The Green Extraction of Blueberry By-Products: An Evaluation of the Bioactive Potential of the Anthocyanin/Polyphenol Fraction

In the context of a circular economy, this study explores the valorization of blueberry pomace (BP) as a source of bioactive compounds using sustainable extraction methods. Microwave-assisted extraction (MAE) and microwave-assisted subcritical water extraction (MASWE) were employed to obtain two distinct fractions: MAE 1 degrees and MASWE 2 degrees. The first extract, MAE 1 degrees, obtained at 80 degrees C, had a high total anthocyanin content (21.96 mgCya-3-glu/gextract), making it suitable as a natural pigment. Additionally, MAE 1 degrees exhibited significant enzyme inhibition, particularly against alpha-amylase and beta-glucosidase, suggesting potential anti-diabetic and anti-viral applications. The second extract, MASWE 2 degrees, obtained at 150 degrees C, contained a higher total phenolic content (211.73 mgGAE/gextract) and demonstrated stronger antioxidant activity. MASWE 2 degrees showed greater inhibition of acetylcholinesterase and tyrosinase, indicating its potential for use in Alzheimer's treatment, skincare, or as a food preservative. MASWE 2 degrees exhibited cytotoxicity against HeLa cells and effectively mitigated H2O2-induced oxidative stress in HaCat cells, with MAE 1 degrees showing similar but less pronounced effects. A tested formulation combining MAE 1 degrees and MASWE 2 degrees extracts in a 3:2 ratio effectively enhanced anthocyanin stability, demonstrating its potential as a heat-stable pigment. The extract characteristics were compared with a conventional method (MeOH-HCl in reflux condition), and the protocol's sustainability was assessed using several green metric tools, which provided insights into its environmental impact and efficiency.