TUN Effect of Pepper Genotype and Processing Conditions on Phytochemical Composition and Antioxidant Activity of Tunisian Harissa

Abstract

Harissa, a traditional Tunisian red pepper paste, is widely appreciated for its sensory attributes and potential health benefits linked to its rich phytochemical composition. This study investigated the combined effects of pepper genotype (local vs. hybrid) and processing conditions on physicochemical properties, phytochemical content, and antioxidant activity of harissa. Two types of harissa were produced: LTH (local traditional harissa) and HTH (hybrid traditional harissa). Physicochemical analysis revealed no significant differences in pH (4.96) and titratable acidity (0.14%) between samples, while LTH exhibited higher total soluble solids and slightly greater ascorbic acid content. Phytochemical analysis showed that LTH had significantly higher total phenolic (325.74 ± 20.55 mg GAE/kg FW) and carotenoid contents (573.95 ± 10.11 mg β-CarE/kg FW) compared to HTH (270.42 ± 20.66 mg GAE/kg FW and 541.88 ± 8.61 mg β-CarE/kg FW, respectively), indicating better preservation of heat-sensitive bioactive compounds under milder processing conditions. In contrast, HTH demonstrated significantly higher hydrophilic and lipophilic antioxidant activities, suggesting that more intense processing may enhance antioxidant capacity through the formation of new antioxidant compounds or improved extractability. These findings highlight the complex interplay between raw material and processing conditions in determining the functional quality of harissa. Optimizing processing parameters may therefore allow for improved retention of bioactive compounds while maintaining or enhancing antioxidant functionality.