• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.1131-1136
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• 1999

The total contents of polyphenolics in potatoes measured by Folin Denis method were 42~76mg/100g in fresh weight. A major phenolic component contained in potato polyphenolics was identified as chlorogenic acid(3.6~15mg/100g in fresh weight). The antioxidative effects of potato polyphenolics and chlorogenic acid on the lipid peroxidation of liver microsome were studied in vivo and in vitro systems by measuring the formation of thiobarbituric acid reactive substances(TBARS) and the content of urine 8 hydroxy deoxyguanosine(OHdG). The TBARS contents of liver showed an increase in the cholesterol diet compared to those in the normal diet. This trend, however, was minimized when potato polyphenolics and chlorogenic acid were supplemented in the cholesterol diet. On the other hands, urinary 8 OHdG contents showed a marked increase with the supplementation of potato polyphenolics in the cholesterol diet. However, there was a trend of marked decrease by the supplementation of chlorogenic acid. In vitro study, potato poly phenolics and chlorogenic acid effectively inhibited the formation of TBARS in liver microsomal system in a dose dependent manners. These results suggest that potato polyphenolics exerts an antioxidative activity in cholesterol fed rat liver.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.24-28
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• 1994

The effects of synthetic and carrot carotene on the browning of polyphenolics extracted from potato for eliminating the effects of other components in potato which inhibit the browning of potato juice and the potato polyphenol oxidase (PPO) activity were investigated. Total phenolics content in potato sample was 1.854mg/g D.W. and PPO activity was 100 unit. Delta 'L'value of polyphenolics extracted from potato decreased makedly, but that of potato with carrot decreased little by little. Potato with P-carotene showed a little decrease after 50 min. At the same time, polyphenolics extracted from potato were mixed with carotene extracted from carrot or with syntetic $\beta$-carotene. As the results, the delta 'L'value of the former increased but decreased similarly to the latter after 1 hour. The effects of enzyme and substrate concentration on the browning of PPO extracted from potato were investigated. Optimum enzyme concentration was 10% and optimum substrate concentration was 13.3% $\beta$-carotene concentration did not appear to influence significantly on PPO activity.

• Korean journal of food and cookery science
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• v.9 no.3
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• pp.181-186
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• 1993

Potato and carrot are the main sourses of vitamin C and vitamin A each. As a folk ramedy, potato-carrot mixtures have been used to cure a stomach ulcer in Korea. To investigate the effects of carrot juice on the browning of potato juice, we examined the brewing in various ratio of two juices. We also investigated the role of potato juice in the carotene oxidation of carrot juice. Delta "L" values of potato juice were abruptly decreased after 5 min. reaction and they were very different from the juice mixture of potato and carrot. Those containing higher ratio of potato were decreased greatly. In blanching treatment to eliminate the effect of the enzymes in potato and carrot, delta "L" values of cooked potato were decreased a little but those of cooked carrot were decreased greatly. To investigate the fact that the inhibitory effect of carrot juice in potato browning was due to the dilution of polyphenolics of potato juices by carrot juice mixing, we added H20 equivalent to carrot water content to potato juice. The diluted sample showed less decreasing pattern than nondiluted sample. We also added appropriate amount of ${\beta}$-carotene to the same samples. Delta "L" values of with added B-carotene were more slowly decreased than those of without added B-carotene.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.274-279
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• 2000

Effect of potato polyphenolic compound on the concentrations of serum and liver lipids, serum glucose, and urine protein was investigated in Sprague Dawley rats by feeding a diet containing 0.5% of cholesterol for 2 weeks. Polyphenolic compound extracted from potato (Solanum tuberosum variety Dejima) was supplemented at a 0.5% level in the basal diet or the cholesterol diet. The supplementation of potato polyphenolic compounds decreased slightly the concentrations of total cholesterol and VLDL+LDL-cholesterol in serum, and atherosclerotic index in rats fed the cholesterol diet, while those measurements were not altered by the supplementation of potato polyphenolic compounds in rats fed the basal diet. In the rats fed the basal diet or the cholesterol diet containing potato polyphenolic compounds, urine protein increased by 12% and 27% at 1st week, respectively, but this change was not seen at 2nd week. The concentration of serum glucose, however, was not significantly different in the dietary groups.