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Carob molasses is widely consumed in many Mediterranean countries, including Tunisia where it is known as ‘Rub El Kharroub’. The main objective of the present study was to evaluate the physicochemical properties and biological activities of both commercial and homemade Tunisian carob molasses. The physicochemical characterization revealed that the main parameters (color and HMF concentration) were related to non-enzymatic browning reactions occurring during juice concentration. The phytochemical analysis proved that the presence of bioactive compounds (volatile compounds, phenolic substances and products of non-enzymatic browning reactions) in carob molasses samples justify their biological effects (antioxidant and antibacterial activities). Accordingly, such characteristics may qualify Tunisian carob molasses (both homemade and commercial) as nutritious and healthy food that could be directly consumed or used a functional ingredient in food and pharmaceutical industry.

The aim of this study was to investigate the phytochemical composition and biological properties of Tunisian propolis from four different regions: Kasserine, Béja, Kèf and Monastir. Ethanolic extracts of propolis were prepared using two extraction methods; solvent and ultrasonic extraction. Total phenolics, flavonoids, ABTS free radical and hydroxyl radicals scavenging abilities, anti-inflammatory, anti-hypertensive, as well as antimicrobial activities of propolis extracts were determined. Identification and quantification of phenolic and flavonoid compounds were performed by using both HPLC-UV and HPLC-ESI-MS. The results revealed high contents of total phenolics and flavonoids and polyphenols extraction was more efficient by sonication. Caffeic acid phenethyl ester (CAPE), galangin, and genistein were the major identified compounds. Antihypertensive activity, evaluated in propolis extracts for first time by HPLC-UV, was higher than 90% for all extracts. Tunisian propolis is an important natural source of polyphenols and flavonoids. The best extraction method was ultrasonic for antioxidants and most of biological activities; conventional method seems to be more suitable for anti-inflammatory activity. Propolis from Béja contains the highest amount of antioxidants and have a stronger potential biological activities. Tunisian propolis could be, therefore, a promising raw material for food and pharmaceutical industry.

Background: This study investigated the amino acids, phenolic compounds and volatile compounds in Maazoun melon seeds. The functional properties of melon seed flour, such as bulk density, swelling capacity, emulsifying capacity, and foaming capacity were also determined.; Results: The findings proved that the functional properties of melon seeds make them useful for incorporation into different food formulations to improve their functionality. The determination of the amino acid composition of melon seeds showed that glutamic acid (205.23 g kg-1 ), arginine (130.44 g kg-1 ), and tryptophan (129.91 g kg-1 ) were the major amino acids of the protein fraction. Chromatographic analysis indicated that phenolic acids (47.78%) constituted the main phenolic class, followed by flavonoids (27.15%). Naringenin-7-O-glycoside and gallic acid were the most abundant phenolic compounds. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses of the volatile compounds demonstrated that esters and terpenoids were the main volatile groups. The study of histological structures showed that melon seeds consist of three distinguishable parts: tegument, endosperm cells, and almond.; Conclusion: The results obtained revealed that melon (Cucumis melo L.) seeds may be a potential source of bioactive compounds and natural substances with nutritive value and functional properties of interest to industrial applications. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

Microwave power effects (100, 300 and 450 W) on drying kinetics of green peas at an initial 3.06 kg water/kg DM (76.2% wb) was investigated. The density level of microwave power (W/g DM) affected the drying kinetics, bioactive substances and green peas color. The parabolic model was found to be the best in matching the experimental data of green pea drying kinetics. It is well known that microwave drying is mainly due to Darcy's law with the gradient of total pressure as the driving force. Thus, this parameter was used to identify the drying operation as being controlled by effective moisture diffusivity. The values obtained ranged between 1.69 and 5.36 × 10−9 m2/s. The activation energy was determined as 1.38 kW/kg, using the modified Arrhenius equation. Application of high microwave power resulted in decreased L* and b* values, and an increase of a* values. The LC-ESI-MS analysis of peas extracts led to the identification of 7 phenolic acids and 8 flavonoids. Interestingly, peas dried at 100 W had the highest phenolic content as well as the highest DPPH• radical-scavenging activity.

The feather is a valuable protein resource. The feather is the major waste by-product resulting from the poultry processing plants. Therefore, increasing the values of poultry feather waste has a significant effect in the environment. In this study, the physicochemical and functional properties as well as the antioxidant activities of the feather protein hydrolysates (FPHs) obtained by acid hydrolysis after 100 min (FPH100), 200 min (FPH200) and 300 min (FPH300) were investigated. The results showed that FPH100, FPH200 and FPH300 presented high protein content 74.04%, 71.05% and 73.94%, respectively. All FPHs had a good solubility and possessed some interfacial properties, governed by their concentrations. The antioxidant activities of the different FPHs were evaluated using various in vitro antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, total antioxidant capacity, reducing power and β-carotene bleaching. FPH100 generally showed a greater antioxidant activity across all the considered methods. The DPPH IC50 of FPH100 values were found to be 0.47 ± 0.011 mg/mL. Moreover, the FPH100 exhibited notable total antioxidant capacity and strong reducing power. Our results suggested that FPHs could be a new potential source for preparing natural antioxidants applied in food, pharmaceutical and cosmetic preparations.

