Summary
Recently, dynamic induction control is gaining the interest of the wind energy community as a promising strategy to increase the overall wind farm power production. Such a technique is based ...on a dynamic variation of the upstream rotor thrust, generated through a suitable blade pitch motion, to promote a faster wake recovery. Notwithstanding some promising results already published, the knowledge of the physical mechanism, connecting dynamic induction to the increased in‐wake velocity, was not yet exploited to enhance control effectiveness. This paper, through a computational fluid dynamics procedure based on large eddy simulations coupled with actuator line models, provides a description of the working principles of this control from a fluid dynamics standpoint. The analyses show that the faster recovery is strictly connected to the ability of the blade tip vortices to roll up and sucking energy from the outer flow. Exploiting such knowledge, a novel control strategy, which improves the vortex roll up mechanism, is proposed and analyzed. The new control proved more effective than standard techniques especially for very low turbine spacing.
•Hydrolysis conditions by trypsin regulate the antioxidant activity of WPC hydrolysates.•Optimal hydrolysis parameters produce powerful antioxidant peptides at low cost.•Peptides with molecular ...weight <3 kDa shown high antioxidant activities.•WPC hydrolysis increases cytoprotection against oxidative stress on IEC-18 cells.
Whey protein is one of the most relevant co-products manufactured by the dairy industry and it is a powerful environmental pollutant. Therefore, the enzymatic hydrolysis of whey protein concentrate (WPC 35) to produce antioxidant peptides is an innovative approach which can provide added value to whey. The WPC 35 hydrolysis with trypsin was carried out for 4.31 h at 41.1 °C with an enzyme/substrate ratio of 0.017. Under such hydrolysis conditions, the peptides produced have the highest radical scavenging activity and cytoprotector effect. The WPC hydrolysate and a permeate ≤3 kDa were characterized by SDS-page, RP-HPLC and MALDI-TOF-MS. Furthermore, O2•− and HO• scavenging activity and the cytoprotective effect against a stress agent in epithelial cells of the rat ileum (IEC-18) were determined. In this study, strong antioxidant and cytoprotective peptides were obtained from a low-cost dairy industry product, which could improve consumers’ health when used as functional ingredients.
We used water-soluble Chitosan obtained by Maillard reaction with glucosamine to microencapsulate soy genistein (Ge) and preserve its biological activity for oral administration. Release of Ge was pH ...dependent with a super Case II mechanism at pH 1.2 and an anomalous transport with non-Fickian kinetics at pH 6.8. Microencapsulated Ge retained its antioxidant properties in vitro and its daily administration to mice attenuated clinical signs of acute colitis, limited inflammatory reaction and reduced oxidative stress and tissue injury as well. Remarkably, after feeding microencapsulated Ge the production of IL-10 in colonic tissue was restored to levels of untreated controls. According to statistical multivariate analysis, this cytokine was the parameter with the highest influence on the inflammatory/oxidative status. Microencapsulation of Ge with derivatized Chitosan becomes an interesting alternative to develop therapeutic approaches for oxidative inflammatory diseases; our findings suggest that the soy isoflavone could be incorporated into any functional food for application in intestinal inflammation.
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•Extraction of peanut skin phenolics was performed using water/ethanol at sub-critical conditions.•Theoretical models were run against experimental data in order to optimize ...extraction conditions.•Peanut skin extracts contained a vast array of polyphenolic compounds.•High extraction rates of polyphenolics were associated with greater antioxidant activity.•The process, based on the use of GRAS solvents, may be adapted toward food industry applications.
This study evaluates the feasibility of using sub-critical water extraction (SWE) processes to obtain antioxidant phenolic compounds from peanut skins. Theoretical models were tested against experimental data in order to optimize extraction conditions and antioxidant activity of target compounds. The maximum concentration of total phenolics was achieved by using 60.5% ethanol as co-solvent, at 220°C extraction temperature and 7g/min solvent flow. Under these extraction conditions, a large number and variety of polyphenols were identified. Phenolic profile was dominated largely by monomeric and condensed flavonoids, particularly procyanidin and proanthocyanidin oligomers. Extracts obtained under those conditions also gave the best radical scavenging capacities, which were higher to those reached by using a synthetic antioxidant (BHT, butylhydroxytoluene). Kinetic studies showed a high extraction rate of polyphenols until the first 30min of extraction, and it was in parallel with the highest antioxidant activity.
The agro-industry produces numerous byproducts that are currently underused, and its waste contributes to environmental pollution. These byproducts represent an important and economical source of ...bioactive ingredients, which can promote the sustainable development of high-value-added functional foods. In this context, micro- and nanoencapsulation systems allow for the incorporation and stabilization of the bioactive agents in foods. This perspective will review recent advances in the use of agro-industrial byproducts as a source of bioactive agents. In addition, the latest advances in micro- and nanoencapsulation to improve the stability, solubility, and bioaccessibility of bioactive agents as functional food ingredients are exposed.
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•Water-soluble chitosans were obtained by Maillard reaction with glucose or lactose.•Chit derivatives enable immobilization of glucose oxidase and lactate oxidase.•A highly efficient ...glucose biosensor was obtained by assembling G-Chit and GOx.•The analytical response was tested in milk samples with negligible matrix effects.
