Thermal behavior of raspberry and blackberry seed flours and oils

This survey was conducted on thermal properties of flours obtained by grinding of blackberry (Rubus fruticosus L., Čačak Thornless cultivar) and raspberry (Rubus idaeus L., Willamette cultivar) seeds, as well as oils extracted from berry seeds. Thermal behavior and stability of berry seed flours were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). Crystallization and melting points of oils were determined using a conventional and modulated DSC techniques. Oils present in the blackberry and raspberry seeds start melting (Ton) at −24.02 and −26.44 °C, respectively. Both berry seeds thermo-oxidatively decompose at temperatures above 210 °C. Thermo-oxidative decomposition of these seed flours takes place in two stages, as TG/DTG curves have two thermal decomposition steps. Polymorphism was detected in both seed oils during heating.