The aim of this work is to establish a comparative investigation of the effect of different drying processes: microwave dehydration (100–600 W), air drying (40–60 °C) and infrared drying (40–60 °C) on drying kinetics and on the main quality attributes (color, total phenols and flavonoids contents, water and oil retention capacities) kinetics’ of lemon (Citrus limon. v. lunari) peels. The experimental drying kinetics’ of lemon peels were fitted to nine thin layer drying models. The Midilli and Kucuk model showed a better fit to experimental drying data for the three drying processes. Microwave drying at 450W preserved the maximum phenols (1.855 ± 0.016 g CAE/100 g DM) and flavonoids (0.802 ± 0.072 g RE/100 g DM) contents respectively. An increase of phenol content was noticed after 9, 13 and 14 min of microwave drying at 600, 450 and 300 W and after 156, 102 and 54 min of infrared drying at 40, 50 and 60 °C. A first-order kinetic model adequately fitted, at the beginning of drying processes, the change of total phenols and flavonoids contents. Total color difference (ΔE) increased progressively with increasing drying time and temperature or microwave power level. ΔE showed a zero-order model whatever the applied drying process. Water retention capacity (WRC) of dried lemon peels decreased during drying processes. However, infrared and microwave drying increased the oil retention capacity (ORC) of lemon peels. The WRC and ORC followed first-order kinetics during air drying and a second order polynomial model during microwave and infrared drying processes.

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.

Studies were conducted on the chemical composition of melon (Cucumis melo L.) seeds, Maazoun variety. Melon seeds were found to contain (on a dry weight basis): moisture (7.16%), oil (30.65%), protein (27.41%), ash (4.83%), carbohydrate (29.96%), fibers (25.32%) and considerable amounts of antioxidant substances as phenolic compounds. The major mineral elements were: potassium, magnesium and calcium. The chemical composition of oil extracted from melon seeds was investigated. The main fatty acids of melon seed oil were linoleic acid and oleic acid. The chromatographic analysis of phenolic compounds showed that flavonoids were the most important group with predominance of amentoflavone (32.80 μg/g). Besides, melon seed oil presented considerable amounts of phytosterols in which β-sitosterol was the major sterol accounting for 206.42 mg/100 g. The seed oil was also found to be rich in tocopherols with a predominance of β+γ-tocopherol fraction. The obtained results revealed that melon seeds presented an alternative source of plant oil which may serve as raw material for food applications.

Tunisian carob pods were used to produce molasses and powders, which were then analyzed for their composional and functional properties. Molasses were made from carob juice by boiling until three different concentrations (60, 70 and 80 °Brix), while powders were prepared by microwave drying of the by-product derived from carob molasses processing at three power levels (100, 300 and 600 W). Results showed that the processed carob products exhibited interesting characteristics. Carob molasses were characterized by important reducing sugars content, dark color and functional properties with high antioxidant activity and emulsifying capacity. On the other hand, carob powders were characterized by high levels of dietary fibers, brown color and water/oil retention capacity. This study provides, for the first time, a potential valorization of the carob by-product into powder and highlights some functional properties of carob products required by food industry.

This work deals with the economic valorization of orange industry by-products by intensification of both drying kinetics and extraction of phenolic compounds of orange peel using the instant controlled pressure-drop DIC technology. DIC treatment is usually performed on partially dried samples. It starts with a heating/pressurizing stage for a short thermal treatment time to end by an instant depressurization towards a vacuum. In the present case, orange-peel was DIC-textured to be airflow oven dried at 40 °C, 2 m s−1, and 265 Pa of vapor as relative humidity, to reach a final moisture of about 0.05 g H2O/g db. By assuming this operation as shrinkage-free with conditions of Negligible External Resistance (NER), the Coupled Washing/Diffusion (CWD) was applied as phenomenological drying kinetic model, and its effects were perceptively identified through the starting accessibility (δWs) and the effective diffusivity Deff of water within the textured material. DIC-texturing was also recognized as a pretreatment possibly able to improve the solvent extraction of phenolic compounds. Four phenolic compounds were identified by HPLC assessments; namely hesperidin, rutin, flavone, and naringin. DIC allowed growing them from 12.10 to 65.01 (537%); from 11.47 to 27.10 (236%); from 0.006 to 0.007 (117%); and from 0.0002 to 0.00032 (160%) mg/g db, respectively. This highly significant increase of availability of these active molecules should be correlated with the presence of broken-wall cells, which Scanning electron microscopy (SEM) later, revealed and confirmed.

This study aimed to evaluate the characteristic features, phenolic compounds and thermal analysis of melon seed oil (Maazoun variety), in order to determine its potential applications in food or pharmaceutical industries. The physicochemical properties of the seed oil revealed a high degree of unsaturation. The average contents of carotenoid and chlorophyll were 2.43 mg/kg and 5.70 mg/kg, respectively. The main fatty acids of melon seed oil were linoleic acid (68.98%) and oleic acid (15.84%), which makes this oil nutritionally valuable. Furthermore, trilinolein (LLL), accounted for 28.99% and constitutes the most abundant triacylglycerol. A chromatographic analysis showed that amentoflavone and luteolin-7-glycoside were the major phenolic compounds. A thermal analysis of melon seed oil was performed by differential scanning calorimetery (DSC). The results of sensorial properties indicated that melon seed oil is appreciated by tasters. The findings suggested that because of its composition, melon seed oil could be used successfully as an alternative source in the food and nutraceutical industries as a functional ingredient. El objetivo de este estudio fue la caracterización, evaluación de compuestos fenólicos y el análisis térmico del aceite de semillas de melón (variedad Maazoun), con el fin de conocer sus potenciales aplicaciones en la industria alimentaria o farmacéutica. Las propiedades fisicoquímicas del aceite de semilla mostraron un alto grado de insaturación. El contenido promedio de carotenoides y clorofila fue de 2,43 mg/kg y 5,70 mg/kg, respectivamente. Los principales ácidos grasos del aceite de semilla de melón fueron el linoleico (68,98%) y oleico (15,84%), lo que hace que este aceite sea nutricionalmente valioso. Además, la trilinoleína (LLL) que representó el 28,99% constituye el triacilglicerol más abundante. El análisis cromatográfico mostró que amentoflavona y luteolin-7-glucósido eran los principales compuestos fenólicos. El análisis térmico del aceite de semilla de melón se realizó mediante calorimetría diferencial de barrido (DSC). Los resultados de las propiedades sensoriales indicaron que los catadores aprecian el aceite de semilla de melón. Los hallazgos sugieren que, debido a su composición, el aceite de semilla de melón podría utilizarse con éxito como una fuente alternativa en la industria alimentaria y nutracéutica como ingrediente funcional.

