The effect of heat treatment on the optical properties of honey

Abstract

A series of liquid and, to varying degrees, crystallized poly- and monofleral honey of different botanical species and zoning was studied by the methods of Fourier infrared spectroscopy and refractometry in order to identify the influence of heat treatment conditions on tautomeric conformational transformations of gluco- and fructopyranose. 22 samples of honey heat-treated at 40 and 90°C for 20 minutes in a water bath and boiled were studied. The data obtained showed a linear dependence of the glucose and fructose content in the samples of heat-treated honey on the refractive index and the anti-bath extreme nature of the change in their content from the processing temperature. For honey brought to a boil, there was an increase in the fructose content in liquid honey and a decrease in crystallized honey. The opposite process in these two groups of honey took place for glucose. Studies of heat-treated honey by Fourier IR spectroscopy allowed us to note a significant change in the optical properties of crystallized samples due to the transition to a liquid state, deactivation of enzymes, and conformation-tautomeric transformations of α- and β-pyranose forms of glucose and fructose, which brought the texture of their spectra closer to the spectra of liquid samples. Due to insufficient knowledge of the diverse and multifactorial properties of honey, the data obtained may be of practical importance in dietetics, pediatrics, gynecology, gastroenterology, cardiology, surgery, burn therapy and other fields of medicine and pharmacology.