Investigation of lactones and lactams Communication 15. Polyvinylpyrrolidinone preparations of various molecular weights and their physicochemical properties

Author(s):  
M. F. Shostakovskii ◽  
P. S. Vasil'ev ◽  
F. P. Sidel'kovskaya ◽  
E. S. Morgunova ◽  
M. G. Zelenskaya ◽  
...  
Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1244
Author(s):  
Malik Adil Nawaz ◽  
Tanoj Kumar Singh ◽  
Regine Stockmann ◽  
Hema Jegasothy ◽  
Roman Buckow

The objective of this research was to develop a model faba bean drink with a high concentration of protein (>4% w/w). The protein molecular weights and frequency for both faba and soy were assessed using SDS-PAGE. Results showed similarities in the protein molecular weight of both faba and soy (mainly 11S globulin ~Glycinin and 7S globulin ~β-conglycinin). Thus, faba can be considered as a potential soy replica in plant-based milk beverages. Oil-in-water emulsions (5–8% w/w available protein) were prepared using faba bean protein concentrate (FPC), 1% sunflower oil, and 0.2% sunflower lecithin. These emulsions were used as model beverages and were further investigated for UHT processibility, stability, and physicochemical properties. The physicochemical properties of emulsions at various processing stages viz., coarse emulsification, homogenisation, and UHT, were measured. An increase in the protein concentration and thermal treatment resulted in an increased oil droplet size, coalescence and flocculation, and protein aggregation. Lower protein concentrations viz., 5–6%, showed greater negative ζ-potential, and thereby, high dispersibility through enhanced electrostatic repulsions than those of higher concentrations (7–8%). Furthermore, an increase in protein concentration and UHT treatment resulted in an increased creaming index. In total, 21 different volatile compounds were detected and quantified, representing different chemical classes, namely alcohols, aldehydes, ketones, esters, furan, and acids. These volatiles have major consequences for the overall flavour chemistry of the model beverage product. Overall, this study showed the potential for application of faba bean as a protein source in UHT-treated legume-based beverages and identified areas for further development.


Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1049 ◽  
Author(s):  
Rosalía Rodríguez-Dorado ◽  
Clara López-Iglesias ◽  
Carlos García-González ◽  
Giulia Auriemma ◽  
Rita Aquino ◽  
...  

Processing and shaping of dried gels are of interest in several fields like alginate aerogel beads used as highly porous and nanostructured particles in biomedical applications. The physicochemical properties of the alginate source, the solvent used in the gelation solution and the gel drying method are key parameters influencing the characteristics of the resulting dried gels. In this work, dried gel beads in the form of xerogels, cryogels or aerogels were prepared from alginates of different molecular weights (120 and 180 kDa) and concentrations (1.25, 1.50, 2.0 and 2.25% (w/v)) using different gelation conditions (aqueous and ethanolic CaCl2 solutions) and drying methods (supercritical drying, freeze-drying and oven drying) to obtain particles with a broad range of physicochemical and textural properties. The stability of physicochemical properties of alginate aerogels under storage conditions of 25 °C and 65% relative humidity (ICH-climatic zone II) during 1 and 3 months was studied. Results showed significant effects of the studied processing parameters on the resulting alginate dried gel properties. Stability studies showed small variations in aerogels weight and specific surface area after 3 months of storage, especially, in the case of aerogels produced with medium molecular weight alginate.


1975 ◽  
Vol 21 (12) ◽  
pp. 2019-2027
Author(s):  
M. Laguerre ◽  
R. Turcotte

The tuberculin activity of protoplasmic extracts isolated from living BCG was purified successively by gel filtration on Sephadex G-100 and G-75, and by electrophoresis on 7.5% and on gradient (6–18%) polyacrylamide gels. The tuberculin-active fractions, as determined in BCG-sensitized guinea pigs, were used as the starting material for each of the following fractionation steps.The physicochemical properties and the antigenic activity of the biologically active fractions have shown that a single component, or only a few ones with similar properties, possessed high tuberculin activity. These active components were proteins having relatively high molecular weights (about 72 000) and could behave as antigens.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 211 ◽  
Author(s):  
Valentina Sabatini ◽  
Tommaso Taroni ◽  
Riccardo Rampazzo ◽  
Marco Bompieri ◽  
Daniela Maggioni ◽  
...  

Polyamide 6 (PA6) suffers from fast degradation in humid conditions due to hydrolysis of amide bonds, which limits its durability. The addition of nanotubular fillers represents a viable strategy for overcoming this issue, although the additive/polymer interface at high filler content can become privileged site for moisture accumulation. As a cost-effective and versatile material, halloysite nanotubes (HNT) were investigated to prepare PA6 nanocomposites with very low loadings (1–45% w/w). The roles of the physicochemical properties of two differently sourced HNT, of filler functionalization with (3-aminopropyl)triethoxysilane and of dispersion techniques (in situ polymerization vs. melt blending) were investigated. The aspect ratio (5 vs. 15) and surface charge (−31 vs. −59 mV) of the two HNT proved crucial in determining their distribution within the polymer matrix. In situ polymerization of functionalized HNT leads to enclosed and well-penetrated filler within the polymer matrix. PA6 nanocomposites crystal growth and nucleation type were studied according to Avrami theory, as well as the formation of different crystalline structures (α and γ forms). After 1680 h of ageing, functionalized HNT reduced the diffusion of water into polymer, lowering water uptake after 600 h up to 90%, increasing the materials durability also regarding molecular weights and rheological behavior.