In this work we demonstrate for the first time the advantages of using water-soluble chitosan polycation obtained by Maillard reaction with glucose (G-Chit) or lactose residues for the immobilization of glucose oxidase (GOx) and lactate oxidase by the layer-by-layer adsorption method onto carbon paste electrodes. Besides its solubility in enzyme-compatible media, these polymers have a suitable charge density for electrostatic adsorption and allow adequate charge transfer at the electrode-solution interface. Based on the analysis of the effect of the type of chitosan derivative on the enzymatic response; we built an efficient biosensor based on G-Chit and GOx. The multilayered structure made of three bilayers of G-Chit and GOx showed the best performance; the biosensor exhibits a sensitivity of (12.4 ± 0.3) µA mM−1 cm−2 in a glucose concentration range from 180 µM to 1.75 mM. In addition, the analytical response of this biosensor was tested in milk samples with negligible effects of the matrix. The results confirm the suitability of these chitosan derivatives for the adsorption of enzymes and the construction of supramolecular structures. The favorable environment for the enzymatic activity results in bioelectrodes with fast responses for quantification of glucose even in a complex matrix like milk.
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•Water-soluble chitosan derivatives showed significantly larger solubility that the native Ch.•Deacetylation degree (DD) of chitosan derivatives decreased by approximately ...12%.•Molecular weight of chitosan derivatives was reduced 6 times, suggesting the breakdown of the Ch chain.•The singlet molecular oxygen quenching abilities of chitosan derivatives were proportional to DD of polysacharides.•Water-soluble chitosan derivatives presented antimicrobial activity against pathogenic bacteria.
New water-soluble chitosan derivatives (WSCh) were obtained by Maillard reaction (MR) between glucosamine (GA) with both low and medium molecular weight chitosans (Ch). The WSCh showed larger solubility than the respective Ch, while their deacetylation degree (DD) decreased by approximately 12%. Infrared spectroscopy experiments of WSCh confirmed the formation of imine bonds after MR with intensified pyranose structure, and sugar molecules as polymer branches. However, a 6-times reduction of the molecular weight of WSCh was measured, indicating the breakdown of the polysaccharide chain during the MR. The polysaccharides quenched singlet molecular oxygen (1O2), with rate quenching constants correlating with the DD value of the samples, suggesting the important role of amino groups (−NH2) in the deactivation of 1O2. Additionally, all polysaccharides presented antimicrobial activity against pathogenic bacteria, e.g. Staphylococcus aureus, Escherichia coli, Salmonella sp., Enterococcus faecalis and Listeria ivanovii, as tested by their minimum inhibitory concentration (MIC). This way we obtained new water-soluble polysaccharides, with similar functional properties to those presented by native Ch, enhancing its potential application as carrier material for bioactive compounds.
Summary The aim of this study was to develop and evaluate the bioactive properties and storage stability of microcapsules (MCs) obtained by co‐encapsulation of the potential probiotic yeast ...Kluyveromyces marxianus VM004 and peanut skin polyphenolic extract (PSE) by spray drying, using whey protein concentrate (WPC) and water‐soluble chitosan (WSCh) as wall materials. The results showed that the selected wall materials provided protection to yeast during spray drying, storage, and simulated gastrointestinal conditions, obtaining better results for WPC and higher concentrations of PSE. Moreover, all formulations demonstrated cytoprotective effects against menadione‐induced oxidative stress in normal rat ileum epithelial cells (IEC‐18) at all concentrations and storage temperatures evaluated. These results suggest that the obtained MCs could be potential functional food ingredients, considering their antioxidant, cytoprotective, and potential probiotic properties.
A chitosan-glucose derivative (ChG) with lower antimicrobial activity against whey native probiotic yeast K. marxianus VM004 was synthesized by the Maillard reaction. The ChG derivative was ...characterized by FT-IR, 1H NMR, and SLS to determine the structure, deacetylation degree (DD), and molecular weight (Mw). In addition, we evaluated the antioxidant, cytotoxic, and antimicrobial activities of ChG. ChG was then used for microencapsulation of K. marxianus VM004 by spray drying. The microcapsules were characterized by evaluating their encapsulation yield, encapsulation efficiency, morphology, tolerance to the gastrointestinal tract, and viability during storage. The results indicated that a non-cytotoxic product with lower MW and DD and higher antioxidant activity than native chitosan was obtained by the Maillard reaction. The yeast ChG microcapsules exhibited an encapsulation efficiency >57 %, improved resistance to gastrointestinal conditions, and enhanced stability during storage. These results demonstrate that ChG may be a promising wall material for the microencapsulation of probiotic yeasts.
•Chitosan-glucose derivative (ChG) did not show antimicrobial activity against yeast.•ChG is not-cytotoxic and shows higher antioxidant activity than native chitosan.•Mw and deacetylation degree of ChG decreases by approximately 10 %.•Microencapsulation in ChG improved resistance to the gastrointestinal conditions.•Crosslinking microcapsules improves tolerance to the intestinal tract and storage stability.
Abstract
Bacteriocins from Gram-positive bacteria have been proposed as natural food preservative and there is a need for large-scale production for commercial purposes. The aim of the present work ...is to evaluate whey, a cheese industrial by-product, for the production and microencapsulation of enterocin CRL35. Whey proved to be a promising basal medium for bacterial growth although the bacteriocin production was quite low. However, it could be much favored with the addition of yeast extract at concentrations as low as 0.5%. Besides improving bacteriocin production, this peptide was successfully microencapsulated by spray drying using whey protein concentrate and a chitosan derivative as wall materials. Microcapsules averaging 10 ± 5 μm diameter were obtained, with good structural integrity and high antimicrobial activity with a stability of at least 12 weeks at 4°C. In summary, sustainable bacteriocin production and microencapsulation was achieved recycling whey or its derivatives. In addition, the formulation owns high antimicrobial activity with a long shelf life. The development of a food preservative may represent a green solution for handling whey.
The production of enterocin CRL35 in whey and yeast extract followed by microencapsulation represents a green solution for industrial byproducts, obtaining an efficient food preservative with long shelf life.
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