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To decrease the lipid content in water-in-oil (W/O) emulsions, high internal phase Pickering W/O emulsions (HIPPE) were fabricated using magnetic stirring using a combination of monoglyceride (MAG) oleogel and polyglycerol polyacrylate oleate (PGPR) as stabilizers. Effects of MAGs (glyceryl monostearate-GMS, glycerol monolaurate-GML and glycerol monocaprylate-GMC) and internal phase components on the formation and properties of HIPPEs were investigated. The results showed that milky-white stabilized W/O HIPPE with up to 85 wt% aqueous phase content was successfully prepared, and the droplet interfaces presented a network of MAG crystals, independent of the MAG type. All HIPPEs exhibited great stability under freeze–thaw cycles but were less plastic. Meanwhile, GML-oleogel-based HIPPEs had larger particle size and were less thermal stable than GMS and GMC-based HIPPEs. Compared to guar gum, the internal phase components of sodium chloride and sucrose were more effective in reducing the particle size of HIPPEs, improving their stability and plasticity, and stabilizing them during 100-day storage. HIPPEs presented great spreadability, ductility and plasticity after whipping treatment. This knowledge provides a new perspective on the use of oleogels as co-stabilizers for the formation of W/O HIPPEs, which can be used as a potential substitute for creams. [ABSTRACT FROM AUTHOR]

In this study, the purpose was to investigate the effects with different concentrations of carrageenan (CG, 0–0.30%) on the gel properties and freeze–thaw stability of soy protein isolate (SPI, 8%) cold-set gels. LF-NMR, MRI, and rheology revealed that CG promoted the formation of SPI-CG cold-set gel dense three-dimensional network structures and increased gel network cross-linking sites. As visually demonstrated by microstructure observations, CG contributed to the formation of stable SPI-CG cold-set gels with uniform and compact network structures. The dense gel network formation was caused when the proportion of disulfide bonds in the intermolecular interaction of SPI-CG cold-set gels increased, and the particle size and zeta potential of SPI-CG aggregates increased. SG20 (0.20% CG) had the densest gel network in all samples. It effectively hindered the migration and flow of water, which decreased the damage of freezing to the gel network. Therefore, SG20 exhibited excellent gel strength, water holding capacity, freeze–thaw stability, and steaming stability. This was beneficial for the gel having a good quality after freeze–thaw, which provided a valuable reference for the development of freeze–thaw-resistant SPI cold-set gel products. [ABSTRACT FROM AUTHOR]

In order to evaluate the freeze-thaw stability of mung bean protein isolate (MPI)-stabilized emulsions and its relationship with protein structure, proteins of eight mung bean varieties were compared. The results revealed that MPIs prepared from all eight varieties were mainly composed of five subunit bands, with albumin and globulin content ranges of 188.4–310.3 and 301.1–492.7 mg/g total protein, respectively. Protein structural analysis revealed that random coil structure (32.34–33.51%) accounted for greater than 30% of MPI secondary structure. Meanwhile, analysis of protein properties revealed emulsifying activity index (EAI), emulsifying stability index (ESI) and flexibility value ranges of 6.735–8.598 m2/g, 20.13–34.25% and 0.125–0.182, respectively. Measurements of freeze-thaw stability of MPI emulsions demonstrated that exposures of emulsions to multiple freeze-thaw cycles resulted in significantly different emulsion creaming index, oiling-off, particle size and zeta potential values for the various emulsions. Moreover, the stabilities of all eight protein emulsions decreased with each freeze-thaw cycle, as demonstrated using optical micrographs. The correlation analysis method was used to study the correlation between the original structures, emulsifying properties of proteins and the freeze-thaw stability of MPI emulsions. Correlation analysis results revealed significant relationships between albumin content, subunit bands with a molecular weight of 26.9 kDa and emulsifying properties were significantly related to the freeze-thaw stability of MPI emulsion. Thus, by determining these indicator values, we can predict the freeze-thaw stability of MPI-stabilized emulsions. [ABSTRACT FROM AUTHOR]

Pickering emulsions with good freeze-thaw stability are essential in frozen food applications. This study developed a high freeze-thaw stabilized soy protein isolate (SPI)-maltose (M) Pickering emulsion and applied it to frozen doughs to investigate and reveal its impacts on the processing properties of the frozen dough. The results showed that after the freeze-thaw cycle, with a volume ratio of 1:2 of SPI to M, the appropriate amount of M changed the structure of SPI. This resulted in the Pickering emulsion prepared by the SPI exhibiting the least droplet coalescence and the best freeze-thaw stability. The results of dough rheological properties, textural properties, and binding capacity with water demonstrated that Pickering emulsions effectively inhibited the loss of gluten protein network structure in the dough after freeze treatment and increased the binding capacity of gluten proteins with starch and water in the dough. The best results were obtained with the incorporation of 3 % SPI-M high freeze-thaw stability, where the amount of bound water following three freeze-thaw cycles was 4.27 times higher than in doughs without Pickering emulsion. Overall, this study is significant for enhancing the freeze-thaw stability of Pickering emulsions stabilized by proteins and providing a new application route for Pickering emulsions. [Display omitted] • Soybean isolate protein-maltose stabilized Pickering emulsion with a 1:2 volume ratio have excellent high freeze-thaw stability. • Highly freeze-thaw stable Pickering emulsions improve the processing characteristics of dough during freezing cycles. • Preparation of SPI-M particles by Glycosylation reaction. [ABSTRACT FROM AUTHOR]

Soybean protein isolate (SPI) is widely used in the food industry. However, SPI-based emulsion gels tend to aggregate and undergo oiling-off during freeze-thawing. In this study, emulsion gels were prepared by a combination of heat treatment and ionic cross-linking using SPI and sodium alginate (SA) as raw materials. The focus was on exploring the mechanistic effects of the SPI-SA double network structure on the freeze-thaw stability of emulsion gels. The results showed that the addition of SA could form different types of network structures with SPI, due to different degrees of phase separation. In addition, SA appearing on the SPI network indicated that the addition of Ca2+ shielded the electrostatic repulsion between SPI and SA to form SPI-SA complexes. The disappearance of the characteristic peaks of SA and SPI in Fourier transform infrared spectroscopy analysis also confirmed this view. Low-field nuclear magnetic resonance data revealed that SA played a role in restricting water migration within the emulsion gels, increasing bound water content, and thereby improving the water-holding capacity of the emulsion gels. Therefore, the incorporation of SA improved the freeze-thaw stability of SPI emulsion gels. These findings offer a theoretical basis and technical support for SPI application in frozen products. [Display omitted] • One-step fabrication of double network emulsion gels through heat treatment and ionic cross-linking. • The addition of sodium alginate led to increased hydrophobicity and changes in the secondary structure of soybean protein isolate. • Various concentrations of sodium alginate significantly affected the emulsion gel microstructure. • Soybean protein isolate-sodium alginate emulsion gels exhibited favorable texture and freeze-thaw stability. [ABSTRACT FROM AUTHOR]

