Antimicrobial, antioxidant, volatile and phenolic profiles of cabbage-stalk and pineapple-crown flour revealed by GC-MS and UPLC-MS ^E

Unconventional parts of vegetables represent a rich source of health-promoting phytochemicals. The phenolic profile of cabbage-stalk flour (CSF), pineapple-crown flour (PCF), and their essential oils were characterized via UPLC-ESI-QTOF-MS^E and GC-FID/MS. Antimicrobial activity was tested against five strains, and antioxidant activities were determined in free and bound extracts. Globally, 177 phenolics were tentatively identified in PCF (major p-coumaric acid, ferulic acid, and 4-hydroxybenzaldehyde) and 56 in CSF (major chlorogenicacid, quercetin 3-O-glucuronide, and p-coumaric acid). PCF exhibited a distinguished profile (lignans, stilbenes) and antioxidant capacity, especially in bound extracts (1.3 g GAE.100 g^-1; 0.6 g catechin eq.100 g^-1; DPPH: 244.7; ABTS: 467.8; FRAP: 762.6 µg TE.g^-1, ORAC: 40.9 mg TE.g^-1). The main classes of volatile compounds were fatty acids, their esters, and terpenes in CSF (30) and PCF (41). A comprehensive metabolomic approach revealed CSF and PCF as a promising source of PC, showing great antioxidant and discrete antimicrobial activities.

Keywords: (-)-Epigallocatechin (PubChem CID: 72277); (E)-β-Famesene (PubChem CID: 5281517); 4-p-Coumaroylquinic acid (PubChem CID: 5281766); 5-Caffeoylquinic acid (PubChem CID: 12310830); Cabbage; Daidzin (PubChem CID: 107971); Essential oil; Isorhamnetin 3-O-glucoside (PubChem CID: 5318645); Linalool (PubChem CID: 6549); Metabolomics; Phenolics; Pineapple crown; Quercetin 3-O-glucuronide (PubChem CID: 5274585); Residue; α-Ionone (PubChem CID: 5282108); α-Terpineol (PubChem CID: 17100).