Effect Of Hydrolysis Degree Research Articles

Effect of hydrolysis degree with Alcalase on antioxidant and antigenic properties of whey and colostrum protein hydrolysates

Enzymatic hydrolysis of dairy proteins is aimed to increase their nutritional value and reduce their allergenic properties. It is relevant to study the effects of enzymatic hydrolysis with highly active endopeptidase alсalase on the bioactivity of the whey and colostrum protein components. Dairy hydrolysates with various degree of Alcalase treatment were obtained in the present study. A comparative analysis of cleaved dairy proteins and their peptide fractions with a 5 and 10 kDa cutoff was performed. The protein and peptide composition of hydrolysates was determined using various techniques. The bioactivity of hydrolyzed whey and colostrum samples were estimated. The antioxidant activity of hydrolyzed and fractionated (5 kDa cutoff) whey samples increased by 5.91/6.62-fold and that of colostrum by 14.22/7.24-fold in fluorimetric/spectrophotometric assay, respectively. A significant decrease in the antigenic potential of milk peptides was observed with increasing degree of hydrolysis and subsequent ultrafiltration. Thus, bioactive dairy protein hydrolysates were obtained, which are applicable as a component of specialized foods with proven hypoallergenic properties and high antioxidant activity.

Effects of hydrolysis degree on ion-doped anion exchange membranes in direct borohydride fuel cells

Herein, polyvinyl alcohol based anion exchange membranes (AEMs) doped with various cobalt and chloride salts are synthesized to investigate the structure-performance relationship of ion-doped AEMs systemically. The performances of ion-doped AEMs are found to be related to the hydrolysis degree (DH) of the doped anions and cations. It is found that cations with varying DH transformed into hydroxides with different sizes and dispersions, which plays a key role in determining the structures and properties of cation-doped AEMs. On the other hand, weak-acid anions remained in the AEMs after alkali immersion, hindering OH− conduction and leading to the degradation of the anion-doped AEMs. High DH cations mildly react with the matrix and transform into more dispersive complexes, while low DH anions are replaced by OH−.The direct borohydride fuel cell using CuCl2-doped AEM exhibits a maximum power density of 202.4 mW cm−2 at 30 °C.

Effects of hydrolysis degree on the formation of ferroelectric-core fillers and the electric performance of polyvinyl alcohol composites

Dielectric materials have been regarded as an emerging field for dielectric energy storage in the last few decades. To improve the dispersion of high-dielectric-constant fillers in polymer, many methods of surface modification and core-shell structure have been reported focusing on the forming of shell. Here we introduce a soluble ferroelectric [Hdabco]ClO4 (TEDA.C, dabco = diazabicyclo[2.2.2]octane) into polyvinyl alcohol (PVA) matrix via solution mixing to create a ferroelectric TEDA.C crystal core by the hydrogen bonding between PVA and TDEA.C. We studied the effects of PVA's chain structure on the interfacial interactions between the two components, the crystalline phase of TEDA.C, and the dielectric, ferroelectric, and physical properties of composites by employing three PVAs of different hydrolysis degree. High hydrolysis degree promoted the homogeneous distribution and fine miscibility of TEDA.C in PVA matrix, but also impeded the hydrogen bond movement of TEDA.C, which resulted in the disordered paraelectric phase of ordered-disordered-type ferroelectric. Comparing the dielectric, ferroelectric and physical properties of three PVA systems provides further insights about the hydrolysis degree of PVA benefitting the interfacial interaction and interfacial effects, leading to a potential facile and powerful tool for tuning the properties of PVA composites.

Effect of hydrolysis degree and mass molecular weight on the structure and properties of PVA films

In this work, we aim to analyze the variation of structural, thermal, and dielectric properties of polyvinyl alcohol (PVA) films by varying the molecular weight (Mw) and the hydrolysis degree (HD). The XRD study revealed the improvement of the crystallinity degree by the increase of HD or the decrease of Mw. The DSC study showed the decrease of the molecular mobility with the increase of either the hydrolysis degree or the molecular weight. The dielectric measurements showed four dielectric processes attributed to electrode/sample polarization, α a-relaxation, α c-relaxation, and β-relaxation. The activation energy attributed to α a-relaxation and α c-relaxation, increase with the increase of the molecular weight Mw, and the decrease of HD. The Ac conductivity is well fitted to the universal Jonsher law in the frequency range where the electrode/sample polarization can be neglected.