This study focused on the formulation of food products, based on sesame and carob. The possibility of developing blends from sesame paste and carob molasses, using molasses concentrations of 30, 40 and 50%, at 60, 70 and 80°Brix, respectively, has been studied. The blend prepared with 50% carob molasses at 60°Brix was found to be the most acceptable product, according to a sensory acceptability test. Sesame paste, supplemented with carob molasses, was evaluated for physical quality (oil separation, colour and texture) and nutritional composition (moisture, sugar, protein, fat, ash and polyphenols). Physical analysis showed that the addition of carob molasses to sesame paste improved its emulsion stability, changed its colour from beige to brown and modified its texture from fluid to solid. Nutritional analysis proved that mixing sesame paste with carob molasses provided a natural product, characterized by interesting nutritional value (protein: 16.97 g/100 g fry matter, fat: 12.05 g/100 g fry matter and sugar: 9.34 g/100 g fry matter), arising from the constituents of the two ingredients. Thus, the developed blend could offer a promising nutritious and healthy foodstuff to consumers.

Background Proteases are hydrolytic enzymes that catalyze peptide linkage cleavage reactions at the level of proteins and peptides with different degrees of specificity. This group draws the attention of industry. More than one protease in three is a serine protease. Classically, they are active at neutral to alkaline pH. The serine proteases are researched for industrial uses, especially detergents. They are the most commercially available enzyme group in the world market. Overall, fungi produced extracellular proteases, easily separated from mycelium by filtration. Results A new basidiomycete fungus CTM10057, a hyperproducer of a novel protease (10,500 U/mL), was identified as Pleurotus sajor-caju (oyster mushroom). The enzyme, called SPPS, was purified to homogeneity by heat-treatment (80 °C for 20 min) followed by ammonium sulfate precipitation (35–55%)-dialysis, then UNO Q-6 FPLC ion-exchange chromatography and finally HPLC-ZORBAX PSM 300 HPSEC gel filtration chromatography, and submitted to biochemical characterization assays. The molecular mass was estimated to be 65 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Native-PAGE, casein-zymography, and size exclusion by HPLC. A high homology with mushroom proteases was displayed by the first 26 amino-acid residues of the NH2-terminal aminoacid sequence. Phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP) strongly inhibit SPPS, revealing that it is a member of the serine-proteases family. The pH and temperature optima were 9.5 and 70 °C, respectively. Interestingly, SPPS possesses the most elevated hydrolysis level and catalytic efficiency in comparison with SPTC, Flavourzyme® 500 L, and Thermolysin type X proteases. More remarkably, a high tolerance towards organic solvent tolerance was exhibited by SPPS, together with considerable detergent stability compared to the commercial proteases Thermolysin type X and Flavourzyme® 500 L, respectively. Conclusions This proves the excellent proprieties characterizing SPPS, making it a potential candidate for industrial applications especially detergent formulations.

The hyperlipidemia is a serious health problem that increases the risk of many complications including cardiovascular disease. This study aims to evaluate the possible antihyperlipidemic effects of the feather protein hydrolysate (FPH) in a mice fed with a high‐fat diet (HFD)‐fed mice during 5 weeks. The FPH administration improved dose‐dependent lipid profile, as well as the liver and renal dysfunction indices in hyperlipidemic mice. The FPH also restored the antioxidant status in liver, kidney, and heart by lowering the lipid peroxidation and enhancing the antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase [SOD]). Moreover, the histological studies proved that FPH administration prevents hepatic steatosis, glomerular hyperfiltration risk, and cardiac muscle hypertrophy. Accordingly, the FPH is a promising novel medicinal ingredient for possible use in the hyperlipidemic treatment and related complications.

Combined osmotic dehydration (sucrose solution: 50–70 % w/w, 30–50 °C for 2 h followed by air drying at 40 and 60 °C) is an appropriate process for preservation of oil retention capacity, lightness and yellowness of lemon peels (Citrus limon. v. lunari). Incorporation of sugars to lemon cuboids pieces increased drying rate during the first falling rate phase of the air dehydration step and improved their color stability. Osmotic dehydration process allows protective effect against further total phenol loss during air drying: significant loss of total phenol content (70–80 %) was recorded during osmotic dehydration and then it remains constant during air drying at 40 and 60 °C. For the investigated temperature of osmotic pre-treatment (30–50 °C), water retention capacities were reduced by up to 70 % and were maintained constant during air drying.

Biological silages were prepared from shrimp head and octopus viscera by-products recuperated from the Tunisian seafood industry. Physical and biochemical changes and microbiological profiles were determined for raw materials during fermentation and on end products. Results showed that biological silage significantly affected (P

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.

