Sustainable Anthocyanin Recovery from Purple Corn Using Green Extraction Techniques: A Comparative Study of Pressurized Liquid Extraction and Ultrasound-Assisted Extraction

The growing interest in sustainable extraction methods for bioactive compounds has spurred advancements in green technologies [1-2]. This study evaluates and compares two such techniques, Pressurized Liquid Extraction (PLE) and Ultrasound-Assisted Extraction (UAE), for recovering anthocyanins from purple corn using an ethanol–water (1:1) mixture with 2% o-phosphoric acid. The analytical determination employed HPLC-UV with a Kinetex C18 core–shell column, ensuring precise quantification. Optimization of the UAE was conducted through a 3441 asymmetrical design to assess variables like the amplitude, time, temperature, sample size, and pulsation cycles. At the same time, the PLE conditions were fine-tuned using a Doehlert response surface methodology.

The optimal conditions for UAE were 20 minutes at 25°C and 64 W, with pulsation cycles of 40 s ON/OFF at 20 kHz. In contrast, PLE achieved peak efficiency with a single static cycle of 3 minutes at 95°C and 1500 psi. Both methods demonstrated excellent linearity (r² > 0.9992), specificity, accuracy, and precision when validated against the FDA guidelines, with PLE exhibiting a superior limit of detection (0.97 μL/mL). A comparative analysis showed similar performance metrics; however, PLE emerged as the preferred method for occurrence studies due to its faster extraction time and robust reproducibility.

This study also incorporated innovative environmental performance metrics to assess sustainability and practical applicability [3], reinforcing the value of these techniques for eco-friendly anthocyanin extraction. The findings underscore the potential for these green methods to meet the food industry's demands and facilitate research, advancing sustainable practices in bioactive compound recovery.

References:

[1] Custodio-Mendoza, J. A., et al. Molecules, 29 (2024) 1735.

[2] de Souza Mesquita, et al., Food chem., 428 (2023) 136814.

[3] Pena-Pereira, F., et al. Adv. Sample Prep., 3 (2022). 100025.