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关键词： Gluten gel   Inulin molecular weight   Physicochemical properties   Chemical interactions   Structure  

摘要： This study evaluates the influences of inulin molecular weight (Mw) on the rheological, textural, and structural properties of heat-induced inulin-gluten gel. L-inulin (420 Da), M-inulin (1020 Da), and H-inulin (3360 Da) were each investigated for their effects on the physicochemical properties and structure of gluten gel. It was found that inulin caused the gels to exhibit a smaller G' at initial heating, however, gluten gels prepared from M-inulin and H-inulin featured increased G', G '', and tans during cooling. Compared to gluten gel, inulin-gluten gels exhibited lower hardness, cohesiveness, chewiness, recovery, and water holding capacity. All inulin, regardless of Mw, reduced the hydrophobic interaction and hydrophobicity index H-0 of the gels. M-inulin and H-inulin reduced ionic bonding but increased hydrogen bonding. In gels comprised of 40% L-inulin, M-inulin, or H-inulin, gluten disulfide bonding was reduced by 31.8%, 68.1%, and 78.2%, respectively. Regardless of Mw, inulin also reduced beta-sheets and increased random coils of gluten, and provoked disulfide bond conformation to change from g-g-g to t-g-t and t-g-g, rendering the inulin-gluten gel structure more disordered and less stable. H-inulin mainly influenced the cross-linking of 30-35 kDa gluten molecules. In short, the impact of inulin on heat-induced inulin-gluten gel properties was Mw-dependent, following H-inulin > M-inulin > L-Inulin. H-inulin strongly inhibited the aggregation of gluten, thereby reducing hydrophobic interactions and disulfide bonding to result in a soft inulin-gluten gel.

关键词： Proteases   Extracellular   Alkaline serine protease   Pediococcus acidilacticiNCDC 252   Soybean trypsin inhibitor  

摘要： Proteases are the most important industrial enzymes capable of hydrolyzing proteins into small peptides and amino acids and used commercially in food, textile and pharmaceutical industries. An alkaline serine protease from Pediococcus acidilactici NCDC 252 was purified using a simple two step purification procedure i.e. ammonium sulphate precipitation and gel filtration chromatography with purification fold of 5.9, a yield and specific activity of 11.8% and 23.3 U mg/ml respectively. Purified enzyme worked optimally at pH 8.5 and 37 degrees C. The enzyme was stable in the pH range of 6.5-9.5 and up to 50 degrees C. The K-m for BAPNA was 38 mu M and V-max was 10.6 U/mg. Purified enzyme exhibited highest hydrolyzing activity for BAPNA. Inhibition of purified enzyme by soybean trypsin inhibitor, benzamide and mu-ME suggested the enzyme to be alkaline serine protease with involvement of cysteine residues either in binding or regulation. In-silico characterization of alkaline serine protease revealed the presence of Ser, His and Asp residues at its catalytic site. This shows the resemblance of alkaline protease under study with other studied serine proteases. [GRAPHICS] .

关键词： Pseudo cereal   Gluten free   Protein digestibility   Antioxidant   Gel electrophoresis  

摘要： The physicochemical and functional properties of grains, flour and protein isolates (QPI) from different quinoa lines were evaluated. Quinoa flour and protein isolates were characterised by high protein (14.1-15.4% and 78.7-86%, respectively) and phenolic content (419 to 655 mg GAE/100 g). Water and oil absorption capacity of QPI (2.0-3.6 g/g and 2.71-3.32 g/g, respectively) was significantly higher than quinoa flour (1.22 and 2.17 gand 0.9 and1.54 g, respectively). QPI showed desirable functional properties in terms of high foaming capacity (50.8 to 60.2%), foam stability (38.5 to 50.4%), protein solubility (30 and 53.3%), and emulsification index (EAI19.2-26.1 m2/g and ESI96.7-149.8 min, respectively). Digestibility of QPI ranged between 70.8 and 77.8% and was negatively correlated to random coils. Quinoa lines with higher grain density (GD) showed higher total phenol content (TPC) and WAC and lower FRSA and OAC. QPI with higher proportions of beta-structure and random coils had enhanced protein surface activities leading to improved emulsification and foaming capabilities. Among the highly conserved polypeptides (PPs), variations were observed in accumulation of 53, 59 and 32 kDa PPs for grains and 33 and 21-24 kDa PPs for QPI.

