tailieunhanh - Báo cáo nghiên cứu khoa học: "INFLUENCE OF INITIAL TANNIN CONCENTRATION IN MUST ON THE KINETICS OF WINE FERMENTATION, USING YEAST IMMOBILIZED IN CALCIUM ALGINATE GEL"

Nghiên cứu này điều tra ảnh hưởng của nội dung tannin ban đầu (1,8, 2,8, 3,8, 9,8 và acid tannic / L) động học của quá trình lên men rượu vang đỏ, sử dụng nấm men cố định trong gel alginate canxi. Kết quả thực nghiệm của chúng tôi cho thấy trong môi trường có hàm lượng tanin cao (9,8 và acid tannic / L), mật độ di động tối đa và tốc độ tăng trưởng tối đa cụ thể của các tế bào bất động cao hơn so với những của các tế bào miễn phí | Science Technology Development Vol 11 - 2008 INFLUENCE OF INITIAL TANNIN CONCENTRATION IN MUST ON THE KINETICS OF WINE FERMENTATION USING YEAST IMMOBILIZED IN CALCIUM ALGINATE GEL Ton Nu Minh Nguyet Nguyen Thi Hien Luong Le Ngoc Lieu Le Van Viet Man University of Technology VNU-HCM Manuscript Received on June 10th 2007 Manuscript Revised April 29th 2008 ABSTRACT This study investigated the effects of five initial tannin contents and of acid tannic L on the kinetics of red wine fermentation using yeast immobilized in calcium alginate gel. Our experimental results showed that in the medium with high tannin content and of acid tannic L maximum cell density and maximum specific growth rate of the immobilized cells were higher than those of the free cells. In all cases the glucose utilization rate and ethanol production rate of the immobilized yeast were always higher than those of the free yeast. Moreover using immobilized yeast in wine fermentation decreased pH value and volatile acidity of the culture. Thus the colloidal and biological stability and the organoleptic characteristics of the final product were ameliorated. Keywords alginate fermentation immobilization tannin wine. 1. INTRODUCTION In the past few years there has been an upsurge of interest in immobilized cells due to attractive technical and economic advantages compared with the conventional free cell system 18 . Activity stability of yeast is prolonged because the immobilization support may act as a protective agent against physico-chemical effects of pH temperature solvents or even heavy metals 12 . Many reports have proposed various immobilization supports for wine making such as gamma alumina and kissiris 1 7 9 delignified cellulosic material and gluten 2 13 14 apple pieces 8 10 11 dried raisin berry 19 polyvinyl alcohol 15 alginate 4 17 . In this study alginate was selected for yeast immobilization because of simple immobilization procedure high cell density in