Is nanofiltration an efficient technology to recover and stabilize phenolic compounds from guava (Psidium guajava) leaves extract?

Guava leaves (Psidium guajava) are popularly known due to their effects antidiabetic, antihypertensive, anti-inflammatory, antidiarrheal, and functional properties. Processes for the concentration of these extracts are necessary since their pharmacological effects are dose-dependent. In this work, guava leaves aqueous extract (GE) concentration was carried out in nanofiltration (NF) equipment. Process performance was evaluated in terms of permeate flux, flux decline modeling, and extract quality (compounds characterization, total phenolic content and antioxidant activity). NF allowed an increase in phenolic compounds next to 20-times, retention coefficients of total phenolic compounds (99%) and enhanced antioxidant capacity (an increase of 4 and 9-fold for ABTS and DPPH, respectively) compared to the initial GE. Forty-two phenolic compounds were identified, being catechin (594.56 mg mL−1) and vescalagin (295.39 mg mL−1) the main compounds. All phenolics presented a significant increase (p < 0.05) after the concentration suggesting that NF is efficient for the recovery and concentration of bioactive compounds and poses as an alternative to obtain functional products and improve added value in agro-industrial residues.