The Municipal Solid Waste of Agareb (Sfax –Tunisia), characterized by high organic fraction and moisture contents is the most worrying pollution source that must be managed by innovative treatment and recycling technologies. Bio-drying, as a waste to energy conversion technology, aims at reducing moisture content of this organic matter. This concept, similar to composting, is accomplished by using the heat generated from the microbial degradation of the waste matrix, while forced aeration is used. The purpose of this work was to reduce the moisture content of the waste, by maximizing drying and minimizing organic matter biodegradation, in order to produce a solid recovered fuel with high calorific value.Keywords: Municipal solid wastes; organic matter; biodrying; composting; energy recovery.

To explore the efficiency of xylitol chewing gum enriched or not with remineralizing agents to protect tooth against cariogenic biofilm formation and demineralization. Six groups of chewing gums were prepared; Group 1: isomalt (1.8%), Group 2: casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (3%) + isomalt (1.8%), Group 3: hydroxyapatite (HAP) (2.5%) + isomalt (1.8%), Group 4: xylitol (1.8%), Group 5: CPP-ACP (3%) + xylitol (1.8%) and Group 6: HAP (2.5%) + xylitol (1.8%). The antibiofilm properties of different chewing gum extracts using seven oral bacterial species including Streptococcus mutans, Streptococcus constellatus, Streptococcus Salivarius and Streptococcus oralis were explored via the crystal violet staining assay. The remineralizing effects of those products were assessed on thirty human permanent teeth, half-protected with varnish before chemical erosion and thermocycling process with chewing gum. Remineralization was evaluated using scanning electron microscopy and microscopic measurements on polarized light microscopy. The ratio R comparing the thickness between unvarnished and varnished sides was evaluated. While the minimum biofilm inhibitory concentration (MBIC50) was low for xylitol alone compared to isomalt, it was inconsistent when enriched with remineralizing agents. The minimum biofilm eradication concentration (MBEC50) was low for xylitol groups compared to isomalt, for all the studied strains. R was significantly lower in Group 1 and Group 2, while Group 6 showed the highest ratio. Xylitol chewing gums confirmed good antibiofilm properties and showed remineralized potential on eroded teeth. When xylitol is associated to CPP-ACP or HAP, antibiofilm activity decreased while remineralization of eroded teeth increased.

Phenolic compounds are secondary plant metabolites which provide defense to plants against oxididizing agents and free radicals.

This investigation examines and compares the water sorption isotherms and the thermodynamic properties of two pharmaceutical preparations (Hypril and Azix) intended to be manufactured with the same process plant and equipment. The moisture equilibrium isotherms were determined at 50, 60 and 70 °C using a gravimetric technique. Five isotherm models were explored for their fitting to the experimental data. Azix showed sigmoid type II isotherms while Hypril showed type III isotherms according to the BET classification. All investigated models fitted well the water sorption isotherms of Hypril. By contrast, only GAB and Adam and Shove equations gave appropriate fit to the experimental data of Azix. For both formulations, the isosteric heat and the differential entropy decreased sharply with the increase of equilibrium moisture content to minimum values and thereafter remain constant. In the case of Azix, the integral enthalpy decreased with equilibrium moisture content while the integral entropy increased until reaching a constant value. Contrariwise, Hypril showed decreasing of the integral enthalpy and entropy with the equilibrium moisture content. Keywords: sorption isotherm, enthalpy, entropy, spreading pressure, pharmaceutical formulations

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 present work examined the effect of air drying conditions on drying kinetics of cactus/brewer's grains mixture fermented with Lactobacillus plantarum HG328248. The drying kinetics was performed in a convective dryer for three air temperatures (40, 50 and 60 °C) and three air velocities (0.7, 1.0 and 1.3 m/s). Four mathematical models were tested to fit the drying curves. The Page model seemed the most appropriate to describe experimental data. The experimental drying curves showed two periods: that at constant rate and that of falling rate. The air temperature was the main factor in controlling the drying rate. The characteristic drying curve equation was determined. The influence of air drying conditions on color, water activity and microbiological quality of the fermented product was also studied. The temperature affected these parameters more significantly than air velocity. All dehydrated products had a satisfactory microbiological quality and consequently could be introduced in ruminant feed.

The sorption isotherms give information about the interaction of biopolymers with water vapor. These isotherms are extremely important in the modeling of the drying processes and in the prediction of the humidity changes during the product storage. An analytical expression for modeling of water vapor sorption isotherms of agricultural products was developed using the statistical physics formalism. The statistical model was further used to fit and interpret desorption isotherms of Tunisian olive leaves and some food products. In this model, five parameters in relation to the desorption process intervene, such as the number of water molecules per site n, the receptor sites density N M , the energetic parameters a 1 and a 2, and the number of multilayers N 2. The fitting results are discussed to explain the behavior of different parameters versus temperature. The statistical model was used to investigate thermodynamics functions that govern in the desorption mechanism, such as entropy, internal energy, and G...

