Search

Three different deep eutectic solvent (DES)-based extraction procedures were rationally designed and optimized for the recovery of antioxidants from chestnut wood fiber (CWF), a clean and largely available solid waste of the tannin industry. First, a mild protocol was developed using a choline chloride (ChCl)/tartaric acid DES at 50 °C, for 90 min. Ellagic acid (EA) was identified as the only low molecular weight phenolic component of the extract. In other experiments, harsher conditions were explored involving treatment of CWF with ChCl-based DESs at 120 °C for 8 h, which afforded a solid sample characterized by high phenolic content (up to 1.0 mg of gallic acid equivalents/mg of sample) and antioxidant properties (EC50

Oxidative stress originates from an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and apoptosis, ultimately impairing cell viability. Antioxidants scavenge free radicals and reduce oxidative stress, which further helps to prevent cellular damage. Medicinal plants, fruits, and spices are the primary sources of antioxidants from time immemorial. In contrast to plants, microorganisms can be used as a source of antioxidants with the advantage of fast growth under controlled conditions. Further, microbe-based antioxidants are nontoxic, noncarcinogenic, and biodegradable as compared to synthetic antioxidants. The present review aims to summarize the current state of the research on the antioxidant activity of microorganisms including actinomycetes, bacteria, fungi, protozoa, microalgae, and yeast, which produce a variety of antioxidant compounds, i.e., carotenoids, polyphenols, vitamins, and sterol, etc. Special emphasis is given to the mechanisms and signaling pathways followed by antioxidants to scavenge Reactive Oxygen Species (ROS), especially for those antioxidant compounds that have been scarcely investigated so far.

Oxidative stress is an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and apoptosis, ultimately negotiating cells viability. Antioxidants can scavenge such free radicals, thus reducing the oxidative stress and eventually prevent cellular damage. Medicinal plants, fruits, and spices remain the prioritized sources of antioxidants and antimicrobial properties since the time immemorial, but in contrast to plants, microorganisms can be grown at a faster rate under controlled conditions. They are non-toxic, non-carcinogenic, and biodegradable as compared to synthetic antioxidants. Microorganisms including actinomycetes, archaea, bacteria, protozoa, yeast, and fungi are auspicious source of vital bioactive compounds. The list comprises ample of bioactive components from microorganisms. One of them is bacteriocins, which are ribosomally synthesized antimicrobial peptides product of Eurotium sp., Streptomyces parvulus, S. thermophiles, Lactococcus lactis, etc. It has a great potential as next-generation antibiotics targeting the multiple-drug resistant pathogens. Pneumocandins are antifungal lipohexapeptides derived from the fungus Glarea lozoyensis, and inhibit 1,3-β-glucan synthase of the fungal cell wall and act as a precursor for the synthesis of caspofungin. It is widely used against invasive fungal infections and has been recently approved by the FDA. Taxol (paclitaxel), a chemotherapeutic drug derived from the bark of Taxus brevifolia can also be produced by endophytic fungi Taxomyces andreanae and Nodulisporium sylviforme. It is known to inhibit several fungi such as Pythium, Aphanomyces and Phytophthora. Hispidin and its derivate isolated from P. hispidus, reduce inducible nitric oxide synthase (iNOS) expression, obstruct the transcriptional activity of NF-κB, and also decrease the production of reactive oxygen species (ROS) in macrophages. Astaxanthin, known as an “aquatic” carotenoid produced by H. pluvialis, also has excellent ROS quenching activity. This study mainly focuses on fascinating antioxidant and antimicrobial compounds that have been scarcely investigated in microorganisms and discuss the promise and challenges of microorganisms as providers of health benefits.

The increasing world population generates huge amounts of wastewater as well as large energy demand. Additionally, fossil fuel’s combustion for energy production causes the emission of greenhouse gases (GHG) and other pollutants. Therefore, there is a strong need to find alternative green approaches for wastewater treatment and energy production. Microalgae biorefineries could represent an effective strategy to mitigate the above problems. Microalgae biorefineries are a sustainable alternative to conventional wastewater treatment processes, as they potentially allow wastewater to be treated at lower costs and with lower energy consumption. Furthermore, they provide an effective means to recover valuable compounds for biofuel production or other applications. This review focuses on the current scenario and future prospects of microalgae biorefineries aimed at combining wastewater treatment with biofuel production. First, the different microalgal cultivation systems are examined, and their main characteristics and limitations are discussed. Then, the technologies available for converting the biomass produced during wastewater treatment into biofuel are critically analyzed. Finally, current challenges and research directions for biofuel production and wastewater treatment through this approach are outlined.

