Effect of Fortification of Tahini with Natural Plant Origin Raw Materials on Its Bioactivity

Food fortification is a strategic approach to enhance the nutritional quality of food by incorporating bioactive compounds derived from food by-products. The objective of this study was to assess the impact on bioactivity of tahini enriched with a 4% (w/w) lyophilized microwave-ultrasound assisted extract of red grape pomace from the Limnio variety and a 6% (w/w) freeze-dried aquafaba obtained from Lemnian chickpeas of the Panagia variety. The evaluation was conducted through in vitro experiments. The samples under study were extracted by the Bligh and Dyer method and analyzed for their polyphenolic content, as well as for their content in total flavonoids. Assessment of the antioxidant capacity of the extracts was determined in vitro by the ABTS, DPPH, CUPRAC, FRAP and human blood plasma oxidation inhibition (hBPOxi) assays, while the antiplatelet activity of the extracts was determined by the Platelet Activating Factor inhibition assay (PAFi). The bioactivity of fortified tahini (LAC) was increased compared to plain tahini (Control sample). Total phenolics and total flavonoids were increased by 76% and 78%, respectively (10.7 ± 0.2 vs. 6.02 ± 0.3 and 8.5 ± 0.14 vs. 4.76 ± 0.1 μmol Trolox/g, respectively). Antioxidant activities based on ABTS, DPPH, CUPRAC, FRAP and hBPOxi were increased by 101%, 65%, 77%, 73% and 110%, respectively (52.8 ± 0.7 vs. 26.3 ± 0.4; 20.1 ± 1.6 vs. 12.2 ± 0.2; 81.9 ± 0.4 vs. 46.1 ± 2.1; 46.4 ± 4.0 vs. 26.8 ± 0.8; and 12.2 ± 0.9 vs. 5.8 ± 0.2 μmol Trolox/g, respectively), and antiplatelet activity based on PAFi was also increased by 41% (0.19 ± 0.01 vs. 0.32 ± 0.02 mg, respectively). Red grape pomace extract and aquafaba boosted tahini’s in vitro antioxidant and antiplatelet capabilities. The results indicate that the valorization of grape and chickpea processing residuals may reduce waste and improve the nutritional value of tahini. Due to its antioxidant and antiplatelet activities, fortified tahini may contribute to the prevention of chronic diseases where oxidation and thrombosis play critical roles. This study exemplifies sustainable resource use and waste reduction, as well as the importance of circular economy strategies in enhancing diets and human welfare.