The work was planned to produce dietetic dehydrated strawberries with application of ultrasound osmotic dehydration (UOD) as pretreatment. A Box-Behnken design (BBD) were employed to characterize the UOD strawberry process, optimize and investigate the effect of independent variables like ultrasound time (10, 20 and 30 min), concentration of osmotic solution (distilled water, 32.5 and 65 °Brix) and temperature (20, 30 and 40 °C) on the water loss (WL), solid gain (SG) and weight reduction (WR). The same BBD were used to estimate the main effects of OD without ultrasound treatment. A multi-criteria optimization based on maximal possible values of WL and WR and minimal value of SG was achieved. This was 20.5 min of ultrasound time, 47.5 °Brix osmotic solution concentration and 31 °C medium temperature. The effects of UOD carried out under the optimized operating conditions on kinetics of convective air drying of strawberry at 40, 50 and 60 °C, and velocity of 1 m/s, using the phenomenological model of Coupled Washing/Diffusion (CWD). Starting accessibility, moisture effective diffusivity Deff value and activation energy (Ea) were calculated from similar-Fick’s law and analogous Arrhenius equation, respectively with and without shrinkage correction. Color difference, Chroma and hue angle of fresh and UOD-air dried strawberries were evaluated. Quality attributes were estimated through the assessment of the phenolic content, antioxidant activity, rehydration capacity, and X-ray powder diffraction characteristics.

Poultry feather keratin is the most important by-product from the poultry industry due to its abundance. Different methods have been still applied to process this by-product such as enzymatic hydrolysis which is expensive and inapplicable at the industrial level. This paper presents a study of acid hydrolysis of poultry feathers using different types of acids, sulphuric acid concentration, different temperatures and solid to liquid ratio to obtain a liquid product rich in peptides. The feathers analysis revealed a crude protein content of 88.83%. A maximum peptides production of 676 mg/g was reached using sulphuric acid, 1 molar acid concentration and 50 g/l solid to liquid ratio at a temperature of 90 °C after 300 min. A reaction scheme for protein aggregation and decomposition to polypeptides and amino acids was proposed and a kinetic model for peptides production was developed. The proposed kinetic model proved to be well adapted to the experimental data with R 2 = 0.99.

The aim of this work is to investigate the phytochemical composition and functional properties of the melon peels, considered as a by-product. Melon peels (maazoun cultivar) are rich in nutritional ingredients such as carbohydrates (69.77%) and ash (3.67%). They contain significant amounts of total dietary fibers (41.69%) and antioxidants as polyphenols and flavonoids (332mg/100g extract and 95.46mg/100g extract, respectively). The identification and the quantification of the phenolic compounds of melon peels were performed by high performance liquid chromatography apparatus. The obtained results indicate that hydroxybenzoic acids and flavones constitute their main phenolic classes. 3-Hydroxybenzoic acid is the major phenolic compound in the melon peels by 33.45mg/100g, followed by apigenin-7-glycoside (29.34mg/100g). Determination of the functional properties (water and oil retention capacities) and color shows that melon peels have properties that may be useful in industrial applications.

The aim of this work is to investigate the effect of microwave dehydration (100, 180, 300, 450 and 600 W) on the physico-chemical (shrinkage, total phenols and color) and technological properties (water and oil retention capacities) and the drying behaviour of three citrus peel cultivars (thompson navel, mandarin and lemon). The fresh citrus peel of thompson navel, mandarin and lemon are characterized by high moisture (3.140 ± 0.159; 3.798 ± 0.070 and 3.010 ± 0.143 kg water/kg db) and fiber (41.644 ± 1.891; 27.894 ± 2.358 and 39.135 ± 1.250 g/100 g db) contents. As excepected, whatever the citrus cultivar, the microwave power level has a significant effect on drying time of the citrus peel (drying time ranges from 51.5 ± 2.828 min to 79 ± 0.707 min at 100 W and from 8.75 ± 0.353 min to 12 ± 0.707 min at 600 W). Shrinkage of volume does not depend on the peel cultivar variety and on the microwave drying level but on the quantity of evaporated moisture. Microwave drying induces a significant increase of the water retention capacities of the three citrus peels. The microwave powers lower than 450 W were in favour of the best water retention capacities. Microwave drying decreases significantly the oil retention capacities of all citrus peels and the total phenolic contents of mandarin and lemon peels. The maximal peel phenolic contents were preserved for drying microwave power higher than 450 W. Also, microwave drying does not have a significant effect on color parameter (L*, a*, b*) of thompson and mandarin peels howerver it induces a significant decrease of the parameter b* and an increase of the global color difference, ΔE, of lemon peels.

The aims of this work were to determine chemical composition and sorption isotherms of Tunisian orange peel and leaves of the “Maltaise” variety. These by-products were found to be rich in fibre, soluble sugars, protein, minerals and phenols. The equilibrium moisture contents of “Maltaise” peel and leaves were measured using the static gravimetric method at three temperatures (40, 50 and 60 °C) and in wide range of water activity (0.109–0.891). Desorption and adsorption data of peel and leaves were best fitted by the Peleg model at 40, 50 and 60 °C. The net isosteric heats of desorption and adsorption were determined from sorption isotherms. For both peel and leaves, the net isosteric heat of desorption was higher than the net isosteric heat of adsorption and both decreased continuously with increasing of the equilibrium moisture content.

International audience; A selective supercritical CO(2) extraction process has been developed in order to extract selectively the vegetal oil and the essential oil from coriander seeds in a consecutive way by tuning experimental conditions. A 4-step process has been set up: (i) seeds preparation by grinding and sieving, (ii) extraction by supercritical CO(2) and (iii; iv) selective separation in two separators with different pressure levels. The first part of this study consisted in studying the effects of the operating conditions (T, P, CO(2) density, flow rate and particle size distribution of ground seeds) on the yield of extraction. The results showed that the global performance of the process depends mainly on the pressure level of extraction, on the CO(2) flow rate and on the size of the ground seeds. An optimization of the parameters led to an extraction ratio of 90%. The second part of this study dealt with the effects of the operating conditions on the quality of extracts, and more precisely on their composition in vegetal oil and essential oil. It was observed that the supercritical extraction had no major effect on the fatty acid composition of the vegetal oil compared to classical extraction techniques, while essential oil is enriched in components such as linalool and that a previous drying of the seeds is deleterious. Finally, we propose a procedure in order to extract separately each oil by adjusting CO(2) density and separation conditions. (C) 2011 Elsevier Ltd. All rights reserved.

