Avocado seed: Modeling extraction of bioactive compounds

Avocado seed is a by-product that contains a large amount of extractable polyphenols, which have attracted the attention of food and cosmetic industries due to their high antioxidant capacity. This fact makes it a promising candidate for the cheap and sustainable extraction of such compounds. This work aims to evaluate the effect of ultrasound power (0-104W) and temperature (20-60 degrees C) on the extraction of total polyphenols from avocado seed using water as a green solvent. Increasing temperature and ultrasound power resulted in extracts with higher polyphenol content and antioxidant capacity. Different mathematical models (Peleg's, empirical, film theory and Fick's law) were also used to find the one that best fit the extraction kinetics. Models based on film theory and Fick's law were able to predict the ultrasound-assisted batch and continuous extractions, respectively, at 95% accuracy. Using a model based on Fick's law, diffusion coefficients of polyphenols in both fast and slow stages were calculated for the extractions. In addition, a linear relationship between total polyphenolic content and antioxidant capacity was proposed. (C) 2016 Elsevier B.V. All rights reserved.