Determining the Content of Macronutrients in Berry Sauces Using a Method of IR-Spectroscopy

Abstract

This paper has substantiated the possibility of using an IR spectroscopy method to study patterns in the chemical composition of wild and cultivated raw materials with the addition of algae as iodine-containing supplements.

It has been found that the IR spectra of sauces based on the mashed blueberry and sea buckthorn or cranberry with or without algae demonstrate a set of absorption bands attributed to the respective types of oscillations. The valence fluctuations in the hydroxyl groups in the molecules of organic acids, carbohydrates, flavonoids are observed at 3,365 cm -1 to 3,400 cm -1 ν(ОН). The bands of valence and deformation fluctuations of the ‒CH double bond of polyunsaturated fatty acids manifest themselves in the range of 3,005 cm-1 and722 cm-1. The bands of 2,925 cm-1, 2,855 cm-1 belong to the asymmetric and symmetric valence oscillations of the n(С–Н) carbon skeleton in -CH2-. The presence of the carboxylic, amino-, and fatty acids is indicated by the following absorption bands: 1,746 cm-1 ‒ ν (C=O) valence fluctuations in the protonated carboxyl group ‒COOH; 1,545 cm–1 ‒ νas(C=O; 1,415 cm–1 ‒ νs(C=O) ‒ the asymmetric and symmetric valence fluctuations of the СОО-groups; and 1,240 cm–1 ‒ the valence fluctuations of ν(C‒O). The presence of flavonoids is confirmed by the presence of bands at 1,380 cm-1 and 1,050 cm-1 ‒ the deformation δ(O‒H) and symmetrical fluctuations of O‒H groups. The fluctuations of pyranose cycles of pectins are manifested in the range of 1,163 cm– 1.

It is noted that the composition of berry raw materials and sauces include polyunsaturated fatty acids, anthocyanins, flavonoids, organic acids, and pectin substances.

An analysis of the IR spectra of berry sauce samples with the addition of algae has shown that the use of these additives in sauce technologies ensures a significant increase in the content of the physiological and functional ingredients and improves the hydrophobic properties of the raw materials.

Keywords: wild and cultivated berries; algae raw materials; iodine-containing additives; berry sauces; IR spectroscopy