In this study, olive leaves, which are known for their therapeutic and antioxidant properties, were used to assess the effect of solar drying conditions (temperature and flow rate) on the drying time and quality parameters of olive leaves. Samples were dried at three drying temperatures (40, 50 and 60 °C) and at two drying air flow rates (1.62 and 3.3 m 3 min ―1 ) in a convective laboratory solar dryer. From the experimental results, it was noted that the drying time required to reduce the moisture content to 0.10 kg kg ―1 d.b. depends mainly on the drying temperature. The quality attributes of the dehydrated olive leaf samples were investigated in term of colour, total phenols and radical scavenging activity. The effect of solar drying on L* , a * b * parameters was significant (P < 0.05) for all the studied olive leaves. Besides, the total phenols of olive leaves were significantly (P < 0.05) influenced by drying air conditions and tended to decrease with increased drying time. The DPPH radical scavenging activity was higher in fresh [EC 50 39.40 (ZR)-39.95 (CH)] than in dried leaves. However, the radical scavenging activity was also high in leaves dried at 60 °C, 3.3 m 3 min ―1 [EC 50 54.21 (ZR)―68.79 (CL)].

This paper presents investigations on thin layer convective solar drying of four olive leaves varieties (Chemlali, Chemchali, Chetoui and Zarrazi). Olive leaves were dried at three drying air temperatures (40, 50 and 60C) and at two drying air velocities (0.566 and 1.133 m/s). The drying air temperature is the main factor in controlling the drying rate. The experimental drying curves show the presence of only a falling rate period. Mathematical models, namely, Newton, Page, Henderson and Pabis, Logarithmic, Wang and Singh, Two-term and Two-term exponential models were fitted to the experimental data. Among these models, the Logarithmic model showed the best agreement with the experimental data. The effective moisture diffusivity was estimated by applying the Fickian law to the drying kinetics. The effective moisture diffusivity values varied from 3.437 10−10(Chemlali variety) to 2.427 10−9 m2/s (Chemchali variety). The values of activation energy were calculated assuming an Arrhenius-type temperature reliance. The activation energy ranged from 24.704 (Chetoui variety) to 53.743 (Chemlali variety) kJ/mol. The quality attributes of the dehydrated olive leaves samples were investigated in term of color. The effect of solar drying on L*, a*and b*parameters was significant (P

The objectives of this work are to study the effect of salting time, salt concentration and temperature on moisture and salt transfers within Sardinella aurita fillets. Temperature rise as well as brine concentration increase (from 5 to 20 °C and from 15 to 26.5% NaCl, respectively) accelerated water exudation and salt diffusion in the sardine fillets. Salt and moisture apparent diffusivities evolution as a function of concentration were determined by a mathematical treatment without fixing any mathematical relationship between values of diffusivity and concentration. Moisture apparent diffusivity increased from 2.40 × 10−10 to 1.90 × 10−8 m2/s with fillets moisture content increase (from 0.35 to 3.00 g/g db, i.e. 25.9–75% w/w). For a salt content range from 0.16 to 12.80 g NaCl/100 g water, salt apparent diffusivity was relatively constant. Hence, sardine fillets water diffusivity is more related to moisture content than salt diffusivity to brine concentration.

The aim of this work was to study the effect of air drying process on the dehydration kinetics of sardine muscles ( Sardina pilchardus ). Experimental drying kinetics were measured at five air temperatures (40, 50, 60, 70 and 80 °C), two relative humidity and at a constant air velocity of 1.5 m/s. The sardine drying kinetics were accelerated by increasing air temperature and were showed down when increasing air humidity. Moisture desorption isotherms of sardine muscles were determined at three temperatures (40, 50 and 70 °C) by using the static gravimetric method. The equilibrium moisture contents of sardine muscles were used to treat mathematically the experimental drying kinetics. Experimental drying kinetics and desorption isotherms of sardine muscles were described by using empiric models available in the literature. Eight models (GAB, BET, Henderson–Thompson, Modified Chung & Pfost, Modified Halsey, Oswin, Peleg and Adam & Shove models) were compared in order to describe the desorption isotherms. The Peleg model showed the best fitting of experimental data. For the drying kinetics, the Page model allowed a better fitting than the Newton and the Henderson and Pabis models. The Page model was thus used for simulating the drying kinetics of sardine muscles between 40 and 80 °C.

In the present work, a diffusion-based model was adopted to represent the convective drying behavior of cylindrical banana samples, taking into consideration the shrinkage along drying. The developed model simulated a significant number of situations resulting from the variations of some operating conditions. The temperatures tested were 50, 60, 67 and 70 °C, the air velocities were 3, 4 and 4.5 m/s and the relative humidity range of the drying air was from 3.5 to 11.5%. The calculated drying curves were compared to the experimental ones in order to determine apparent moisture diffusivity. An empirical equation was suggested, describing the apparent moisture diffusivity within the banana versus product temperature and local moisture content. A good agreement was found between experimental and calculated drying kinetics.

