Evaluation of freezing point in milk from buffalos reared in Calabria, Italy

Abstract

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.