Abstract
<jats:p>Carbonyl derivatives, determined by methods using dinitrophenylhydrazine (DNPH) R.L. Levine et al., are recognized as common markers of protein oxidation both in tissues and cells, and in food. To identify early and late markers of oxidative modifications of proteins, optical density is recorded at various wavelengths, but there is no clear gradation of wavelengths characteristic of aldehyde derivatives (ADNPH) and ketones (CDNPH). To establish the possibility of increasing the informational significance of spectrophotometry indicators, the correlation relationships between individual indicators of carbonyl derivatives of proteins of adapted milk mixtures were determined. The research materials were samples of adapted infant formulas: NAN EXPERT pro (Nestle Deutschland AG), Malyutka (JSC DP Istra-Nutricia), Nutrilon 2 Premium (Nutricia), Bellakt 0-12 (Volkovysk, JSC Bellakt), as well as for comparison -samples of ultra-pasteurized cow's milk (Tema, JSC Unimilk, Russian Federation). The level of carbonyl compounds was determined by the absorption spectra of dinitrophenylhydrazones, which were recorded on a UNICO 2800 spectrophotometer. Statistical processing of the obtained results was carried out using correlation and regression analysis. The correlation analysis confirmed the importance of determining aldehyde-dinitrophenylhydrazones at a wavelength of 356 nm, and ketone-dinitrophenylhydrazones at 370 nm in the ultraviolet part of the spectrum. At these lengths, a strong statistically significant direct correlation was found between ADNPH and CDNPH in ultrapasteurized milk and all the studied mixtures. In addition, strong direct correlations between ADNPH and CDNPH during spontaneous oxidation have been established at the wavelengths of the visible spectrum of 428/434 nm and 430/434 nm. The presence of similar correlations between adapted milk mixtures and pasteurized milk indicates that there is no significant effect of additional technological factors on the formation of carbonyl compounds during spontaneous oxidation. However, unlike spontaneous oxidation during metal-catalyzed oxidation at 356/370 nm wavelengths, a strong significant correlation was found only in terms of ultrapasteurized milk and NAN EXPERT pro mixtures, the correlation is statistically insignificant among the indicators of other mixtures, which requires further clarification. The results of the appearance of strong significant correlations at the wavelengths of the visible spectrum of 428/535 nm(vs) and 430/535 nm(vs) during metal-catalyzed oxidation in the proteins of all milk mixtures, with the exception of Malyutka and Tema milk, also attract attention. Finding out the reasons for such significant differences in the correlation indices of individual mixtures at different wavelengths requires further study.</jats:p>