The aim of this work was to optimize the conventional parameters for the extraction of phenolic compounds from potato (Solanum tuberosum L.) peels (PP). A central composite design (CCD) was used to establish the impacts of ethanol concentration (%), extraction time (min), and liquid/solid ratio (mL/g). The optimal experimental conditions that maximized extraction were ethanol at a concentration of 80% (v/v) for a time of 150 min with a ratio of 1 g/30 mL. Under optimal conditions, the total phenolic content (TPC) and the total flavonoid content (TFC) were 204.41 ± 8.64 mg GAE/100 g DW and 21.47 ± 0.76 mg QE/100 g DW, respectively. The PP extract had a potent antioxidant capacity tested by phosphomolybdate and DPPH assays with IC₅₀ of 10.65 ± 0.21 and 179.75 ± 3.18 µg/mL, respectively. Furthermore, by fortifying yogurt with PP as a natural ingredient, an improvement ofits physical, nutritional, antioxidant, and sensorial qualities was attempted in this study. The yogurts formulated with PP revealed significantly higher (p ≤ 0.05) TPC, TFC, and antioxidant capacity in comparison with the control sample. In addition, the sensory evaluation showed that the yogurts enriched with PP were preferred over the control yogurt. The results indicate that PP can be considered an interesting byproduct since it can improve the nutritional, bioactive, and sensorial profile of yogurt, highlighting that PP, due to its high phenol content, can substantially improve the antioxidant effect of the new formulated yogurt.

The use of Nigella seeds in the food, pharmaceutical, and cosmetic fields is common, since the iniquity and the virtues of these plants are directly related to their characteristic phytochemical composition. This investigation focused on the comparative study of the botanical aspect, phenolic profile, and in vitro and in vivo biological activities of Nigella sativa L. (NS) and Nigella damascena L. (ND) seeds. The macro- and micro-morphological properties of these seeds were studied, and the key dissimilarities between them were clearly illustrated. The phytochemical contents and phenolic profiles were determined, and the in vitro antioxidant activity was assessed using four methods. The in vivo antioxidant and biochemical parameters of the blood of supplemented mice were determined. The results of the macro- and micro-structure analysis revealed differences between the two plants. Here, ND is characterized by higher phytochemical contents and the best antioxidant activities. The HPLC analysis indicated the presence of nine compounds, namely seven phenolic acids, particularly hydroxybenzoic and caffeic acids, and two flavonoids. The administration of ND extract to mice for 21 days at a concentration of 500 mg/kg allowed a substantial amelioration of plasma antioxidant properties. In addition, the extracts ameliorate blood parameters (cholesterol, triglycerides, glycemia, and urea). Furthermore, the antimicrobial activity of extracts demonstrated their effects on Staphylococcus and Aspergillus. Nigella seeds, in particular ND, expressed considerable in vitro antioxidant properties and demonstrated significant amelioration of mice blood properties. Consequently, these species can serve as a valuable source of compounds with various applications.

Functional ingredients rich in bioactive compounds can be added to conventional ingredients for the formulation of food to increase its nutraceutical potential. Three prickly pear parts, namely flowers, seeds, and seed cake were utilized in the current work as natural antioxidant resources. The flower extract gave the best amounts of antioxidants as estimated by spectrophotometric methods, which were 68.08 mg GAE/100 g DM for total phenolics; 6.91 mg QE/100 g DM for total flavonoids; 13.05 mg QE/100 g of DM for flavonols; and 0.22 mg/100 g of DM for condensed tannins. The three extracts showed a high proportion of antioxidant effect as determined by DPPH, ABTS, FRAP, and TAA in vitro assays. Chemical analysis and sensory testing were performed on biscuits that were made by adding powdered flowers, seeds, or seed cake. The biscuits made from the seed cake gave a higher protein content (83.97 mg/100 g) and the biscuits made from the seeds had the best ash concentration (3.21%), while the biscuits containing flower powder had the highest anti-radical activity (81.04%). Sensory analysis disclosed the preference for biscuits formulated with flowers or seeds (80%) by the experts. These findings demonstrated that the nutritional value of the biscuits was improved by their enrichment with cactus parts powders, and they were appreciated by tasters.