engleski

Green extraction of bioactive compounds from bilberry pomace

Extractions engineered from a concept of environmental sustainability, as pressurised liquid extraction (PLE), were developed as a "green" solid-liquid technology for obtaining bioactive compounds (BACs) from various fruits, and other herbal (by) products. The main advantages of PLE vs. traditional Soxhlet extraction includes improved yield, reduced time and solvent consumption, while inflicting less deterioration to thermolabile compounds. Bilberry pomace (Vaccinium myrtillus L), which is a byproduct of its juice production, is a valuable alternative source of BACs. The aim of this work was to evaluate the use of PLE to valorise bilberry pomace. PLE employed water as solvent, varying the static extraction time (SET ; 5, 10, 15 min), temperature (40, 80, 120°C) and number of cycles (NC ; 1, 2, 3). HPLC-DAD profiled phenolic compounds from the aqueous extracts. Among the seven identified polyphenols, quercetin derivatives predominated in the samples (>60%). The average mass fraction of total phenols (19.49 mg/100 g), which is the sum of total flavonoids (12.70 mg/100 g) and total hydroxycinnamic acids (HCA ; 6.80 mg/100 g), was used for PLE optimization. The total phenolic content (TPC) was significantly affected (p≤0.01) by all studied PLE parameters (i.e. temperature, SET, and NC). The optimal conditions for PLE to obtain an extract with the highest TPC (31.19 mg/100 g) and HCA (10.45 mg/100 g) included T=40 ℃, SET=5 min, and NC=1. However, to obtain extracts with the highest content of flavonoids, parameters included higher temperature (59.74 ℃), SET=5 min, and NC=1. Since pomace is rich in various flavonoids and that they are much more abundant than HCA, a higher temperature probably favours faster diffusion and better solubility of a broader range of analytes in water, hence the need for higher temperature. In conclusion, the use of water as an extraction solvent during PLE shows good prospects for the isolation of BACs from bilberry pomace, which can be further used in the development of sustainable functional food production.

Bilberry ; by-product ; pressurized liquid extraction ; green extraction ; sustainability

Faculty of Technology, University of Novi Sad