Solid Residue after Alcoholic Maceration of Madagascar Vanilla: Residual Aroma, Dietary Fiber, and Bioactivity for Food Valorization

Cured Madagascar vanilla beans (Vanilla planifolia Andrews, Orchidaceae) are macerated in hydroalcoholic solutions to obtain natural extracts used by the food, cosmetic, and perfumery industries. The process generates an underused solid residue, although aromatic substances and structural components may remain. This study exclusively evaluated this post-maceration residue for proximate composition, water activity (aw), 168-h hygroscopicity, and total extractives. A hydroethanolic re-extraction (EtOH:H2O, 70:30) was assessed for yield, total phenolics, DPPH, ABTS, FRAP, ORAC, and LC–ESI–IT3D–MS/MS profile.The residue contained 56.49 g/100 g total dietary fiber on a dry basis, predominantly insoluble fiber (48.60 g/100 g; soluble fiber: 7.89 g/100 g), together with 6.81 g/100 g protein and 1.68 g/100 g ash. Water activity was 0.415 and 168-h hygroscopicity was 4.73 g/100 g powder. Even after alcoholic maceration, total extractives reached 28.21 g/100 g dry biomass and hydroethanolic re-extraction yielded 21.64%, showing that a substantial fraction remained recoverable. The re-extracted fraction contained 0.54 mg GAE/g total phenolics and residual antioxidant activity: 55.2 µmol TE/g by ABTS, 54.1 by ORAC, 24.6 by DPPH, and 2.54 by FRAP. In MS/MS, the nominal [M−H]− m/z 151 precursor, exclusive to the sample, yielded mainly m/z 136 and 123, while [M+H]+ m/z 153 yielded m/z 125, a pattern compatible with vanillin. An [M−H]− m/z 121→93 feature was compatible with 4-hydroxybenzaldehyde, another characteristic constituent of the V. planifolia aroma profile, and m/z 193→178/149/134 was compatible with ferulic acid. These markers show that the first maceration did not exhaust the bean's natural aromatic signature.The residue retains a fiber-rich matrix, substances associated with natural vanilla aroma and taste, and measurable antioxidant activity. This supports cascade valorization through secondary recovery of aromatic substances for natural concentrates, followed by use of the dried and micronized solid as a fibrous and aromatic ingredient in biscuits, bakery products, chocolate, desserts, snack bars, and dry mixes. Application should consider sensory intensity, vanillin standardization, and residual-solvent control.Acknowledgments: CNPq (PIBIC / PIBITI – 2026 and 400122/2025-1), FAPESP (2025/11374-6) and PIDA/PRPI/USP 1602025/01.