Hot water-extracted tuber sugars from Pachyrhizus erosus: Structure, antioxidant capacity, and enzyme inhibition

Abstract This study characterises sugars extracted from Pachyrhizus erosus (L.) Urb. using hot water extraction at 80 °C. The extract was analysed for total sugar, reducing sugar, non-reducing sugar, total phenolic content (TPC), flavonoid content (TFC), and DPPH radical-scavenging activity. Structural analysis confirmed the core inulin structure and identified sucrose, glucose, and fructose via gel permeation chromatography and 1 H NMR. FT-IR spectroscopy verified characteristic sugar functional groups, and scanning electron microscopy revealed a flat-flake morphology. The extract exhibited high levels of bioactive compounds, with TPC and TFC measured at 859.6 ± 2.6 mg GAE/g and 106.5 ± 2.0 mg QE/g, respectively. Antioxidant activity showed an IC 50 of 228.7 ± 6.3 μg mL −1 . Enzyme inhibition assays yielded IC 50 values of 374.1 ± 2.9 μg mL −1 for α-glucosidase and 79.5 ± 1.3 μg mL −1 for α-amylase. The total sugar content was 84.6 ± 0.0%, comprising 21.5 ± 0.2% reducing sugars and 63.0 ± 0.2% non-reducing sugars. These findings indicate that P. erosus extract is a rich source of natural antioxidants with potential applications in the food industry, particularly for the prevention and management of diabetes.