Use of infrared spectroscopy to evaluate the maturation of Minas Padrão and Prato cheeses added with probiotic bacteria

Abstract

Among the most consumed cheeses in Brazil are Minas Padrão and Prato. The objective of this work was to discriminate these cheeses added with probiotic bacteria from the control cheeses by Infrared Spectroscopy during maturation. The probiotic cultures (Lactobacillus acidophilus L10, Lacticaseibacillus casei L26 and Bifidobacterium lactis B94) were individually added in amounts of 10⁸ cells/mL of pasteurized milk and cheeses were prepared. Also, cheeses without the addition of probiotics, control, containing only the starter culture were produced. The acquisition of data by Fourier transforms mid-infrared spectroscopy with Attenuated Total Reflectance (FT-MIR-ATR) and Fourier transform near-infrared spectroscopy (FT-NIR) occurred at times 0, 20, 40, 60, 80 and 100 days in Minas Padrão and at 0, 25, 50, 75 and 100 days in Prato, both cheeses being stored between 7 °C and 10 °C. Subsequently, data processing and Principal Component Analysis were carried out. The FT-MIR technique separated control samples, mainly, at time 0, from those containing probiotics, but did not differentiate maturation times. One of the factors responsible for limiting the discriminatory power of the FT-MIR was the heterogeneity of the samples, revealed by the differences in terms of relative peak intensities for each spectrum of the triplicates. The FT-NIR technique only discriminated against the types of cheese, but did not separate the control samples from those containing probiotics. Therefore, the MIR and NIR techniques showed sensitivity to identify the differences between the cheeses, showing potential for use in the quality control of cheeses added with probiotics.