关键词： Physicochemical properties  

摘要： This work aims to optimize a new formulation of orange nectar sweetened with Stevia and enriched with Pectin using full factorial design with two factors, two levels, and one central point. Factors were the concentration in stevia and pectin. Physicochemical characterization and stability study were carried-out at 4 and 25 degrees C where pH, Brix degrees, total titratable acidity, turbidity, sedimentation, and redispersibility are controlled for 1 month. The evaluation of antioxidant activity degradation during 3 months and organoleptic test were required for the selection of optimal formulation. The hypoglycemic effect of the optimal nectar was evaluated in rats targeting the postprandial blood glucose levels kinetics. After optimization, the formulation F1 (with 0.03% stevia and 0.05% pectin) was found to be the most stable and favorable. Its half-life times were, respectively, 147.67 days at 4 degrees C (R-2 = .996) and 74.66 days at 25 degrees C (R-2 =.997). Its organoleptic score was 9.67 (R-2 = .994). The in-vivo hypoglycemic study has been confirmed, the effect of this supplementation has permitted the regulation of post-prandial glycemic levels. Thus, this formulation deserves to be recommended for diabetic subjects. Practical applications The addition of stevia (0.03%) and pectin (0.05%) improved the physico-chemical stability of natural orange nectar. Referring to the antioxidant activity degradation;half-life time was 147.67 days at 4 degrees C and 74.66 days at 25 degrees C. The consumption of this orange nectar by diabetic patients allows the normalization of their postprandial blood glucose levels.

关键词： Polyester waste   Physicochemical treatment   Polyester powder   Alkali hydrolysis  

摘要： Polyester has the highest share of world fibre market, which also leads to a large volume of polyester waste. In this study, a compact process combining alkali treatment and stone milling was used to recycle waste polyester fibre into ultrafine powder efficiently. The morphology of the original polyester fibre, alkali modified fibre and milled polyester powder were observed by Scanning electronic microscopy (SEM) and atomic force microscope (AFM). The particle size, crystallinity and strength loss were also studied. It was found that the alkali treatment greatly reduced fibre strength and the crystallinity of the fibre largely decreased after stone milling. The waste polyester fibre was converted into micron powders easily and efficiently. About 700 g dry ultrafine powders with particle size of around 60 mm were achieved in 2 h. This method shows a great potential for industrial application of waste polyester in the future. (c) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

关键词： starch nanocrystals   rice starch   morphology   crystalline   thermal properties  

摘要： BACKGROUND Starch nanocrystals have received considerable attention, due to their biodegradability, nontoxicity and renewable and abundant sources. The objective of this research is to compare the morphology, physicochemical characteristics and rheological properties of native (NSNC) and waxy rice starch nanocrystals (WSNC). RESULTS Both NSNC and WSNC exhibited a platelet-like shape, and they tended to show square-like platelet morphology with increasing initial amylopectin content. Compared to native starches, three weight loss stages of NSNC and WSNC in thermogravimetric analysis curves were observed, while the thermal depolymerization of NSNC started earlier than that of WSNC. The relative crystallinity of NSNC and WSNC was 38.6% and 48.3%, respectively, which were markedly higher than that of native starches. Fourier transform infrared spectra revealed that NSNC presented the highest ratio of 1045/1014 cm(-1)bands among the tested samples, which was probably due to the re-association of retrograded amylose to double-helices structure in NSNC. Moreover, the introduction of sulfur atoms on the surface of NSNC and WSNC was confirmed from the results of X-ray photoelectron spectroscopy. At 5% (w/v) and 10% (w/v) concentration levels, all SNC suspensions exhibited a shear-thinning behavior as the shear rate increased from 0.1 to 100 s(-1). CONCLUSIONS Starch nanocrystals obtained from native and waxy rice starch can be potentially used as reinforcement in biodegradable nanocomposites for packaging, fat replacers, thickening agents and emulsion stabilizers. (c) 2020 Society of Chemical Industry

关键词： Pretreatment   Physicochemical property   Structural property   Canola seeds protein  

摘要： The present research was to investigate the influences of pretreatments on the structural and physicochemical properties of proteins isolated from canola seeds (CSP) after oil extraction by supercritical CO2 fluid. The results showed that the CSPs pretreated with microwave treatment (MV-CSP) and ultrasound treatment (UL-CSP) significantly differed in terms of molecular weight distribution, amino acid composition, and the primary conformation of CSP. The crystalline properties and secondary structural conformation as well as average particle sizes of CSPs were not significantly influenced by pretreatments, but the morphological characteristics were remarkably changed. The physicochemical properties including solubility, water/oil holding capacity, emulsifying capacity and stability, as well as foaming capacity and stability were substantially altered by the pretreatments. The MV-CSP and UL-CSP possessed better physicochemical characteristics. Therefore, microwaveand ultrasound-pretreatments could serve as potential technologies to improve the physicochemical properties of canola seeds proteins. Moreover, different oil extraction methods greatly influenced the quality and functional properties of isolated CSPs. The supercritical CO2 (SC-CO2) process protected intact functional properties and enhanced the overall quality of the isolated CSPs compared to solvent extraction.

