Espectrometria no infravermelho médio e PLS-DA aplicados na classificação de leites UHT submetidos à hidrólise enzimática: um estudo exploratório

Abstract

There is a clear increase in the percentage of new beverages and food products available to consumers that are positioned “zero lactose or reduced lactose” in Brazil in recent years. However, increased production demands strict control of the reported contents of dairy packaging, since such control has direct implications for the health of individuals with lactose intolerance. Within this context, this dissertation had as its investigative proposal the application of Fourier transform medium infrared (FT-MIR) in association with partial least squares Discriminant analysis (PLS-DA), as a fast, exact and accurate method to differentiate hydrolyzed milks available to the consumer. Six brands of regular UHT and zero lactose milk purchased from the local market were used. A principle prior to experience the FT-MIR analysis step, the sample was subjected to temperature homogenization and stabilization, requiring only a 1.0 μL aliquot for the measurement, which was dripped on the ATR crystal, the scans performed inside from the spectral window of 350 to 4500cm-1 wavelength where we seek to find the chemical bonds referring to the stretch (-OH). Three latent variables were used. Six brands of UHT milk were used, one from each group, totaling 12 samples in three replicates. The results obtained through FT-MIR / PLS-DA was able to discriminate and classify regular zero lactose milks effectively and efficiently.