In this study, different drying methodologies (convective air, oven and microwave) of Myrtus communis L. (M. communis L.) leaves were conducted to investigate their effects on the levels of phenolic compounds, antioxidant capacity of ethanolic extracts (EEs) as well as the soybean oil oxidative stability. Drying methodology significantly influenced the extractability of phenolic compounds. Microwave drying led to an increase in the amounts of total phenols, flavonoids and proanthocyanidins followed by oven drying at 70 °C. Higher temperature of drying (100 and 120 °C) led to a significant reduction of their amounts (p < 0.05). An ultra-performance liquid chromatography method combined with high resolution mass spectroscopic detection was used to analyze the phenolic fraction of extracts. Higher amounts of the identified compounds were observed when leaves were heat treated. Furthermore, the evaluation of the antioxidant activity showed that the studied extracts possess in general high antioxidant capacities, significantly dependent on the employed drying methodology. The incorporation of the different extracts at 200 ppm in soybean oil showed that its oxidative stability was significantly improved. Extracts from leaves treated with microwave (EE_MW) and at 70 °C (EE_70) have better effect than BHT. The results of the present study suggest that microwave drying could be useful to enhance the extractability of phenolic compounds and the antioxidant capacity of M. communis L. leaf extract.

Essential oil (EO) extraction is a widespread practice generating huge amounts of solid plant by-products a potential source of bioactive compounds, on the one hand, and a detrimental risk for the environment that needs to be carefully considered on the other hand. The present study aims to valorize Myrtus communis L. leaf by-products obtained following EO extraction using a steam distillation unit through the recovery of phenolic compounds and the evaluation of their biological activities. The total phenols, flavonoids, and proanthocyanidins contents of the ethanolic extract by-product were higher than the control (leaves without extraction of EO). Their amounts increased from 69.30 to 88.06 mg GAE/g for total phenols, from 36.31 to 70.97 mg QE for flavonoids and from 19.74 to 21.49 mg CE/g of extract for proanthocyanidins. The identification of phenolic compounds by high-performance liquid-chromatography equipped with a reversed-phase (RP-HPLC) system revealed that the by-product sample includes more gallic acid, catechin, syringic acid and luteolin 7-O-glucoside but less p-coumaric acid and kaempferol than the control. Moreover, the mid-infrared spectroscopy (MIR) showed the presence of benzene ring characteristic of phenolic compounds at 756 cm⁻¹, esters of aromatic acids and stretching vibrations of polyphenols at 1141–1234 cm⁻¹, C=C stretching present in phenolic acids such as coumaric acid and catechin at 1604 cm⁻¹. The assessment of antioxidant activity revealed that the ABTS^+• radical scavenging activity was significantly increased, whereas the DPPH^• radical inhibition activity and the ferric reduction antioxidant power were significantly decreased. The results indicated, as well, that Myrtus communis L. leaf by-products maintained a considerable antibacterial activity depending on the tested bacterial strain. Additionally, the anti-α-amylase activity was higher for the Myrtus communis L. leaf by-product extract. Therefore, Myrtus communis L. leaf by-products of EO extraction offer phenolic compounds with significant biological activities, contributing to the sustainable development and the promotion of circular economy by the recovery of valuable inputs from plant by-products.

The production of date paste from second-grade date fruits is a fast-growing industrial activity which promotes more sustainable food systems. The industrial date paste process is mainly dependent on the thermal treatments of hydration and drying that precede flesh crushing. These thermal treatments are commonly performed industrially using steam hydration instead of water soaking and convective hot air drying, which are known to be energy-intensive operations leading to high greenhouse gas emissions. The objective of this work was to optimize, on the one hand, the operations of hydration and drying of dates at an industrial scale using a response surface Box–Behnken experimental design in order to reduce the energy consumption and, on the other hand, to assess the biochemical and microstructural properties of date paste produced under optimized conditions. Optimization was performed based on the measurements of sensory attributes, instrumental texture firmness, moisture content, water activity (a_w), and color parameters (L*, a*, b*), as well as on the energy savings related to the factors of hydration duration and temperature and time of drying. The optimal conditions to ensure the highest quality of the final product and the lowest energy consumption were 9.6 min of hydration at 80 °C and 3 h of drying at 52.28 °C. The biochemical analysis of the date paste produced under the optimized process showed that it is rich in dietary fibers (9.80 ± 2.10%) and total phenols (261 ± 6.2 mg gallic acid equivalent/100 g of extract). Furthermore, the studied sample exhibited a higher antioxidant potential than the raw date material as a result of the heat-inhibitory effect of oxidases. The obtained results suggest that date paste presents a good source of natural bioactive molecules and could potentially be considered as a functional food ingredient. SEM analysis showed that the microstructural properties of date paste produced under optimal conditions may promote its quality preservation during storage.

Argan oil is known wordwide for its nutritional, therapeutic and cosmetic benefits. However, the extraction process produces 40-50% of Argan Press Cake (APC), which is rich in protein, fiber, and minerals. Despite its nutritional potential,the high saponin content of APC imparts a bitter taste and anti-nutritional properties, making it unsuitable for human consumption and often wasted. This study addresses this issue by using boiling treatments with citric acid (CA) and distilled water (DW) to reduce the saponin content, while evaluating the impact on APC quality. In addition , the study explores for the first time, the incorporation of treated argan press cake, APC-CA and APC-DW, at different levels (5%, 10%, 15% and 20%) into whole wheat flour (WWF) for bread production to improve the nutritional profile. The results indicate that both treatments significantly reduce saponin content while maintaining nutritional quality comparable to untreated APC. This includes a 50% reduction in phytic acid levels. The absence of tryptophan fluorescence emission was observed in APC-CA, which may be related to chemical degradation or interactions with other molecules. Substitution of APC-CA and APC-DW increased the protein of composite flours in a level-dependent manner. At substitution levels up to 10%, APC-CA and APC-DW positively influenced the technological properties of the bread. This study demonstrates the potential of APC to improve the nutritional value of bread and supports zero-waste initiatives by reusing by-products.