPs was increased with increases of heating temperature and time, but pH value were decreased In Muter color value L and b value were decreased, while a value was increased. and absorbance at 280 nm in spectrum of the WS-BRPs was increased according to the increase of heating temperature. When the WS-BRPs were applied on Bio-Gel P-30 column after heating and pH treatment, two majors browning products increased according to the progress on time. And pH 3.0 increased in quantity of high molecular fractions and pH 8.0 increased in quantity of low molecular fractions.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.6
• /
• pp.998-1004
• /
• 1995

This study was carried out in order to investigate the browning reaction of fish oil-amino acid model system at different temperatures and watger activities. The 23 amino acids, induced during dehydration in the presence of oil and avicel(5 to $45^{\circ}C$), Aw 0.33 to 0.95, were resulted in three types of browning patterns : Type I showed high browning rates at Aw 0.33, 0.95 than at Aw 0.52, 0.75(phenylalanine, trans-4-hydroxy-L-proline, methionine, valine). Type II showed high browning rates decreased with increasing water activity(poline, leucine, isoleucine, arginine). Type III showed high browning rates at Aw 0.52, 0.75 than at Aw 0.33, 0.95(tryptophan, cystein, threonine, lysine). The temperature effect on the browning development of the four most active amino acids : phenylalanine, valine, trnas-4-hydroxy-proline and methionine are shown to represent the 23 amino acids. Above $25^{\circ}C$ the browning rate began to increase. Activation energy of the amino acids-fish oil was 8 to 40kcal/mole, and $Q_{10}$ were 2 to 10.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.1
• /
• pp.160-168
• /
• 1995

Desmutagenicities against 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine(PhIP) and 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline(MelQx) of tea extracts (steamed green tea, roasted green tea, oolong tea and black tea) were investigated. All the fractions obtained from tea extracts showed strong desmutagenic activity against PhIP and MeIQx toward S. typhimurium TA 98 in the presence of the S-9 mix. The crude catechin fraction exhibited the strongest desmutagenic activity. Among these tea extracts, black tea especially exhibited the strongest desmutagenic activity and the activity was 70.9~91.0% against PhIP and 92.2~98.8% against MelQx at a concentration(0.5~1.0mg/plate) for drinking. The activity of authentic catechins of (-)-EGC, (-)-EGCg, (-)-ECg and (-)-EC were 79.5%, 60.2%, 46.1% and 43.5% against PhIP, and were 52.3%, 11.6%, 8.2% and 22.1% against MelQx by addition of 1.0mg/plate, respectively. The desmutagenic activity was supposedly due to the (-)-EGCg, (-)-EGC and (-)-EC in tea polyphenols, and the browning materials. The desmutagenicity was stronger when mutagens were preincubated with S-9 mix after reaciton with black tea extracts than when preincubated with them after reaction with S-9 mix. The desmutagenicity of tea extracts was rather expressed by reacting directly with mutagens than by deactivating the activated forms of mutagens.