Influence of kernel thermal pre-treatments on 5-n-alkylresorcinols, polyphenols and antioxidant activity of durum and einkorn wheat

Nowadays by-products and waste originated from agro-food processes are considered a source of bioactive molecules. The recovery of the greatest amount of these compounds using advantageous processes is important from an economic perspective. In this work, three different thermal pre-treatments, i.e. hydrothermal, hot air-drying (at three different temperatures) and freeze drying, were applied on intact kernels of durum and einkorn wheat to investigate their effects on the recovery and on the homologue chains composition of alkylresorcinols (AR), on total soluble phenolic (TSP) compounds and on total antioxidant capacity (TAC). The results of this preliminary study showed that thermal processing generally improved AR extractability and caused changes in AR homologue composition, whereas a decrease in TSP content was observed in both wheat species. TAC was not affected by the treatments, suggesting that other antioxidant compounds besides TSP contribute to the total antioxidant capacity of wheat. These findings indicate that just modulating the physical parameters of the thermal pre-processes, it could be possible to promote the recovery of specific bioactive compounds most involved in the biological activities.