摘要：
Raffinose family oligosaccharides (RFOs) are alpha-galactosyl derivatives of sucrose or glucose. They are found in a large variety of seeds from many different families such as beans, vegetables and whole grains. Due to absence of alpha-galactosidase in the digestive tract of humans and other monogastric animals, RFOs are responsible for intestinal disturbances (flatulence) following the ingestion of legume-derived products. Structural relationships of RFOs and their enzymatic degradation mechanism are described. Concentration and distribution from various seed sources are introduced. The present status on removal of the RFOs (such as soaking, cooking, germination, and addition of alpha-galactosidase) is summarized. At the meantime, alpha-galactosidases from botanic and microbial sources and their partial enzymatic properties are also presented in detail. Based on a comparison of various removal treatments, the microbial a-galactosidases are thought as the most optimum candidate for removing RFOs in legumes, and the ideal system for the RFO removal is proposed.
摘要：
Side chain modification of collagen provides an attractive way to enhance their structure and functions, which is highly desirable for the development of promising biomaterials. However, the impact of structural change of side chains on the intrinsic self-assembly property of collagen was always ignored. Here, a series of acrylic acid-grafted-collagen (AA-g-Col) with different grafting density were prepared to explore the impact of side chain structural variation on the self-assembly of collagen. The results showed that excessive grafting density would weaken or even disappear the self-assembly property of AA-g-Col, but only affects the triple helix to a minor extent. Compared to pristine collagen, the mechanical property and cytocompatibility of AA-g-Col based matrices also deteriorated, along with the increase of grafting density. Therefore, this work contributed a new insight into the importance of grafting density for the study of modified collagen, which would be helpful for the design of optimized formulate collagen-based hybrid materials with both additional novel functions and tissue-mimicking fibrillary structures.
关键词：
atelocollagen;collagen;fluorescein isothiocyanate;telopeptide;tropocollagen;Article;collagen fibril;extracellular matrix;grass carp;morphology;nonhuman;pig;polyacrylamide gel electrophoresis;priority journal;scanning electron microscopy;skin;viscoelasticity
摘要：
Xenogeneic collagen co-assembly (XCCA) is a novel and efficient strategy for improving and regulating the performance of collagen assembled products. However, the effect of collagen molecular structures on XCCA has long been neglected and remains unclear. Herein, we investigated the telopeptide effect of collagen on XCCA by employing grass carp skin collagen (GCSC) with two different structures (tropocollagen and atelocollagen) and porcine skin collagen (PSC). Kinetic analysis showed that the co-assembly rate of PSC and grass carp skin atelocollagen (AC-GCSC) was faster than that of PSC and grass carp skin tropocollagen (TC-GCSC). Based on this observation, we further obtained different concentration dependences of XCCA by the alteration of telopeptide. Compared with PSC/TC-GCSC co-assembly, PSC/AC-GCSC co-assembly exhibited a higher sensitivity and a lower detection limit. Furthermore, telopeptide promoted the fabrication of thicker fibrils and improved the mobility of gels.
摘要：
A sensitive and robust electrochemical aptasensor for determining dopamine (DA) was developed using a grass carp skin collagen-graphene oxide (GCSC-GO) composite as a transducer and a label-free aptamer as a biological recognition element for the first time. In order to fabricate this sensor, the GCSC-GO composite was firstly prepared by ultra-sonication method and characterized by atomic force microscope, infrared spectroscopy, Raman spectroscopy, and electrochemical impedance spectroscopy. Subsequently, a label-free DA-binding aptamer was immobilized through strong interaction between collagen and aptamer. The fabricated electrochemical aptasensor was used to determine DA by differential pulse voltammetry. The results indicated that the peak current changes of the developed aptasensor was linear relationship with the DA concentrations from 1 to 1000 nM, and the detection limit was 0.75 nM (S/N = 3). Moreover, the fabricated aptasensor showed high selectivity for DA More importantly, the obtained aptasensor exhibited satisfactory recovery toward DA in human serum specimens with excellent stability. (C) 2019 Elsevier B.V. All rights reserved.
