International Journal of Life Science and Agriculture Research

Cold-press processing of blueberries for juice production generates a wet pomace that retains bioactive compounds of interest. To recover these compounds from the by-product, this study evaluated the extraction performance of five choline chloride-based natural deep eutectic solvents (NADES), formulated with urea, fructose, malic acid, oxalic acid, or lactic acid at a 1:1 molar ratio and containing 15% water, under three extraction conditions: heating with agitation, ultrasound, and microwave treatment. Six independent extracts were prepared for each combination. In each of six independent pressing operations, 250 g of fruit were processed, yielding 175.3 ± 1.6 g of juice and 70.0 ± 1.5 g of fresh pomace. Solvent formulation and extraction technology significantly affected the recovered amounts of phenolics, flavonoids, and monomeric anthocyanins. Heating with agitation using the choline chloride:lactic acid solvent produced the highest total phenolic and flavonoid values, at 667.43 ± 15.33 mg gallic acid equivalents and 256.36 ± 10.37 mg catechin equivalents per 100 g fresh pomace, respectively. The highest monomeric anthocyanin content was obtained with choline chloride:oxalic acid under heating (187.39 ± 7.18 mg cyanidin-3-glucoside equivalents per 100 g). The acidic formulations emerged as promising candidates for further analytical validation, chromatographic characterization, and process optimization.

blueberry pomace, phenolic compounds, green extraction, NADES, anthocyanins, emerging technologies.

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