The aim of this study was to assess the effects of commercially available and relatively inexpensive enzyme preparations based on endo 1,4-&beta, xylanase, pectinase and xyloglucanase on the thermal (TGA), morphological (SEM), chemical (FT-IR) and mechanical (single yarn tensile tests) properties of flax yarns. The preparation based on pectinase and xyloglucanase provided the best results, resulting in the effective removal of hydrophilic components such as hemicellulose and pectin, the individualization of yarns and increased thermal stability at the expense of a reduction in mechanical properties, depending on the treatment parameters. Single yarn fragmentation tests pointed out an improved interfacial adhesion after enzymatic treatment, with reduced debonding length values of 18% for an epoxy matrix and up to 36% for a vinylester resin compared to untreated flax yarns.

The feasibility of exploiting secondary raw materials from marine food-chains as a source of molecules of nutritional interest, to create high-value food products and to meet nutritional challenges, is described in this report. A reduction in food waste is urgent as many sectors of the food industry damage the environment by depleting resources and by generating waste that must be treated. The project herein described, deals with the recovery of natural molecules, omega-3 fatty acids (EPA, DHA) and of α-tocopherol, from fish processing by-products. This would promote the sustainable development of new food products for human nutrition, as well as nutraceuticals. The growing awareness of increasing omega-3 fatty acids intake, has focused attention on the importance of fish as a natural source of these molecules in the diet. Therefore, a study on the concentration of these bioactive compounds in such matrices, as well as new green methodologies for their recovery, are necessary. This would represent an example of a circular economy process applied to the seafood value chain. Fish processing by-products, so far considered as waste, can hopefully be reutilized as active ingredients into food products of high added-value, thus maximizing the sustainability of fish production.

The stability of lycopene in two vegetable oils, sunflower seed oil (SSO) and grape seed oil (GSO), was investigated by analysing the carotenoid degradation kinetics in the temperature range of 10–40°C. A tomato oleoresin containing 6% (w/w) of lycopene was used to prepare lycopene-enriched oil samples. Analysis of kinetic data showed that lycopene degradation follows first-order kinetics, with an apparent activation energy of 70.7 kJ mol–1 in SSO and 69 kJ mol–1 in GSO. The estimated half-life of lycopene was found to depend on oil type and storage temperature. At 20°C, it varied between 59 and 122 days, while at 4°C it was comprised between 302 and 650 days. At all temperatures, lycopene was more stable in SSO than in GSO, which is likely due to the higher content of antioxidant compounds in SSO.

The use of UV-C light as a means to inactivate pathogens in biological media containing blood components or plasma derivatives has recently been rediscovered. Although highly effective, these treatments may have deleterious effects on plasma proteins such as albumin, fibrinogen and immunoglobulins. Here we investigate the use of three natural antioxidants, gallic acid, nicotinic acid and ascorbic acid, as potential stabilizers of human albumin (HA) during irradiation by UV at 254 nm. The effects of UV-C on HA were monitored by measuring the absorbance changes in the protein spectrum at 320 nm. Experiments carried out at irradiance levels of 3.5–15 W m–2 and application times of up to 40 min showed that albumin undergoes rapid aggregation and that this process is dose-dependent. When added at 0.2 mM to the protein solution, all of the antioxidants inhibited HA aggregation, with ascorbic acid being the most effective. To quantitatively describe the observed effects, a fluence-based model was developed. The model predicted a quadratic dependence of the spectral changes of HA on the radiation dose and was validated by experiments performed under different exposure conditions.

