Degradation Mechanisms of Six Typical Glucosidic Bonds of Disaccharides Induced by Free Radicals

Abstract

Increasing hydrogen peroxide (H 2 O 2 )-based systems have been developed to degrade various polysaccharides due to the presence of highly reactive free radicals, but published degradation mechanisms are still limited. Therefore, this study aimed to clarify the degradation mechanism of six typical glucosidic bonds from different disaccharides in an ultraviolet (UV)/H 2 O 2 system. The results showed that the H 2 O 2 concentration, disaccharide concentration, and radiation intensity were important factors affecting pseudo-first-order kinetic constants. Hydroxyl radical, superoxide radical, and UV alone contributed 58.37, 18.52, and 19.17% to degradation, respectively. The apparent degradation rates ranked in the order of cellobiose ≈ lactose > trehalose ≈ isomaltose > turanose > sucrose ≈ maltose. The reaction pathways were then deduced after identifying their degradation products. According to quantum chemical calculations, the cleavage of α-glycosidic bonds was more kinetically unfavorable than that of β-glycosidic bonds. Additionally, the order of apparent degradation rates depended on the energy barriers for the formation of disaccharide-based alkoxyl radicals. Moreover, energy barriers for homolytic scissions of glucosidic C 1 −O or C 7 −O sites of these alkoxyl radicals ranked in the sequence:glucosidic bonds. This study helps to explain the mechanisms of carbohydrate degradation by free radicals.

Focusing on New Discoveries in Food Technology and Creating a New Future of Nutrition and Health: An Introduction to the 4th International Symposium of Food Science, Nutrition and Health in Dalian, China

“…Furthermore, several other processing methods demonstrated their potential in enhancing food texture and quality. Papers entitled ‘Coexisting with ice crystals: Cryogenic preservation of muscle foodmechanisms, challenges, and cutting-edge strategies’ by Dr. Baocai Xu, ‘Degradation mechanisms of six typical glucosidic bonds of disaccharides induced by free radicals’ by Dr. Lijun You, and ‘Regulation of protein flexibility and promoting the cod protein gel formation using ultrasound treatment’ by Dr. Yisha Xie collectively served as an insightful showcase, demonstrating the efficacy of diverse food processing methods and technologies. They not only contribute significantly to our understanding of food processes but also underscore their correlations with enhanced quality experiences.…”