Clay Minerals ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 325-336 ◽  
Author(s):  
A. Violante ◽  
A. de Cristofaro ◽  
M.A. Rao ◽  
L. Gianfreda

AbstractProteins (catalase, albumin, pepsin and lysozyme with different molecular weights and isoelectric points) were differently adsorbed at pH 7.0 on the clay fraction of three raw Na-saturated smectites (Crook and Uri montmorillonites and one hectorite). The adsorption isotherms of proteins on clay minerals showed typical Langmuir characteristics. Lysozyme was adsorbed under the effect of electrostatic interactions between the opposite charges of clay surfaces and protein molecules, whereas catalase and albumin were adsorbed under the effect of non-electrostatic forces. Pepsin was held in relatively high amounts only on the surfaces of hectorite. Proteins were intercalated in the interlayers spaces of smectites, usually undergoing extensive unfolding. Protein-smectite complexes showed different behaviour to heating treatment. Some complexes remained practically unchanged after heating at 200°C. Presence of ‘wrecks’ of interlayered materials was found after heating at 500°C for two hours. The amounts of proteins adsorbed on the external and interlamellar surfaces of clay minerals, partially coated with OH-Al species, were much lower than those fixed on the clean clays. Only lysozyme was intercalated in chlorite-like complexes.


1964 ◽  
Vol 42 (10) ◽  
pp. 1487-1498 ◽  
Author(s):  
R. R. Matsuo ◽  
A. G. McCalla

Gluten dispersed in 8% sodium salicylate and in lactic acid – sodium chloride solutions yielded intrinsic viscosity values in decreasing order, hard, soft, and durum wheats. Dispersions prepared under nitrogen yielded higher values than those prepared in air. Treatment of gluten with performic acid or with large excesses of sodium sulphite reduced the intrinsic viscosity of all glutens but the order of the values remained the same. Sedimentation coefficients were significantly reduced by the treatments, with the greatest reduction for gluten from durum wheat treated with performic acid. Sulphydryl group analysis gave the lowest value for gluten from hard wheat and the highest for that from durum. Results suggest that disulphide and sulphydryl groups are involved in determining physicochemical properties of gluten.No significant differences among the glutens from the three wheats were found in sedimentation coefficients, in distribution of such coefficients, or in amino acid composition, nor in the diffusion constants or molecular weights for the most soluble fraction from each.


2017 ◽  
Vol 68 (10) ◽  
pp. 2385-2388
Author(s):  
Raoul Vasile Lupusoru ◽  
Laurentiu Simion ◽  
Ion Sandu ◽  
Daniela Angelica Pricop ◽  
Aurica Chiriac ◽  
...  

We studied the way in which stability and physicochemical properties of gold (Au) nanoparticles (NP) coated with chitosan are influenced by the molecular weight of chitosan and Au precursor concentration when samples are subjected to aging. Pharmaceutical use of AuNPs coated with chitosan is closely related to stability and physicochemical properties in relation to storage conditions and processing. For this purpose, series of AuNPs of different sizes were prepared by aqueous chemical reduction method using chitosan with various molecular weights as template. The physicochemical properties and stability at room temperature of AuNPs in aqueous solutions of chitosan have been investigated by following the temporal evolution of surface plasmon absorbance, Zeta potential, average dimension, and Au-chitosan interaction, after synthesis and through a period of 24 months. In our experiment, during the observed aging period, the AuNPs coated with chitosan presented a better colloidal stability, while using chitosan with medium molecular weight and medium concentration of Au precursor.


2019 ◽  
Vol 96 ◽  
pp. 663-670 ◽  
Author(s):  
Shuping Ma ◽  
Peilei Zhu ◽  
Mingchun Wang ◽  
Futao Wang ◽  
Naifu Wang

2020 ◽  
Vol 10 (3) ◽  
pp. 419-429
Author(s):  
Jiaxin Tian ◽  
Yuhang Wang ◽  
Jinling Li ◽  
Yonggang Chen ◽  
Jiarui Qinchen ◽  
...  

This work is aimed to investigate the effects of molecular weights on physicochemical properties of fish gelatins and their potential application to food capsule film fabrication. Firstly, high/medium/low component fish gelatins (HCG/MCG/LCG) were obtained by ultrafiltration. Physicochemical property assay results showed that high molecular weight content of gelatin contributed to the increase in gelling strength, viscosity, melting point, and denaturation temperature due to extensive inter–intra molecular interactions. Meanwhile, parameters (temperature, weight ratio, and drying time) had been comprehensively investigated to determine the effects of three molecular weights of gelatins on capsule film manufacture. MCG-derived capsule film was found to achieve good balance among tensile strength, elongation at break, and dissolution rate constant. Furthermore, 90-day acceleration storage stability experiment suggested that MCG showed an appropriate ɛ-amino acid residue content and crosslink density. This work provides a comprehensive insight into the effect of molecular weights on physicochemical properties of fish gelatins and their application in food capsule film manufacture.


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