A Comprehensive Optimization of Ultrasound-Assisted Extraction for Lycopene Recovery from Tomato Waste and Encapsulation by Spray Drying
Junyang Li, Margherita Pettinato, Alessandro Alberto Casazza, Patrizia Perego
Abstract
This study aimed to extract bioactive compounds from tomato waste through ultrasound-assisted extraction (UAE), using ethanol as solvent. Process optimization was carried out by a central composite design of 33 runs for response surface modelling, simultaneously analyzing the effect of temperature (T), time (t), volume (V), liquid-to-solid ratio (L/S), amplitude (A), the pulser duration (on), and their interaction. The best conditions found by the desirability method (T = 65 °C, t = 20 min, L/S = 72 mL/g, A = 65%, on = 33 s, V = 90 mL) were experimentally verified, leading to the production of an extract with interesting properties (total carotenoids of 1408 ±14 µglycopene equivalents/g, lycopene yield of 1536 ± 53 µg/g, 36.1 ± 0.9 µgtrolox equivalents/g as antiradical power). Due to the instability of lycopene, the extract encapsulation by spray drying was undertaken using inulin and maltodextrins as coating agents. The evaluation of wall material composition provided high product recovery (73%), a high content of encapsulated compared to superficial lycopene (15.3 ± 2.9 and 0.30 ± 0.02 µg/g), and a product with good water solubility. The novelty of this work concerned the simultaneous study of the effect and interdependences of the UAE parameters, and the use of inulin to enhance the properties of microparticles.