36E-60 |
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E.-C. SHIN1, H.-J. Jang1, M.-S. Hur2, J.-E. Seo2, Y.-B. Lee1, and S.-B. Kim1. (1) Faculty of Food and Biotechnology/Institute of Seafood Science, Pukyong National Univ., Pusan 608-737, KOREA, 599-1, Daeyeon-3-Dong, Nam-gu, Pusan, 608-737, South Korea, (2) Faculty of Food Science and Biotechnology, Pukyong National Univ., 599-1,Deayeon-3-Dong, Nam-gu, Pusan, 608-737, South Korea Polyphenol oxidase has been recognized as a main source of enzymatic browning, and its methyl mercaptan-capturing property was studied for removing methyl mercaptan as an indicator of bad odors. This study demonstrated that, after the oxidation of phenollic compounds by lettuce, the elimination of methyl mercaptan was appeared and PPO from lettuce strongly repressed the bad smell on methyl mercaptan. Polyphenol oxidase was purified from lettuce and the deodorizing activity of the lettuce PPO on the reduced amount of methyl mercaptan was measured by using gas chromatography. This study was designed for determina-tion of methyl mercaptan capturing properities of the lettuce PPO and for an application to other natural sources for deodorization products. Polyphenol oxidase from lettuce was purified by gel chromatography and ion chromatography and its molecular weight was determined by SDS-PAGE. For determining the enzyme activity, 0.3 mL enzyme was added in the 2.7 mL 0.01 M sodium phosphate buffer (pH 6.5) containing 10 mM catechol as the substrate solution and the absorbance was measured at 420 nm on a spectrophotometer (Ultrospec 2000, Pharmacia Biotech, USA). The amount of methyl mercaptan was measured by gas chromatography (Hewlett Packard 5890, USA) with flame photometric detector. The purified PPO from lettuce was estimated to be 56 kDa. The PPO and deodorizing activities were highest at the pH range of 6.0 at 200o C and 5.0 at 100o C, respectively. The substrate specification was high for chlorogenic acid and caffeic acid, showing up to 95% deodorizing activity. The deodorizing activity of lettuce extract was highest in Cu++ appeared almost 100% deodorizing activity and 88% of enzymatic activity was showed by Ca++. Ascorbic acid and sodium hydrosulfite inhibited the deodorizing activity to 25% and 23%, respectively. Polyphenol oxidase isolated from lettuce showed the strong deodorization activity through its methyl mercaptan-capturing property. These results will provide basic information for an optimum manufacturing condition for commercial mouth rinse products using lettuce extracts.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |