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).

Herein is described a green and original alternative procedure for the extraction of oil from microalgae. Extractions were carried out using terpenes obtained from renewable feedstocks as alternative solvents instead of hazardous petroleum solvents such as n-hexane. The described method is achieved in two steps using Soxhlet extraction followed by the elimination of the solvent from the medium using Clevenger distillation in the second step. Oils extracted from microalgae were compared in terms of qualitative and quantitative determination. No significant difference was obtained between each extract, allowing us to conclude that the proposed method is green, clean and efficient.

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This study aims total valorization of rosemary for food applications, moving toward developing an original biorefinery concept using solar steam distillation (SSD) to extract essential oil while preserving active compounds in the raw material, mainly antioxidants, for a further extraction. The deodorization process is important to avoid the extraction of antioxidants with strong aromas which limit their utilization for food preservation. The SSD process was compared with conventional steam distillation (CSD) for essential oil extraction as well as deodorization of dried rosemary leaves. The treated leaves were recovered afterward for the extraction of antioxidants by solvent extraction to recover rosmarinic, carnosic, and ursolic acids. With standard protocol extraction and analysis, the antioxidants seem to be mostly preserved by SSD rather than by CSD. The Folin–Ciocalteu reagent was used to determine the polyphenol content, whereas diphenylpicrylhydrazyl (DPPH) was used to analyze the antiradical properties. It was found that both the polyphenol content and antioxidant activity were preserved after SSD. Scanning electron microscopy (SEM) and fluorescence microscopy showed complete destruction of glandular trichomes for both processes, which indicates that the extraction of essential oil was complete. Overall, the results specify clearly that solar steam distillation (SSD) is a green alternative, an efficient and economical process for essential oil extraction and leaf deodorization.

Sea buckthorn (SBT) pomace, a by-product of juice production, has been studied as a potential carotenoids source because such compounds are of great interest in the food industry. Ultrasoundassisted extraction (UAE) has been used to improve the direct enrichment of edible oils (sunflower, rape seed, olive, and soya) with SBT carotenoids. These oils do not naturally contain carotenoids. After a preliminary study, a RSM has been used to maximize total carotenoid content of extracts and the influence of process variables on the UAE has been investigated. The results provided by the statistical analysis revealed that the optimized conditions were: sonication power of 0.67 W/g oil and a temperature of 358C. The optimization parameters of this ''green'' process provide a greatly improved enrichment of the edible oil in terms of quantity and process time from 33.83 mg/L extract in 90 min obtained by conventional extraction to 51.64 mg/L extract in only 20 min by UAE. Ultrasound-assisted carotenoids extraction from SBT by-products appears to be a simple, rapid, and sustainable alternative to conventional procedures.Practical applications: Improving the value of low quality edibles is important for the food, cosmetic, or nutraceutical industry. It is done by adding ingredients such as carotenoids which are extracted by hexane or other solvents. In this study we show an innovative application of a direct extraction by maceration of by-products in edible oil without solvent and eliminating evaporation and extraction unit operations. Using ultrasound, full extractions can now be completed in minutes with high reproducibility, reducing the consumption of solvent, simplifying manipulation and work-up, giving higher purity of the final product, eliminating post-treatment of waste water, and consuming only a fraction of the fossil energy normally needed for a conventional extraction method such as Soxhlet extraction, maceration, or steam distillation.