A combined treatment based on electrochemical oxidation on boron-doped diamond (BDD) anodes and UV-C irradiation was used to degrade the emerging contaminant coumarin, an ingredient of many personal care products. The efficiency of the process was assessed by monitoring the coumarin concentration decay and the total organic carbon (TOC). The effect of chloride was evaluated and the occurrence of inorganic chlorinated products was quantified. The photo-assisted electrochemical degradation resulted in a faster removal and mineralization of the pollutant, compared to the treatment without UV irradiation. The observed synergistic effect was mainly ascribed to the ability of UV light to activate the peroxides electrogenerated during the electrolysis on BDD. An additional contribution was due to the photolysis of electrogenerated hypochlorite/hypochlorous acid in the presence of chloride. UV irradiation reduced the amount of residual active chlorine but not of chlorates. TOC analysis showed that mineralization occurred together with coumarin removal from the solution, indicating that no persistent organic by-products were formed during the treatment. The possibility of reducing the energy consumption of the process by shortening the exposure time of the solution to UV light was also investigated.

Corn husks are an important byproduct of the corn processing industry. Although they are a rich source of bioactive compounds, especially flavonoids, corn husks are usually disposed of or used as animal feed. In this paper, we investigate their recovery by an enzyme-assisted extraction process consisting of a pretreatment of the plant material with cellulase followed by solvent extraction with aqueous ethanol. A four-factor, three-level Box&ndash, Behnken design combined with the response surface methodology was used to optimize the enzyme dosage (0.3&ndash, 0.5 g/100 g), incubation time (1.5&ndash, 2.5 h), liquid-to-solid ratio (30&ndash, 40 mL g&minus, 1) and ethanol concentration in the solvent (60&ndash, 80% v/v). Under the optimal conditions, about 1.3 g of total flavonoids per 100 g of dry waste were recovered. A statistical analysis of the results was performed to provide a quantitative estimation of the influence of the four factors, alone or in combination, on the extraction yields. Overall, the results from this study indicate that corn husks are a valuable source of flavonoids and that they can be easily recovered by a sustainable and environmentally friendly extraction process.

This study investigates distillery wastewater, commonly known as vinasse, as a potential culture medium for the production of Chlorella vulgaris and its most relevant metabolites. The effect of vinasse concentration on the composition of the biomass (proteins, carbohydrates and lipids) was evaluated in treatments performed in 6-L tubular air-lift reactors. The reactors were operated at 25 °C for 18 days, in total darkness, under a continuous flow of air. Results showed a rapid growth of microalgae in the first ten days, when an average production of 0.87 g/L was reached. Then, the daily biomass productivity began to decrease, up to an average value of 11.8 g/L at the 16th day. For all treatments, there was a significant reduction in the concentration of most metabolites in the first eight days. This was likely due to the adaptation of the biomass to the new conditions, with a transition from autotrophic to heterotrophic metabolism. From the 10th day, the concentration of metabolites in the biomass began to increase, reaching a nearly constant value at the 16th day. The observed maximum concentrations (%w/w) were: 48.95% proteins, 2.88% xylose, 7.82% glucose, 4.54% arabinose, 8.28% fructose and 4.82% lipids. These values were only marginally affected by the type of treatment. Overall, the results obtained suggest that vinasse is a promising and sustainable medium for the growth of C. vulgaris and the production of valuable metabolites.

This study investigates distillery wastewater, commonly known as vinasse, as a potential culture medium for the production of Chlorella vulgaris and its most relevant metabolites. The effect of vinasse concentration on the composition of the biomass (proteins, carbohydrates and lipids) was evaluated in treatments performed in 6-L tubular air-lift reactors. The reactors were operated at 25 °C for 18 days, in total darkness, under a continuous flow of air. Results showed a rapid growth of microalgae in the first ten days, when an average production of 0.87 g/L was reached. Then, the daily biomass productivity began to decrease, up to an average value of 11.8 g/L at the 16th day. For all treatments, there was a significant reduction in the concentration of most metabolites in the first eight days. This was likely due to the adaptation of the biomass to the new conditions, with a the transition from autotrophic to heterotrophic metabolism. From the 10th day, the concentration of metabolites in the biomass began to increase, reaching a nearly constant value at the 16th day. The observed maximum concentrations (%w/w) were: 48.95% proteins, 2.88% xylose, 7.82% glucose, 4.54% arabinose, 8.28% fructose and 4.82% lipids. These values were only marginally affected by the type of treatment. Overall, the results obtained suggest that vinasse is a promising and sustainable medium for the growth of C. vulgaris and the production of valuable metabolites.

