The effect of high hydrostatic pressure on the anthocyanins of raspberry (Rubus idaeus)

The colour stability of fruit puree made from raspberries (Rubus idaeus), which were subjected to high hydrostatic pressure, was studied by measuring the anthocyanin content. High hydrostatic pressure is an alternative method of food preservation to heat treatment. In this study, we assess the impact of high pressure on the colour molecules in raspberries. Fruit samples were pressured under 200, 400, 600 and 800 MPa for 15 min at a temperature controlled between 18 and 22 °C. After application of pressure, the high pressure treated samples were kept at refrigerator temperature (4 °C), room temperature (20 °C) and at 30 °C. The anthocyanin content of the raspberries was analysed after 1, 2, 4, 7 and 9 days of storage by HPLC-UV using an isocratic elution system. Two pigments were identified and quantified: cyanidin-3-glucoside and cyanidin-3-sophoroside. The highest stability of the anthocyanins was found when raspberries were pressured under 200 and 800 MPa and stored at 4 °C.