Adsorptive removal of direct red 80 and methylene blue from aqueous solution by potato peels: a comparison of anionic and cationic dyes.

Adsorption of direct red 80 (DR 80) and methylene blue (MB) from aqueous solutions on potato peels (PP) has been compared. The use of peels in decontamination technology is very promising given the near zero-cost for the synthesis of those adsorbents. The selected potato peels were first analyzed by scanning using electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). Then the adsorption behavior was studied in a batch system. The adsorption process is affected by various parameters such as the solution pH (2-11), the initial concentration of the dye (20, 50, 100, 150 and 200 mg L-1), the adsorbent dose (0.1-3%), the temperature (303.16 K, 313.16 K, and 323.16 K), agitation (up to 250 rpm), as well as the contact time. Adsorption isotherms of the studied dye on the adsorbent were determined and compared with the Langmiur, Freundlich and Temkin adsorption models. The results show that the data was most similar to the Freundlich isotherm (R2 = 0.99). The maximum adsorption capacities (Qmax) of MB and DR 80 by the PP at temperatures 303.16 K, 313.16 K and 323.16 K were found to be approximately 97.08 mg g-1; 45.87 mg g-1; 61.35 mg g-1 and 27.778 mg g-1; 45.45 mg g-1; and 32.258 mg g-1. The kinetic data was compared to the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. This revealed that adsorption of methylene blue onto PP abided mostly to the pseudo-second-order kinetic model. Calculations of various thermodynamic parameters such as enthalpy change (ΔH), entropy change (ΔS), and free energy change (ΔG) display the endothermic and spontaneous nature of the adsorption process.

Date Seeds as a Natural Source of Dietary Fibers to Improve Texture and Sensory Properties of Wheat Bread.

The aim of this work was to investigate the effect of date seed water-soluble polysaccharides (DSP) and hemicellulose (DSH) as dietary fiber sources in enhancing the wheat bread's quality. DSP and DSH were extracted from the three date seed varieties Deglet Nour, Ghars Souf, and Allig. The extraction yields ranged from 3.8% to 6.14% and from 13.29% to 18.8%, for DSP and DSH, respectively. DSP and DSH showed interesting functional properties and were incorporated at 0.5% and 0.75% (w/w) in wheat flour with low bread-making quality (FLBM). The results showed that the addition of 0.75% DSH significantly improved the alveograph profile of the dough, and in a more efficient way than that of DSP. Furthermore, bread evaluation revealed that the addition of DSH considerably improved the volume (by 24.22%) and the texture profile of bread (decrease of the hardness and chewiness by 41.54% and 33.81%, respectively), compared to control bread (prepared with FLBM). A sensory analysis showed that the better overall acceptability was found for bread supplemented with DSH. Results in this work demonstrate that hemicellulose fraction extracted from date seeds (DSH) and added with a level of 0.75% to FLBM represents the component that improved bread quality the best.

Structural, functional, and biological properties of potato peel oligosaccharides.

Enzymatic hydrolysis of water-soluble polysaccharides from potato peel waste (PPPW) generates low molecular weight oligosaccharides with a yield of 63%. The oligosaccharides generated from potato peel polysaccharides (OPPP) were purified by Superdex-30 column. The results showed the presence of 8 peaks (OPPP1-OPPP8). The identification of all the fractions by chromatography analysis (GC-FID) illustrated that the most prominent residues were glucose with traces of galactose, arabinose and rhamnose. Finally, mass spectrometry (MALDI-ToF-ToF) analysis showed that the generated oligosaccharides were heterogeneous and contained different degree of polymerization (DP). Indeed, the obtained oligosaccharides fractions OPPP3, OPPP4, OPPP5, OPPP6 and OPPP7 were compose of the following degree of polymerization DP5; DP4; DP2; DP1 and DP1, respectively. Potato peel oligosaccharides (OPPP) efficiency were tested using different concentrations in functional properties. The results showed good foaming and emulsion properties. This study also aimed to investigate the antioxidant activity of OPPP. The items explored included the DPPH radical-scavenging capacity (IC50 OPPP=2.5mg/mL), reducing power (OD: 0.622±0.032 at a concentration of 20mg/mL), ß-carotene bleaching inhibition activity (45.335±3.653%), and also the ABTS radical scavenging activity (14.835±0.1%).These findings indicate that potato peel oligosaccharides have potent antioxidant activities. Hence, one can suggest that these oligosaccharides might contribute as additives in food, pharmaceutical and cosmetic preparations.

