Effect of processing on the drying kinetics and functional value of dried apricot

Apricots can be considered as a good source of phenolic compounds, which are beneficial for human health. Microwaves may be an alternative to the conventional sun or hot air drying techniques used to obtain dried apricot. Nevertheless, their impact on the functional compounds must be taken into account if they are to be recommended as an attractive drying option. This work compares the drying kinetics and the change in the organic acids, phenolic compounds and antioxidant activity of dried apricot when using hot air drying and microwave energy. Empirical (linear and Page) equations can be used to model the drying kinetics in air, combined air-microwave and microwave processes. From the obtained results, it can be concluded that the industrial processing of dried apricots may be improved by using microwave energy, as the drying time is considerably reduced, and the obtained fruit had a higher phenolic content, particularly of chlorogenic acid, catequin and epicatequin. Nevertheless, as the contribution of these phenols to antioxidant capacity was not significant, microwave dried samples maintained the same antioxidant capacity as the air-dried ones. When sulphite is added previous to the drying processes, care should be taken with the total phenols and the antioxidant capacity quantified as it may interfere with the results depending on the methodology used.

► Microwave is a good industrial alternative to hot air to obtain dried apricots. ► Microwave application reduces drying time and increases apricot phenol content. ► Chlorogenic acid, catequin and epicatequin are the phenols that increased the most. ► The main antioxidants of apricot are caffeic and gallic acids and kaempferol.