The current research in the food industry regarding enzymatic modification to enhance the freeze–thaw (FT) stability of starch is limited. The present study aimed to investigate the FT stability of normal corn starch (NCS) modified using 1,4-α-glucan branching enzyme (GBE) derived from Geobacillus thermoglucosidans STB02. Comprehensive analyses, including syneresis, scanning electron microscopy, and low-field nuclear magnetic resonance, collectively demonstrated the enhanced FT stability of GBE-modified corn starch (GT-NCS-30) in comparison to its native form. Its syneresis was 66.4 % lower than that of NCS after three FT cycles. Notably, GBE treatment induced changes in the pasting properties and thermal resistance of corn starch, while simultaneously enhancing the mechanical strength of the starch gel. Moreover, X-ray diffractograms and microstructural assessments of freeze–thawed gels indicated that GBE treatment effectively hindered the association of corn starch molecules, particularly amylose retrogradation. The enhanced FT stability of GBE-modified starch can be attributed to alterations in the starch structure induced by GBE. This investigation establishes a foundation for further exploration into the influence of GBE treatment on the FT stability of starch and provides a theoretical basis for further research in this area. [ABSTRACT FROM AUTHOR]

Cassava stems contain up to 40% starch (by dry mass) and are currently discarded as agricultural waste. The current study aims to understand the physicochemical traits of cassava stem and root starches for investigating trends in industrial cassava applications. In total, 11 traits of both cassava stem and root starches of 15 genotypes are investigated. All the examined traits of cassava root and stem starches vary by genotype. The amylose contents of root and stem starches are in the range of 19.0–33.0% and 18.44–34.51%, respectively. The resistant starch of root and stem starches are in the range of 1.72–17.72% and 4.42–13.37%, respectively. Only the starch content, solubility, and swelling power of root starches are significantly higher than those of stem starches. The root starch gel is more stable than the stem starch gel after the fourth and fifth freeze‐thaw cycles. Furthermore, principal component analysis calculated based on starch and amylose contents, degree of swelling, digestibility, and freeze‐thaw stability demonstrates that genotypes GW46, GW88, S1, E26, and GC49 gain higher scores than control varieties South China 12 and South China 205, which are the most favorable ones by farmers in China because of good root yields. [ABSTRACT FROM AUTHOR]

This study used Soy Protein Isolate (SPI), Soy Protein Isolate Hydrolysates (SPH) and Dextran (D) as raw materials. Covalent compounds were prepared by grafting soy protein isolate and soy protein isolate hydrolysate with dextran by water‐heating method, which were SPI‐D and SPH‐D, respectively. The effect of ionic strength (0–500 mM) on the freeze–thaw stability of SPI, SPI‐D, and SPH‐D emulsions was investigated. Fourier transform infrared analysis and Fluorescence emission spectroscopy analysis indicated that the structure of the protein changed. In this study, it was found that with the increase of ionic strength, the zeta potential of the three samples presented a downward trend and the surface hydrophobicity first decreased and then increased. The addition of ions effectively improved the freeze–thaw stability of the emulsions. The particle size of the emulsions changed little after freeze–thaw cycles, and coalescence degree, creaming index, and oiling off significantly decreased. Especially when the ionic strength reached 300 mM, the degree of coalescence was 248.46%, 170.92%, and 167.77%, respectively, and the oiling off was also reduced by 68.52%, 68.25%, and 59.92%, respectively. The creaming index of the SPI emulsion was 48.49% lower than the creaming index without ions. However, when the ionic strength exceeded 300 mM, the coalescence degree, creaming index, and oiling off of the emulsions increased. Optical microstructures also found that at ionic strength of 300 mM, the oil droplets produced by the three kinds of emulsion after freeze–thaw were smaller than those without ions. [ABSTRACT FROM AUTHOR]

In this study, freeze-thaw cycle experiments were conducted on food-grade Pickering emulsions co-stabilized with konjac glucomannan (KGM) and xanthan gum/lysozyme nanoparticles (XG/Ly NPs). The rheological properties, particle size, flocculation degree (FD), coalescence degree (CD), centrifugal stability, Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and microstructure of Pickering emulsion stabilized by KGM before and after freeze-thaw were characterized. It was found that as the concentration of KGM increased, the flocculation degree (FD) and coalescence degree (CD) of the emulsion decreased after the freeze-thaw cycle compared to the control sample, and the microscopic images showed that the droplets became smaller and less affected by the freeze-thaw cycles. The rheological and water-holding properties also confirmed that the KGM-added emulsions still had a strong gel network structure and prevented the separation of the continuous and dispersed phases of the droplets after freezing and thawing. Freeze-thaw treatments had a negative effect on the stable emulsion of XG/Ly NPs, while the addition of KGM improved the freeze-thaw stability of the emulsion, which provided a theoretical basis for the development of emulsion products with high freeze-thaw stability. [ABSTRACT FROM AUTHOR]

In this study, soy protein isolate (SPI) and maltose (M) were employed as materials for the synthesis of a covalent compound denoted as SPI-M. The emulsion gel was prepared by transglutaminase (TGase) as catalyst, and its freeze-thaw stability was investigated. The occurrence of Maillard reaction was substantiated through SDS-PAGE. The analysis of spectroscopy showed that the structure of the modified protein was more stretched, changed in the direction of freeze-thaw stability. After three freeze-thaw cycles (FTC), it was observed that the water holding capacity of SPI-M, SPI/M mixture (SPI+M) and SPI emulsion gels exhibited reductions of 8.49 %, 16.85 %, and 20.26 %, respectively. Moreover, the soluble protein content also diminished by 13.92 %, 23.43 %, and 35.31 %, respectively. In comparison to unmodified SPI, SPI-M exhibited increase in gel hardness by 160 %, while elasticity, viscosity, chewability, and cohesion demonstrated reductions of 17.7 %, 23.3 %, 33.3 %, and 6.76 %, respectively. Concurrently, the SPI-M emulsion gel exhibited the most rapid gel formation kinetics. After FTCs, the gel elastic modulus (G′) and viscosity modulus (G″) of SPI-M emulsion were the largest. DSC analysis underscored the more compact structure and heightened thermal stability of the SPI-M emulsion gel. SEM demonstrated that the SPI-M emulsion gel suffered the least damage following FTCs. • The covalent reaction between maltose and SPI made the protein changed in the direction of freeze-thaw stability. • Grafting with maltose can enhance the freeze-thaw resistance of emulsion gel. • Maillard reaction remarkably improved freeze-thaw stability and strength of emulsion gels. • Rheological tests demonstrated that the maltose access contributed to increased gel mechanical strength and formation. • SEM confirmed microstructure changes of SPI-M emulsion gels after freeze-thaw cycles. [ABSTRACT FROM AUTHOR]

Trypsin is a serine protease with important applications such as protein sequencing and tissue dissociation. Preserving protein structure and its activity during freeze-thawing and prolonging its shelf life is one of the most interesting tasks in biochemistry. In the present study, trypsin cryoprotection was achieved by altering buffer composition. Sodium phosphate buffer at pH 8.0 led to pH shift-induced destabilization of trypsin and formation of a molten globule, followed by significant activity loss (about 70%). Potassium phosphate and ammonium bicarbonate buffers at pH 8.0 were used with up to 90% activity recovery rate after 7 freeze-thaw cycles. The addition of non-ionic surfactants Tween 20 and Tween 80 led to up to 99% activity recovery rate. Amide I region changes, corresponding to specific secondary structures in the Fourier transform infrared (FTIR) spectrum, were modest in the case of Tween 20 and Tween 80. On the other hand, the addition of Triton X-100 led to the destabilization of α-helicoidal segments of trypsin structure after 7 freeze-thaw cycles but also increased protein substrate availability. Image 1 • Phosphate and bicarbonate buffers are suitable for trypsin freeze-thawing. • Sodium-phosphate destabilized trypsin to the molten globule upon freeze-thawing. • Tween 20 and Tween 80 modestly affect trypsin activity upon freeze-thawing. • Triton X-100 destabilized trypsin α-helicoidal structures upon freeze-thawing. [ABSTRACT FROM AUTHOR]

