Resumo

GUTIERREZ-TOLENTINO, Rey et al. Detection of foreign fat in milk fat by gas-chromatography and multivariable statistic. Agrociencia [online]. 2007, vol.41, n.7, pp.733-742. ISSN 2521-9766.

The addition of non-milk fat (NMF) to milk and its derivates is considered to be an adulteration of the product. The objective of our study was to develop a statistical methodology that will make it possible to detect NMF in mixtures of NMF with milk fat (MF). A sampling was made of raw milk from the Mexican Highlands every 15 d during one year (total, 216 samples). The samples of NMF included two for each oil: fish, sunflower and canola, as well as two of lard and tallow. The percentages (% p/p) of triacylglycerols (TAG) in each fatty material were obtained by gas chromatography with flame ionization detector; the identified TAG varied between 28 and 56 carbon atoms. MF was mixed with the NMF: 95:5, 90:10, 85:15 and 80:20. A linear multiple regression analysis was made and three equations were obtained for the NMF: 1) Y =1.71C42+11.76C44−1.93C46+3.13C52−0.25C54 (fish oil); 2) Y=4.24C38−2.18C40+2.33C42+2.19C44−0.03C48+2.86 C50−0.69C52+2.20C54 (canola and sunflower oils, tallow); 3) Y=2.41C34+1.37C36−0.30C38+2.67C40+3.63C48−0.6 9C50+1.70C52+0.71C54 (lard). With these equations, 75.3 and 98.11% of the cases were detected when the adulterations with NMF were 5 and 10%.

Palavras-chave : Adulteration; milk fat; non-milk fat; multiple linear regression.

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