The untargeted metabolomics approach was used to compare the chemical profiles of acerola (Malpighia emarginata DC.) pomace extracts. The effect of drying the raw material before subcritical water extraction (SWE) at different temperatures on the yield, phenolic content, and in vitro antioxidant activity was evaluated. The results were compared with those obtained via Soxhlet and the findings suggest that SWE saves time (15 min) and solvent for extracting valuable components as compared to Soxhlet (6 h). An increase in temperature significantly improved the extraction yield (23.9 to 33.4 %), phenolic content (119.1 to 362 mgGAEg-1), and antioxidant activity, and higher values were obtained with SWE as compared to Soxhlet. The most abundant compounds detected by UPLC-ESI-QTOF-MS were ascorbic acid, kaempferol, quercetin, and isorhamnetin. The investigation of different moisture contents in the SWE showed promising results for eliminating the drying operation, saving time and energy, and obtaining highly concentrated phenolic-rich by-products.
Keywords: Antioxidant activity; Heatmap analysis; Malpighia emarginata DC by-product; Phenolic compounds; Subcritical water extraction.
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