This study aims to investigate chitosan (CS) with five different molecular weight (Mw) on freeze–thaw stability of Arenga pinnata starch (APS) gel subjected to five freeze–thaw cycles (FTC). The syneresis of APS gels was reduced by adding CS and the APS gel with high Mw CS had lower syneresis duo to a higher water holding capacity (P < 0.05). The addition of CS significantly decreased the hardness and molecular ordered structure of APS gel. In addition, CS could improve the microstructural stability. The results suggested that CS could effectively improve the freeze–thaw stability of APS gel, and CS with higher Mw might have more practical utility to improve stability of APS gel. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the impact of ultrasonic modification at various ultrasonic power extents on the freeze-thaw stability of soy protein isolate (SPI) gel. The freeze-thaw stability of the gel was evaluated by examining the changes in texture, water holding capacity, microstructure and soluble protein content during the process of 5 freeze-thaw cycles. In addition, effects on particle size, surface hydrophobicity and structure were also explored. The results showed that within a certain range, the average particle size of the protein gradually decreased, and the particle size distribution was narrower with ultrasonic intensity, it may be due to the high shear and cavitation effects of sonication that reduce the degree of protein aggregation. Furthermore, we also detected that treated proteins had lower fluorescence intensity, higher surface hydrophobicity and more flexible molecular structure with the reduction of α-helical structure as well as the rise of random coil. In terms of gel freeze-thaw stability, moderate ultrasound treatment made the water holding capacity and soluble protein content of SPI gel reduce by 38.27% and 3.58%, whereas the hardness and elasticity increased by 510.23g and 0.06mm after 5 FTC. The corresponding changes of indexes of the control group were 75.05%, 51%, 1062.75g and 0.11mm, respectively. It can be observed that the change range of treated SPI gel properties was smaller than that of natural SPI gel, indicating that ultrasonic treatment can remarkably improve the freeze-thaw stability of the gel which might have something to do with changes of protein structure. [ABSTRACT FROM AUTHOR]

The poor freeze-thaw stability and weak thermal gel properties of plant-based egg substitutes limit their opportunity for application. In the current study, the impact of modification by pH-shifting and transglutaminase (TG) cross-linking on the freeze-thaw stability and thermal gel properties of mung bean protein-based emulsions made by two different oil phases (canola oil and coconut oil) were studied. The pH-shifting induced improved emulsifying activity (up to 77.6% increased) and smaller droplets sizes (from 39.27 to 7.03 μm). After the freeze-thaw process, no matter with TG cross-linking or in different oil phase systems, all emulsion samples prepared with pH-shifting treated mung bean protein (BMBP) exhibited a superior freeze-thaw stability than that with native mung bean protein (NMBP). The apparent viscosity of BMBP emulsion was higher than that of NMBP, and the viscosity of BMBP-based CO-emulsion (222.50 mPa s) before freeze-thaw process was closest to that of real egg liquid (184.86 mPa s). In particular, BMBP was more sensitive to TG, resulting in a superior thermal gel hardness of BMBP-based emulsion. This study could serve as a feasible solution to enhance the freeze-thaw stability and thermal gel properties of plant-based emulsions by pH-shifting and TG cross-linking, providing some novel strategies for their applications as stabilized plant-based egg substitutes. [Display omitted] • pH-shifting induced improved emulsifying activity and smaller droplet size. • pH-shifting mung bean protein emulsion exhibited a superior freeze-thaw stability. • pH-shifting protein is more sensitive to TG, resulting in higher gel hardness. • The viscosity of BMBP emulsion was higher than NMBP and was closest to real egg. • NMBP emulsion partially replaces egg, but BMBP emulsion makes higher substitute. [ABSTRACT FROM AUTHOR]

Protein hydrolysis on the freeze-thaw stability of emulsions prepared with soy protein - dextran conjugates were investigated. Soy protein isolate-dextran (SPI-D) and soy protein hydrolysates-dextran (SPH-D) conjugates with different degree of hydrolysis (DH) were formed by Maillard reaction. The formation of protein-polysaccharide conjugates between SPI/SPH and dextran molecules was confirmed by SDS-PAGE; this finding was consistent with the degree of glycation and the browning index. The freezethaw emulsion stability was investigated. The results confirmed that the SPH3-D (DH at 3%) emulsion with 3% DH of SPI exhibited the lowest creaming index after experiencing 1, 2, and 3 freeze-thaw cycles, with results of 7.69%, 20.74% and 31.30%, respectively. The SPH3-D emulsion had a significantly lower average particle size, which was reduced by 48.28% compared to the SPI-D emulsion. Meanwhile, the SPH3-D solution had low interfacial tension. The confocal laser scanning microscopy analysis indicated that the SPH3-D emulsions were strongly stable against the freeze-thaw treatment and could be used as effective emulsifiers in frozen foods. [ABSTRACT FROM AUTHOR]

A comprehensive study was conducted to elucidate structural and functional properties of waxy starches. The specific objectives were to examine the relationship between gelatinization/pasting properties and morphology of starch cooks, determine how the retrogradation properties are affected by chain-length distribution, and use a novel sensory approach to assess freeze-thaw stability of starch pastes. Waxy potato starch had a greater degree of granule swelling, higher paste viscosities, and better paste clarity than waxy starches from maize, wheat, rice, and tapioca. Waxy starches typically had greater paste viscosities than their normal counterparts, but the exception was potato starches. Waxy potato starch, which had no amylose, had lower paste viscosity than normal potato starch. Both waxy rice and waxy tapioca starches had less retrogradation tendency, which was closely related to the higher proportion of chains with DP 6–11 and the lower proportion of chains with DP 12–24. The sensory evaluation in this study allowed for an easier assessment of water separation as compared to the conventional centrifuge methods. Waxy maize and waxy potato starches had noticeable water separation from the paste after 1–2 freeze-thaw cycles, whereas both waxy rice and waxy tapioca starches could survive 6 freeze-thaw cycles without apparent syneresis. Waxy wheat, waxy rice and waxy tapioca starches are potential starting materials from which clean-label functional starches may be produced. Image 1 • A comprehensive study was done on structure and properties of waxy starches. • Waxy potato starch had the best paste clarity among waxy starches. • A sensory approach was developed to assess freeze-thaw stability of starch pastes. • Waxy rice and waxy tapioca starches had the least retrogradation among waxy starches. • Unit chains with DP 6–11 and 12–24 correlated with cold stability of waxy starch. [ABSTRACT FROM AUTHOR]

Abstract Soybean oil-based organogel was structured using monostearin, and the organogel had a gel-sol melting temperature of 44.0 °C. Loading amount of hesperidin in soybean oil-based organogels could be about twice as much as metastable solubility of hesperidin in soybean oil. Organogel-in-water Pickering emulsion was formed using the soybean oil-based organogel as the oil phase and ovotransferrin (OVT) fibrils as the emulsifier. Visual observation indicated that organogel-based Pickering emulsions stabilized by OVT fibrils (40 mg/mL) at oil fractions of 0.50–0.85 had excellent storage stability and could withstand three cycles of freeze-thaw treatments. Conventional oil-in-water Pickering emulsion was prepared as control to better understand impact of organogel incorporation on freeze-thaw stability, and conventional Pickering emulsion was formed using soybean oil as the oil phase and OVT fibrils as the emulsifier. Freeze-thaw stability of organogel-based Pickering emulsions was better than that of conventional Pickering emulsions (without organogel) stabilized by OVT fibrils. In vitro digestion study revealed that organogel-based Pickering emulsion could improve both the extent of lipolysis and hesperidin bioaccessibility when compared with organogel. This study demonstrates the feasibility of formulating novel food-grade organogel-based Pickering emulsions with high nutraceutical loading, excellent freeze-thaw stability and improved nutraceutical bioaccessibility. Graphical abstract Image 1 Highlights • Organogel-based Pickering emulsions with a higher loading of hesperidin were developed. • Organogel-based Pickering emulsions stabilized by ovotransferrin fibrils had good storage stability. • Organogel-based Pickering emulsions could withstand three freeze-thaw cycles. • Organogel-based Pickering emulsion could improve the extent of lipolysis. • Organogel-based Pickering emulsion could improve hesperidin bioaccessibility. [ABSTRACT FROM AUTHOR]

Abstract Oil-in-water (o/w) emulsions stabilized by soybean protein isolate (SPI) and enzyme-modified soybean protein isolate (SPI + TGase, SPIH, SPIH + TGase) were subjected to three freeze-thaw cycles, and changes in the molecular weight distribution, secondary structure contents, particle size, oiling off (OF), creaming index (CI) and microstructures were investigated. The emulsions exhibited different freeze-thaw tolerance stabilities, which were dependent on the type of enzyme used to prepare the SPI as well as the cycle number of freeze-thaw treatments. Differential scanning calorimetry suggested that emulsion destabilization was mainly due to water crystallization. After three freeze-thaw cycles, the emulsion stabilized by SPIH + TGase showed a decrease of 78.89% in CI and 72.35% in OF compared with SPI. Correspondingly, the particle size decreased by 70.76% (in water) and 88.99% (in 1% SDS). The improvement in the freeze-thaw stability could be largely attributed to the increased molecular flexibility due to the increased α-helix and random coil contents after enzymatic hydrolysis and the formation of gel-like network structures after the addition of TGase cross-linking. The observation of the microstructure also indicated that SPIH + TGase was an effective food emulsifier. These findings could be of great importance for the formulation of food grade emulsions with excellent freeze-thaw stability. Highlights • Freeze-thaw stabilization of SPI, SPIH, SPI + TGase, SPIH + TGase was studied. • Different modification methods and freeze-thaw cycles were investigated. • ζ-potential, particle size, microstructure, OF and CI reflect the stability. • SPIH + TGase can effectively improve the freeze-thaw stability of the emulsion. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of pH on the freeze-thaw stability of glycated soy protein isolate (SPI) and soy protein isolate hydrolysate (SPH) were studied. The covalent compounds were prepared by conjugating SPI, SPH and dextran under heated Maillard reaction, which the macromolecules were named SPI-D and SPH-D. SDS-PAGE analysis verified that SPI-D and SPH-D form a covalent bond through the Maillard reaction. Afterwards, the effects of pH on the freeze-thaw stability of SPI, SPI-D and SPH-D emulsions were evaluated. The covalent conjugate stabilized emulsions improved the stability of the emulsions to pH stress. After freeze-thaw cycles, SPH-D revealed the lowest particle size, degree of coalescence (CD) and oiling off. The results above were also supported by optical microscopy analysis. [ABSTRACT FROM AUTHOR]

Animal or plant-based meat products are typically stored and transported using freezing. Freezing-thawing cycles can lead to detrimental changes in the texture, appearance, and mouthfeel of fat substitutes, thus affecting their quality. In this work, a protein/polysaccharide composite emulsion gel was created by emulsifying soybean isolate protein (SPI) and palm oil (PO), and incorporating curdlan (CL). It can serve as a potential replacement for animal fat in meat products, such as sausage, and plant-based meat. The study aimed to investigate the stability of the complex fat substitutes during freeze-thaw at various melting points and palm oil content. The results showed that the 52°C-palm oil samples were the most freeze-thaw stable compared to samples with other melting points. 52°C-palm oil samples were tested for texture and water holding capacity (WHC), increasing the oil content from 5g/100g–20g/100g improved the gel strength and WHC after freeze-thaw. The samples containing high melting point palm oil were less affected by temperature changes and showed higher stability as detected by low-field NMR and differential calorimetric scanning. The confocal laser scanning and rheological detection further confirmed the enhanced structural strength and freeze-thaw stability of the emulsion gels containing solid fat particles with high melting points. • Freeze-thaw treatment causes fat substitutes to syneresis and lose oil, creating folds and pores. • Increased content of low melting point oil will destroy the structure of emulsion gel. • High melting point oil will improve the strength and water holding capacity of the emulsion gel. • High melting point palm oil improves freeze-thaw stability of fat substitutes. [ABSTRACT FROM AUTHOR]

The alkali-induced heat-set konjac glucomannan (KGM) hydrogels have drawn increasing attention due to their high absorbency and thermal irreversibility ability, but pure KGM hydrogels generally have defects of low strength and high syneresis rate. Cellulose nanocrystals and their derivatives, which have a very high specific surface area, good biocompatibility, biodegradability, and low toxicity, are promising candidates to solve this challenge. In this work, we propose the use of carboxylated cellulose nanocrystals (C–CNCs) as nanofillers for the strengthening of KGM hydrogels. The effects of the C–CNCs content on the microstructure and physical properties of the KGM hydrogels and their possible mechanism were investigated. The compressive test results indicate great improvement in the mechanical properties upon the addition of the C–CNCs for the KGM hydrogel and reached a maximum value at 20% loading. The microstructure analyses of the KGM hydrogel revealed that the well-distributed C–CNCs can act as a physical cross-linker to connect the neighboring KGM chains to strengthen the resultant hydrogel, based on their strong interactions, including hydrogen bonding and chain entanglements. Moreover, adding 20% C–CNCs can significantly decrease the syneresis after five repeated freeze-thaw cycles of the KGM hydrogels. Compared to pure KGM hydrogels, KGM/C–CNCs nanocomposite hydrogels demonstrated higher water-binding capability based on Low-field nuclear magnetic resonance. These findings indicate that C–CNCs are considered anchors for KGM chains as well as reinforcement fillers in the polymer matrix, which contributes significantly to the mechanical property of the nanocomposite. Therefore, C–CNCs were a promising material to be applied for modulating the mechanical and freeze-thaw stability properties of the polysaccharide-based hydrogel in food and biomedical applications. [Display omitted] • C–CNCs were proposed as nanofillers for the strengthening of alkali-induced heat-set KGM hydrogels. • Nanocomposite hydrogels exhibited good mechanical property, enhanced thermal stability, and excellent freeze-thaw stability. • Physicochemical of nanocomposite hydrogels were regulated by controlling the content of C–CNCs. • C–CNCs can act as a physical cross-linker to connect the neighboring KGM chains to strengthen the resultant hydrogel. [ABSTRACT FROM AUTHOR]

