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•The results of fracture toughness KIIc of fly ash concrete were validated through DIC method.•There is a correlation between KIIc parameter obtained by using two measuring ...devices.•Fracture processes based on the images of major strain and displacement X were analyzed.•An original solution for measuring the actual length of a crack propagating in the material were presented.•A new sophisticated crack tip tracking (CTT) method was introduced.
This article focuses on the analysis of fracture processes in fly ash (FA) concrete considering the second model of cracking. The basic parameter of fracture mechanics in concrete elements according to Mode II fracture, i.e. KIIc, was determined. Two measuring devices were used in the studies. One of them was the Digital Image Correlation (DIC), which is now a popular and extensively used metrology technique. During the experiments, an attempt was made to validate the results of fracture toughness obtained in strength press tests. The main goal of the studies was to confirm the convergence and determine the discrepancy ranges, between the KIIc results obtained on the MTS 810 press and using the DIC technique. During the investigations a new concept was proposed in the analysis of concrete fracture processes under Mode II using the DIC method, i.e. evaluation the fracture toughness of the composite by the direct testing of the material with an initial defect – in the crack propagation area (Fig. 7b). In addition, it was attempted to determine the usefulness of the DIC system for the analysis of initial cracks development in concrete elements subjected to shear. For this purpose, basing on the images of major strains and displacements in the X direction, an in-depth assessment of the initial cracks growth was made. The article also presents an original, sophisticated solution for measuring the actual length of a propagating crack in the material with the use of the crack tip tracking (CTT) method. Principal strains ε11 were used to visualise the cracks, while their length was determined as the sum of the relative crack increments (generated at successive stages of the loading of the specimen) measured on the XY plane (rel XY).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The addition of pectin significantly decreased peak viscosity of CS.•The syneresis of starch gel during freeze–thaw process was reduced by pectin addition.•Low Mw pectin significantly lowered the ...hardness of starch gel.•The relative crystallinity of starch-pectin mixtures significantly weakened.•The proportion of SDS and RS for retrograded starch-pectin mixtures increased.
Effects of pectin with different molecular weight (Mw) on gelatinization behavior, textural properties, retrogradation, and in vitro digestibility of corn starch (CS) were investigated. The pectin addition led to the decrease of peak, setback, and final viscosities of CS, and a further decrease was provided with the pectin of high Mw, whereas the pasting temperature was increased. The syneresis of starch gel during freeze–thaw process was reduced by the addition of pectin. High Mw pectin significantly lowered the hardness of the starch gel from 238.9 and 350.2 N to 222.7 and 318.5 N after 7 and 14 days storage (P < 0.05), respectively. Compared with the retrograded CS alone, the relative crystallinity of starch-pectin mixtures significantly decreased (P < 0.05), but the crystal type of starch remained unchanged. A significant increase was observed in both the proportion of slowly digestible starch and resistant starch for retrograded starch-pectin mixtures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Starches and proteins are two major types of biopolymer components, especially in many flour (starch)-based foods consumed worldwide, which provide energy and nutrition needed by the human body. In ...many such starch-based matrices (the main structural component of such foods), proteins and their interactions with starches greatly influence the matrix structure and properties. Studying the different roles played by proteins (endogenous and exogenous) in various starch-based food systems can provide a frame of reference for the design and production of improved starch-based food products with tailored properties and desirable nutritional functions.
Significant efforts have recently been made to tailor the morphology, structure, and properties of many starch-based food systems, and thus to design various starch-based food products with satisfactory attributes. This review surveys the latest literature on starch-based matrices containing proteins. Discussed are the influences of proteins and their interactions with starches on the morphologies and structures (e.g. short- and long-range orders) of starch-based matrices, as well as on their pasting, thermal, rheological, textural, sensory, and digestive properties. Also, current understandings of structure–property links are presented, along with their implications on the production of various starchy foods (e.g. pastas, breads, cakes, and biscuits), including gluten-free versions.
Proteins in many starchy food matrices can encapsulate the starch phase (or be adsorbed on its surfaces) on a micron scale, and thereby interact with starch chains via both non-covalent (e.g. hydrogen bonding, hydrophobic, and electrostatic) and covalent bonds (e.g. via Maillard reactions). These facts and protein features (e.g. hydration and gelation abilities) can play major roles in inhibiting starch retrogradation (the reassembly of cooked starch chains into ordered structures) and in regulating various other properties of such starch-based matrices, including viscosity, transition temperatures, moduli, hardness, sensory, digestibility, and shelf-life. Despite the fact that the current literature presents considerable information on the structure–property relationships of many different starch-based matrices and their applications in the processing of various starchy foods (e.g. pastas, noodles, and biscuits), it is still highly necessary to define more comprehensive correlations among starch–protein interactions, starch–protein matrix structures, and the resulting properties of such food products.
