Sweet Biotechnology: Enzymatic Production and Digestibility Screening of Novel Kojibiose and Nigerose Analogues

Abstract

In view of the global pandemic of obesity and related metabolic diseases, there is an increased interest in alternative carbohydrates with promising physiochemical and health-related properties as a potential replacement for traditional sugars. However, our current knowledge is limited to only a small selection of carbohydrates, whereas the majority of alternative rare carbohydrates and especially their properties remain to be investigated. Unraveling their potential properties, like digestibility and glycemic content, could unlock their use in industrial applications. Here, we describe the enzymatic production and in vitro digestibility of three novel glycosides, namely, two kojibiose analogues (i.e., D-Glc p -α-1,2-D-Gal and D-Glc p -α-1,2-D-Rib) and one nigerose analogue (i.e., D-Glc p -α-1,3-L-Ara). These novel sugars were discovered after an intensive acceptor screening with a sucrose phosphorylase originating from Bifidobacterium adolescentis (BaSP). Optimization and upscaling of this process led to roughly 100 g of these disaccharides. Digestibility, absorption, and caloric potential were assessed using brush border enzymes of rat origin and human intestinal Caco-2 cells. The rare disaccharides showed a reduced digestibility and a limited impact on energy metabolism, which was structure-dependent and even more pronounced for the three novel disaccharides in comparison to their respective glucobioses, translating to a low-caloric potential for these novel rare disaccharides.

Rare Sugar Metabolism and Impact on Insulin Sensitivity along the Gut–Liver–Muscle Axis In Vitro

“…This is confirmed by the HPAEC-PAD findings, while these analyses also showed that the monosaccharide composition has an impact. Although the decreased glucose levels upon exposure to D-Glc-α1,2-D-Gal, D-Glc-α1,2-D-Rib and D-Glc-α1,3-L-Ara could be related to the fact that only one molecule of glucose is released during their digestion, we have previously demonstrated that cellular ATP production and the change in disaccharide concentration over time is similar for these sugars in comparison to a mannitol control [ 38 ]. Therefore, the decrease in glucose concentration during exposure to Glc-α1,2-D-Gal, D-Glc-α1,2-D-Rib and D-Glc-α1,3-L-Ara is most likely a result of both a lower glucose content of the sugar and delayed digestion.…”