Frozen storage effects on anthocyanins and volatile compounds of raspberryfruit

The quantitative and qualitative evolution of the anthocyanins and volatile compounds of four raspberry cultivars (cvs. Heritage, Autumn Bliss, Zeva, and Rubi) growing in Spain were analyzed raw, just frozen, and during long- term frozen storage at -20 degrees C for a 1 year period. HS-SPME coupled w ith GC-MS and HPLC techniques were employed to study the evolution of the v olatile compouds and the individual anthocyanins, respectively. The volatil e aroma composition changes produced by the freezing process and long-term frozen storage were minimal. Only a significant increase in extraction capa city was obtained for alpha-ionone (27%) and for caryophyllene (67% in Heri tage at 12 months of storage. The stability of anthocyanins to freezing and frozen storage depends on the seasonal period of harvest. Heritage and Aut umn Bliss early cultivars) were less affected by processing and long-term f rozen storage (1 year), and the total pigment extracted showed the tendency to increase 17 and 5%, respectively. Rubi and Zeva (late cultivars) suffer ed a decreased trend on the total anthocyanin content of 4% for Rubi and 17 .5% for Zeva. Cyanidin 3-glucoside most easily suffered the degradative rea ctions that take place during processing and the storage period.