Kinetics of Carotenoids Degradation During the Storage of Einkorn (Triticum monococcum L. ssp. monococcum) and Breadwheat (Triticum aestivum L. ssp. aestivum) Flours

To evaluate the effect of storage temperature, the degradation kinetics of carotenoids in wholemeal and white flour of einkorn cv Monlis and bread wheat cv Serio, stored at -20, 5, 20, 30 and 38 °C, was assessed by normal-phase HPLC. In Monlis carotenoids content (8.1 and 9.8 mg/kg for wholemeal and white flour, respectively) was eight-fold higher than in Serio (1.0 and 1.1 mg/kg). Only lutein and zeaxanthin were detected in bread wheat, while significant quantities of ( and )-carotene and -cryptoxanthin were observed in einkorn. Carotenoids degradation was influenced by temperature and time, following first order kinetics. The degradation rate was similar in wholemeal and white flour; however, loss of lutein and total carotenoids was faster in Serio than in Monlis. The activation energy Ea ranged from 35.2 to 52.5 kJ/mol. Temperatures not exceeding 20 °C better preserve carotenoids content and are recommended for long-term storage.