关键词： Desorption technique   inulin   Lacticaseibacillus casei   modified starch   polydextrose  

摘要： In this research communication we evaluate the impact of the addition of prebiotic components (inulin, polydextrose, and modified starch, 40 g/l) as fat substitutes on the physicochemical characteristics, probiotic survival, and sensory acceptance of probiotic (Lacticaseibacillus casei 01, 10(8) CFU/ml) Greek yogurts during storage (7 degrees C, 28 d). All formulations had probiotic counts higher than 10(7) CFU/ml during storage and simulated gastrointestinal conditions (SGIC). The prebiotic components increased the probiotic survival to the enteric phase of the SGIC, with inulin producing the most pronounced effect. Inulin addition resulted in products with lower pH values and consistency and higher titratable acidity during storage, with negative impact on the sensory acceptance (flavor, texture, and overall impression) at the end of the storage period. Modified starch addition impacted negatively on the acceptance of the products (appearance, flavor, texture, and overall impression). Polydextrose addition resulted in products with lower consistency, but similar sensory acceptance to the full-fat yogurt. It can be concluded that it is possible to prepare potentially synbiotic Greek yogurts by desorption technique using L. casei as probiotic culture and inulin, polydextrose or modified starch as prebiotic components, with the utilization of polydextrose being advisable.

关键词： cellular reprogramming   induced pluripotent stem cells   mesenchymal‐   epithelial transition   physicochemical 3D microenvironment  

摘要： Understanding the biophysical relationships between stem cells and applied biomaterials can facilitate the ability to control the functions and behaviors of stem cells. However, the role of 3D microenvironment in stem cell biology remains largely unexplored, compared with that of 2D cell-culture environment. Here, a new strategy that improves the efficacy of Yamanaka's four-factor-induced cellular reprogramming into induced pluripotent stem cells (iPSCs) by incorporating cues derived from the 3D microenvironment and biophysical ligands is reported. Among the various 3D hydrogel systems tested, methacrylated hyaluronic acid (HA) hydrogel significantly improves cellular reprogramming into iPSCs. Additionally, the initial upregulation of CD44 in encapsulated cells in low-level methacrylated soft HA hydrogel accelerates the reprogramming. In conclusion, the reported HA hydrogel with low modulus accelerates reprogramming into iPSCs and thus offers potential advantages for translational applications.

关键词： Chlorapatite   Adsorption   Hexavalent chromium   Reusability   Fixed bed-column  

摘要： Apatite-based minerals have attracted much attention in the remediation of heavy metal-contaminated environment. However, exploring apatite with efficient adsorption performance for inorganic oxyanions such as Cr(VI) remains a challenge. Herein, a novel nanocrystalline chlorapatite (CIAP) was promptly prepared by a green method using eggshell wastes as calcium source with the purpose to enhance Cr(VI) adsorption capability. The generated CIAP was characterized by XRD, SEM-EPMA, TEM, FTIR, and BET analyses. Batch and column experiments were subsequently carried out to explore the influencing factors, adsorption capacity and removal mechanism. Results showed that CIAP exhibited excellent stability and adsorption performance for Cr(VI) (63.47 mg g(-1)), which was much greater than that of hydroxyapatite and most reported materials. The adsorption process was fitted well by the pseudo-second-order model and the Langmuir model. In fixed bed column experiments, a novel time-fractional derivative model exhibited much better suitability in interpreting the observed breakthrough curves of Cr(VI) than traditional models. Furthermore, the reusability of CIAP in column was evaluated. Results showed that the adsorption capacity maintained well after consecutively reused for five cycles. Studies of the effect of pH, as well as FTIR and XPS investigations indicated that Cr(VI) adsorption was mainly ascribed to electrostatic interactions and surface complexation, while the reduction of Cr(VI) to the low-toxicity Cr(III) also existed in the adsorption process. The CIAP adsorbent was also successfully used for Cr(VI) remediation from real wastewater. Hence, nanocrystalline CLAP can be a promising material for enhancing the elimination of oxyanion contaminants such as Cr(VI) from water. (C) 2020 Elsevier Ltd. All rights reserved.