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关键词： Industrial hempseed   Hemp protein   Plant protein   Functionality   Solubility   Defatting method  

摘要： Hempseed has been identified as a good source of plant proteins, which is characterized with high quality, such as well-balanced amino acids profile and excellent digestibility. Most of hempseed protein isolate (HPI) obtained in previous studies were prepared from whole meal or hexane-defatted flour and precipitated unanimously at pH 5.0 of alkaline extraction-isoelectric precipitation (AE-IEP) method. The aim of the current study was to investigate the influence of precipitation pH and defatting solvent on the chemical composition, structure and functional properties of HPI. Our findings suggested that HPI prepared from hexane/Folch defatted hemp flour at pH 6.0 precipitation exhibited increased extraction and protein recovery yields with higher protein purity (93.26%) and desired nutrition profile. In addition, Folch defatting process in combination with precipitation at pH 6.0 accumulated more edestin protein in HPI with more beta-sheet structure and higher thermal stability. The aromatic profile determined by HS-SPME-GC-MS showed that Folch defatting process lowered the level of terpenes as well as secondary lipid oxidation products. The present work demonstrated that additional polar solvent defatting process could remarkable increase the physicochemical properties of HPI with cleaner aromatic profile.

关键词： Palm kernel expeller dietary fiber   Acidic treatment   Carboxymethylation   Hydroxypropylation   Heating combined with enzymatic hydrolysis  

摘要： Effects of acidic treatment, hydroxypropylation, carboxymethylation and heating combined with enzymatic hydrolysis on structural and physicochemical properties of palm kernel expeller dietary fiber (PKEDF) were studied. The carboxymethylation, hydroxypropylation and heating combined with enzymatic hydrolysis effectively improved soluble dietary fiber (SDF) content, water retention capacity (WRC), emulsifying ability index (EAI), water swelling capacity (WSC), viscosity and a-amylase inhibition activity of PKEDF. The carboxymethylation also significantly (p < 0.05) increased emulsion stability index (ESI), but decreased oil retention ability (ORA) and brightness of PKEDF. Besides, the enzymatic hydrolysis with heating significantly enhanced ORA of PKEDF (p < 0.05). In contrast, the acidic treatment decreased the WRC, ORA and EAI of PKEDF. These effects were mainly attributed to the composition and structural modifications as evident from scanning electron microscopy, Fourier-transformed infrared spectroscopy and X-ray diffraction analysis. The changes in physicochemical properties of PKEDF caused by these modification methods can expand its applications in food and other industries.

关键词： Soy protein hydrolysate   Ultrasound treatment   Protein solubility   Secondary and tertiary structure   Antioxidant capacity   Morphological structure  

摘要： The effect of ultrasound on the conformational and physicochemical properties of soy protein isolate hydrolysates (SPHs) was investigated. SPHs were prepared at hydrolysis times of 20 min, 60 min, and 180 min, then treated with ultrasound for 10 min, 20 min, and 30 min at a frequency of 20 kHz and output powers of 150 W and 450 W. The structural properties and antioxidant capacities of the aqueous layer of SPHs (ASPHs) after sonication were evaluated by Fourier-transform infrared spectroscopy (FTIR), intrinsic fluorescence, DPPH radical scavenging activity assays, and microscopy observations. Results obtained showed that ultrasound treatment significantly disrupted the peptide aggregates formed during protein hydrolysis. The protein solubility was significantly increased after sonication (by up to 18.33%), as did the percentage of proteins with MW < 1 kDa in ASPHs. The antioxidant capacity of ASPHs also increased, as measured by DPPH assay. FTIR analysis of ASPHs indicated that the protein secondary structures were different, with an increase in beta-sheet and a decrease in alpha-helix and beta-turn. Furthermore, the changes in fluorescence spectra of ASPHs showed the transition of protein tertiary structure with a greater exposure of Trp residues in the side chains. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations of the morphological structure of ASPHs further confirmed the significant effect of sonication on disrupting peptide aggregates. In conclusion, ultrasound can be used as an efficient treatment to promote the solubility of protein hydrolysates.

关键词： Municipal solid waste   Landfill   Microbial community   16S rRNA sequencing  

摘要： This study assessed the bacterial populations in a non-sanitary landfill around Guarani Aquifer recharge zone in Brazil. Samples from two different positions (sites 1 and 2) at three different depths were evaluated, totaling six solid waste samples;two samples from an impacted stream were also collected. 16S rRNA sequencing was performed using the Ion S5TM XL platform;3113 operational taxonomic units (OTUs) and 52 phyla were identified. Proteobacteria (37%) and Firmicutes (28%) were the most abundant phyla in the landfill, whereas Proteobacteria (similar to 50%) and Bacteroidetes (similar to 10%) were more profuse in surface water samples. Canonical correlation analysis (CCA) enabled us to clearly separate the samples according to their spatial location (site 1 or 2) or environmental matrix (surface water or solid waste samples), showing that microbiological populations are strongly associated with site-specific conditions and the kind of environmental matrix they come from. Environmental factors that mostly influenced the microbial communities were organic matter, oxidation-reduction potential, moisture, alkalinity, nitrogen (TKN), sodium, potassium, and zinc. Exiguobacterium (phylum Firmicutes) was overwhelmingly dominant at site 1 and was associated with higher concentrations of organic matter and potassium. Differently, site 2 did not present such dominant genera and was more diverse having lower concentrations of organic matter and nutrients. Distinct environments co-exist inside the same waste deposit, including zones which are representative of active and closed landfills and the occurrence of considerable physicochemical and microbiological shifts within short distances. Those shifts indicate that microbial populations are well adapted to the heterogeneity typical of urban solid waste, which is possibly beneficial to contaminant degradation.

