Evaluación espectroscópica de la leche de diferentes especies de mamíferos en la granja experimental Villa Marina.

Abstract

Today, the milk of a variety of animals (donkeys, horses, sheep, goats, buffalo and cows) is used, not only for infant feeding, but also as an important source of general nutrition. In Colombia the consumption of non-bovine milk is very low, even for many regions there are no statistical data that reflect the consumption of these milks. Additionally, the authenticity of milk and dairy products is important in many regions of the world and has widespread health, cultural and financial implications. Therefore, the determination of the main components of milk is important in the dairy food industry, to establish the value of milk, for consumer information and for quality control. Therefore, a number of routine analyzes are required to be performed, but current analytical methods for milk quality control are time consuming, laborious and therefore impractical to use in the routine analysis of this product for part of the dairy industry. Fourier transform infrared spectroscopy (FTIR) is an excellent alternative, as it is a fast, non-destructive technique that can be used for the quantitative analysis of the main components (biochemical profile) and obtain compositional details, significantly reducing the period sample analysis and is currently being used in the dairy industry to predict fat and protein content. In this work, a spectroscopic evaluation of the cow's milk produced in the Villa Marina farm was carried out and compared with the milk produced by different species of mammals (goat, sheep and buffalo), comparing their biochemical profiles using ATR-FTIR accompanied with methods of multivariate analysis (PCA and HCA). Additionally, the atomic absorption spectroscopy technique, with a graphite furnace and hydride generation, was used to determine the presence of heavy metals in the samples, after microwave-assisted digestion. Twelve bands were obtained in the spectral region between 4000-400 cm1 through the FTIR, corresponding to functional groups of fats, proteins and lactose, whose absorbance’s were integrated to determine the relative percentage of each of these components. It was found that sheep's milk contains the highest relative percentage of proteins, fats and carbohydrates. The PCA correctly discriminated the milk of different species, showing the correlation between buffalo, goat and bovine milk, which corroborated the HCA, describing the grouping of these milk samples and rectifying the differences with sheep milk. Finally, in the analysis of heavy metals by absorption, the presence of heavy metals (Cu, Pb, Zn, Cd) was found in goat, sheep and cow milk in low concentrations even below the standards established by international authorities such as codex Alimentarius and Romanian regulations.