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•Starch–protein interactions are affected by biopolymer type, proportion, and processing.•Proteins often inhibit starch gelatinization and restrict starch retrogradation.•Proteins affect the textural, sensory, and digestive properties of many starch-based foods.•Understandings that are instrumental to the development of high-quality, healthy foods are reviewed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Gluten-free bread crusts are known for their crumbly texture, light colour, poor nutritional quality and weak aroma. The objective of this research was to improve crust quality of gluten-free breads ...by the addition of rice, pea, egg white and whey proteins to the bread formulation in two levels (5% and 10%). Moisture, water activity, thickness, microstructure, texture, colour and volatile compounds were measured. A 99% negative significant correlation between spatial frequency of structural ruptures and crust moisture content was found. Results from texture analysis indicated that animal and 10% pea protein crusts were less crispy than control. Moreover, crust microstructure of animal protein bread was very different from control and vegetal protein crusts. Animal and vegetal protein crusts showed darker colour than control and the darkest was obtained from whey protein inclusion. With respect to the volatile profiles, rice protein crusts had the highest content of 2-acetyl-1-pyrroline while whey protein crusts had high level of pyrazines, which was in concordance with their dark colour. However, whey protein and, above all, rice protein also increased the content of volatile compounds from lipids oxidation. Thus, the suitable proportion between rice and whey protein should be found to achieve the most pleasant aroma.
•Animal protein enriched crusts were less crispy than control.•Differences between animal protein crusts and control microstructure were observed.•Protein enriched crusts were darker than control, and whey crusts were the darkest.•Rice protein crusts had the highest content of 2-acetyl-1-pyrroline.•Whey protein crusts had high level of pyrazines.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The combined effects of microbial transglutaminase (MTGase) and ethanolic coconut husk extracts (ECHE) at various concentrations on gelling properties of spotted golden goatfish (SGG) (Parupeneus ...heptacanthus) surimi were investigated. When gel was added with MTGase at various levels (0.5–2 U/g paste), the gel containing 1 U/g paste (MT-1) had the highest increase (284%) in breaking force (BF), compared to that of the control gel (CON). Similarly, with ECHE incorporation (0.05–0.25%, based on protein content), BF was increased to the maximum value with the addition of 0.1% ECHE (EC-0.1), in which BF was augmented by 59% than the CON. When MT-1 sample was incorporated with 0.15% ECHE (MT-EC), BF was increased by 709% as compared to that of CON. Gel added with ECHE alone had lower whiteness than the CON (p<0.05). However, MTGase increased the whiteness of all gel samples, regardless of ECHE addition. MT-EC samples had higher water holding capacity than the CON (p<0.05). Electrophoretic studies showed the disappearance of myosin heavy chain (MHC) bands with the incorporation of both additives at all levels used. MT-EC sample showed the highest Gʹ value, followed by MT-1. Impact of in-vitro digestion on antioxidant activity of selected SGG surimi gels was also elucidated. During in-vitro digestion, the MT-EC and MT-1 samples had the lowest TCA-soluble peptide content. The highest antioxidant activity was obtained for MT-EC and EC-0.1 samples (p<0.05). Hence, the combination of MTGase and ECHE at appropriate levels could yield a gel with improved gelling properties and enhanced antioxidant potential after the in-vitro digestion.
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•Surimi from spotted golden goatfish was added with MTGase or ECHE.•Gel added with MTGase at 1 U/g paste had the highest breaking force.•ECHE affected gelling properties of surimi gel, in which the proper level was 0.1%.•MTGase (1 U/g) and 0.15% ECHE effectively improved texture and whiteness of gel.•ECHE increased antioxidant activity of in-vitro digest containing MTGase (1 U/g).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The purpose of this study was to investigate the effect of Kappa (к)-carrageenan on texture and perception of saltiness of low salt surimi. The low-field nuclear magnetic resonance (LF-NMR) and ...microstructure results showed that к-carrageenan could promote the formation of more immobilized water in low salt surimi gel, change its matrix structure, and lead to the uneven spatial distribution of sodium, thus enhancing saltiness perception. The rheological properties of surimi showed that к-carrageenan could increase the network strength of low salt surimi gel and improve its thermostability. Furthermore, the low salt surimi gel added with к-carrageenan has lower cooking loss, higher water holding capacity (WHC), gel strength and improved texture properties. Therefore, к-carrageenan has the effects of improving the quality and increasing salt perception of surimi gel. This study provides a new method for reducing salt consumption in food industry.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nitrogen management, especially panicle nitrogen fertilization (PNF), can affect cooked rice textures by altering starch quality, but the details are unclear. In this study, the starch multi-level ...structures, physicochemical properties and cooked rice textures of indica under different nitrogen managements were analysed and their internal relations were investigated. With an increase in PNF, large granules, amylopectin short chains, amylose content, thermal temperatures, setback, and hardness first exhibited decreasing trends and then increasing trends, which were relatively lower under moderate PNF (N3), whereas α-1,6 linkage, relative crystallinity, protein content, enthalpy of gelatinization (△Hgel), peak viscosity, breakdown and stickiness exhibited the opposite trends. N3 treatment significantly increased △Hgel and breakdown and decreased setback, hardness and chewiness, suggesting that it might contribute to better starch thermal stability and pasting properties, ultimately improving cooked rice texture. Nitrogen management affected the texture of cooked rice mainly by improving starch multi-level structures, thermal and pasting viscosities.
