Effect of freezing and frozen storage on phenolic compounds of raspberry and blackberry cultivars

The phenolic compounds in raspberry and blackberry cultivars grown in Turkey were determined by liquid chromatography-mass spectrometry (MS)/MS in fresh, just-frozen, and stored fruits at -22 A degrees C for 6 months period. The major phenolic compounds in water extracted samples were ellagic acid (1,350.36-727.9 mg/kg fresh fruit), ferulic acid (820.78-338.27 mg/kg fresh fruit), caffeic acid (754.85-202.78 mg/kg fresh fruit), p-coumaric acid (361.68-142.63 mg/kg fresh fruit), p-hydroxybenzoic acid (534.20-233.29 mg/kg fresh fruit), and quercetin (46.97-27.31 mg/kg fresh fruit) in raspberry and ellagic acid (1,828.07-1,555.13 mg/kg fresh fruit), ferulic acid (757.69-413.82 mg/kg fresh fruit), caffeic acid (736.85-337.89 mg/kg fresh fruit), p-coumaric acid (877.45-287.15 mg/kg fresh fruit), and quercetin (74.69-56.78 mg/kg fresh fruit) in blackberry. The varietal differences in the phenolic compound contents were larger among the blackberry cultivars (from 1,828.07 to 56.78 mg/kg fresh fruit) than among the raspberry cultivars (1,350.36 to 27.31 mg/kg fresh fruit). A significant decrease was observed in the content of p-hydroxybenzoic acid (from 534.20 to 114.30 mg/kg; Aksu KA +/- rmA +/- zA +/- sA +/-) and the least decrease was in the content of caffeic acid (from 545.42 to 530.91 mg/kg; Heritage) in raspberry cultivars. On the other hand, ferulic acid (from 475.16 to 113.33 mg/kg) decreased significantly in blackberry (Bursa 2) after storage for 6 months