The production of silver nanoparticles (Ag-NPs) from bilberry waste (BW) and red currant waste (RCW) extracts was studied. Red fruit extracts were obtained by treating BW and RCW with aqueous ethanol (50% v/v) at 40 &deg, C. The formation of nanoparticles was monitored spectrophotometrically by measuring the intensity of the surface plasmon resonance band (SPR) of silver. The effects of temperature (20&ndash, 60 &deg, C) and pH (8&ndash, 12) on the reaction kinetics and on the properties of Ag-NPs were investigated. Characterization by XRD and dynamic light scattering (DLS) techniques showed that Ag-NPs were highly crystalline, with a face-centered cubic structure and a hydrodynamic diameter of 25&ndash, 65 nm. The zeta potential was in the range of &minus, 35.6 to &minus, 20.5 mV. Nanoparticles obtained from BW were slightly smaller and more stable than those from RCW. A kinetic analysis by the initial-rate method showed that there was an optimum pH, around 11, for the production of Ag-NPs. Overall, the results obtained suggest that BW and RCW can be advantageously used as a source of reducing and stabilizing agents for the green synthesis of Ag-NPs.

Brewers&rsquo, spent grain (BSG) is the most abundant by-product of the brewing process. BSG is currently disposed of or used as a supplement for animal feed, although it contains significant amounts of bioactive compounds of great interest to the pharmaceutical, cosmetic and food sectors. In this study we investigate the feasibility of using a simple solvent extraction procedure to recover phenolic antioxidants from BSG. Acetone&ndash, water and ethanol&ndash, water mixtures were used as extraction solvents. Phenolic extracts obtained by treatment of BSG with the two solvent systems were characterized in terms of total phenolics and antioxidant activity. For both systems, the extraction yield was maximum at 60% (v/v) organic solvent concentration. At all solvent compositions, mixtures containing acetone provided higher extraction yields. As suggested by the strong correlation between the antioxidant activity of BSG extracts and their phenolic content, the antioxidant capacity of the extracts can be mainly attributed to polyphenols. Overall, the obtained results strongly support the exploitation of BSG as a source of phenolic antioxidants and the possibility of recovering them by a mild and green extraction process.

Bergamot peel oil is highly attractive for food and pharmaceutical industries due to its content of valuable essential oil, which is enriched with high-added valuable compounds, such as limonene, linalool and linalyl acetate. Nevertheless, there are some limitations for the separation of such compounds. In this framework, pervaporation (PV) technology was proposed as a tool for the separation of limonene, linalool, and linalyl acetate from bergamot oil by using two different commercial organophilic membranes (PDMS-1070 and POMS-PEI). The use of an enzymatic pre-treatment was also investigated in order to enhance the performance of selected membranes. All PV experiments were carried out at different temperatures (ranging from 25-40 ºC) in order to analyze the temperature dependence by the Arrhenius relationship. Experimental data indicated that both investigated membranes did not present significant differences in terms of enrichment factor, independently from the enzymatic pre-treatment (at 25 ºC). However, the enrichment factors increased significantly at 40°C when enzymes were applied. The experimental results clearly indicate that PV is a viable approach for the recovery of such aroma solutes from bergamot peel oils as it yields good separations under mild operating conditions. The efficiency of the pervaporative process is indeed enhanced if assisted by an enzymatic treatment.

The presence of azo dyes in textile effluents is an issue of major concern due to their potential impact on the environment and human health. In this study we investigate the photocatalytic degradation under visible light of Reactive Violet 5 (RV5), an azo dye widely used in the textile industry. A preliminary screening of different titania-based catalysts was carried out to identify the best candidate for RV5 removal. The selected catalyst was then tested in a stirred and aerated lab-scale reactor illuminated with a blue light-emitting diode (LED) source emitting in the wavelength range of 460&ndash, 470 nm. The effects of pH, catalyst load, and hydrogen peroxide additions on the efficiency of dye removal were evaluated. Under the best conditions (pH 10, 3 g/L of catalyst, and 60 mM hydrogen peroxide), the dye solution was completely decolorized in about 2 h. Overall, the results obtained suggest that the proposed process may represent a suitable method for the removal of RV5 from textile effluents.