Binary gels with various microstructures, including apricot kernel protein isolate-gellan gum gels with high freeze-thaw stability, were obtained by combining transglutaminase covalent cross-linking and gellan gum modification. Adding 0–0.1% gellan gum (w/w) can form continuous protein network structures dominated by covalent networks and disulfide bonds. In addition to covalent cross-linking, the increase in the strength of hydrophobic and electrostatic interactions at gellan gum concentrations below 0.2% (w/w) facilitated the formation of a bicontinuous network (AGG3). When excess gellan gum was added (0.03%, w/w), gellan gelation occurred in the system, leading to the formation of heterogeneous aggregated structures (AGG4). Confocal laser microscopy revealed a dense porous structure in the continuous protein network after freeze-thaw treatment, and AGG4 showed heterogeneous and loose aggregated microstructure, while the bicontinuous network structure was maintained. The water holding capacity of AGG3 was increased by 21.36% after freezing compared with the gels without gellan gum, and AGG3 maintained high hardness and springiness. Low-field nuclear magnetic resonance and magnetic resonance imaging showed that the bicontinuous network was more conducive to the tethering ability and uniform distribution of hydrogen protons than the continuous network structure of proteins. Therefore, AGG3 exhibited excellent freeze-thaw stability. • Cold-set apricot kernel protein isolate-gellan gum binary gels were obtained. • Gels with various microstructures were fabricated by different interactions. • The TGase covalent cross-linking added a certain strength to the gel network. • The noncovalent interactions and chain entanglement could enhance gel springiness. • Gels with bicontinuous microstructures had excellent freeze-thaw stability. [ABSTRACT FROM AUTHOR]

There is still a debate about the influence of salts on the freeze-thaw stability of emulsions. In this research, the influence of the NaCl addition (before or after the emulsification; 100–500 mM) on the freeze-thaw stability of the Pickering emulsions stabilized by heat-induced soy protein isolate (SPI) nanoparticles, at a given protein concentration of 1.0% (w/v) and oil fraction of 0.4, was investigated. The addition of NaCl resulted in considerable changes in particle characteristics (including particle size, surface hydrophobicity and ζ -potential) of the SPI nanoparticles, with the extent of the changes varying with the applied ionic strength ( μ ). Despite the NaCl addition before or after the emulsification, the presence of NaCl remarkably improved the freeze-thaw stability against droplet coalescence and creaming of the emulsions, though the improvement was related to the applied μ . The improvement of the freeze-thaw stability would be largely attributed to the strengthening of the interfacial protein or protein nanoparticle films coating droplets, rather than the inhibition of ice crystal formation by the presence of NaCl. If the salt was introduced before the emulsification, a gel-like network might be formed in the corresponding emulsions, which would further provide an additional stabilization against the freeze-thaw treatment. Optimal freeze-thaw stability was observed in the presence of appropriate concentrations of NaCl (e.g., 100–200 mM). This is the first report to indicate the importance of the electrostatic screening to the improvement of the Pickering emulsions stabilized by charged particles. The findings would be of great importance for the formulation of food grade emulsions with excellent freeze-thaw stability. [ABSTRACT FROM AUTHOR]

This study developed water-in-oil (W/O) Pickering emulsions stabilized by ethylcellulose (EC) nanoparticles and EC oleogels, which presented significantly improved freeze-thawing (F/T) stability. Microstructural observation suggested EC nanoparticles were distributed at the interface and within the water droplets, and the EC oleogel trapped oil in the continuous phase. Freezing and melting temperatures of water in the emulsions with more EC nanoparticles were lowered and the corresponding enthalpy values were reduced. F/T led to lower water binding capacity but higher oil binding capacity of the emulsions, compared to the initial emulsions. Low field-nuclear magnetic resonance confirmed the increased mobility of water but decreased mobility of oil in the emulsions after F/T. Both linear and nonlinear rheological properties proved that emulsions exhibited higher strength and higher viscosity after F/T. The widened area of the elastic and viscous Lissajous plots with more nanoparticles suggested the viscosity and elasticity of emulsions were increased. [Display omitted] [ABSTRACT FROM AUTHOR]

This study examined the destabilization of an oil-in-water (O/W) emulsion by freeze-thawing with a focus on the influence of the morphology and polymorph of fat crystals. For a model of food emulsion, this study used a mayonnaise-type O/W emulsion containing 70 wt% canola oil (canola emulsion) or soybean oil (soybean emulsion) stored at − 15, − 20, and − 30 °C. The freeze-thaw stabilities of the emulsions were evaluated by measuring the upper oil layer after freeze-thawing. The soybean emulsion kept at − 20 °C had the highest stability; the other emulsions were destabilized during 6 h of storage. Crystallization in the emulsions was determined using differential scanning calorimetry (DSC), time variation of temperature, X-ray diffraction measurement, and polarized light microscopy. DSC thermograms indicated that crystallization in emulsions occurred first in the high-melting fraction of oil, followed by water and, last, in the low-melting fraction of oil during cooling to − 40 °C. In the canola emulsion, the amount of fat crystals derived from the low-melting fraction of oil increased during storage at all temperatures, resulting in partial coalescence. The soybean emulsion was expected to be destabilized by polymorphic transformation (sub-α to β′ and β) of fat crystals derived from the high-melting fraction during storage at − 15 and − 20 °C. However, the soybean emulsion did not exhibit polymorphic transformation stored at − 30 °C, and the amount of fat crystals did not increase during freezing; thus, it was destabilized via a different mechanism. [ABSTRACT FROM AUTHOR]

Edible biphasic gels with high lipid fractions (>50%) were developed and characterized for their freeze-thaw and lipid oxidation stability. Gels consisted of gelatin in aqueous buffer (hydrogel; HG), and rice bran wax (RBW) in high-oleic soybean oil (oleogel; OG). Freeze-thaw stability was studied by rheology, liquid loss measurement, and microstructural characterization of the gels before and after one freeze-thaw cycle. Biphasic gels were stored for 6 months under accelerated oxidation conditions to assess oxidative stability through peroxide value (PV) analysis. Biphasic gels led to superior systems compared to control OG and HG. The storage modulus (G′) increased with increasing OG. Yield stress (σ*) for biphasic gels were greater than for OG alone, and σ*increased as the proportion of HG increased. Micrographs of biphasic gels showed OG-in-HG matrix for all gels, including those of >50% OG. After one freeze-thaw cycle, biphasic gels had less total liquid loss by approximately 50% compared to the controls and showed an increase in G′. No samples were rancid after the storage period, as demonstrated by the low PV (<3 meq/kg). Changing the ratio of OG:HG for this biphasic gel demonstrates the potential to design semi-solid fat replacers of desired properties with good overall physico-chemical stability. [Display omitted] • Increasing HG or OG in biphasic gels increased yield stress or G′, respectively. • Biphasic gels revealed optimal freeze-thaw stability compared to neat hydrogel and oleogel. • Biphasic gels showed high oxidative stability for f all regardless of OG:HG ratio. [ABSTRACT FROM AUTHOR]

