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

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-QTOE-MSE 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 chlorogenic acid, 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 tg 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.