关键词： carbonitriding   microhardness   structure  

摘要： We present the results of investigations of the influence of hydrogen-free carbonitriding in glow discharge on the physicochemical characteristics of the hardened layer of 40Kh steel depending on the content of propane and the pressure of gas atmosphere. We consider three versions of saturation: carbon + nitrogen, nitrogen + carbon, and simultaneous saturation with nitrogen and carbon. The analysis of the obtained results reveals the highest efficiency of hardening of the surface of 40Kh steel for the third version of saturation.

关键词： Physicochemical properties  

摘要： The effect of different degrees of pre-crystallised lactose (PCL) (0-45%) on the physico-chemical properties of infant formula (IF) containing hydrolysed whey protein was investigated during ageing at two temperatures (25 and 45 degrees C) and three levels of relative humidity (RH;11%, 33%, 54%). An increase in the proportion of PCL resulted in higher particle size and higher surface free fat immediately after drying. Lactose crystallisation at RH 54% at both storage temperatures exhibited a logarithmic decline in T-g in IF containing 18% PCL as opposed to exponential decline in IF containing >18% PCL. The degree of PCL directly affected the changes in surface free fat and IF containing 18% PCL and resulted in lowest surface free fat at all ageing conditions. Overall, the proportion of PCL in IF strongly influenced the changes in their physicochemical properties after drying and during storage. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Nanocomposites  

摘要： NpCdS nanocrystals are prepared by a microbial synthesis technique at the NRC "Kurchatov Institute"—GOSNIIGENETIKA. The stabilizing layer of nanocrystals consists of proteins, and the composition of the protein layer depends on the strain used in nanoparticle (NP) biosynthesis. The morphology and size, hydrodynamic diameter, zeta-potential, and luminescence properties of the biogenic NPs are investigated using electron microscopy, dynamic light scattering, and spectrofluorimetry, and the NPs are identified as quantum dots. The effects that temperature, pressure, and solvents have on the stability and luminescence intensity of biogenic NPs are studied in collaboration with the National Research Center Kurchatov Institute—IREA. For the aqueous NpCdS suspension, the dependence of luminescence intensity on the NP concentration range is established. The feasibility of incorporation and identification of NpCdS in an epoxy resin, polyimide, and polyvinyl alcohol is evaluated. Polymer nanocomposites find use in optoelectronics, biomedicine, and agriculture. © 2020, Pleiades Publishing, Ltd.

关键词： antiglycation   antioxidant   hypoglycemic   polysaccharides   ultrafiltration  

摘要： Both fermentation degree and preparation method of polysaccharides could influence the bioactivity of tea polysaccharides. The aim of this study was to compare the physicochemical characterization and biological activities of the polysaccharides isolated by ultrafiltration method from three kinds of tea (green tea, oolong tea, and black tea). The bioactivities of tea polysaccharide fractions were compared from four aspects, including antioxidant activities, antiglycation activities, alpha-glucosidase inhibitory capability, and hypoglycemic effects on L6 myotubes. Results showed that six polysaccharides (GTPS1, GTPS2, OTPS1, OTPS2, BTPS1, and BTPS2) had different contents of neutral sugar and uronic acid, and they showed different morphologies. Six polysaccharides were composed of the seven monosaccharides with different molar ratios. BTPS1 exhibited the highest DPPH scavenging activity and hydroxyl radical scavenging activity (P< 0.05), and BTPS1 also showed the strongest antiglycation inhibitory effects (P< 0.05). BTPS1 and BTPS2 showed strong inhibitory capacity on alpha-glucosidase and hypoglycemic effects in L6 skeletal muscle cells. The result suggested that the degree of fermentation of tea could improve their bioactivities (BTPS > OTPS >GTPS), and TPS1 with smaller molecular weight distribution showed higher bioactivities than TPS2. This study can provide a scientific foundation for the application of tea polysaccharides and related functional products.

关键词： Cheese   mozzarella cheese   physicochemical properties   raw milk  

摘要： Porungo is a traditional pasta filata cheese produced using raw milk throughout the southwest region of the state of Sao Paulo, Brazil. The objectives of this Research Communication were to evaluate the quality of raw milk used to make Porungo cheese, to characterize its production process, and to determine its chemical composition. The results showed that the raw milk met both Brazilian and international quality requirements. Chemically, Porungo can be classified as a medium to full fat semi-hard fresh cheese. Our study has allowed the first standards and regulations for Porungo to be established in Brazil. By virtue of this, the local producers are able to formalize their activity while consumers can have access to a safe and certified product.

关键词： Hydrophobic   Hexafluoroantimonate ionic liquids   Molar surface Gibbs energy   Polarity  

摘要： Series of hydrophobic hexafluoroantimonate [C(n)eim][SbF6] (n = 4, 5, 6) were synthesized and characterized by H-1 NMR and ESI-MS. It is obvious that the reactive hydrogen is replaced with ethyl group on N-3 position of imidazole cation, and it could have an effect on the corresponding physicochemical properties. The density, surface tension, refractive index, and conductivity of the hydrophobic ILs [C(n)eim][SbF6] (n = 4, 5, 6) were measured in the temperature range of (293.15 to 343.15) +/- 0.05 K with an interval of 5 K. The volume properties and surface properties were calculated. According to Kabo's method, the vaporization enthalpy was also calculated, and the polarities were predicted. The applications of the mole surface Gibbs free energy were investigated. In addition, the relationship between the conductivity and temperature was also explored, and the molar conductivity and diffusion coefficient for ILs were obtained.