36B-6 |
|
J. Y. SUH1, D. H. Lee2, H. S. Shin1, B. S. Hong2, H. Y. Cho2, and Y. J. Kim1. (1) Dept. of Food & Biotechnology, Korea Univ., 208 Seochang-dong, Chochiwon, Chungnam, 339-700, South Korea, (2) Graduate School of Life Sciences and Biotechnology, Korea Univ., 1, 5-ga, Anam-dong, Sungbuk-gu, Seoul, 136-701, South Korea Green tea has a variety of health promoting effects. After extraction procedure with hot water, about 40% of phytochemicals remains in the green tea by-products. Cell wall degrading enzyme in combinations may increase the yield of phytochemicals as well as other nutrients in green tea by-products. Our objective was to evaluate the contents of reducing sugar, protein and polyphenols in green tea by-product using cellulases from Aspergillus niger and Rhizopus sp. with pretreatment procedures including hot water, acid, and ethanol. By-product of green tea was treated in the following conditions; 0.2% of sulfuric acid, 90oC of boiling water and 95% of methanol. After drying at 50oC overnight, cellulases from Aspergillus niger and Rhizopus sp. were treated for green tea by-product. To confirm the contents of reducing sugar, protein and polyphenol, we used DNS, Bradford and Folin Ciocalteau assay, respectively. Reducing sugar contents of cellulase-treated green tea by-products were increased after 4 hour of incubation compared to the control with no enzyme treatment in the pretreatment of sulfuric acid and boiling water. Protein contents of cellulase-treated green tea by-products increased after 4 h. of incubation compared to the control in the pretreatment of boiling water and methanol (p < 0.05). Polyphenol contents of cellulase-treated by-products were increased in a time-dependent manner compared to the control in all pretreatments. Since Aspergillus niger is a food-grade microorganism, it could be used to increase the bioavailability of soluble proteins, amino acids, reducing sugars and polyphenols of plant foods such as green tea by-product. This could contribute to the inhibition of oxidation of by-product and increase in oxidative stability.
Session 36B, Biotechnology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |