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关键词： Synthesis   Hydrazone   Thin films   Characterization   Optical properties   Energy conversion and storage  

摘要： We synthesized a novel isatin hydrazone derivative 3-(((E)-3-ethoxy-2-hydroxybenzylidene)hydrazineylidene) indolin-2-one (IL) via condensation of isatin hydrazide with 3-ethoxy-salicylaldehyde in methanol. Then ZnO was chelated with the ligand (IL) to produce a novel ZnOIL complex. The characteristics of the IL and ZnOIL compounds were compared using various techniques, including nuclear magnetic resonance, ultraviolet-visible, infrared, and mass spectroscopy, and elemental analyses to confirm their chemical compositions. The optical properties of the IL and ZnOIL thin films were studied based on spectroscopic measurements of their absorbance, transmittance, and reflectance within the range of 300-2500 nm. The optical constants, dielectric parameters, and dispersion energies were determined and interpreted. The electronic inter-band transitions of the IL and ZnOIL films were characterized by indirect allowed transitions. The value of the optical band gap (E-g) was determined as 2.14 eV for the IL film, but chelation of IL with ZnO decreased E-g to 2.02 eV. The surface and volume energy loss functions were lower for ZnOIL compared with IL. The structural and the optical features of ZnOIL may be tuned, and thus it is a promising candidate material for applications in energy conversion and storage devices.

关键词： 物理化学  

ISBN: (纸本)9787122383525

摘要： 本教材是根据工科课程体系特点编写的物理化学实验教材，内容包括热力学、化学动力学、电化学、表面与胶体化学、结构测定等25个实验。为了通过实验培养学生发现和解决实际问题的能力，增强学生的创新意识和探索精神，本教材还编入了8个研究创新型实验。

关键词： Moisture  

摘要： In this study, the antioxidant and antimicrobial effects of carboxymethyl cellulose (CMC) enriched with Thymus vulgaris L. extract (TE) on physicochemical, microbial, and sensorial properties of fresh hazelnut were investigated. Hazelnuts treated with CMC coating solution (0.0, 0.5, and 1.5% wt/vol) containing TE (0.0, 0.5, and 1.0% vol/vol) and stored at ambient temperature for 147 days. The results showed that the uncoated sample had the highest mean moisture content (4.03%), yeast and mold count (2.63 Log cfu/g), and development of Aspergillus spp. (36.25%). The oxidation rate of coated hazelnut with 1.5% CMC and 1.0% TE was lower (PV = 0.47 meq ***(-1), TBA = 0.02 mg ***(-1), and FFA = 0.40%) than that of uncoated sample (PV = 1.07 meq ***(-1), TBA = 0.04 mg ***(-1), and FFA = 0.76%). According to the results of an instrumental mechanical and sensory evaluation, 0.5% CMC and 0.5% TE is an optimal coating to extend shelf life and promote the nutritional value of hazelnut. Practical applications The enhancement of characteristics of fresh hazelnut during storage should be a major concern for the industry and market. It could be admirable to have hazelnut that is well preserved for as long as possible. Consequently, to convince long shelf life and to expand protection from rancidity processes and microbial growth, the nuts have to be preserved, instantly after harvest. Carboxymethyl cellulose (CMC) is a natural, abundant, unexpansive biodegradable biopolymer, and is a possible material for edible coating applications. In this study, the use of TE as a natural preservative adds nutritional value to the hazelnut and contributed to a shelf life extension of fresh hazelnut. Furthermore, CMC containing TE with its barrier properties vis-a-vis moisture, and oxygen, allows less expensive synthetic materials to be used, prevents loss of flavor, and serves as a suitable carrier for various additives.