Quality deterioration caused by ice formation and growth is a prevailing problem in frozen food, therefore, exploration of natural cryoprotectants has been attracting more attention. In this study, Flammulina velutipes mycelium polysaccharides (FVP) were obtained by autoclave extraction and their effect on freeze-thaw stability of surimi gels were investigated. The results showed that FVP consisted mainly (59.02%) of high-molecular-weight polysaccharides (>450 kDa), and were composed of Glu, Xyl, Man, Gal, and Fuc in a molar ratio of 33.4: 28.72: 26.31: 8.01: 3.55. FVP (1.0 mg/mL) showed superior Ice Recrystallization Inhibition (IRI) activity. Freeze-thaw stability tests demonstrated that frozen-thawed surimi gels with FVP addition exhibited a more uniform and continuous matrices than the control ones. FVP could significantly improve the water holding capacity, the hardness, springiness and cohesiveness of surimi gels during the repeated freeze-thaw cycles. Studies on water state and properties showed that FVP could decrease the freezable water content, restrict water mobility, and inhibit water migration in frozen surimi gels. These results suggest the potential of FVP as a promising cryoprotectant candidate in the frozen food industry. [Display omitted] • Flammulina velutipes polysaccharides (FVP) extracted in autoclave showed IRI activity. • 0.1% FVP preserved the quality of surimi gels during freeze-thaw cycles. • FVP decreased freezable water content, water mobility and migration of surimi gels. [ABSTRACT FROM AUTHOR]

This study aimed to explore freeze-thaw (FT) stability of rice starch modified by Improved Extrusion Cooking Technology (IECT). FT stability of IECT-modified rice starch was investigated and compared with native one. Syneresis and SEM analysis showed that IECT-modified rice starch had better FT stability than native starch. Furthermore, IECT-modified rice starch had less significant changes in the rheological parameters during the FT cycles than the native starch. XRD and iodine binding analysis demonstrated that IECT treatment inhibited the association of rice starch, especially amylose retrogradation. Additionally, the peak at around 20° was detected in XRD patterns of IECT-modified rice starch, which confirmed the formation of amylose-lipid complex during the IECT treatment. These results suggested that the IECT treatment could improve FT stability of rice starch, which was ascribed to inhibition of starch retrogradation by IECT. [ABSTRACT FROM AUTHOR]

Amylomaltase (α-1,4-glucanotransferase, AM; EC 2.4.1.25) from Corynebacterium glutamicum expressed in Escherichia coli was used to prepare the enzyme-modified cassava starch for food application. About 5% to 15% (w/v) of cassava starch slurries were incubated with 1, 3, or 5 units of amylomaltase/g starch. Apparent amylose, amylopectin chain length distribution, thermal properties, freeze-thaw stability, thermo-reversibility, and gel strength of the obtained modified starches were measured. The apparent amylose content and retrogradation enthalpy were lower, whereas the retrogradation temperatures, freeze-thaw stability, and thermo-reversibility were higher than those of the native cassava starch. However, when amylomaltase content was increased to 20 units of amylomaltase/g starch and for 24 h, the modified starch showed an improvement in the thermo-reversibility property. When used in panna cotta, the gel strength of the sample using the 20 units/24 h modified cassava starch was similar to that of using gelatin. [ABSTRACT FROM AUTHOR]

The impact of microcrystalline cellulose (MCC) on the physical stability, microrheological property and freeze-thaw stability of papain hydrolysate of soybean isolate protein (SPIH) stabilized curcumin emulsion was studied. Curcumin emulsions were prepared by Microfluidizer containing SPIH and various concentrations of MCC. The curcumin emulsions were assessed by zeta potential, average particle size through dynamic light scattering technique (DLS), stability index by Turbiscan and microrheological behavior through diffusive wave spectroscopy (DWS) technique. With addition of MCC, the negative charge of the droplets was increased, which indicated that the negatively charged fraction from MCC interacted with the protein at the interface. An increase in droplet size and decrease in TSI were noted with increasing MCC concentration. It demonstrated that enough MCC changed microrheological property of curcumin emulsions from purely viscous to viscoelastic over the range of decorrelation times, indicating that the droplets were not free to move due to the droplets network interaction. Freeze-thaw stability analysis demonstrated that MCC brought about a remarkable improvement, which can be attributed to the enhancement of repulsive steric forces between the curcumin droplets. It demonstrated that combined enzymatic hydrolysate of protein and addition of polysaccharide MCC could be an effective method for protecting bioactive compound in emulsions. [ABSTRACT FROM AUTHOR]

Abstract: The present research is aimed to evaluate the effects of sucrose fatty acid esters (SEs) on the pasting, rheological properties and the freeze–thaw stability of rice flour. Four types of SEs including S-570, S-970, S-1170 and S-1570 with hydrophilic–lipophilic balance (HLB) values varying from 5 to 15 have been compared. Viscosity behavior of rice flour with different SEs was first measured with the Rapid Visco Analyzer (RVA). The RVA profile showed that pasting temperature, peak and final viscosities of rice flour gels increased with SEs addition except for S-570. Rheological properties including the steady shear characteristics, the viscoelastic parameters (storage and loss moduli) and the creep-recovery response were determined. The obtained steady shear and creep data were fitted by power law (R 2 > 0.983) and Burger's models (R 2 > 0.993) respectively. The results revealed that the addition of SEs except for S-570 increased the storage and loss moduli, apparent viscosity, flow behavior index and the retardation time, and decreased loss tangent. Finally, the freeze–thaw measurement demonstrated that all types of SEs enhanced the freeze–thaw stability of rice flour with the order of S-1570 > S-1170 > S-970 > S-570. These results could have important theoretical and practical implications in choosing suitable SEs for the particular requirements of final food products based on rice flour. [Copyright &y& Elsevier]

Main conclusion: Expression of amylosucrase in potato resulted in larger starch granules with rough surfaces and novel physico-chemical properties, including improved freeze-thaw stability, higher end viscosity, and better enzymatic digestibility. Starch is a very important carbohydrate in many food and non-food applications. In planta modification of starch by genetic engineering has significant economic and environmental benefits as it makes the chemical or physical post-harvest modification obsolete. An amylosucrase from Neisseria polysaccharea fused to a starch-binding domain (SBD) was introduced in two potato genetic backgrounds to synthesize starch granules with altered composition, and thereby to broaden starch applications. Expression of SBD-amylosucrase fusion protein in the amylose-containing potato resulted in starch granules with a rough surface, a twofold increase in median granule size, and altered physico-chemical properties including improved freeze-thaw stability, higher end viscosity, and better enzymatic digestibility. These effects are possibly a result of the physical interaction between amylosucrase and starch granules. The modified larger starches not only have great benefit to the potato starch industry by reducing losses during starch isolation, but also have an advantage in many food applications such as frozen food due to its extremely high freeze-thaw stability. [ABSTRACT FROM AUTHOR]

