Production of Fermented Tea with Rhodotorula Yeast and Comparison of its Antioxidant Effects to those of Unfermented Tea

Abstract This study was conducted to investigate the antioxidant effect and properties of unfermented tea and fermented tea made with Rhodotorula yeast. The levels of crude fat and crude protein in the fermented tea were higher than those in the unfermented tea. The water-soluble phenol levels of unfermented tea and fermented tea were 912.5 and 2,445.24 ppm, respectively. The total amino acid content of fermented tea was greater than that of unfermented tea;,- the amino acid concentrations of alanine, valine, leucine, and lysine were 25.58, 24.38, 27.96, and 14.14 µg/mL, respectively. The DPPH radical scavenging activities of the unfermented and fermented teas were 32.14 and 41.57%, respectively; this is in contrast to 29.73% for L-ascorbic acid(150 ppm). The reducing power activity of fermented tea was 41.57%, and that of unfermented tea was 32.14%. Key words: antioxidants, fermented tea, free amino acid, unfermented tea, reducing power, Rhodotorula yeast † Corresponding author: Ok-Ju Kang, Department of Food and Nutritio-nal Science, Kyungnam UniversityTel: 055-249-2235Fax: 055-245-5001E-mail: koj117@kyungnam.ac.kr