Abstract：
Driven by the acknowledged health and functional properties of milk fat globules (MFGs), there is a growing interest to develop gentle methodologies for separation of fat from milk. In this study, separation of fat from raw milk and fractionation in streams containing MFGs of different size was achieved using a series of two silicon carbide ceramic membranes. A first step consisting of a 1.4 µm membrane aimed to concentrate the bulk of the fat, i.e. the larger MFGs (D[4,3] ∼ 4 µm) followed by a 0.5 µm fractionation aimed to concentrate the residual milk fat in the permeate, i.e. fraction with the smaller MFGs (D[4,3] ∼ 1.8-2.4 µm. The fat separation performance showed a yield of 92 % for the 1.4 µm membrane and 97 % for the 0.5 µm membrane. Both fat enriched retentates showed, by the confocal laser scanning microscopy, intact MFGs with limited damage in the MFG membrane. The fatty acid profile analysis and SAXS showed minor differences in fat acid composition and the crystallization behavior was related to differences in the fat content. The 0.5 µm permeate containing the smallest MFGs however showed larger aggregates and a trinomial particle size distribution, due to probably pore pressure induced coalescences. The series of silicon carbide membranes showed potential to concentrate some of MFGM proteins such as Periodic Schiff base 3/4 and cluster of differentiation 36 especially in the 0.5 µm retentates. A shift in casein to whey protein ratio from 80:20 (milk) to 50:50 was obtained in the final 0.5 µm permeate, which opens new opportunities for product development.
摘要：
在乳脂球（MFGs）公认的健康和功能特性的驱动下，人们越来越感兴趣开发温和的方法从牛奶中分离脂肪。在这项研究中,使用一系列两个碳化硅陶瓷膜实现了从原料奶中分离脂肪并在含有不同大小的MFG的流中进行分馏。第一步由1.4微米的膜组成，旨在浓缩大部分脂肪，即较大的MFG（D[4,3]〜4µm），然后进行0.5µm分馏，旨在浓缩渗透物中的残留乳脂，即具有较小MFG的分数(D[4,3]〜1.8-2.4µm。脂肪分离性能显示1.4μm膜的产率为92％，0.5μm膜的产率为97％。两种富含脂肪的滞留物都显示，通过共聚焦激光扫描显微镜，在MFG膜中具有有限损伤的完整MFG。脂肪酸谱分析和SAXS显示了脂肪酸组成的微小差异，结晶行为与脂肪含量的差异有关。然而，含有最小MFGs的0.5μm渗透物显示出较大的聚集体和三元粒度分布，可能是由于孔隙压力引起的聚结。一系列碳化硅膜显示出浓缩一些MFGM蛋白的潜力，例如周期性席夫碱3/4和分化簇36，尤其是在0.5µm的滞留物中。在最终的0.5μm渗透物中，酪蛋白与乳清蛋白的比例从80：20（牛奶）转变为50：50，这为产品开发开辟了新的机遇。
