Efficacy of ultrasound-assisted extraction of bioactive constituents from Psidium guajava leaves

Abstract

Targeting the sensitivity of process parameters in due course of the optimal ultrasound assisted extraction of bioactives from guava leaves. The purpose of the conducted investigations was to scope and optimize the efficacy of ultrasound assisted extraction in conjunction with hot water extraction. Addressing the criticality of loading ratio, low temperature drying as pre-treatment step and consideration of all desired responses, the article addresses the normal and pulsed ultrasound assisted extraction of bioactive constituents from guava leaf powder. The experimental methodology involved face centered design (FCD) based response surface methodology (RSM). The investigations affirmed that the normal ultrasound assisted extraction process exhibited 15.5 – 68.8 mg GAE/g total polyphenolic content (TPC), 50.1 – 80.3 % antioxidant activity (AA), 5.7 – 25.7 mg/100g vitamin C (VITC) content and 44.7 – 289.77 mg QE/g total flavonoids content (TFC) for a variation in the degrees of freedom as 0.02 – 0.2 g/mL loading ratio, 5 – 20 min extraction time and 40 – 70 °C extraction temperature. Pertinent observations have been documented in terms of comparative criticality of the degrees of freedom, best fit model and efficacy of the pulsed mode.