Work

Metabolomics reveals the effect of sand roasting, freeze-drying, and different hydrothermal treatments on the physical, functional and bioactive profile of Rice bean (Vigna umbellata)

Year: 2026

Type: article

Abstract: This study comprehensively investigated the effects of five processing treatments–soaking (SK), germination (GR), sand roasting (SR), freeze-drying (FD), and pressure cooking (PC) on the physicochemical, functional, structural, antioxidant, and metabolomic characteristics of rice bean ( Vigna umbellata ), an underutilised legume with high nutritional potential. Significant variations ( p ≤ 0.05) were observed among treatments. GR proved most effective in enhancing nutritional and bioactive quality, yielding the highest protein content (24.3%), total phenolics (8.42 mg GAE/g), flavonoids (4.22 mg QE/g), DPPH radical scavenging activity (72.67%), foaming capacity (32.82%), and emulsion stability (76.3%). PC maximised sphericity (68.85%), swelling index (5.31 g/g), and hydration properties, while SR enhanced oil absorption capacity (2.42 g/g). Untargeted HR-MS metabolomics detected 10,533 metabolite features, with GR samples showing the richest profile and enrichment of quercetin, kaempferol, and naringenin derivatives; 283 metabolites constituted the shared core metabolome. FT-IR revealed treatment-induced modifications in protein, lipid, and carbohydrate structures, and XRD confirmed A-type starch crystallinity, largely preserved by FD but disrupted by PC. These findings demonstrate that processing-specific structural modifications govern functionality, highlighting the targeted use of rice bean flour in functional food applications.

Source: Food Chemistry X

DOI: 10.1016/j.fochx.2026.104553