This article focused on the freeze-thaw stability and rheological properties of soy protein isolate (SPI) emulsion gels induced by NaCl. The freeze-thaw stability was characterized by particle size, ζ-potential, and differential scanning calorimetry (DSC) measurements. The salt concentration (200–400 mM) could promote protein aggregation and improve freeze-thaw stability. The study of both linear and nonlinear rheology properties proved that SPI emulsion gels exhibited the maximal gel strength at 300 mM NaCl that could resist structure disruption and oil droplet migration. The nonlinear responses were further analyzed using Lissajous plots. Initial SPI emulsion gels had higher peak stress values at 300 mM NaCl, indicating more resistance to deformation and increased elastic-dominant behavior as well as improved freeze-thaw stability. While the area of the elastic and viscous Lissajous plots narrowed as the salt concentration exceeded 300 mM, suggesting the viscosity and elasticity decreased. Scanning electron microscopy (SEM) images further confirmed that the SPI emulsion gels had smaller pores and denser structures at 300 mM NaCl, resulting in good freeze-thaw stability. Besides, the maximum gel strength emerged in 300 mM NaCl and 100 mM NaCl before and after freeze-thaw cycles, respectively, which was due to moderate dehydration and a small amount of oil leakage from the network. These findings provide valuable information for the relationships between freeze-thaw stability and rheology property of emulsion gels. [Display omitted] • The presence of NaCl remarkably improved freeze-thaw stability and strength of emulsion gels. • At 200–400 mM NaCl, no coalescence was observed after freeze-thaw cycles. • SPI emulsion gels had the maximal peak stress and gel strength at 300 mM NaCl. • The gel strength changed after freeze-thaw cycles due to dehydration. • LAOS rheology confirmed microstructure changes of SPI emulsion gels after freeze-thaw cycles. [ABSTRACT FROM AUTHOR]

In this study, different emulsifiers were used to improve the bonding performance and freeze-thaw stability of renewable starch-based wood adhesive. The improved bonding performance and freeze-thaw stability were supported by the enhanced shear strength, grafted parameters, and viscosity stability after repeated freeze-thaw cycling. ζ-Potential determination, differential scanning calorimetry and pulsed nuclear magnetic resonance analysis indicated that the emulsifiers improve the grafting of vinyl acetate monomers into the starch bonds via free radical vinyl polymerization and hinder the aggregation of starch molecules. Among the emulsifiers tested, sodium dodecyl sulfate showed the highest improvement in the bonding performance and freeze-thaw stability of starch-based wood adhesives. [ABSTRACT FROM AUTHOR]

Abstract: Freeze–thaw (FT) cycles can aggregate particles in aqueous paint suspensions. To understand the mechanism of particle aggregation, cryogenic scanning electron microscopy (cryoSEM) was used to visualize the microstructure after the freezing and thawing steps of the FT cycle. After the freezing step, cryoSEM images show that the microstructure contains ice crystals and particle-rich regions. Adding propylene glycol, a FT stabilizing additive, leads to formation of larger ice crystals. After thawing, the dispersion structure revealed by cryoSEM shows that the particles redisperse only in the paint with the highest amount of propylene glycol. The other paints contain clusters that are different from the particle-rich regions found after the freezing step. Increasing the thawing rate leads to a more dispersed microstructure even in the absence of propylene glycol. Analysis of the cryoSEM results shows that particle aggregation into these clusters occurs during the thawing stage, and slow thawing conditions lead to more aggregation. The cryoSEM results reported here are used to propose a mechanism of aggregation of particles in the paint. [Copyright &y& Elsevier]

Abstract: Native starches from twenty-six botanical sources were determined for their structural features and stability against freeze–thaw treatments. Starch gels (5%, w/w) were prepared and repeatedly freeze–thawed up to five cycles by storing at −18°C for 21h and then at 30°C for 3h. Water release (syneresis) from the thawed gel after the 1st, 3rd and 5th cycle was measured gravimetrically, and evaluated in relation to apparent amylose content (AAC) and distribution of amylopectin branch chains with degree of polymerization 6–12 (APC ratio). Syneresis was not observed for starch gels of cassava, normal and waxy japonica rice up to the 1st, 3rd and 5th cycle, respectively. On the other hand, syneresis rapidly occurred for starch gels of elephant yam, new cocoyam, potato, edible canna, and water yam. Optimal multiple linear regression models were generated to predict individual effect of AAC and APC ratio on syneresis of starch gels. The prediction models illustrated the positive unit-contribution of AAC and negative unit-contribution of APC ratio to syneresis (P <0.001). [Copyright &y& Elsevier]

This study aimed to investigate the effects of freeze-thaw treatment on the structure and texture of transglutaminase crosslinked soy protein isolate gels with glycated modifications. Different mass ratios (1:1, 2:1, 3:1 and 4:1) of a soy protein isolate/dextran mixture (SPI + D) and the structural properties and gel texture of a soy protein isolate-dextran conjugate (SPI-D) were investigated. The results showed that the degree of grafting increased with increasing dextran content and was maximized when SPI:D was 1:1 (16.51%). The SDS-PAGE results showed that the glycation reaction generated glycoprotein. Fluorescence spectroscopy and surface hydrophobicity results confirmed the change in the structure of the soy protein isolate. The SPI-D (2:1) gel exhibited the highest water holding capacity, with values of 90.33%, 68.67%, 60.11% and 58.49% at 0, 1, 3 and 5 freeze-thaw cycles (FTCs), respectively. Scanning electron microscopy results showed that the structure of the SPI-D gel was uniform and more regular after being subjected to FTCs. The hardness and gumminess of all experimental groups increased with the increasing number of FTCs. Glycation could reduce the degree of SPI gel soluble protein reduction during freezing and thawing. - Glycosylation reduces the adverse effect of freeze-thaw treatment on the formation of SPI gel. - The freeze-thaw treatment resulted in a rough network structure in the composite gels. - Soy protein isolate-dextran conjugate gel was uniform and more regular after freeze-thaw cycles. [ABSTRACT FROM AUTHOR]

Quinoa protein isolate (QPI) dispersions were ultrasonicated to generate nanoparticles, which were applied to emulsify olive, rapeseed and corn oil to form stable Pickering high internal phase emulsions (HIPEs). The effects of different oil phases and ultrasonic intensity on the particle size, zeta potential, rheological properties and microscopic distribution of Pickering HIPEs were analyzed. The contact angle of QPI nanoparticles with 450 W ultrasonic treatment was 68.83 ± 3.32°, which was remarkably higher than natural particles of 53.69 ± 0.84°. Pickering HIPEs exhibited a three-dimensional network structure and high viscoelasticity. The storage modulus of HIPEs with olive oil was higher than HIPEs with rapeseed and corn oil. The HIPEs with high oleic acid content in oil phase showed high viscoelasticity, because the rheological properties of HIPEs were positively correlated with oleic acid content. Furthermore, QPI HIPE gels were prepared and the freeze-thaw stability of HIPE gels was analyzed. The HIPE gels emulsified by natural QPI showed weak freeze-thaw stability, while the HIPE gels stabilized by sonicated QPI exhibited high freeze-thaw stability. Microstructure of HIPEs by confocal laser scanning microscopy also confirmed the finding. Moreover, different vegetable oils had no significant effects on the freeze-thaw stability of the HIPE gels. [Display omitted] • Ultrasound improved hydrophobicity of quinoa protein isolate (QPI) nanoparticles. • QPI stabilized high internal phase emulsions (HIPEs) with oil volume up to 75%. • The viscoelasticity of HIPEs with olive oil was higher than those with other oils. • The storage modulus of HIPEs were positively correlated with oleic acid content. • Sonicated QPI particles effectively improved freeze-thaw stability of HIPE gels. [ABSTRACT FROM AUTHOR]