关键词： Bacillus coagulans   physicochemical   rheological properties   volatile compounds  

摘要： Bacillus coagulans 13002 (13002) as a new potential starter was incorporated into the yoghurts for fermentation in this study. We compared three groups of yoghurt, including Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (SL), 13002 (BCS), and 13002 and SL (BCS + SL). Compared with the combination of SL and BCS, the group of BCS + SL exhibited better flavour, higher titratable acidity, cohesiveness and richer volatile compounds, suggesting that the combination of BCS and SL was more efficient to produce the best sensory properties of yoghurt (P < 0.05). The production of volatile compounds in fermentation with and without the addition of BCS was mainly affected by aldehydes, ketones, esters and hydrocarbons, respectively. Furthermore, BCS additions into traditional starters resulted in increasing organic acids and speeding up the usage of sucrose and lactose during the fermentation period of yoghurt. Our study suggested that BCS is a favourable starter supplement for improving the quality of probiotic yoghurts.

关键词： Pyridone   Chromenopyridone   Anti-inflammatory   Antipyretic   Ulcerogenic   And physicochemical studies  

摘要： Throughout this study, we present the victorious synthesis of a novel class of 2(1H)-pyridone molecules, bearing a 4-hydroxyphenyl moiety through a one-pot reaction of 2-cyano-N-(4-hydroxyphenyl)acetamide with cyanoacetamide, acetylacetone or ethyl acetoacetate, and their corresponding aldehydes. In addition, the chromene moiety was introduced into the pyridine skeleton through the cyclization of the cyanoacetamide 2 with salicylaldehyde, followed by treatment with malononitrile, ethyl cyanoacetate, and cyanoacetamide, in order to improve their biological behaviour. Due to their anti-inflammatory, ulcerogenic, and antipyretic characters, the target molecules have undergone in-vitro and in-vivo examination, that display promising results. Moreover, in order to predict the physicochemical and ADME traits of all synthesized compounds and standard reference drugs, paracetamol and phenylbutazone, the in-silico prediction methodology was provided.

关键词： Shear thinning  

摘要： Application of both homogenization and microfluidization offer remarkable reformations in the structures of food. In this research, the outcome of the homogenization and microfluidization on the emulsion of mayonnaise and resultantly on the rheological and sensory attributes of the mayonnaise was evaluated and compared. Implementation of individual processes was analyzed with regard to rheological properties and physicochemical parameters by preparing samples with and without addition of stabilizers. Mayonnaise samples showed thixotropic behavior and then categorized as shear thinning (Pseudoplastic liquid) showing yield stress. Irrespective of sample testing parameters such as different temperatures and shear rates, all samples revealed shear thinning characteristics. The viscosity of microfluidized sample with or without stabilizer was significantly increased (p < .05) as judged against the homogenized sample at both temperatures (20 degrees C and 40 degrees C). The storage modulus of all samples was higher as compared with the loss modulus which shows elastic nature of the mayonnaise. Power law and Weltman model were studied to explain the rheological behavior of the mayonnaise and both models were found best suited. Experimental values illustrated through attempted models very well contribute to future studies on the product and process development. As per the current literature, microfluidization can be used to achieve quick mayonnaise emulsion with better rheological characteristics and hence superior sensosry attributes. Practical Applications Stabilizers play a critical role in the development of mayonnaise as an additive or constituent. The present study reveals that high-pressure homogenization (microfluidization) can be exploited to enhance rheological, physical, and chemical properties of the mayonnaise by influencing interaction between fat (oil) and gums (polysaccharides), eventually increasing viscosity. The quality of mayonnaise is usually judged by

关键词： Bound phenolic acids   in vitrodigestion   interaction   pasting properties   purple sweet potato starch   thermal properties  

摘要： Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was employed to investigate free phenols that were released from purple sweet potato (PSP) by alkaline, acid and enzymatic hydrolysis. Four phenolic acids, including ferulic, isoferulic, 4-hydroxybenzoic and caffeic acids, were identified. Based on their effects on the characteristics of purple sweet potato starch (PSPS), the four phenolic acids were studied. Furthermore, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were employed to explore the microstructures of the complexes of the phenolic acids and PSPS. The obtained results demonstrated that the pasting, thermal, retrogradation, as well as digestive properties of PSPS were all influenced by the phenolic acids which interacted with PSPS through noncovalent hydrogen bonds. The influence of the four phenolic acids on the properties of PSPS was in the descending order: 4-hydroxybenzoic acid > ferulic acid > caffeic acid > isoferulic acid.