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•Moderate panicle nitrogen fertilization (N3) treatment decreased the starch large granule.•N3 treatment increased the α-1,6 linkage, amylopectin long chains and relative crystallinity.•N3 treatment improved the starch thermal stability, pasting viscosities and taste of cooked rice.•The amylopectin long chain, breakdown and gelatinization enthalpy altered the taste of cooked rice.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•NiFe-LDH/Hal composites with tunable morphology were developed for CO2 uptake.•Optimum calcination temperature of halloysite for best CO2 adsorption performance was detected to be ...600℃.•NiFe-LDH/Hal600 displayed highest CO2 adsorption capacity of 60.7 mg g−1.•Open mesoporous structure and high pore volume favor the CO2 adsorption.
The cost- and use-effects for solid CO2 adsorbents have accelerated development of the clay-based adsorbents. Herein, a series of NiFe-layered double hydroxides/halloysite (NiFe-LDH/Hal) composites were fabricated via facile hydrothermal strategy using calcined halloysites (Hal) as supports. Depending on treatment temperatures of halloysite, the supported NiFe-LDH exhibited different morphologies in form of nanoparticle or intertwined nanosheets. Based on the distinct morphology, these NiFe-LDH/halloysite composites displayed different textural properties and CO2 adsorption performance. Particularly, the sample NiFe-LDH/Hal600 using halloysite calcined at 600 °C as support possessed 3D hierarchical structure, and displayed superior CO2 adsorption capacity of 60.7 mg g−1 and 40.3 mg g−1 at 273 K and 298 K, respectively, much higher than those of NiFe-LDH/Hal composites supporting LDH nanoparticles. The high isosteric heat of adsorption calculated from Clausius-Clapeyron equation (21.7 kJ mol−1) indicated the strong interaction between basic NiFe-LDH surface and CO2 molecules. It was validated that the dehydroxylation and forming of silanols groups during calcination process changed the activity of internal and external surface, resulting in distinct morphology and distribution difference of the supported NiFe-LDH. The prepared clay-based composites displayed satisfying recyclability of CO2 adsorption at a high retention level after 25 cycles of adsorption–desorption.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The present investigation aims to examine the influence of textural, structural and chemical properties of biomass chars on the CO2 gasification rate. Various lignocellulosic biomass chars were ...prepared under the same conditions. Different analytical techniques were used to determine the char properties such as Scanning Electronic Microscopy, nitrogen adsorption manometry, Raman spectroscopy and X Ray Fluorescence. Gasification tests were carried out in a thermobalance under 20% CO2 in nitrogen at 800 °C.
Significant differences of the total average reactivity were observed with a factor of 2 between the prepared chars. Moreover, different behaviors of gasification rate profiles versus conversion were obtained. This difference of behavior appeared to be correlated with the biomass char properties. Hence, up to 70% of conversion, the gasification rate was shown to depend on the char external surface and the potassium content. At higher conversion ratio, a satisfactory correlation between the Catalytic Index and the average gasification rate was identified. The results highlight the importance of knowing both textural and structural properties and mineral contents of biomass chars to predict fuel reactivity during CO2 gasification processes. Such behavior prediction is highly important in the gasifiers design for char conversion.
•CO2 gasification reactivity of various lignocellulosic chars were examined.•Chars properties affect strongly samples gasification behavior.•Initial gasification rate is affected by external surface, K content and D3/G ratio.•Gasification rate behavior depends on the Alkali index at high conversion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
With advantages of long shelf life and high convenience, frozen steamed bread (FSB) is suitable for commercialization and industrialization. However, FSB has to be reheated before consumption. Since ...steam reheating is the most commonly used method for steamed bread reheating, the quality variation of FSB during the steam reheating process was evaluated in this research. Because of the simultaneous energy and moisture transfer, both the temperature and moisture content of reheated FSB gradually increased during steaming process. Starch gelatinization and crystallinity results showed that the retrograded starch was gelatinized again during steaming process. With the increase of steam reheating time, the increase of springiness and resilience as well as the decline of hardness and chewiness indicated the improved textural properties of steamed bread. Considering the sensory evaluation, the optimal steaming time was about 12 min with a maximum sensory evaluation score of 93.3. However, the springiness, resilience and sensory evaluation results of reheated FSB were still lower than those of the fresh steamed bread. The microstructure results showed that the damaged gluten network of FSB could not be recovered by steam reheating.
•The retrograded starch was gelatinized again by steam reheating.•The mechanically damaged gluten network cannot be recovered by steam reheating.•Textural properties improved continuously during the steam reheating process.•The textural and sensory evaluation properties were still below the fresh samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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