Artichoke waste was investigated as a potential source of phenolic compounds and bioenergy. The total phenolic content of the waste, expressed as gallic acid equivalents (GAE) per unit dry weight, was 32.2 mg GAE/g. Polyphenols were recovered from the waste by an environmentally friendly solvent extraction procedure using 50% (v/v) aqueous ethanol as solvent. Experiments were conducted according to a central composite design and response surface methodology was used to evaluate the effect of temperature (T), extraction time (E) and liquid-to-solid ratio (R) on the yield of phenolic extraction. Under optimal conditions (T = 53.3 °C, E = 110.4 min and R = 3.3 mL/g), over 90% of the phenolic compounds present in the waste were recovered. The three main factors T, E and R were all statistically significant and their influence on the extraction efficiency increased in the order: R

This work investigates the feasibility of using coffee silverskin (CSS), one of the most abundant coffee waste products, as a reinforcing agent in biopolymer-based composites. The effect of using two compatibilizers, a maleinized linseed oil (MLO) and a traditional silane (APTES, (3-aminopropyl)triethoxysilane), on mechanical and thermal behavior of sustainable composites based on a poly(butylene adipate-co-terephthalate/Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) PBAT/PHBV blend filled with coffee silverskin, in both the as-received state and after the extraction of antioxidants, was studied. Thermal (by differential scanning calorimetry), mechanical (by tensile testing), and morphological properties (by scanning electron microscopy) of injection molded biocomposites at three different weight contents (10, 20, and 30 wt %) were considered and discussed as a function of compatibilizer type. The effects of extraction procedure and silane treatment on surface properties of CSS were investigated by infrared spectroscopy. Obtained results confirmed that extracted CSS and silane-treated CSS provided the best combination of resistance properties and ductility, while MLO provided a limited compatibilization effect with CSS, due to the reduced amount of hydroxyl groups on CSS after extraction, suggesting that the effects of silane modification were more significant than the introduction of plasticizing agent.

A deeper knowledge of the chemical composition of coffee silverskin (CS) is needed due to the growing interest in its use as a food additive or an ingredient of dietary supplements. Accordingly, the aim of this paper was to investigate the metabolic profile of aqueous extracts of two varieties of CS, Coffee arabica (CS-A), Coffee canephora var. robusta (CS-R) and of a blend of the two (CS-b) and to compare it to the profile of Coffee arabica green coffee (GC). Chlorogenic acids, caffeine, furokauranes, and atractyligenins, phytotoxins not previously detected in CS, were either identified or tentatively assigned. An unknown compound, presumably a carboxyatractyligenin glycoside was detected only in GC. Caffeine and chlorogenic acids were quantified while the content of furokauranes and atractyligens was estimated. GC and CS were also characterized in terms of total polyphenols and antioxidant capacity. Differences in the metabolites distribution, polyphenols and antioxidant capacity in GC and CS were detailed.

We have investigated the recovery of lycopene from tomato processing waste (TPW) by treating the peel fraction of the waste with pectinolytic and cellulolytic enzyme preparations. To optimize the enzyme-assisted extraction, we used a two-level factorial design with five factors: extraction temperature (T), pretreatment time (P), extraction time (E), enzyme solution-to-solid ratio (R), enzyme load (L). A 7-to 16-fold increase was observed in lycopene recovery, compared to the untreated TPW. From a response surface analysis of the data, a second-degree polynomial equation was developed which provided the following optimal extraction conditions: T = 30 °C, P = 3.5 h, E = 3.2 h, R = 30 dm3/kg, L = 0.17 kg/kg.

Low-grade coffee beans (LCBs), a waste produced in large quantities by the coffee industry, was investigated as a potential low-cost adsorbent for the removal of methylene blue (MB) from wastewater. The waste was characterized by SEM analysis and FTIR spectroscopy. Equilibrium and kinetic experiments were performed to study the adsorption process. The equilibrium data were found to be well described by the Langmuir model, from which a maximum adsorption capacity of 476.2 mg g1was derived. A half-adsorption time ranging from 12.5 to 96.2 min was estimated by fitting the experimental kinetic data to the pseudo-second-order model.

