• Journal of the East Asian Society of Dietary Life
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• v.14 no.1
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• pp.70-73
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• 2004

The browning rate of potato juice alone and potato juice with added carrot juice or water(1:1 by volume) were studied. As the amount of carrot juice added was increased, the browning rate proportionally decreased: from 1.86 of potato juice alone to 0.36 for the potato juice and carrot juice mixture(l:1). This inhibitory effect of carrot juice on browning led us to assume that $\beta$-carotene, the major constituent of carrot carotenoids, may be involved in impeding the browning reaction of potato juice. Therefore, model system of enzymatic browning, consisting of chi orogenic acid/tyrosine and $\beta$-carotene/carrot carotenoids, were studied. The results shows the browning rates of chlorogenic acid alone and chlorogenic acid with added $\beta$-carotene. The initial browning rate of chlorogenic acid was faster($\delta$L= 1.1/min.)than that of chlorogenic acid with added $\beta$-carotene($\delta$L=0.6/min.).

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.474-479
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• 2017

Five types of coffee bean, which are usually imported and consumed in Korea, were roasted at $250^{\circ}C$ for 15 min and extracted by using a filter coffee machine. The physicochemical properties, functional components, and radical scavenging activity of coffee bean extracts were investigated. The pH of extract was the highest among the extracts and the soluble solid contents of extracts were $0.9-1.0^{\circ}Bx$. The acidity of the extracts was in the range from 0.46-0.55%, which was not significantly different from the control. Indonesian coffee bean extract showed the highest brown color intensity and contained the highest amounts of caffeine and chlorogenic acid. The highest total polyphenol content was found in Kenyan coffee bean extract. Coffee bean extracts from Indonesia and Kenya showed significantly higher radical scavenging activities than the other extracts. This study showed that coffee bean extracts from Indonesia and Kenya contained a large number of bioactive compounds and high antioxidant activity.

• Journal of Food Hygiene and Safety
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• v.34 no.5
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• pp.413-420
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• 2019

In this study, a sample preparation method and a simultaneous determination method by ultra-high performance liquid chromatography coupled with tandem mass spectrometry for 9 isomers of chlorogenic acid and arbutin in fruits were developed. The samples were extracted using 90% methanol (pH 3.0), with the solutions being shaken and then sonicated for 10 min each. After centrifugation at 4,000 rpm for 10 min, the extraction was concentrated under a vacuum at $40^{\circ}C$ using a vacuum evaporator. The residue was dissolved in 5 mL of 5% methanol and filtered through a $0.45{\mu}m$ membrane before UHPLC-MS/MS analysis. The separations were performed on a C18 column with gradient elution of water (containing 0.1% formic acid) and methanol (containing 0.1% formic acid). The specificity, linearity, limit of detection, limit of quantification, accuracy, and precision of the proposed methods were also evaluated.