作者机构：
[Zhang, Jian] Wuhan Polytech Univ, Sch Chem & Environm Engn, Wuhan 430023, Hubei, Peoples R China.;[Jha, Sunil Kr.] Ton Duc Thang Univ, Dept Management Sci & Technol Dev, Ho Chi Minh City, Vietnam.;[Jha, Sunil Kr.] Ton Duc Thang Univ, Fac Sci Appl, Ho Chi Minh City, Vietnam.;[Liu, Chuanjun; Hayashi, Kenshi] Kyushu Univ, Grad Sch Informat Sci & Elect Engn, Dept Elect, 744 Motooka, Fukuoka, Fukuoka 8190395, Japan.
通讯机构：
[Jha, Sunil Kr.] T;Ton Duc Thang Univ, Dept Management Sci & Technol Dev, Ho Chi Minh City, Vietnam.;Ton Duc Thang Univ, Fac Sci Appl, Ho Chi Minh City, Vietnam.
关键词：
Banana storage quality;Overripe odor;GC-MS;Volatile chemical compounds;Principal component analysis
摘要：
A promising research to evaluate the quality of ripe banana during storage period by analyzing the variability of the volatile chemical components in odor from peels and flesh based on solid-phase microextraction-GC-MS characterization and statistical analysis has been discussed. A rapid increase of ethanol concentration in peels and flesh contributes to rotting of the banana. Specifically, occurrence of some compounds, including 1,2-dimethoxybenzene, 3,4-dimethoxybenzaldehyde, and isoeugenol, is an important feature of banana rotting. The decrease of 3-hydroxy-4-methoxybenzaldehyde concentration signifies a weakening of antiseptic, bactericidal, fungicidal, and antioxidant properties of banana. Besides, the principal component analysis (PCA) has been implemented in the discrimination of banana odor at different days of storage.
摘要：
The complexes of gossypol with Fe2+ were prepared by using methanol as solvent in the presence of CO2 atmosphere. The results from FT-IR spectra analysis indicated that the aromatic aldehyde groups in gossypol molecules were entirely involved in coordination with Fe2+. UV-Vis absorption spectrum of the complexes in methanol solution displays blue-shift in comparison with that of gossypol. Five compounds from the complexes were isolated by high performance liquid chromatography. The structures of the complexes are consistent with PM3 calculations. Two compounds were formed by coordination of gossypol with Fe2+ at 1:2 molar ratio, other three compounds were formed by chelation of gossypol with Fe2+ at molar ratio by 1:1, 1:3, and 1:4 respectively.
通讯机构：
[Xie, Dong] I;Indiana Univ Purdue Univ, Purdue Sch Engn & Technol, Dept Biomed Engn, Indianapolis, IN 46202 USA.
关键词：
Dimethacrylamide;photopolymerization;degree of conversion;compressive strength
摘要：
A dimethacrylamide was synthesized and used to formulate with the selected (meth)acrylates to form the in situ photocureable resins and composites. The effects of the selected comonomers with different functional groups on polymerization rate, degree of conversion, gel time, and compressive strength were investigated. The results show that in situ photopolymerization of the synthesized dimethacrylamide with comonomers having an electron-withdrawing and/or acrylate group dramatically increased the polymerization rate, degree of conversion, and compressive strength. On the other hand, an electron-donating group on either carbon-carbon double bond or ester linkage slowed down the polymerization. In contrast, the triethylene glycol dimethacrylate-based system did not show a clear pattern. The synergistic effect of the strong hydrogen-bonding between dimethacrylamide and organic acid groups may be responsible for higher compressive strengths. The formed composites showed the similar trend in compressive strength to the corresponding resins. Within the limitation of this study, it seems that in situ photopolymerization of dimethacrylamide or diacrylamide can be greatly accelerated by copolymerization with monomers having electron-withdrawing and/or acrylate groups. The monomers with methacrylate group can significantly reduce the polymerization rate and degree of conversion.