Improvement of texture and sensory properties of cakes by addition of potato peel powder with high level of dietary fiber and protein.

Demand for health oriented products such as low calories and high fiber product is increasing. The aim of the present work was to determine the effect of the addition of potato peel powders as protein and dietary fiber source on the quality of the dough and the cake. Powders obtained from the two types of peel flour showed interesting water binding capacity and fat absorption capacity. Potato peel flours were incorporated in wheat flours at different concentration. The results showed that peel powders additionally considerably improved the Alveograph profile of dough and the texture of the prepared cakes. In addition color measurements showed a significant difference between the control dough and the dough containing potato peels. The replacement of wheat flour with the potato powders reduced the cake hardness significantly and the L(*) and b(*) dough color values. The increased consumption of cake enriched with potato peel fiber is proposed for health reasons. The study demonstrated that protein/fiber-enriched cake with good sensory quality could be produced by the substitution of wheat flour by 5% of potato peel powder. In addition and technological point of view, the incorporation of potato peel powder at 5% increase the dough strength and elasticity-to-extensibility ratio (P/L).

Pea and Broad Bean Pods as a Natural Source of Dietary Fiber: The Impact on Texture and Sensory Properties of Cake.

Attention has focused on bakery products such as cake which is one of the most common bakery products consumed by people in the world. Legume by-products, pea pods (PPs) (Pisum sativum L.) and broad bean pods (BBPs) (Vicia faba L.) mediterranean (Tunisian), has been studied for its high dietary fiber content (PP: 43.87 g/100 g; BBP: 53.01 g/100 g). Protein content was also a considerable component for both by-products. We investigated the effect of substituted of 5%, 10%, 15%, 20%, 25%, and 30% of PP and BBP flours on the sensory and technological properties in cake. Cakes hardness increased whereas L* and a* color values decreased. The overall acceptability rate showed that a maximum of 15% of PP and BBP flours can be added to prepare acceptable quality cakes.

Evaluation of dough rheological properties and bread texture of pearl millet-wheat flour mix.

This study was undertaken with the objective of formulating composite bread using pearl millet (Pennisetum glaucum) and wheat (Triticum aestivum) flours . Rheological and bread making properties of composite flours were evaluated. Mixolab results revealed torque increased and dough stability time decreased upon incorporation of pearl millet flour in wheat flour. The incorporation of millet flour at optimum level (5 %) led to an increase of the dough strength (W) and the elasticity-to-extensibility ratio (P/L) by 31 % and 65 % respectively. The bread texture and volume were also improved. These findings indicated the potentiality of using millet flour in bread making.

Structural, functional, and antioxidant properties of water-soluble polysaccharides from potatoes peels.

Water-soluble polysaccharides were extracted from potato peel waste (PPW). The structure of the polysaccharides from PPW (PPPW) was examined by means of Fourier transform-infrared spectroscopy (FT-IR) analysis, X-ray diffractometry (XRD) and gas chromatography-mass spectrometry (GC-MS). The results suggest that the extracted polysaccharides form a semi-crystalline polymer constituted essentially of the functional groups CO, CH and OH. Acid hydrolysis of this polymer yielded glucose (76.25%) as the dominant sugar functional properties (water holding capacity: WHC, oil holding capacity: OHC, foaming, and emulsion properties) of this polymer were studied. The PPPW showed interesting water-holding and fat-binding capacities which were 4.097 ± 0.537 g/g and 4.398 ± 0.04 g/g, respectively. In addition, it presented good foaming and emulsion properties. The antioxidant activity of this polymer was also studied and revealed that the polysaccharides showed interesting 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity (IC50 PPPW=11.578 mg/mL), reducing power and ß-carotene bleaching inhibition activities, and also a strong ABTS radical scavenging activity (IC50 PPPW=2mg/mL). Overall, the results suggest that the polysaccharide is a promising source of natural antioxidants and can be used as additive in food, pharmaceutical and cosmetic preparations.

