Ceniti Carlotta, Britti Domenico, Trimboli Francesca, Morittu Valeria Maria, Lopreiato Vincenzo, Costanzo Nicola
Department of Health Science and Interdepartmental Services Centre of Veterinary for Human and Animal Health, Magna Græcia University of Catanzaro, Italy.
Ital J Food Saf. 2019 May 23;8(2):7895. doi: 10.4081/ijfs.2019.7895.
Evaluation of freezing point is one of the most common technique used to detect milk adulteration such as addition of external water to increase volume. The aim of this study was to evaluate the freezing point of buffalo milk using infrared spectroscopy and to assess how it is influenced by other milk components. A total of 361 individual buffalo milk samples were collected monthly from March to August of 2017 in a dairy farm in Catanzaro district, Italy. Samples were tested for freezing point, urea, acetone and beta-hydroxybutyrate, percent of fat, protein, lactose, casein, by Fourier Transformed Spectroscopy. The pH and daily milk production were also recorded. Freezing point ranged from -0.574°C to - 0.512°C and the mean values was -0.545°C ±0.010. According to lactation stage, freezing point decreased until 210 days post-partum reaching the minimum value of -0.550°C, then it slightly increased during lactation; according to sampling month the highest and lowest values were recorded in August and June, respectively. A positive correlation between freezing point and lactose content were evidenced (r=0.1806, P<0.05). Moreover, a faintly positive correlation was also found between freezing point and beta-idroxibutirrate (r=0.0869, P<0.05) and acetone (r=0.0096, P<0.05), whereas a negative correlation with fat (r=-0.2356, P<0.05), protein (r=-0.1855, P<0.05), casein (r=-0.2127, P<0.05) and urea (r=-0.1229, P<0.05) was evidenced.
冰点评估是检测牛奶掺假（如添加外部水以增加体积）最常用的技术之一。本研究的目的是使用红外光谱法评估水牛奶的冰点，并评估其如何受到其他牛奶成分的影响。2017年3月至8月，每月从意大利卡坦扎罗地区的一个奶牛场收集总共361份个体水牛奶样本。通过傅里叶变换光谱法对样本进行冰点、尿素、丙酮和β-羟基丁酸盐、脂肪百分比、蛋白质、乳糖、酪蛋白的检测。还记录了pH值和每日产奶量。冰点范围为-0.574°C至-0.512°C，平均值为-0.545°C±0.010。根据泌乳阶段，冰点在产后210天之前下降，达到-0.550°C的最小值，然后在泌乳期间略有上升；根据采样月份，最高值和最低值分别记录在8月和6月。冰点与乳糖含量之间存在正相关（r=0.1806，P<0.05）。此外，在冰点与β-羟基丁酸盐（r=0.0869，P<0.05）和丙酮（r=0.0096，P<0.05）之间也发现了微弱的正相关，而与脂肪（r=-0.2356，P<0.05）、蛋白质（r=-0.1855，P<0.05）、酪蛋白（r=-0.2127，P<0.05）和尿素（r=-0.1229，P<0.05）存在负相关。
