The possibility to improve the nutritional value of olive oil by enriching it in phenolic compounds from olive leaves (e.g., oleuropein) by ultrasonic maceration was studied. The experimental design used led to the following optimal extraction conditions: ultrasonic power of 60 W, temperature of 16°C and sonication duration of 45 min. The high total phenolic content (414.3 ± 3.2mg of oleuropein equivalent/kg of oil), oleuropein (111.0 ± 2.2mg/kg of oil) and α-tocopherol (55.0 ± 2.1g/kg of oil) concentrations obtained by optimized ultrasound-assisted extraction (UAE) proved the efficiency of this process when compared with the conventional solid-liquid extraction. Histochemical analyses showed that this efficiency is due to specific alteration of the phenol-containing leaf structures. Furthermore, the radical-scavenging activity of the processed oil (DPPH test) and its stability toward lipid autoxidation (heating test) confirmed its enrichment in antioxidants. Sensory evaluation of the enriched olive oil showed a slight increase in bitterness but an overall acceptability. Finally, the enriched olive oil was characterized by clear green color (L*, a*, b* parameters).

The antioxidant activity of dietary phenols in humans (direct reduction of radicals and other highly oxidizing species) could be largely restricted to fighting postprandial oxidative stress in the gastric compartment. Hence, the development of chemical tests simply modelling this situation is pertinent. In this work, the antioxidant properties of the olive phenols hydroxytyrosol and oleuropein are investigated in pH 5-6 micellar solutions through the reduction of the DPPH radical and the inhibition of the metmyoglobin-induced peroxidation of linoleic acid. In the first test, hydroxytyrosol and oleuropein proved as efficient as common polyphenols and their reactivity was only moderately affected by β-cyclodextrin and bovine serum albumin, taken as models of food macromolecules. In the second test, hydroxytyrosol and oleuropein by themselves came up as relatively weak inhibitors, despite their efficiency at reducing hypervalent haem iron. However, hydroxytyrosol was able to act in synergy with the typical chain-breaking antioxidant α-tocopherol.

The present study aims to valorize the apple peels (AP) and grape seeds (GS) by the fortification of the yogurts using their powder. Firstly, the optimization of the extraction parameters for assessing maximum of total phenolic content (TPC) was achieved. Under the optimized conditions, the experimental maximum yields of TPC were 19.33 ± 2.33 and 240.59 ± 4.77 mg Gallic Acid Equivalents (GAE)/100 g Dry Weight (DW) for AP and GS, respectively, which was in close agreement with predicted values (19.32 ± 0.91 and 242.26 ± 11.08 mg GAE/100 g DW for AP and GS, respectively). The antioxidant capacity of GS extract was better with IC50 of 12.22 ± 0.89 and 225.47 ± 7.10 µg/ml in DPPH and phosphomolybdenum assays, respectively. Besides, powder from these by‐products was incorporated into yogurt samples. The classification test revealed that the yogurt prepared with GS powder was the preferred one. Practical applications Natural products rich in antioxidants are increasingly in demand for their use to preserve, in particular, the perishable foods such as dairy products. Apple and grape are widely consumed fruits and they generate an enormous amount of waste, including peels and seeds. These by‐products are valuable sources of natural antioxidants especially the phenolic compounds. In this line, the present study aims to optimize the extraction conditions to obtain the highest PC from these by‐products. Additionally, a yogurt enriched with AP and GS as natural ingredients with antioxidant virtue was produced.

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.

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Machine learning and mathematical modeling techniques have been conducted to model the thin layer drying kinetics of pea pods, under either microwave or conventional air drying,. The effect of nine different microwave output powers (200-1000 W) and five different ventilated oven temperatures (40, 60, 80, 100, and 120 C) on drying kinetics was studied. The experimental drying rates were fitted to 11 literature semi-empirical models to determine the kinetic parameters, finding the higher goodness-of-fit for the Midilli et al. model (average R 2 = 0.999 for both drying methods). Moreover, the data were modeled using support vector machine (SVM) for regression which was optimized with dragonfly algorithm (DA) technique. The best result was obtained by Gaussian kernel with the optimal parameters σ, C, and ε values estimated as 0.2871, 78.45, and 0, respectively. The small root mean square error (RMSE = 0.0132) and the high determination coefficient (R 2 = 0.9983) values proved how robust the SVM model is. DA-SVM techniques can reliably be utilized to describe the thin layer drying kinetics of pea pods. It is useful to provide models that can assist in the development of food process control algorithms, and provided insights into complex processes, for the technological design of microwave or convective drying for pea pods preservation. Practical applicationsDrying of by-products from pea processing industry was investigated as a critical step prior to their valorization. The drying of pea pods has never been investigated before which is the case of the present study whose objective was to study and model the

The purpose of this review is to compile the literature published about different aspects of microwave-assisted extraction (MAE) use and ultrasound-assisted extraction (UAE) applied on jujube worldwide and to compare the results on the antioxidant activity obtained for each extraction method. As a result of the increased consumers demand for natural products, as well as for those of agro-food, nutraceutical, cosmetic industries, and green extraction techniques are nowadays trending to be potential alternatives that can improve antioxidant yield and its quality from an economical and environmental point of view by reducing time, energy, and solvent consumption. Ultrasounds and microwaves are widely used methods in the extraction of active principles due to their cavitation and dipolar rotation effect, respectively. These two techniques provide efficiency of extraction while minimizing the time and preserving the quality of the food matrix, overcoming the disadvantages of conventional techniques characterized by their consumption of large quantities of solvents and providing a sparse quantity of extraction. Jujube, a shrub with a high antioxidant potential, which can be affected by various extraction conditions can be the target of UAE and MAE to increase the antioxidant extraction yield. Exploiting the beneficial properties such as the antioxidant activity can lead to an industrialization process, replacing therefor synthetic antioxidants with natural compounds. These can also help in the development of new nutraceuticals and can be used, for instance, in agro-food industries as preservatives. Keywords : Microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), antioxidants, Ziziphus lotus (L.) Lam plant.