Espectroscopia FT-MIR e calibração multivariada para determinação simultânea dos teores de gordura, proteínas e lactose e adulterações por adição de água em amostras de leite

Abstract

The quantification of the constituents of milk is crucial for the establishment of its nutritional quality, fitness for human consumption and market value of the product. It is estimated that milk has approximately 100,000 different constituents, although most of them have not yet been identified. The main constituents of milk are water, lipids (fats), proteins and lactose, and the minerals and vitamins are called secondary constituents. Theseconstituents,theirdistributionandinteractionsdeterminethephysicalcharacteristics of milk, that are monitored by specialized institutions to verify the occurrence of problems that affect the composition of milk and check the suspected tampering of the product after milking. The objective of this study was to apply the technique of infrared spectroscopy in the medium-red region for the identification and quantification of the major constituents of the milk (fat, protein and lactose), as well as determining the percentage of added water in samples of liquid milk. The technique used has high sensitivity and reproducibility of results. As a result it was found that the methodology of analysis developed in this study showed no difference compared with the results obtained by official methods of analysis to quantify the levels of fat, protein and lactose in samples of liquid milk, the same was observed for the determination the percentage of water added to milk. The advantages of using this spectroscopic technique in the analysis of milk is that, besides being a rapid technique compared to traditional methods of chemical analysis, you can analyze about 40 samples in one hour, it is also inexpensive, since it is not necessary any chemical reagents or sample preparation.