Affiliation:
1. Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
Abstract
Infant formulas and their quality are an extremely important factor for proper growth and development and their composition and nutritional quality are extremely important. Fast, green, and cheap quality analysis methods are definitely desirable. Therefore, the aim of this work was to examine the potential of applying near-infrared (NIR) spectroscopy using two devices: a (i) laboratory NIR analyzer and (ii) portable NIR device. Both devices record the vibrations of molecules in the NIR region of 900–1699 nm. Infant formulas intended for children up to 6 months (n = 6) and for infants with a sensitive digestive system or confirmed allergy to cow’s milk proteins (n = 5) were tested. Each infant formula was recorded in the form of powder and in the form of prepared samples corresponding to different ages, according to the instructions on the product declaration. The parameters of color, conductivity, and total dissolved solids (TDS) were also measured. The measured parameters and the chemical composition of infant formulas were associated with NIR spectra and with the application of chemometric tools (principal component analysis (PCA) and partial least squares regression (PLSR)), the similarity and/or difference between the samples was determined and the qualitative/quantitative potential was determined through applications of both devices. Characteristic peaks at certain wavelengths indicate the presence of carbohydrates, proteins, and water were identified and are specific for regular and specific purpose infant formulas. It is precisely these specificities in the composition, which are visible in the NIR spectrum, that make it possible to distinguish samples on a qualitative level. The connection of NIR spectra as input variables and 22 parameters (color, TDS, conductivity, and energy–nutrient composition) as output variables, using PLSR, gave an insight into the quantitative potential, i.e., the possibility of predicting the observed parameters on the basis of NIR spectra (recorded using two devices). The quantitative potential was confirmed on the basis of model parameters that resulted in acceptable values for both NIR devices: the coefficient of determination for the calibration, Rc2 > 0.9, and Range Error Ratio, RER > 6.