Extraction of phenolic compounds from bilberry (Vaccinium myrtillus L.) press residue: Effects on phenolic composition and cell proliferation

- Phenolic compounds in bilberry press residue were extracted using hot water.
- The yields were highest at high temperature (80 °C) and short duration (4-15 min).
- Anthocyanins, flavonols and cinnamic acids were characterized and quantified.
- Bilberry press residue extracts had promising antiproliferative effects.
- Extracts obtained at high temperatures showed the strongest antiproliferation.

The press residue after industrial juice production from bilberry (Vaccinium myrtillus L.) contained high concentration of polyphenols, a group of compounds with possible health benefits. The effects of temperature (22-100 °C) and duration (4-45 min) utilized in aqueous extraction of phenolic compounds from the press residue were studied. The yield of anthocyanins in the extracts increased with temperature and extraction time up to a point, and then declined. The recovery of flavonols and cinnamic acid containing compounds in the extracts increased with increasing temperature and reached 97% and 63%, respectively. Extraction at 80 °C for 15 min and 100 °C for 4 min gave the highest retrieval of both total phenolics (TP) and total monomeric anthocyanins (TMA), 37% and 67-68%, respectively. Extracts obtained at high extraction temperatures showed a stronger inhibition of cell proliferation of three colon cancer cell lines (Caco-2, HT-29, and HCT 116) than extracts obtained at lower temperatures.