Application of enzyme and ultrasound assisted extraction of polyphenols from avocado (Persea americana Mill.) peel as natural antioxidants

Abstract

Background. Hass avocado ( Persea americana Mill.) peel is a rich source of natural antioxidants. The pre-sent work aims to evaluate ultrasound and enzyme-assisted extraction methods of polyphenols with antioxidant properties from avocado peel. Materials and methods. The impact of extraction parameters on the extraction yield of polyphenols was as-sessed using the Folin-Ciocalteu reagent method, while the antioxidant activity of the extracts was evaluated using DPPH and FRAP assays. The polyphenolic compounds were identified by HPLC. Results. The major polyphenolic compounds identified in the investigated extracts were benzoic acid, vanil lic acid, resveratrol and syringic acid. The highest yield of polyphenols ~35.4 mg GAE/g of dried peel was obtained with a solid-to-solvent ratio of 1:20 (w/v) using 20% ultrasonic intensity for 30 min or by treatment with viscozyme at a 1% level for 60 min. The IC 50 values by DPPH and FRAP in the ultrasound assisted extract were statistically lower than those in the enzyme assisted extract. The avocado peel extract is a prom-ising source of antioxidants. Conclusion. The ultrasound assisted extraction proved to be more efficient than enzyme aided extraction in terms of the antioxidant activity of the extractable phenolic compounds.