Optimization, Kinetic and Phenomenological Modeling of Ultrasound-Assisted Extraction Process of Bioactive Compounds from Raspberries (Rubus idaeus L .)

Bioactive compounds are of considerable interest due to their antioxidant properties and potential beneficial health effects. Thus, this study aimed to optimize and model the ultrasound-assisted extraction process (UAE) of response variables total anthocyanins (TA) and total phenolic content (TPC) from raspberries, and to compare the optimized extraction process with the conventional one. The variables used were time (5 to 75 min), temperature (30 to 70 °C), and solid: liquid ratio (1:5 to 1:15 m/v), applied to the Box-Behnken Design. The optimal condition of the UAE process occurs at a temperature of 70 °C and a solid: liquid ratio of 1:12.5 m/v, for both response variables. The optimal time for extraction of TA occurs in 22.5 min predicting the content of 23.181 mg/100 g and for TPC occurs in 57.5 min predicting the content of 156.30 mg GAE/100 g. On validation of the optimized conditions, less than a 5% difference was found between the predicted and experimental values (24.131 mg/100 g for TA, and 149.226 mg GAE/100 g for TPC). When comparing the optimized UAE with the conventional extraction, it wares observed that UAE increased ( p < 0.05) the extraction of TA content by 18.28% and TPC by 28.88%. The process time reduction from 24 h in conventional extraction to less than 1 h in optimized UAE stands out. Furthermore, the Film Theory model tested fitted well to the extraction process under study. Thus, the study indicates that the UAE process is an efficient green methodology for recovering bioactive compounds from raspberries.