Recent advances in Rosaceae gum exudates: From synthesis to food and non-food applications.

In recent years, great interest has been devoted to the development of new applications for natural gums. These molecules were used for a variety of purposes since they are chemically inert, non-toxic, less expensive, biodegradable and widely available. They represent one of the most abundant raw materials used not only in commercial food products, but also in cosmetic and pharmaceutical products. Plant gums take their advantages compared to other gums (e.g., from animal and microbial sources) mainly because of their acceptance by consumers. Despite of the well description given in literature for the features of plant gum exudates, there is a lack distinguishing the different families that are producing gums, and their potential applications. Among these gums, the ones produced by Rosaceae family (e.g., almond, apricot, cherry, peach, and plum plants) have been taking special attention. Thus, the aim of this review is to report the recent advances in Rosaceae gum exudates. An emphasis is given for the formation mechanisms of these gums, their chemical composition, functional properties and structures, beneficial properties, as well as their food/non-food applications.

Antibacterial and antioxidant properties of mixed linkage beta-oligosaccharides from extracted ß-glucan hydrolysed by Penicillium occitanis EGL lichenase.

The aim of this study was first to ascertain the chemical composition and the physicochemical properties of cereal extracted ß-glucan from barley flour. Secondly, to assess the antioxidant properties and the antibacterial properties of extracted ß-glucan hydrolysates. The proximate composition, FT-IR and scanning electron microscopy of extracted ß-Glucan were studied. Hydrolysates from extracted ß-glucan, obtained by lichenase EGL from Penicillium occitanis, were a mixed linkage beta-oligosaccharides (MLBO) of trisaccharides and tetrasaccharides. MLBO showed a DPPH radical scavenger with IC50 about 1.8 ± 0.01 mg/mL whereas the IC50 of extracted ß-glucan was about 5 ± 0.01 mg/mL. MLBO showed a high antioxidative capacity (175 µmol/mL α-tocopherol equivalents) at 5 mg/mL. The antimicrobial activity was confirmed against all tested bacteria especially at 20 mg/mL of MLBO while no inhibition was observed for all the strains used after the addition of either EGL or extracted ß-glucan.

Improvement of Heart Redox States Contributes to the Beneficial Effects of Selenium Against Penconazole-Induced Cardiotoxicity in Adult Rats.

The present study was performed to evaluate the protective effect of selenium (Se) against penconazole (PEN)-induced oxidative stress in the cardiac tissue of adult rats. Male Wistar rats were divided into four groups of six each. The first group represented the controls. For the second group (PEN), no treatment was performed during the first 6 days, and then, the rats received intraperitoneally 67 mg/kg body weight (bw) of PEN every 2 days from day 7 until day 15, the sacrifice day. For the third group (Se + PEN), Se was administered daily through the diet at a dose of 0.5 mg/kg of diet for 15 days. Rats of this group received also every 2 days PEN (67 mg/kg bw) from day 7 until day 15. The fourth group (Se) received daily, through the diet, Se (0.5 mg/Kg of diet) during 15 days. Our results showed that Se reduced significantly the elevated cardiac levels of malondialdehyde and protein carbonyl following PEN treatment, and attenuated DNA fragmentation induced by this fungicide. In addition, Se modulated the alterations of antioxidant status: enzymatic (superoxide dismutase, glutathione peroxidase, and catalase) and nonenzymatic (glutathione and vitamin C) antioxidants in the heart of PEN-treated rats. This trace element was also able to alleviate perturbations of lipid profile. The protective effect of selenium was further evident through the histopathological changes produced by PEN in the heart tissue. Taken together, our results indicated that Se might be beneficial against PEN-induced cardiac oxidative damage in rats.

Isolation and characterization of starch from industrial fresh pasta by-product and its potential use in sugar-snap cookie making.