Triclosan (TCS), an antimicrobial agent widely used in consumer and medical products, was complexed with 2-hydroxypropyl-β-cyclodextrin (HPβCD) and methyl-β-cyclodextrin (MβCD). Phase-solubility studies indicated that inclusion complexes of 1:1 stoichiometry were formed and allowed estimation of the associated equilibrium constants and free-energy changes. At the highest cyclodextrin concentrations investigated, an almost 20-fold increase in the apparent water solubility of TCS was determined. Susceptibility tests against Escherichia coli and Staphylococcus aureus showed that the TCS-HPβCD and TCS-MβCD complexes exhibited antibacterial properties higher than those of uncomplexed TCS. The two complexes were also found capable of interfering with cell-to-cell communication mechanisms in the C. violaceum model system relying on N-acylhomoserine lactone autoinducers. The inhibitory activity of TCS increased significantly upon inclusion of the drug in HPβCD or MβCD, with small differences between the two CDs. The results obtained suggest that the investigated complexes could be used for treating infections caused by TCS-susceptible pathogens or for preventing biofilm formation on indwelling medical devices such as catheters, stents and orthopedic implants.

The electrochemical decolorization of the Reactive Violet 5 azo dye on a boron-doped diamond anode was used as a model process to test a novel definitive screening design (DSD). This method allows a dramatic reduction in the number of experiments needed to investigate those systems characterized by a large number of variables. In this study, the effect of nine quantitative parameters was investigated: initial dye concentration (60–120 mg L−1), current density (100–500 A m−2), NaCl concentration (5–20 mM), Na2SO4 concentration (35–65 mM), pH (3–11), temperature (20–45 °C), inter-electrode distance (0.5–3.5 cm), stirring rate (250–750 rpm) and electrolysis time (2–8 min). Analysis of DSD data showed that four out of the nine factors (initial dye concentration, current density, pH and electrolysis time) were statistically significant. These factors were retained for process characterization using a subsequent central composite design. Overall, the number of experiments was reduced from over 500 to only 41, thus confirming the validity of the proposed approach as a time-saving and efficient method.

Large amounts of a waste known as tomato pomace and consisting mainly of the fruit peel and seeds are generated annually from the industrial processing of tomatoes. This material is rich in lycopene, a phytochemical with antioxidant and chemopreventive properties, and contains many valuable nutrients. In this study, we have investigated the possibility of using the whole waste to produce a lycopene-enriched seed oil. The oil was obtained by cold-pressing the seeds and was subsequently enriched in lycopene (up to 500 ppm) by incorporation of a tomato oleoresin derived from the peels. To increase lycopene recovery, the peels were pretreated with cell-wall-degrading enzymes and solvent extracted. This procedure allowed the production of about 25 kg/ton oleoresin with an average lycopene content of 6.8 wt.%. The compositional characteristics of the oil combined with the production of significant amounts of oleoresin strongly support the use of tomato pomace for producing lycopene-based functional products.

A central composite design was used to optimize the enzyme-assisted extraction of lycopene from the peel fraction of tomato processing waste. Tomato skins were pretreated by a food-grade enzyme preparation with pectinolytic and cellulolytic activities and then subjected to hexane extraction. The factors investigated included extraction temperature (10–50 °C), pretreatment time (0.5–6.5 h), extraction time (0.5–4.5 h), enzyme solution-to-solid ratio (10–50 dm 3 /kg) and enzyme load (0–0.2 kg/kg). Overall, an 8- to 18-fold increase in lycopene recovery was observed compared to the untreated plant material. From a response surface analysis of the data, a second-degree polynomial equation was developed which provided the following optimal extraction conditions: T = 30 °C, extraction time = 3.18 h and enzyme load = 0.16 kg/kg. The obtained results strongly support the idea of using cell-wall degrading enzymes as an effective means for recovering lycopene from tomato waste.

