Mulas G, Roggio T, Uzzau S, Anedda R
Porto Conte Ricerche S.r.l., SP 55 Porto Conte/Capo Caccia Km 8.400, Loc Tramariglio 07041 Alghero (SS), Italy.
J Dairy Sci. 2013;96(12):7393-403. doi: 10.3168/jds.2013-6607. Epub 2013 Oct 11.
The evaluation of milk heat treatment on dairy products via reliable analytical methods is a challenging issue that involves both industrial and fundamental research. We describe a new magnetic resonance imaging (MRI) protocol for discriminating Sardinian sheep milk cheese originating from heat-treated or raw milk. Thirty-six samples (18 pecorino cheeses manufactured from heat-treated milk and 18 Fiore Sardo cheeses made from raw milk) were investigated by means of MRI and bi-exponential signal decay analysis. The protocol is capable of discerning cheeses by virtue of the different distribution of the transversal (T2) relaxation time constant. Cheeses from heat-treated milk showed a significantly higher area fraction (≈70-80%), corresponding to the fast relaxing water protons (T2 ≈ 9 ms), compared with raw milk cheeses, whereas the opposite was observed for the long T2 (T2 ≈ 35 ms) proton population. The MRI protocol described is rapid and nondestructive, and it provides statistically significant discrimination between ewe milk cheeses made from heat-treated and raw milk.
通过可靠的分析方法评估乳制品中牛奶的热处理是一个具有挑战性的问题，涉及工业和基础研究。我们描述了一种新的磁共振成像（MRI）方案，用于区分源自热处理牛奶或生牛奶的撒丁岛绵羊奶奶酪。通过MRI和双指数信号衰减分析对36个样品（18个由热处理牛奶制成的佩科里诺奶酪和18个由生牛奶制成的菲奥雷·萨尔多奶酪）进行了研究。该方案能够凭借横向（T2）弛豫时间常数的不同分布来辨别奶酪。与生牛奶奶酪相比，热处理牛奶制成的奶酪显示出明显更高的面积分数（约70 - 80%），对应于快速弛豫的水质子（T2≈9毫秒），而对于长T2（T2≈35毫秒）质子群则观察到相反的情况。所描述的MRI方案快速且无损，并且能在由热处理牛奶和生牛奶制成的母羊奶奶酪之间提供具有统计学意义的区分。