In this paper, starch was extracted from fresh pasta by-product (PS) and its chemical composition and physical and microscopic characteristics were determined. Commercial wheat starch (CS) was used as reference. In general, purity was similar between starches studied. However, others compounds such as protein, lipid and ash were significantly different. PS starch granules had large lenticular-shape (25-33 µm) and small spherical-shape (5-8 µm). The pH and color of PS starch were similar to those reported for CS starch. On the other hand, PS had higher water absorption capacity, viscosity and cooking stability than CS. The gelatinization temperature of PS was similar to that of CS (60 and 61 °C). At high temperature (90 °C) both starches had similar rheological behavior. The results achieved suggest that PS starch has potential for application in food systems requiring high processing temperatures such the manufacture of sugar snap cookie. The effects of PS starch addition on the dough making stage and the final cookie quality were analyzed. Improvements in dough cohesiveness (24 %) and springiness (10 %) were significant relative to those of CS dough. Texture profile analysis confirmed the rheological changes.

Extraction, characterization and antimicrobial activity of sulfated polysaccharides from fish skins.

Sulfated polysaccharides were extracted from gray triggerfish (GTSP) and smooth hound (SHSP) skins. Their chemical and physical characteristics were determined using X-ray diffraction and Infrared spectroscopic analysis. The antibacterial activities of GTSP and SHSP against Listeria monocytogenes (ATCC 43251), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), Salmonella enterica (ATCC 43972) and Enterobacter sp were evaluated by determining clear growth inhibition zone diameters and the minimum inhibitory concentration (MIC) values and by essays in liquid media. GTSP and SHSP were fractionated by a Diethylaminoethyl-cellulose chromatography. Fraction FGII, from GTSP, and fraction FSII, from SHSP, showed the most important inhibitory effects against the tested bacterial species. The sulfated polysaccharides from fish skins did not show hemolytic activity towards bovine erythrocytes. Overall, the results suggested that those polysaccharides could offer promising sources of polysaccharides for future application as dietary ingredients in the nutraceutical industry.

New food from a potato somatic hybrid: nutritional equivalence and safety assessment by a feeding study on rats.

BACKGROUND: Potato tubers from the STBd somatic hybrid line that exhibited improved tolerance to salinity and resistance to fungal and PVY infections were characterised. They were compared for their chemical composition to the Spunta variety produced by conventional agronomic practices. This study aimed to compare nutritional value and safety by feeding rats with STBd or commercial tubers added to the standard diet (20/80 w/w). RESULTS: The analysis of soluble sugar, fat, fibre and ash content of tubers did not reveal any significant differences between the hybrid line and the control Spunta variety. Small differences were observed in dry matter, starch and protein content of hybrid potatoes in comparison to controls. However, all values were within normal ranges reported in the literature. The feeding study on rats showed that overall health, weight gain, food consumption, morphological aspects and weights of organs were comparable between rat groups fed the STBd hybrid and the Spunta variety. CONCLUSION: Taken together, 28 days of consumption of STBd hybrid potato did not exert any adverse effect on rats compared with commercial Spunta potato. The STBd potato line was therefore considered to be as safe for food utilisation as the commercial variety.

Biological Activities of xylooligosaccharides generated from garlic straw xylan by purified xylanase from Bacillus mojavensis UEB-FK.

A newly isolated Bacterium strain named UEB-FK was selected from Tunisian Sahara, exhibiting the highest clear zone on agar plates containing oat spelt xylan by staining with Congo red. On the basis of 16S rDNA sequence analysis, this strain was identified as Bacillus mojavensis. This strain produced extracellular xylanase. Xylanase from the strain was purified to homogeneity and had an apparent molecular weight of 14 kDa. The K m and V max values of the purified xylanase on oat spelt xylan were 3.85 mg/mL and 250.02 U/mg, respectively. The optimum pH and temperature for the enzyme were found to be 4.0 and 50 °C, respectively, and the enzyme exhibited significant heat stability. In addition, the enzyme was found to be stable in a wide range of pH (3-9). The main hydrolysis products yielded from garlic straw-extracted xylan were xylobiose and xylotriose. The antioxidant and antibacterial activities of xylan oligosaccharide (XOS) were investigated. As regards to the in vitro antioxidant activities, the XOS showed a important DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity (IC50 = 0.45 mg/mL) and a high ß-carotene bleaching (IC50 = 2.2 mg/mL). Furthermore, XOS had a high antimicrobial activity against Klebsiella pneumoniae, Enterococcus faecalis, Bacillus thuringiensis, and Pseudomonas aeruginosa.

