Gadaga T H, Mutukumira A N, Narvhus J A
Institute of Food, Nutrition and Family Sciences, University of Zimbabwe, Mt. Pleasant, Harare.
Int J Food Microbiol. 2001 Aug 15;68(1-2):21-32. doi: 10.1016/s0168-1605(01)00466-4.
Nine yeast and four lactic acid bacterial strains, previously isolated from Zimbabwean traditionally fermented milk, were inoculated into ultra-high temperature treated (UHT) milk in both single and yeast-lactic acid bacteria co-culture. The lactic acid bacteria (LAB) strains consisted of Lactococcus lactis subsp. lactis biovar. diacetylactis C1, L. lactis subsp. lactis Lc39, L. lactis subsp. lactis Lc261 and Lactobacillus paracasei subsp. paracasei Lb11. The yeast strains used were Candida kefyr 23, C. lipolytica 57, C. lusitaniae 63, C. lusitaniae 68, C. tropicalis 78, Saccharomyces cerevisiae 71, S. dairenensis 32, C. colliculosa 41 and Dekkera bruxellensis 43. After 48-h fermentation at 25 degrees C, the samples were analysed for pH, viable yeast and bacterial counts, organic acids, volatile organic compounds (VOC) and carbon dioxide. The Lactococcus strains reduced the pH from about 6.6 to between 4.0 and 4.2, while Lb. paracasei subsp. paracasei Lb11 reduced the pH to about 5.4. Most of the yeasts, however, did not affect the final pH of the milk except for C. kefyr 23, which reduced the pH from 6.6 to 5.8. All the Lactococcus strains grew two log cycles during the 48-h fermentation period, while Lb. paracasei subsp. paracasei Lb11 grew about one log cycle. S. cerevisiae 71, C. colliculosa 41 and D. bruxellensis 43 showed poor growth in the milk in both single and co-culture. The other species of yeast grew about two log cycles. Candida colliculosa 41, S. dairenensis 32 and D. bruxellensis 43 showed reduced viability when in co-culture with Lb. paracasei subsp. paracasei Lb11. The samples in which C. kefyr 23 was used were distinct and characterised by large amounts of acetaldehyde, carbon dioxide and ethanol. However, in the samples where S. dairenensis, C. colliculosa, D. bruxellensis, C. lusitaniae, C. tropicalis, C. lipolytica and S. cerevisiae were used in co-culture, the final pH and metabolite content were mainly determined by the correspondin
将之前从津巴布韦传统发酵牛奶中分离出的9株酵母菌株和4株乳酸菌菌株，以单一培养以及酵母 - 乳酸菌共培养的方式接种到超高温处理（UHT）牛奶中。乳酸菌菌株包括乳酸乳球菌乳酸亚种双乙酰乳酸变种C1、乳酸乳球菌乳酸亚种Lc39、乳酸乳球菌乳酸亚种Lc261和副干酪乳杆菌副干酪亚种Lb11。所使用的酵母菌株有开菲尔假丝酵母23、解脂假丝酵母57、葡萄牙假丝酵母63、葡萄牙假丝酵母68、热带假丝酵母78、酿酒酵母71、耐冷酿酒酵母32、小球假丝酵母41和布鲁塞尔德克酵母43。在25摄氏度下发酵48小时后，对样品进行pH值、酵母和细菌活菌计数、有机酸、挥发性有机化合物（VOC）以及二氧化碳的分析。乳酸乳球菌菌株将pH值从约6.6降至4.0至4.2之间，而副干酪乳杆菌副干酪亚种Lb11将pH值降至约5.4。然而，除了开菲尔假丝酵母23将pH值从6.6降至5.8外，大多数酵母对牛奶的最终pH值没有影响。在48小时的发酵期内，所有乳酸乳球菌菌株生长了两个对数周期，而副干酪乳杆菌副干酪亚种Lb11生长了约一个对数周期。酿酒酵母71、小球假丝酵母41和布鲁塞尔德克酵母43在单一培养和共培养的牛奶中生长不佳。其他酵母菌种生长了约两个对数周期。当与副干酪乳杆菌副干酪亚种Lb11共培养时，小球假丝酵母41、耐冷酿酒酵母32和布鲁塞尔德克酵母43的活力降低。使用开菲尔假丝酵母23的样品有明显特征，含有大量乙醛、二氧化碳和乙醇。然而，在共培养中使用耐冷酿酒酵母、小球假丝酵母、布鲁塞尔德克酵母、葡萄牙假丝酵母、热带假丝酵母、解脂假丝酵母和酿酒酵母的样品中，最终pH值和代谢物含量主要由相应的……（原文此处不完整）