The color ( L *, a *, b * parameters), the total phenols content and the global chemical composition (moisture, protein, fat, carbohydrates and ash) of four fresh varieties of olive leaves ( Chemlali , Chemchali , Zarrazi and Chetoui ) were determined. Fresh olive leaves are characterized by a green color (greenness parameter, a *, varying from −5.01 ± 0.26 to −9.14 ± 1.21), an intermediate moisture content (0.85 to 1.00 g/g dry matter, i.e. 46 to 50 g/100 g fresh matter) and a variable amount of total phenols according to the olive leaf variety (from ≈2.32 to ≈1.40 g caffeic acid/100 g dry matter). Fresh leaves were submitted to blanching and/or infrared drying at 40, 50, 60 and 70 °C in order to be stabilized by reducing their moisture contents. The impact of IR drying temperature on some quality attributes (color, total phenols and moisture rate removal) was evaluated. Nevertheless, the effect of prior blanching treatment on the quality attributes of dried leaves is less significant and it depends on the olive leaf variety. The infrared drying induces a considerable moisture removal from the fresh leaves (more than 85%) and short drying durations (varying from ≈162 at 40 °C to 15 min at 70 °C). IR drying temperature showed a significant effect of on total phenols content and the color of the leaves whatever the leaf variety. In fact, total phenols content of dried olive leaves increased if compared to fresh ones. For example, total phenols of Chemlali leaves increased from 1.38 ± 0.02 (fresh leaves) to 2.13 ± 0.29 (dried at 40 °C) and to 5.14 ± 0.60 g caffeic acid/100 g dry matter (dried at 70 °C). IR drying allows preserving the greenness color of fresh leaves and enhancing their luminosity. It could be suggested for preserving olives leaves before their use in food or cosmetic applications.

Desorption isotherms of sardine muscles were determined at three temperatures (25, 35 and 50 °C) for a water activity range varying from 0.10 to 0.75. Gravimetric static methods using saturated salt solutions were used (continuous and discontinuous measurements). Six models were taken from the literature to describe experimental desorption isotherms. The OSWIN model shows the best fit of the experimental data. The net isosteric heat of desorption and the isosteric heat of desorption were determined by using the CLAUSIUS–CLAPEYRON equation. The isosteric heat of desorption decreases continuously with the increase of the equilibrium moisture content. A mathematical correlation was established between the isosteric heat of desorption and equilibrium moisture content.

Moisture sorption isotherms are valuable tool for prediction of the stability and shelf-life of agricultural products. The aims of this work were to determine sorption isotherms of four varieties of olive leaves and to compare the experimental and calculated results by using models available in the literature. The equilibrium moisture contents of olive leaves were measured using the static gravimetric method, at water activities and temperatures ranging from 0.058 to 0.898 and from 30 to 50 °C, respectively. Seven models were applied for analysing the experimental data: Guggenheim-Anderson-de Boer, modified Oswin, Henderson-Thompson, White and Eiring, Peleg, Smith and Caurie models. The desorption and adsorption data were best fitted by the Peleg model. Thus, this model can be used for the estimation of the equilibrium moisture contents of olive leaves in the investigated ranges of temperature and water activity. The net isosteric heats of desorption and adsorption of olive leaves were calculated by applying the Clausius–Clapeyron equation to the sorption isotherms and an expression for predicting these thermodynamic properties was developed.

The effect of air temperature and air flow rate on the drying kinetics of Gelidium sesquipedale was investigated in convective solar drying. Drying was conducted at 40, 50 and 60 °C. The relative humidity was varied from 50% to 57%, and the drying air flow rate was varied from 0.0277 to 0.0833 m 3 /s. The expression for the drying rate equation is determined empirically from the characteristic drying curve. Thirteen mathematical models of thin layer drying are selected in order to estimate the suitable model for describing the drying curves. The two term model gives the best prediction of the drying curves and satisfactorily describes the drying characteristics of G. sesquipedale with a correlation coefficient R of 0.9999 and chi-square ( χ 2 ) of 3.381 × 10 −6 .

The influence of pulsed electric field (PEF) and subsequent centrifugal osmotic dehydration (OD) on the convective drying behavior of carrot is investigated. The PEF was carried out at an intensity of E = 0.60 kV/cm and a treatment duration of t PEF = 50 ms. The following centrifugal OD was performed in a sucrose solution of 65% (w/w) at 40°C for 0, 1, 2, or 4 h under 2400 × g. The drying was performed after the centrifugal OD for temperatures 40–60°C and at constant air rate (6 m3/h). With the increase of OD duration the air drying time is reduced spectacularly. The dimensionless moisture ratio Xr = 0.1 is reached for PEF-untreated carrots after 370 min of air drying at 60°C in absence of centrifugal OD against 90 min of air drying after the 240 min of centrifugal OD. The PEF treatment reduces additionally the air drying time. The total time of dehydration operations can be shortened when OD time is optimized. For instance, the minimal time required to dehydrate untreated carrots until Xr = 0.1 is 260 m...

Experimental drying curves of sardine muscles ( Sardinella aurita ) in parallelepiped form were performed under different drying air conditions (three air temperatures: 35, 40 and 50 °C ± 1 °C, two air velocities: 1 and 2.5 m s −1 , and at atmosphere humidity). A diffusive three-dimensional model was established to describe drying of sardine sample in parallelepiped form. The calculated drying curves was compared to the experimental ones in order to determine apparent moisture diffusivity. An empirical equation describing the apparent moisture diffusivity within the sardine muscles was suggested versus temperature and local moisture content of the product. A good agreement was found between experimental and calculated drying kinetics.