Water-soluble polysaccharides from agro-industrial by-products: functional and biological properties.

Water-soluble polysaccharides were isolated from almond (AWSP) and pistachio (PWSP) juice processing by-products. Their chemical and physical characteristics were determined using NMR and Infrared spectroscopic analysis. The complexities of the spectra reflected the heterogeneity of these polysaccharides. The ACE inhibitory activities (IC50 AWSP=2.81mgmL(-1) and IC50 PWSP=2.59mgmL(-1)) and antioxidant properties of AWSP and PWSP were investigated based on the DPPH radical-scavenging capacity assay (IC50 AWSP=2.87mgmL(-1) and IC50 PWSP=1.61mgmL(-1)). Reducing power, ß-carotene bleaching inhibition (IC50AWSP=4.46mgmL(-1) and IC50 PWSP=3.39mgmL(-1)), and ferrous chelating assays (IC50 AWSP=0.22mgmL(-1) and IC50 PWSP=0.19mgmL(-1)) were also performed. The findings revealed that water-soluble polysaccharides exhibited antioxidant and antihypertensive activities. AWSP and PWSP showed excellent interfacial concentration-dependent properties. Overall, the results suggested that both AWSP and PWSP are promising sources of natural antioxidants and ACE inhibitory agents and could, therefore, be used as alternative additives in food, pharmaceutical and cosmetic preparations.

Production of xylooligosaccharides by immobilized His-tagged recombinant xylanase from Penicillium occitanis on nickel-chelate Eupergit C.

Penicillium occitanis xylanase 2 expressed with a His-tag in Pichia pastoris, termed PoXyn2, was immobilized on nickel-chelate Eupergit C by covalent coupling reaction with a high immobilization yield up to 93.49 %. Characterization of the immobilized PoXyn2 was further evaluated. The optimum pH was not affected by immobilization, but the immobilized PoXyn2 exhibited more acidic and large optimum pH range (pH 2.0-4.0) than that of the free PoXyn2 (pH 3.0). The free PoXyn2 had an optimum temperature of 50 °C, whereas that of the immobilized enzyme was shifted to 65 °C. Immobilization increased both pH stability and thermostability when compared with the free enzyme. Time courses of the xylooligosaccharides (XOS) produced from corncob xylan indicated that the immobilized enzyme tends to use shorter xylan chains and to produce more xylobiose and xylotriose initially. At the end of 24-h reaction, XOS mixture contained a total of 21.3 and 34.2 % (w/w) of xylobiose and xylotriose with immobilized xylanase and free xylanase, respectively. The resulting XOS could be used as a special nutrient for lactic bacteria.

Functional characterization of Penicillium occitanis Pol6 and Penicillium funiculosum GH11 xylanases.

Xylanases are hemicellulolytic enzymes, which are responsible for the degradation of heteroxylans constituting the lignocellulosic plant cell wall. Xylanases from the GH11 family are considered as true xylanases because of their high substrate specificity. In order to study in depth a crucial difference in the thumb region between two closely related xylanases from Penicillium in terms of kinetic parameters and inhibition sensitivity, the GH11 xylanases from Penicillium occitanis Pol6 (PoXyn3) and from Penicillium funiculosum (PfXynC) were heterologously expressed in Pichia pastoris. The PoXyn3 and PfXynC cDNAs encoding mature xylanases were cloned into pGAPZαA vectors and integrated into the genome of P. pastoris X-33 under the control of the glyceraldehyde 3-phosphate dehydrogenase constitutive promoter. PfXynC was expressed as a His-tagged recombinant protein and purified from the supernatant homogeneity by a one-step purification protocol using immobilized metal affinity chromatography. The recombinant PoXyn3 was purified using a single anion-exchange chromatography. The purified recombinant enzymes were optimally active at 45°C and pH 4.0 for PoXyn3 and 40°C and pH 3.0 for PfXynC. The measured kinetic parameters (k(cat) and Vmax) showed that PfXynC was five times more active than PoXyn3 irrespective of the substrate whereas the apparent affinity (K(m)) was similar. The recombinant enzymes showed distinct sensitivity to the Triticum aestivum xylanase inhibitor TAXI-I.

