Fermentation Of White Wine By Co-immobilized Two Microorganism

In this study,two microorganisms (Saccharomyces cerevisiae and Hansenula anomala var.anomala) were co-immobilized with sodium alginate-CaCl2 embedding method to improve the fermentation efficiency of white wine and keep stable quality of different batches of white wine.The studies show that the alginate Sodium-CaCl2 embedding method is the optimal method,through the comparison of the fermentation quality and the white wine physical and chemical indicators between several common immobilization methods,such as sponge assay, alginate- CaCl2 embedding method, polyvinyl alcohol-acid embedding method,κ-carrageenan two-step embedding method, agar embedding method and gelatin embedding method.Immobilized particles are made of sodium alginate with Aluminum sulfate, zinc chloride, ferric chloride instead of CaCl2,respectively. Through the comparison of the quality of them, it is found that as the immobilization agent, CaCl2 is the best for integrated properties (mechanical strength and ATP production capacity).According to response surface methodology(RSM),particle mechanical strength and ATP production as the indicator optimizes the concentration of sodium alginate-CaCl2 embedding carrier (alginate), immobilization agent (CaCl2) and vinyl alcohol to improve the mechanical strength of the particles. The results show that the optimum immobilization composition contains 4% sodium alginate, CaCl2 0.08mol / L and 0.6% polyvinyl alcohol,and the 4~6mm immobilized particles in diameter have the highest fermentation efficiency .Finally, it is optimized that the fermentation temperature, inoculation volume(v/v), the ratio of Saccharomyces cerevisiae and Hansenula anomala var.anomala based on sensory score by response surface methodology(RSM). The study demonstrates that the optimum fermentation conditions are fermentation temperature 16℃, inoculum volume 5.10%, yeast ratio 11.50, and the final sensory score reached 88.0346.Repeatedly, nine groups of white wine are fermented with immobilized particles, among of four groups to detect physical and chemical indicators and GC/MS pattern analysis. The researches demonstrat that white wines still have stable quality with immobilized cells fermented repeatedly, and continuous fermentation more than 60 days immobilized cells still have a good performance. Immobilized cells after repeated fermentation domestication, with which white wine has gradual increasing quality. Significantly, immobilized cells can increase main fragrance materials in wine, reduce acid materials. Optimum fermentation temperature of immobilized particles is lower, and the lower temperature is advantageous to keep original grape fragrances, and increase the second category fragrance of white wine.