Four commercial enzyme preparations containing cell-wall degrading enzyme activities were tested for their ability to facilitate lycopene extraction from tomato paste. At 25°C, up to 75.6% of the lycopene present in the tomato product was extracted by a two-stage procedure that consisted of a preliminary 5 hour enzyme incubation followed by a 3 hour solvent (hexane or ethyl acetate) extraction. Increasing the duration of the enzymatic treatment to 12–18 h allowed the recovery of 85–90% of total lycopene. The highest extraction yields were achieved by using enzyme preparations with polygalacturonase and pectin methylesterase in addition to pectin lyase or cellulase activities.

Four commercial enzyme preparations with pectinolytic, cellulolytic and hemicellulolytic activities were tested for their ability to enhance lycopene extraction from tomato peels. Screening experiments were performed at 25 °C by subjecting the peels to a 4-h enzyme incubation followed by 1-h hexane extraction. Peclyve EP and LI were the most efficient, with an almost 20-fold increase in extraction yield. Peclyve LI was used to evaluate the influence of solvent type and enzyme incubation time on lycopene recovery. Hexane, ethyl acetate and the mixture hexane/acetone/ethanol 50:25:25 (v/v) were used as solvents. Under the best extraction conditions (1-h enzyme incubation followed by a 3-h solvent extraction at 40 °C) up to 440 mg of lycopene per 100 g of dry tomato peels were obtained. The percentage recoveries were in the range of 3–30%, for the untreated peels, and 77–98% for the enzymatically treated material.

Three nectar honeys (eucalyptus, thyme and forest) and two honeydew honeys (fir and Metcalfa) from Italy were tested for their antibacterial activity against pathogens commonly associated with wound and burn infections, including Methicillin-Resistant Staphylococcus Aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE) and Vancomycin-Resistant Enterococcus Faecalis (VREF). All honeys showed bactericidal activity against the microorganisms used, with honeydew honeys being the most effective. They also inhibited, in a dose-dependent manner, violacein production in Chromobacterium violaceum, thus demonstrating their ability to affect quorum sensing-regulated biofilm formation. Overall, the results obtained suggest that the honeys examined may have potential for developing natural antimicrobial compositions or dressings for the treatment of infected wounds or burns.

The kinetics of hydrogen peroxide decomposition by the enzyme catalase was studied at pH 7.4 in the temperature range 10–30 ◦ C. Experiments were performed by the LKB-2277 Thermal Activity Monitor equipped with a flow-mix cylinder. The calorimetric reaction unit was schematised as a tubular reactor operating under plug-flow conditions. A first-order kinetic expression, with respect to both the substrate and the enzyme, was used to describe the rate of hydrogen peroxide decomposition. Regression analysis of calorimetric data provided a molar reaction enthalpy of −87.55 kJ mol −1 and an activation energy of 11 kJ mol −1 . Analysis of model residuals and the normal probability plot indicated that the results obtained were statistically significant. © 2002 Elsevier Science B.V. All rights reserved.

The influence of the naturally occurring osmolytes xylitol, glycine and betaine on the thermal stability of human haemoglobin was investigated. Experiments were made in the temperature range of 55–70 °C, adding up to 30% w/w of osmolytes to the protein solution. All the additives stabilized haemoglobin, with xylitol and glycine appearing more effective. A kinetic analysis based on the Lumry–Eyring inactivation scheme showed that the denaturation process can be described by a second-order rate expression, with an apparent activation energy ranging from 45 to 82 kcal/mol.

The azo dye Reactive Green 19 (RG19) is extensively used for dyeing textiles due to its cost effectiveness and excellent fastness properties. Treatment of wastewaters containing this dye by conventional methods is often inadequate because of its resistance to biological and chemical degradation. In this study, the suitability of an advanced oxidation process based on the use of UV radiation and hydrogen peroxide to degrade RG19 was investigated. Analysis of degradation data showed that the decolorization process followed pseudo-first-order kinetics. The existence of an optimum pH and H2O2 dose was also observed. Under the best conditions, complete decolorization of the dye solution was achieved in about 20 min. Total organic carbon (TOC) measurements showed that mineralization was slower than decolorization, but over 63% of TOC was removed in 90 min. Overall, the results obtained indicate that the UV/H2O2 treatment can be an effective method for the removal of RG19 from textile effluents.

