engleski

Green-based microwave-assisted extraction for isolation of anthocyanins from black elderberry pomace

Due to the growing influence of oxidative stress on the development of many diseases, there is a tendency to isolate and select natural compounds with antioxidant activity. Anthocyanins have been described as compounds that prevent or inhibit oxidation by scavenging free radicals and reducing oxidative stress. The main compounds of the black elderberry (Sambucus nigra L.) are anthocyanins mostly cyanidin-3-sambubioside (C3- Sam), cyanidin-3-glucoside (C3-Glu), and cyanidin-3- galactoside (C3-Gal)1. These anthocyanins remain in the elderberry pomace after juice pressing, being discarded. In order to isolate valuable compounds from elderberry pomace, green-based microwave-assisted extraction (MAE) has been applied. MAE is emerging as a good alternative to the conventional extraction of bioactives, mainly due to the relatively high extraction yield, short extraction time, and simplicity2. MAE has been performed at temperatures from 40 to 120 ℃, for 5 and 10 min, with 30% aqueous ethanol solution as solvent. Solid-liquid extraction (SLE) was used as a reference extraction technique for the selection of optimal extraction solvent. The contents of C3- Gal, C3-Glu, and C3- Sam were determined and quantified by high-performance liquid chromatography with a diode-array detector (HPLC- DAD). The most dominant anthocyanin was C3-Sam, followed by C3-Glu and C3-Gal. By increasing the temperature from 60 to 120 ℃ during 10 min, the concentration of C3-Sam significantly decreased from 904.00 to 116.18 μg/mL extract. The highest concentration of C3-Glu (724.18 μg/mL of extract) was obtained at extraction conditions of 60 ℃ and 10 min, while the most suitable MAE conditions for C3-Gal (55.72 μg/mL of extract) were the extraction temperature of 100 ℃ and extraction time of 10 min. The concentrations of all three anthocyanins were higher during 10 min of MAE in comparison to 5 min, at temperatures from 40-80 ℃, while at higher temperatures, the Based on the obtained results, MAE was shown to be a suitable technique for the isolation of anthocyanins from elderberry pomace. In addition to significantly reduced extraction time, higher content of the target compounds was obtained.

elderberries pomace ; anthocyanins ; microwave-assisted extraction ; valorization

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