关键词： Insoluble soybean fiber   Homogenization sequence   Structure-function relationship   Emulsion stability   Network stabilization  

摘要： Comprehensive utilization of okara has received a growing interest from manufacturers and researchers in the food industry. In this work, ISF was extracted from defatted okara in the sequence of "homogenization followed by pH12 treatment" and "pH12 treatment followed by homogenization", which are indicated as HA-ISF and AH-ISF, respectively;Subsequently, the basic properties and initial structure of these ISFs, as well as their emulsification performance were systematically characterized. The results indicated that as the homogenization intensity was enhanced, more negatively charged, smaller particle as well as porous structures were detected in the extracted ISF. The size of oil droplets in ISF-emulsions decreased and then increased, the absolute value of the zeta-potential and the loss angle (tan delta) were reduced, the apparent viscosity and elastic modulus (G') increased, and the flocculated structure in the ISF-emulsions was promoted as the homogenization intensity was increased. Creaming in the ISF-emulsions was effectively inhibited by homogenization via adsorption of ISF onto the interface and network stabilization. More obvious aforementioned changes were observed in AH-ISF than HA-ISF, as well as in the corresponding emulsions. These results provided valuable information for the exploitation of ISF as emulsifier, which is a promising approach to enhance the added-value of okara.

关键词： Prickly pear seed cake   Proteins   Albumin   Glutelin   Antioxidant   Functional properties  

摘要： Proteins were extracted from a prickly pear seed cake using the Osborne extraction method. Physico-chemical, antioxidant and functional properties of the major protein fractions (albumin and glutelin) were studied. Glutelin fraction presented good amount of proteins (60.42% dry weight) with appreciable essential amino acids content (24.45% of total amino acids). The Fourier transform-infrared spectroscopy spectra showed between similar to 1200 and 1700 cm(-1), characteristically peaks of proteins, namely, amide I, II and III for both fractions. Antioxidant activities of protein fractions were assessed in vitro through different antioxidant tests. The protein fractions exhibited good DPPH and metal scavenging activities. However, they demonstrated moderate reductive ability. Protein fractions had a minimum equilibrium surface tension at the isoelectric pH. They were characterized by interesting techno-functional properties such as emulsifying and foaming capacities which were affected by pH values. They also displayed significant water holding (480% for albumin fraction at pH 7) and oil holding (420% for glutelin at pH 7) capacities. The found results suggested that albumin and glutelin extracted from prickly pear seed cake could have important applications in food formulations. [GRAPHICS] .

关键词： Biopolymers  

摘要： Yoghurts were prepared by fermentation in the absence (control) or presence of different concentrations of inulin, tragacanth gum, or gellan gum, and effects of the biopolymers on physicochemical and sensory characteristics of yoghurts during cold storage were examined. No significant difference in pH, colour, total solid, and bacterial viability was observed among all the yoghurts prepared. Rheological analysis revealed that yoghurts prepared with biopolymers were pseudoplastic, and firmness and apparent viscosity were greater in yoghurts with added biopolymer than in control. Syneresis was weaker in yoghurts with added biopolymer, and showed a decreasing trend with biopolymer concentration but an increasing pattern with storage time due to gel shrinkage. Yoghurts with added biopolymer showed homogeneous and more compact microstructures than control. Yoghurt prepared with 0.01% tragacanth gum exhibited the best sensory scores. Results demonstrated that small amounts of tragacanth gum could effectively replace gellan gum as a thickener of synbiotic yoghurt. (c) 2020 Elsevier Ltd. All rights reserved.