A high-fat (HF) diet increases lipid storage and oxidative stress in mouse liver and this process seems to be mediated by Peroxisome Proliferator-Activated Receptor α (PPARα). In this study we evaluated the protective effect of cocoa against hepatic steatosis induced by a HF diet. The HF diet down-regulated PPARα expression and turned off PPARα-signalling, deregulated the β-oxidation (β-Ox) system and catalase (CAT) activity, increased fat storage, reduced expression of enzymatic activity involved in oxidative defence in the liver and doubled the weight gain per calorie consumed compared to animals under the normal diet. In contrast, cocoa improved hepatic β-Ox, activated PPARα-signalling and up-regulated both gene and protein expression of SOD1. Moreover, when co-administered with the HF diet, cocoa treatment counteracted lipid storage in the liver, improved the lipid-metabolizing activity and oxidative stress defences and normalized the weight gain per calorie consumed.

The efficacy of the UV/H2O2 process to degrade the antibiotic chloramphenicol (CHL) was investigated at 20 °C using a low-pressure mercury lamp as UV source. A preliminary analysis of CHL degradation showed that the process followed apparent first-order kinetics and that an optimum H2O2 concentration existed for the degradation rate. The first-order rate constant was used as the response variable and its dependence on initial CHL and H2O2 concentrations, UV light intensity and reaction time was investigated by a central composite design based on the response surface methodology. Analysis of response surface plots revealed a large positive effect of radiation intensity, a negative effect of CHL concentration and that there was a region of H2O2 concentration leading to maximum CHL degradation. CHL solutions submitted to the UV/H2O2 process were characterized by TOC and their activity against Escherichia coli and Staphylococcus aureus was assessed. No residual antibiotic activity was detected, even at CHL concentrations higher than those used in the designed experiments. Overall, the obtained results strongly support the possibility of reducing the risks associated with the release of CHL into the environment, including the spread of antibiotic resistance, by the UV/H2O2 process.

Sarcosine and sorbitol at 10–30% (w/w) stabilized haemoglobin from human erythrocytes to thermal denaturation. At 65 °C, the protein's half life was increased from 0.85 to 50 min in 30% sarcosine and to 24 min in 30% sorbitol. A kinetic analysis based on the Lumry-Eyring mechanism of inactivation showed that the denaturation process can be described by a second-order rate expression with an apparent activation energy ranging from 56 to 87 kcal mol−1.

The potential use of the enzyme catalase to oxygenate blood was investigated. A microcalorimetric technique was used to study the kinetics of oxygen generation in human blood serum at 25 and 37°C. Experiments carried out in serum and in phosphate buffer provided the apparent rate constants for the enzymatic and non-enzymatic oxygen-generation reactions. A simplified mathematical model was then developed to analyse the behavior of a hollow-fiber membrane oxygenator with catalase covalently bound to the membrane surface. The model was used to simulate an extracorporeal oxygenation treatment and outline differences with current devices.

Spent coffee grounds (SCG) were extracted with an environmentally friendly procedure and analyzed to evaluate the recovery of relevant natural antioxidants for use as nutritional supplements, foods, or cosmetic additives. SCG were characterized in terms of their total phenolic content by the Folin-Ciocalteu procedure and antioxidant activity by the DPPH scavenging assay. Flavonoid content was also determined by a colorimetric assay. The total phenolic content was strongly correlated with the DPPH scavenging activity, suggesting that phenolic compounds are mainly responsible for the antioxidant activity of SCG. An UHPLC-PDA-TOF-MS system was used to separate, identify, and quantify phenolic and nonphenolic compounds in the SCG extracts. Important amounts of chlorogenic acids (CGA) and related compounds as well as caffeine (CAF) evidenced the high potential of SCG, a waste material that is widely available in the world, as a source of natural phenolic antioxidants.

Spent coffee grounds (SCG) and coffee silverskin (CS), the two main coffee industry residues, were magnetically modified by contact with an aqueous ferrofluid containing magnetite nanoparticles. The materials were characterized by SEMEDX analysis, X-ray diffraction and FTIR spectroscopy. Batch adsorption experiments were performed to assess their suitability as biosorbents, using methylene blue as a model pollutant. Adsorption equilibrium data were analysed by the Langmuir model, which allowed estimation of the maximum adsorption capacity. The magnetic biosorbents were easily regenerated by treatment with hydrochloric acid.