Effect of Hydrolysis Degree on Structural and Interfacial Properties of Sunflower Protein Isolates

Effect of Hydrolysis Degree on Structural and Interfacial Properties of Sunflower Protein Isolates

Effect of hydrolysis degree on functional properties of sesame cake protein hydrolysates

Effect of hydrolysis degree on functional properties of sesame cake protein hydrolysates

Preparation, characterization and properties of partially hydrolyzed ethylene vinyl acetate copolymer films for controlled drug release

In this study, partially hydrolyzed ethylene vinyl acetate (EVA) copolymers with three hydrolysis degrees (12.2%, 32.6% and 46.9%) were obtained by alkaline hydrolysis of EVA copolymer, characterized by Fourier-transform infrared spectroscopy (FTIR), 1H NMR and gel permeation chromatography (GPC). Paclitaxel-loaded and drug-free films based on the partially hydrolyzed EVA copolymers were fabricated. The swelling behaviors, crystallinities, mechanical properties of the fabricated films were investigated, and the effects of hydrolysis degree, film thickness and drug loading dose on in vitro drug release from the films were also investigated. In vitro swelling study showed that the swelling of partially hydrolyzed EVA films was greater than the EVA film and the film with higher hydrolysis degree swelled more intensively. X-ray diffraction (XRD) results exhibited that the crystallinity of the polymer increased with increasing hydrolysis degree. In paclitaxel-loaded EVA film, a part of paclitaxel was in crystalline form; while in paclitaxel-loaded partially hydrolyzed EVA films, paclitaxel was distributed in amorphous form or molecularly dispersed. In the in vitro drug release test, the film with higher hydrolysis degree and smaller thickness released paclitaxel more quickly. With higher drug loading dose, the drug release rate was larger. The partially hydrolyzed EVA films were applied for drug delivery systems for the first time, and demonstrated to have great capability of controlling drug release thanks to the adjustable hydrolysis degree.

The Effect of Hydrolysis Degree on the Properties of Antibacterial Polymeric Films Based on Poly(vinyl alcohol) and Zinc Sulphate for Biomedical Applications

Fully and partially hydrolyzed poly(vinyl alcohol) (PVA) was modified with zinc sulphate in the concentration range from 0 to 9 wt% of recalculated zinc content using the solvent cast technique. The resulting polymeric films were characterized by optical microscopy, stress–strain analysis, differential scanning calorimetry and Fourier transform infrared spectroscopy (FT-IR–ATR). In addition, agar diffusion test and dilution and spread plate technique were used for determination of antibacterial properties of the films against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) bacterial strains. A mathematical model was applied on the measured data and parameters characterizing the antibacterial efficiency of the material were calculated and discussed. The results revealed that the PVA hydrolysis degree can play an important role in all studied properties, including antibacterial activity of the all PVA-based materials.

Oxo-biodegradable polymers – Effect of hydrolysis degree on biodegradation behaviour of poly(vinyl alcohol)

Poly(vinyl alcohol) (PVA) is considered to be one of the very few vinyl polymers soluble in water and susceptible to biodegradation in aqueous media by specific microorganisms, implying oxidation of the carbon backbone followed by a random endocleavage of the polymer chains. The overall process does not appear to be appreciably affected by either degree of polymerization (DPn) or degree of hydrolysis (HD) of PVA at least in the 100–1000 and 80–100% ranges, respectively. In order to assess the effect of HD on the biodegradation propensity of PVA, different PVA samples having similar DPn and noticeably different HD values were synthesized by controlled acetylation of commercial PVA (HD = 99%) and submitted to biodegradation tests in aqueous medium, mature compost and soil by using respirometric procedures. Re-acetylated PVA samples characterized by HD of between 25 and 75% underwent extensive mineralization when buried in solid media, whilst PVA (HD = 99%) showed recalcitrance to biodegradation under those conditions. An opposite trend was indeed observed in aqueous solution, thus suggesting that biodegradation is not an absolute attribute directly related to structural features of the substrate under investigation. Boundary conditions related to the framework under which the biodegradation assessment is undertaken have to be taken into account and specifically well defined.

PRECURSOR-MONOMER METHOD OF SOL-GEL FOR FABRICATION PT/PZT/PT FERROELECTRIC FILMS

ABSTRACT Lead zirconate titanate Pb(Zr0.52Ti0.48)O3 (PZT) thin films was successfully deposited on Pt(111)/Ti/SiO2/Si(100) substrates by a new modified sol-gel technique: precursor-monomer method. In this process three separated Pb2 +, Zr4 +, Ti4 + precursor-monomers and metal chelating agents were mixed together to prepare PZT sol-solution (precursor). The precursor-monomer method has several advantages over conventional sol-gel methods, including easy change the atomic ratio of Pb2 +/Zr4 +/Ti4 + and doping metallic ions, rapid PZT precursor synthesis, low processing temperature, without dry condition and distillation, long storage period, simplicity and low cost, etc. The paper investigated the effects of hydrolysis degree on the stability of PZT precursor, and it was found that the sample with 12.5% (v/v) adding water had the longest storage time. The inference of lead titanate (PbTiO3, PT) seeding layers on the microstructures, surface morphologies and ferroelectric properties of PZT films has also been systematically examined. We found that PZT films with PT/PZT/PT structure had lower perovskite phase crystallization temperature, larger grain size, better microstructure and ferroelectric properties as compared with no PT seeding layers films.