Kinetics of tocols degradation during the storage of einkorn (Triticum monococcum L. ssp. monococcum) and breadwheat (Triticum aestivum L. ssp. aestivum) flours

The kinetics of tocols degradation in wholemeal and white flours from einkorn cv Monlis and bread wheat cv Serio were studied during storage at five different temperatures (-20, 5, 20, 30 and 38 °C) up to 242 days. Tocols decreased as a function of time and temperature, following a first order kinetics. Degradation rates and their dependence from temperature were similar for the two Triticum species studied. Tocols decrease was quicker in white flour than in wholemeal flour (on average for total tocols at 38 °C k = 7.79 x 10-3 days-1 vs 3.15 x 10-3 days-1, respectively). The temperature-dependent degradation was similar for all homologues (Ea = 34.3 – 49.4 kJ/mol) except for -T, less thermostable in white flours (Ea = 61.2 kJ/mol in einkorn and Ea = 54.7 kJ/mol in bread wheat). The results clearly indicate that storing flours under refrigeration or at temperatures not exceeding 20 °C better preserved their tocols content.