Study of <i>D</i>-glucose influence on <i>L</i>-ascorbic acid destruction in aqueous-ethanolic media

Abstract

The study of ascorbic acid transformation processes in aqueous - ethanolic systems is an important area of research in food chemistry, and therefore recently there has been an increased interest in studying the possibility of stabilizing ascorbic acid in the form of O -derivatives by the biologically active substances. The paper examines the behavior of ascorbic acid - D -glucose double systems in aqueous-ethanolic media of various compositions (96 % EtOH, 40 % EtOH) under thermal degradation conditions compared to systems without carbohydrate additives. It has been shown that in 40 % ethanol, degradation processes develop faster compared to reactions in 96 % ethanol; in dual systems, regardless of solvent composition, ascorbic acid reacts faster than carbohydrate-free systems. Based on electronic and vibrational spectroscopy data, the joint participation of ascorbic acid and monosaccharide in thermodestruction reactions has been established, which is accompanied by the sequential formation of dehydroascorbic acid derivatives. These derivatives are L -gulono-γ-lactones with different degrees of substitution, containing no endiol fragments of ascorbic acid, and as a result do not have antioxidant properties. As a result of the studies, the absence of ascorbic acid stabilization by D -glucose in the form of O -derivatives in the studied double systems is shown, which is probably due to the formation of thermodynamically stable of dehydroascorbic acid derivatives during the reactions, even in low-water systems. Further studies are planned in the direction of choosing the optimal conditions that allow isolating ascorbic acid derivatives (or molecular complexes) with reducing properties, which will make it possible to obtain products with antioxidant functionality.