Improvement of bread dough quality by Bacillus subtilis SPB1 biosurfactant addition: optimized extraction using response surface methodology.

BACKGROUND: Statistically based experimental designs were applied to Bacillus subtilis SPB1 biosurfactant extraction. The extracted biosurfactant was tested as an additive in dough formulation. RESULTS: The Plackett-Burman screening method showed that methanol volume, agitation speed and operating temperature affect biosurfactant extraction. The effect was studied and adjusted using response surface methodology. The optimal values were identified as 5 mL methanol, 180 rpm and 25 °C, yielding predicted responses of 2.1 ± 0.06 for the purification factor and 87.47% ± 1.58 for the retention yield. Study of the incorporation of purified lipopeptide powder into the dough preparation in comparison with a commercial surfactant - soya lecithin - reveal that SPB1 biosurfactant significantly improves the textural properties of dough (hardness, springiness, cohesion and adhesion) especially at 0.5 g kg⁻¹. At the same concentration (0.5 g kg⁻¹), the effect of SPB1 biosurfactant was more pronounced than that of soya lecithin. Also, this biosurfactant considerably enhanced the gas retention capacity in the course of fermentation. CONCLUSION: These results show that SPB1 biosurfactant could be of great interest in the bread-making industry. A method for preparative extraction of lipopeptide biosurfactant with methanol as the extraction solvent has been effectively established.

Improving the nutritive value of Olive Cake by solid state cultivation of the medicinal mushroom Fomes fomentarius.

Olive Cake (OC) generated by the olive oil industries, well implanted in Tunisia, represents a major disposal and potentially severe pollution problem. This work presents the study of bioconversion of OC in solid state fermentation with the medicinal mushroom, Fomes fomentarius so as to upgrade its nutritional values and digestibility for its use as ruminants feed. The fungus was cultured on OC for 7-30 d, and subsequently the chemical composition, lignocellulolytic enzyme activities and in vitro digestibility of the resultant substrate were determined. The results obtained showed an increase in the crude protein ranging from 6% to 22% for the control and for treated OC, respectively. Significant (P<0.05) decreases in the values of neutral detergent fiber (hemicelluloses, cellulose and lignin), acid detergent fiber (lignin and cellulose) and acid detergent lignin were detected (23%, 13% and 10%, respectively). The estimated in vitro digestibility improved from 9% (control) to 25% (treated OC). The present findings revealed F. fomentarius to be an efficient organism for lignocellulolytic enzymes production and simultaneous enhancement in crude protein and in vitro digestibility of OC.

Retracted: Improvement of Breadmaking Quality by Xylanase GH11 from Penicillium occitanis Pol6.

In this study xylanase from Penicillium occitanis Pol6, as a bread improver, was tested in whole-wheat bread. The purified xylanase termed PoXyn2 was used as an additive at a very small quantity (0.12 U/g flour basis) during mixing of wheat flour. The effects of xylanase addition on the fermentation stage and the final bread quality were analyzed. Remarkable decrease (8%) in water absorption and increase in dough rising (36.8%) were noticed. Final moisture content of the bread was higher (37.50%) than control (23.56%). Improvements in volume (17.8%) and specific volume (34.9%) were also significant. Sensory evaluation indicated better flavor, taste, softness and overall acceptability. Texture profile analysis confirmed the rheological changes. Firmness was decreased by more than twofolds. Improvements in cohesiveness and decline in springiness and gumminess were observed. PRACTICAL APPLICATIONS: The baking industry is shifting toward producing whole-wheat fiber-rich bread using enzymes such as xylanase, which can improve dough machinability and stability, oven spring, loaf volume, crumb structure and shelf life. This hypothesis is supported by determining the functional and rheological properties of supplemented dough with purified Penicillium occitanis xylanase. The improved bread was assessed by a panel of five judges for sensory evaluation. Furthermore, significant improvement in textural properties was noticed.