Ảnh hưởng của hàm lượng sulfur dioxide ban đầu trong động học rượu lên men chính, sử dụng men cố định trong gel alginate canxi đã được kiểm tra. Ban đầu hàm lượng sulfur dioxide trong phải được điều chỉnh từ 12ppm đến 312ppm. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 11, SOÁ 09 - 2008 EFFECT OF INITIAL SULFUR DIOXIDE CONTENT IN MUST ON THE KINETICS OF WINE PRIMARY FERMENTATION, USING YEAST IMMOBILIZED IN CALCIUM ALGINATE GEL Ton Nu Minh Nguyet, Le Ngoc Lieu, Nguyen Thi Hien Luong, Le Van Viet Man University of Technology, VNU-HCM th th (Manuscript Received on June 10 , 2007, Manuscript Revised April 29 , 2008) ASTRACT: Effect of initial sulfur dioxide content in must on the kinetics of wine primary fermentation, using yeast immobilized in calcium alginate gel was examined. Initial sulfur dioxide content in must was adjusted from 12ppm to 312ppm. Our experimental results indicated that the maximum specific growth rate of the immobilized yeast was 1-2 times less than that of the free yeast. On the contrary, the sugar uptake rate and ethanol production rate of the immobilized yeast were times and times, respectively, more than those of the free yeast. The volatile acid content and pH value of the final wine fermented by immobilized yeast were lower. Thus, the organoleptic properties and biological stability of the wine were ameliorated. In general, the yeast immobilized in calcium alginate gel was more resistant to sulfur dioxide than the free yeast. Key words: alginate, immobilization, fermentation, sulfur dioxide, yeast 1. INTRODUCTION Cell immobilization in alcoholic fermentation is a rapidly expanding research area because of its attractive technical and economic advantages compared to the free cell system such as enhanced fermentation productivity, feasibility of continuous processing, cell stability and lower costs of recovery and recycling processing as well as tolerance to disadvantage factors [5,6,8]. Although many immobilization supports have been proposed for use in wine-making, industrial application of the technology is still uncertain and should be investigated. This is mainly due to difficulty in finding a low-cost material that is abundant, durable, of .
