Athanasiadis I, Boskou D, Kanellaki M, Koutinas A A
Laboratory of Food Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece.
J Agric Food Chem. 2001 Feb;49(2):658-63. doi: 10.1021/jf0006628.
The suitability of delignified cellulosic (DC) material supported kefir yeast to ferment raw materials that contain various single carbohydrates, for the production of potable alcohol and alcoholic drinks, is examined in this investigation. Results are reported of fermentations carried out with sucrose, fructose, and glucose in synthetic media. Repeated batch fermentations at various initial sugar concentrations of sucrose, fructose, and glucose were performed at 30 degrees C in the presence of the aforementioned biocatalyst. The results clearly show feasible yields in the range of 0.38-0.41 g/g, alcohol concentrations of 7.6-8.2% v/v, fermentation time of 90-115 h, and conversion of 92-96%. DC material supported kefir fermented 11-fold more rapidly than free cells and 9-fold more rapidly in comparison to kissiris supported kefir. The main volatile byproducts such as amyl alcohols (mixture of 2-methyl-1-butanol and 3-methyl-1-butanol), ethanal, and ethyl acetate were formed in all sugar fermentation products. The formation of 65-110 ppm of ethyl acetate is as high and even higher than that obtained with traditional wine yeasts. The increase of the initial concentration of sugar in the fermentation media resulted in an increase in contents of volatiles. The fine aroma that was obtained in the product of fructose could be attributed to the high percentage of ethyl acetate on total volatiles. The efficiency of DC material supported kefir was the same for the fermentations of individual sugars or a mixture of fructose, sucrose, and glucose. When whey with raisin extracts was fermented, lower yields were obtained but the aroma of the product was even better.
本研究考察了脱木质素纤维素（DC）材料负载的开菲尔酵母对含有各种单糖的原料进行发酵以生产饮用酒精和酒精饮料的适用性。报告了在合成培养基中用蔗糖、果糖和葡萄糖进行发酵的结果。在上述生物催化剂存在下，于30℃对蔗糖、果糖和葡萄糖在不同初始糖浓度下进行了重复分批发酵。结果清楚地表明，产量在0.38 - 0.41 g/g范围内可行，酒精浓度为7.6 - 8.2% v/v，发酵时间为90 - 115小时，转化率为92 - 96%。DC材料负载的开菲尔发酵速度比游离细胞快11倍，与基西里斯负载的开菲尔相比快9倍。在所有糖发酵产物中均形成了主要挥发性副产物，如戊醇（2 - 甲基 - 1 - 丁醇和3 - 甲基 - 1 - 丁醇的混合物）、乙醛和乙酸乙酯。乙酸乙酯形成量为65 - 110 ppm，与传统葡萄酒酵母相当甚至更高。发酵培养基中初始糖浓度的增加导致挥发性成分含量增加。果糖产物中获得的良好香气可归因于乙酸乙酯在总挥发性成分中所占的高比例。DC材料负载的开菲尔对单糖或果糖、蔗糖和葡萄糖混合物的发酵效率相同。当对含有葡萄干提取物的乳清进行发酵时，产量较低，但产物的香气更好。