摘要：
Ultra-high pressure technology has attracted a great deal of attention in recent years, and has been widely used in food science, medicine, and other fields. This study aimed to determine the effect of ultra-high pressure on the structure and properties of collagen. Native collagen extracted from bullfrog skin was processed under different ultra-high pressure treatment conditions (300, 400, and 500 MPa). Then systematic analysis of the molecular structures and properties of the samples after ultra-high pressure treatment were performed. It was found that the conformation of collagen molecules could be adjusted by ultra-high pressure treatment, and this regulation was closely related to the level of treatment pressure. A possible mechanism of the impact of ultra-high pressure on the collagen molecular structures was speculated according to the experimental results. At low pressure levels (300-400 MPa), the pressure perpendicular to collagen axis dominates and leads to a tightening of the triple helix structure of collagen, while the pressure parallel to collagen axis is dominant and the triple helix tends to dissociate like a zipper at high pressure levels (> 400 MPa). These structural changes would simultaneously result in various changes to thermal stability, self-assembly properties, and antigenicity of collagen. (C) 2018 Elsevier B.V. All rights reserved.
作者机构：
[Wang, Tingting; Sun, Yang; Yu, Bo; Cheng, Hua] Hubei Univ Arts & Sci, Sch Chem Engn, Xiangyang 441053, Hubei, Peoples R China.;[Sun, Yang] Tsinghua Univ, Sch Life Sci, Beijing 100084, Peoples R China.;[Oliveira, Cristiano L. P.; Sun, Yang] Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05314970 Sao Paulo, Brazil.;[Wang, Haibo; Zhang, Juntao] Wuhan Polytech Univ, Sch Chem & Environm Engn, Wuhan 430023, Hubei, Peoples R China.
通讯机构：
[Oliveira, Cristiano L. P.] U;Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05314970 Sao Paulo, Brazil.
摘要：
With well-known nutritional properties, casein contributes to about 80% of protein content in milk and has been classified as highly intrinsically disordered protein (IDP). In this paper, the sulfate dodecyl sodium (SDS)-induced conformational changes of bovine casein were studied by multi-techniques. Isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) were used to obtain the stoichiometry of conformational changes and the thermal stability of the formed complexes. Spectral results indicated that casein presented a higher helical content but loss of tertiary structure above critical micelle concentration of SDS, namely, the so-called molten globule like state. The thermal selfassociation of casein could be prevented by SDS according to far-UV CD even at 70 degrees C. The H-1 NMR spectrum of casein showed that the resonance around 1.0 ppm, the region of a-hydrogen, shifted to the higher field, and the aromatic region around 5.5-8.0 ppm shifted to the lower field, while the NOESY spectra of casein exhibited few chemical shifts with binding of SDS. Combining the results of dynamic light scattering (DLS), scanning electron microscope (SEM) and small angle x-ray scattering (SAXS), one obtains that casein micelles presented an elliptical shape of similar to 800 nm in diameter and upon binding with SDS, the casein micelles disassociated into more compact globular particles of 10 nm in diameter with a core-shell structure composed by SDS molecules and casein proteins. The present work, not only provides molecular insights into the mechanism of SDS-induced stability of a model IDP, casein, but also helps understand the role of surfactants on the structureefunction relationship of bovine casein in the food industry. (C) 2018 Elsevier Ltd. All rights reserved.
摘要：
Several new urethane-based dimethacrylates were synthesized, characterized and used to formulate the resin composites. Compressive strength (CS) was used as a screen tool to evaluate the mechanical property of the formed composites. Flexural strength, diametral tensile strength, water sorption, degree of conversion and shrinkage of the composites were also evaluated. The results show that most of the synthesized urethane-based dimethacrylates were solid, which are not suitable to dental filling restorations. However, it was found that liquid urethane-based dimethacrylates could be derivatized using asymmetrical methacrylate synthesis. Not only the newly synthesized urethane-based dimethacrylates showed lower viscosity values but also their constructed composites exhibited higher mechanical strengths. Without triethyleneglycol dimethacrylate (TEGDMA) addition, the new urethane-constructed composites showed significantly lower water sorption and shrinkage.
