Optimization of ultrasound-assisted extraction of astaxanthin from black tiger shrimp (Penaeus monodon) shells using deep eutectic solvent and ethanol as a co-solvent

Abstract

The study aimed to enhance the extraction of astaxanthin (ASX) from black tiger shrimp shells by combining Deep eutectic solvent (DES) and ultrasound-assisted extraction (UADE). The DES used in the research consisted of choline chloride (Ch) and lactic acid (LA) in a 1:2 M ratio with 20% water. Response surface methodology (RSM) utilizing a Box-Behnken design (BBD) was employed to optimize the UADE conditions, considering ultrasound power (200–400 W), ethanol concentration in the DES (5–65 %), and extraction time (5–45 min). The optimal UADE parameters identified by BBD were 330 W ultrasound power, 35% ethanol content, and 33 min of extraction, resulting in the highest ASX content of 47.42 μg/g, closely matching the predicted value of 48.65 μg/g. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis revealed structural alterations in samples treated with DES-based UAE, setting it apart from soxhlet extraction, maceration, and ethanol-based DES extraction. The outcomes indicated that UADE outperformed traditional extraction methods like soxhlet extraction, maceration, and ultrasound-assisted ethanol extraction (UAET) regarding ASX yield and antioxidant activity, while also needing shorter extraction durations. These results underscore UADE as a productive and eco-friendly approach for extracting ASX from shrimp shells.