University of Hohenheim, Institute of Food Science and Biotechnology, Soft Matter Science and Dairy Technology, Stuttgart, Germany.
University of Hohenheim, Institute of Food Science and Biotechnology, Soft Matter Science and Dairy Technology, Stuttgart, Germany.
Food Res Int. 2018 May;107:19-26. doi: 10.1016/j.foodres.2018.02.005. Epub 2018 Feb 8.
Endospores of thermophilic bacilli are a major concern for producers of dairy powders. In this study, we heat treated 10 different spore suspensions at 110 °C in skim milk and skim milk concentrate (36% dry matter) of the species Geobacillus stearothermophilus (10 min) and Anoxybacillus flavithermus (5 min) in a new shear-heating device. The highest log reduction in skim milk concentrate was 3.5. The death behavior of the spores was strain dependent. Particle formation and Maillard reaction were observed. By increasing the shear-rate up to 1500 s the particle size was reduced for both heating times (D90 reduction: 57.4 and 77.0%, respectively). The particle size was lessened by a reduction of dry matter of 27%, compared to 36%. This work emphasizes, that heat treatment of concentrated dairy products represents a technological option to reduce thermophilic spores in skim milk concentrate and powders produced thereof.
嗜热芽孢杆菌的芽孢是乳制品生产者的主要关注点。在这项研究中，我们在一种新型剪切加热装置中，将 10 种不同的芽孢悬浮液在 110°C 下加热处理 10 分钟（脱脂乳）和 5 分钟（脱脂乳浓缩物，干物质含量为 36%）的嗜热脂肪芽孢杆菌（Geobacillus stearothermophilus）和黄嗜热杆菌（Anoxybacillus flavithermus）。在脱脂乳浓缩物中的最大对数减少量为 3.5。芽孢的死亡行为取决于菌株。观察到颗粒形成和美拉德反应。通过将剪切速率提高到 1500 s-1，两种加热时间的粒径都减小了（D90 减少率分别为 57.4%和 77.0%）。与 36%相比，干物质减少 27%时，粒径减小。这项工作强调了浓缩乳制品的热处理是减少脱脂乳浓缩物和由此产生的粉末中嗜热孢子的一种技术选择。
