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•Carboxymethyl chitosan (CMCh) restrained the water re-distribution of frozen dough.•Freezing-induced protein deterioration was alleviated.•CMCh improved storage stability and ...textural properties of dumpling wrappers.•High-DS-CMCh exhibited better cryo-protective effect.
Carboxymethyl chitosan (CMCh), an ampholetic chitosan derivative, has found broad applications in the food industry. However, its cryo-protective properties remained less explored compared to other viscous polysaccharides, such as carboxymethyl cellulose, carrageenan etc., which have been widely utilized as frozen food additives. In this study, we investigated the effect of CMCh addition to frozen dough in terms of water state, protein structure, and the textural properties of prepared frozen dumpling wrappers. Results indicated that CMCh restricted the water migration in dough and delayed protein deterioration during frozen storage. Specifically, the content of freezable water in dough was reduced and the water distribution became more uniform as reflected by DCS and LF-NMR analysis. CMCh also stabilized disulfide bond and secondary structures of the protein, leading to inhibition of dough rheology changes. Accordingly, the obtained frozen dumplings wrappers demonstrated decreased cracking rate and water loss, and improved textural properties. Moreover, CMCh with higher degree of carboxymethyl substitution (DS: 1.2, CMCh-B) exhibited better cryo-protective effects compared to CMCh of lower DS (DS: 0.8, CMCh-A). Our study provides novel insights and scientific basis for the development of ampholetic polysaccharides as high-performance food additives.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, the effect of conventional solvothermal and a microwave-assisted method for the synthesis of MIL-101(Fe) and NH2-MIL-101(Fe) as adsorbents for the removal of tetracycline in wastewater ...is reported for the first time. The results had shown that the microwave treatment led to a significant reduction in the material synthesis time, which greatly saved the energy. It was also found that the microwave-assisted synthesized material exhibited small particle size, high specific surface area and better adsorption capacity. The introduction of amino group further enhanced the adsorption capacity of MIL-101(Fe). The adsorption capacity of MIL-101(Fe) and NH2-MIL-101(Fe) samples for tetracycline adsorption by microwave assisted synthesis method reached up to 332 mg/g and 378 mg/g, respectively. Moreover, the adsorption isotherm was well-fit with Freundlich model, indicating a multilayer adsorption. The kinetic studies indicated that the reaction followed pseudo second-order reaction kinetics with a best fit to the theoretical value. Due to the higher adsorption efficiency and lower energy consumption of the synthesis, the as-prepared microwave assisted materials could be used as potential adsorbents for different pollutants in wastewater.
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•MIL-101(Fe) and NH2-MIL-101(Fe) MOFs were successfully synthesized by a facile microwave-assisted method.•A detailed physicochemical characterization of the prepared samples were studied.•The MW–NH2–MIL-101(Fe) sample exhibited highest TC adsorption capacity of 378 mg/g .•The adsorption followed a pseudo second order kinetics with Freundlich isotherm.•A plausible adsorption mechanism and thermodynamics of the process is discussed.
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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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•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 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
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
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