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In this work, the effect of Detente Instantanee Controlee (DIC) (French for instant controlled pressure drop) on the total polyphenol, flavonoids, α-tocopherol contents, and antioxidant activities of olive leaves was studied. Olive leaf extracts were pre-treated at one cycle DIC under 0.1 MPa pressure for 11 s and followed by an extraction with 95% ethanol at 55 °C during 3 h. The phenolic compounds, flavonoids, oleuropein, and α-tocopherol contents were determined, showing 66.63 mg gallic acid equivalent (GAE)/g db, 12 mg catechin equivalent (CE)/g db, 43.9 mg/g db, and 0.15 mg/g db for the untreated leaves against 239.37 mg GAE/g db, 28 mg CE/g db, 70.3 mg/g db, and 0.59 mg/g db for DIC-treated leaves, respectively. Therefore, DIC allows more availability of bioactive compounds contributing to a high antiradical activity (DPPH) compared to a synthetic antioxidant butylated hydroxytoluene (BHT). Both extracts showed a total antioxidant capacity (method of phosphomolybdenum) greater than that of the standard BHT. Likewise, both extracts have a reducing power (FRAP test) significant concentration-dependent. The DIC-treated leaves showed a higher antioxidant capacity compared to that of untreated leaves. Thus, DIC could be an effective treatment to promote the extraction of bioactive molecules of high antioxidant activities from olive leaves.

The aim of this investigation is to study the impact of the technology of instant controlled pressure drop: “DIC” on the kinetics extraction of olive leaf ( Olea europaea L.) polyphenols. The conditions of extraction were: ethanol 95%, temperature: 55 °C and ratio r = 40 g g −1 dry basis for 3 h. The extraction kinetics of total polyphenols content (TPC) of DIC-treated and untreated leaves were performed according to the method of Folin–Ciocalteau. The ultra-performance liquid chromatography (UPLC) was used to study the extraction kinetics of seven phenolic compounds of olive leaves: apigenin-7-glucoside, hydroxytyrosol, luteolin-7-glucoside, oleuropein, tyrosol, vanillic acid, and verbascoside. DIC-assisted solvent extraction allowed reducing the extraction time from 120 to 15 min while increasing the extracted yields. Phenomenological analysis of extraction kinetics was determined through the two-stage Coupled Washing/Diffusion CWD kinetic model. DIC texturing could, in favorable cases, increase the starting accessibility and systematically the internal effective diffusivity for phenolic compounds.

In this work, the process of “Detente Instantanee Controlee”: DIC (French for Instant controlled pressure drop) assisted to ethanol solvent extraction of phenolic compounds of olive ( Olea europaea ) leaves was studied. Response surface methodology (RSM) was used to optimize the conditions of solvent extraction carried out on the raw material, as well as the operating parameters DIC texturing taking place as pretreatment; both for getting the highest extraction yields of total phenolic compounds (TPC). The studied parameters were the ethanol concentration in the aqueous solution ( S ), the temperature ( T ) and the liquid/solid ratio ( r ). The maximum yield was 49.84 mg GAE per g of dry raw material, and the optimal conditions were: 95.6% EtOH, 55 °C and 40 ml g −1 dm. Under these optimal solvent extraction conditions of the polyphenols extraction, RSM was also used for optimizing DIC treatment. The total phenolic compounds yield of dry DIC-textured material was higher than that of untreated material with an optimized value of 248.6 mg GAE g −1 at the following conditions: saturated steam pressure: P = 0.1 MPa, number of cycles C = 1 and thermal treatment time t = 11 s. Ultra Performance Liquid Chromatography analysis (UPLC) of the treated and untreated olive leaf extracts revealed that the principal polyphenols were oleuropein, verbascoside, luteolin-7-glucoside and smaller amounts of hydroxytyrosol, apigenin-7-glucoside, tyrosol, vanillic acid and vanillin. Scanning electron microscopy (SEM) showed that, after DIC treatment, there is a change in the structure of olive leaves cells with a destruction of cell walls in comparison with untreated leaves.

The interest of this study is to recover the date's by-products the most common in Tunisia by applying the drying process. The product is getting to be a powder for animal feed. The physicochemical analysis of raw materials showed that dates have a high content of soluble sugars and polysaccharides. The study of dates drying at 50, 60 and 70°C showed that the temperature rises more drying time is reduced. Indeed, dates have initial moisture content of around 0.38kg/kg DM and become stable at the end of drying to moisture content of about 0.15kg/kg DM. The physico-chemical composition of the dates powders at different temperatures show that they are rich in soluble sugars and polysaccharides, high levels of potassium and magnesium and law protein, crude fiber and fat content., L'intérêt de cette étude consiste à valoriser les écarts de triage des dattes (noyau+pulpe) les plus répandus en Tunisie par application du procédé de séchage. Le produit visé est l'obtention d'une farine qui sera destinée à l'alimentation animale. L’analyse physicochimique de la matière première a montré que les écarts de triage des dattes présentent une teneur élevée en sucres solubles et en polysaccharides. L'étude de séchage des dattes à 50, 60 et 70°C a montré que plus la température augmente plus la durée de séchage est réduite. En effet ; les écarts de triage de dattes ont une teneur en eau initiale aux alentours de 0,38 kg/kg MS et deviennent stables à la fin du séchage à une teneur d'humidité de l'ordre de 0,15 kg/kg MS. La composition physico-chimique des poudres de dattes séchées à différentes températures montrent que ces dernières sontriches en sucres solubles et en polysaccharides et ont des teneurs élevés en potassium et en magnésium et présentent des faibles teneurs en protéines, en cellulose brute et en matières grasses.