The osmotic dehydration (OD) kinetics of carrot disc untreated and treated by pulsed electric field (PEF) was studied under centrifugation (2400 × g), stirring (250 rpm) and with a salt addition (NaCl/sucrose solutions 0%/65%, 5%/60% and 15%/50%). The PEF intensity was E = 0.60 kV/cm and the treatment duration was tPEF = 0.05 s (500 rectangular monopolar pulses each of 100 μs). The water loss (WL), solids gain (SG) and water loss/solids gain ratios (WL/SG) were evaluated in the binary (sucrose + water) and ternary (sucrose + salt + water) solutions at the temperature of 20 °C during 4 h. The mass ratio of sample to solution was 1:3. The PEF treatment and salt addition enhanced the OD kinetics. WL and SG were increased under centrifugation (centrifugal OD) and under stirring (static OD). The centrifugal field enhanced the WL, however, decreased the SG comparing to the static OD. Therefore, the static OD has advantages for the higher SG (confectionary adds), while the centrifugal OD is better appropriated if the WL should be increased and the solids (sugar) uptake should be limited (dietetic products). The two-exponential kinetic model fitted well to experimental data for both static and centrifugal OD. The correlation coefficient was R2 = 0.982–0.999 and the standard error was 5–10%.

This paper studies the centrifugal osmotic dehydration (OD), rehydration and texture of carrot tissue treated by pulsed electric field (PEF). The influence of centrifugal acceleration (0–5430g), salt addition (NaCl/sucrose solutions 0/65, 7/44 and 15/50% w/w), and temperature (20–40 °C) on the OD kinetics was investigated in the presence and absence of PEF (E=0.60 kV/cm, treatment duration tPEF=0.05 s). The centrifugal OD of samples untreated and treated by PEF was compared with OD under stirring (250 tr/min). Centrifugal force, PEF and salt addition increase the amount of water removed during OD. However, the centrifugal force decreases the intake of solids by the product. The application of PEF enhances both water loss (WL) and solid gain (SG) during OD (under stirring or centrifugation), increases the rehydration capacity of carrot tissue, but somewhat decreases the firmness of rehydrated product. The combination of centrifugal field with PEF and salt addition can be advantageous for reducing the OD duration. The textural study shows that the product obtained with OD is less affected by thermal treatment than the directly dried product.

Dry salting and wet salting in 21% brine solution of sardine ( Sardinella aurita ) were carried out at 20 °C. Drying of salted fish were run at 40 °C, 15% RH and 1.5 m/s. Salting method affected salt uptake and water loss during salting. Drying experiments showed two falling drying periods; no constant rate period was observed. Drying rate during the first falling period was affected by salting method. Models for salting and drying processes were tested.

The aim of this work was to determine the effect of air drying temperature (40 °C, 50 °C, and 60 °C) on the degradation kinetics of quality parameters of lemon peels. Drying at 40 °C was in favor of maximal water and oil retention capacities and lowest color loss (35%), but it also induced lower phenolic and flavonoids residual contents. First-order reaction model showed a good fit for lightness and yellowness color parameter. Zero-order reaction model fitted well redness color parameter and total color difference. A higher value of activation energy indicated greater heat sensitivity of lightness and redness during air drying.

The osmotic dehydration mechanism of apple sample pre-treated by pulsed electric field (PEF) was investigated over a range of 44.5–65 ° Brix sucrose concentrations. Apple disks treated by PEF field of 0.90 kV/cm during a constant time t PEF = 0.75 s were immersed in sucrose solution at ambient temperature with 3:1 syrup to apple ratio (w/w). Increase of the initial solute concentration and the PEF treatment resulted in acceleration of the osmotic dehydration (OD). The PEF-treated samples had a higher water loss (WL) and higher solid gain (SG) than the untreated samples. The osmotic dehydration kinetics was studied on the basis of two approaches: Fick's unsteady state diffusion equation and a two-exponential kinetic model. The coefficients of effective diffusion of water and solute were calculated. Their values were higher for samples pre-treated electrically. The effect of PEF was more pronounced for the WL comparatively to the SG. The two-exponential kinetic model permits evaluating of both convective and diffusion stages of OD. The PEF pre-treatment accelerates the kinetics of water and solute transfer during convective and diffusion stages of OD.

Moisture desorption isotherms of sardine were determined at 40 °C and within the range of 0.11–0.89 water activity using a gravimetric method with saturated salt solutions. Three models were tried to describe these isotherms: GAB, Oswin and Ratti. A good fitting was obtained. Salting of sardine was run at three concentrations: 15%, 21% and 26.5% of NaCl and at 20 °C. Experimental isohalic isotherms were determined for each NaCl concentration and at 40 °C. Physical properties of sodium chloride solutions together with the sorption characteristics of fish muscle were used in order to predict sorption behavior of salted sardine.

The osmotic dehydration (OD) of food plant tissue constitutes an alternative step for drying. As OD is relatively slow, pulsed electric field (PEF) can be used to accelerate this process. The appli...

Moisture equilibrium data for adsorption and desorption of water from prickly pear peel ( Opuntia ficus indica ) were investigated at temperatures in the range of 30–50 °C and water activity ranging from 0.05 to 0.9. The experimental procedure used was based on the gravimetric static method. The experimental curves of sorption are then described by GAB, Henderson’s and BET models. The BET and Henderson models were found to be the most suitable for describing the sorption curves. The monolayer moisture content values for the sorption at different temperature are calculated.