The effect of salt ion on the freeze-thaw stability of protein-polysaccharide emulsions remains controversial. In this study, we investigated the effects of two salts, CaCl 2 and NaCl, on the freeze-thaw stability and digestion characteristics of soybean lipoprotein-hydroxypropyl methyl cellulose (LP-HPMC) emulsions. Analysis of the particle size, protein adsorption, and ζ-potential showed that addition of salt ions led to an increased extent of interfacial protein adsorption. The best oxidation stability and emulsification were observed when 100 mM salt was added. Analyses of the microstructure, creaming index, oiling off, and coalescence degree revealed that the presence of salt ions significantly improved the freeze-thaw stability of the emulsion, and addition of monovalent ions of NaCl to the emulsion to showed better interface protein crack resistance performance during the freeze-thaw cycle, low oiling off (8.75 ± 0.5 %), and coalescence degree (43.67 ± 2.5 %) compared to adding divalent ions of CaCl 2. Moreover, Fourier infrared spectroscopy data revealed that the α-helix content in the secondary structure of LP was closely related to the freeze-thaw stability of the emulsion. Addition of salt ions delayed the release rate of internal oils in the LP-HPMC emulsion. These results provide a foundation of producing new emulsified foods with favorable freeze-thaw stability. [Display omitted] • The freeze-thaw stability of protein–polysaccharide emulsions is undetermined. • Salt ion effects of CaCl 2 and NaCl were investigated on the freeze-thaw stability. • Examined emulsions of soybean lipoprotein-hydroxypropyl methyl cellulose (LP-HPMC). • The effect of salt ion on the digestibility of LP-HPMC emulsion. • Oxidation stability was at its best with the addition of 100 mM NaCl. [ABSTRACT FROM AUTHOR]

The use of unmodified starch in frozen foods can cause extremely undesirable textural changes after the freeze-thaw process. In this study, using cyclodextrin glucanotransferase (CGTase) and branching enzymes, an amylopectin cluster with high freeze-thaw stability was produced, and was named CBAC. It was found to have a water solubility seven times higher, and a molecular weight 77 times lower, than corn starch. According to the results of a differential scanning calorimetry (DSC) analysis, dough containing 5% CBAC lost 19% less water than a control dough after three freeze-thaw cycles. During storage for 7 days at 4 °C, bread produced using CBAC-treated dough exhibited a 14% smaller retrogradation peak and 37% less hardness than a control dough, suggesting that CBAC could be a potential candidate for clean label starch, providing high-level food stability under repeated freeze-thaw conditions. [ABSTRACT FROM AUTHOR]

In 25% (v/v) ethanol system, an acid induced pectin gelling mechanism was proposed in this study, which could be used to construct emulsion gel system. FT-IR, GPC, and monosaccharides analysis were used to investigated the structure of pectins. HMP and LMP are different in molecular wight and chain structure, and HMP shows excellent gelling property. Intermolecular interaction of acid/ethanol induced HMP gel was investigated with SDS, Urea, and shifted pH. Those results indicated HMP has larger molecular wight, more neutral sugar side chain, and lower zeta potential than LMP, which facilitates the construction of compact gel network. LMP and HMP emulsions with 25% (v/v) ethanol were prepared and HMP emulsions with different oil volume fractions (Φ 0.2–0.75) exhibit gelling properties. Furthermore, the compact structure of HMP gel is stable during the freeze-thaw cycle which improved the freeze-thaw stability of pectin emulsions. The purposed mechanism for acid/ethanol induced HMP emulsion gel and its freezing-thawing stability. [Display omitted] • In 25% (v/v) ethanol, acid could induced high methoxyl pectin (HMP) gelling. • HMP have better gel properties than low methoxyl pectin in acid/ethanol system. • Gelling of HMP in acid/ethanol system was dominated by hydrogen bonds. • Acid/ethanol induced HMP emulsion gel remained stable over 3 × freeze-thaw cycles. [ABSTRACT FROM AUTHOR]

Rapeseed protein isolate (RPI) was used as a natural particulate emulsifier for production of high internal phase emulsions (HIPEs) for the first time. RPI was prepared by an alkali solution and acid precipitation process, following mixed with rapeseed oil (oil phase) to form HIPEs using a combination of low-speed stirring and high-speed homogenization. The best condition of homogeneous and stable HIPEs that formed by RPI was at a pH = 9.0 and a protein concentration of 20 g/L. Under this condition, the proteins adsorbed around the oil phase to form a stable network structure. Stable HIPEs could have a maximum oil content of up to 840 g/kg (oil phase/emulsion), and the appearance and microstructure of which containing above 300 mmol/L NaCl did not change significantly (p = 0.08) after three freeze-thaw cycles. Overall, the HIPEs stabilized by RPI exhibited an excellent oil loading capacity and freeze-thaw stability, which not only utilizes the low value protein resources in the waste rapeseed meal, but also provides a theoretical basis for the application of HIPEs in food industry. • The rapeseed protein isolate (RPI) was used as an emulsifier in food industry. • RPI-based high-internal phase emulsions (HIPEs) were investigated. • The minimum mean size and the maximum G′ were obtained at pH = 9.0 of RPI solution. • Stable RPI-based HIPEs with limit oil phases up to 840 g/kg could be prepared. • 300 mmol/L NaCl had the best improvement on the stability of the RPI-based HIPEs. [ABSTRACT FROM AUTHOR]

Research on intravenous emulsions has been ongoing for several decades, and their unique advantages bring many opportunities for insoluble drugs. However, emulsions cannot withstand freezing in practical applications because their quality is severely affected. In this study, we used coenzyme Q10 as a model drug to prepare emulsions. Monosialotetrahexosylganglioside (GM1) was used to modify the emulsion to solve the freeze-thaw intolerance problem. The particle size, sterilization and freeze-thaw stability were affected by the oil content, phospholipid content, drug loading and homogenization conditions, which showed significant effects on the preparation properties. Emulsions prepared with a high oil content (30%, W/V) withstood three freeze-thaw cycles when the GM1 content was 0.2%–1.0% (W/V). In addition, pharmacokinetic studies indicated that emulsions modified with high-density GM1 had a long circulation time. Compared with the coenzyme Q10 solution, the emulsions showed different degrees of heart, liver, spleen and brain targeting. The relative uptake rate of the 0.2% GM1-modified emulsion in the heart was 37.06, while that of the 1.0% GM1-modified emulsion in the brain was 17.43. These results strongly suggest that coenzyme Q10 emulsions coated with GM1 can tolerate freeze-thaw cycles and are excellent for treatment of cardiac and neurodegenerative diseases. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Pickering emulsions gels were formed using complex protein as stabilizers. • Preheat treatment (80 °C) inhibited water separation in freeze-thaw cycles. • Salt addition (200 mM NaCl) to Pickering emulsion gels retarded oiling-off. • Freeze-thaw stability could be enhanced by altering gel strength of emulsion. Salt addition and thermal pretreatment were used to improve the freeze-thaw stability of Pickering emulsion gels (PEGs) stabilized by compound proteins. Thermal pretreatment with the presence of salt could promote the formation of gel-like structure and alter the interactions between the emulsion droplets of PEGs, sequentially increase the resistance of the PEGs to water separation, creaming, and oiling-off during freeze-thaw cycles (freeze at −20 °C for 22 h and thawing at 37 °C for 2 h), especially at higher salt levels (200 and 500 mM). Microstructures indicated that the presence of high salt concentration and heat pretreatment could help to maintain the gel-like structures of PEGs during freeze-thaw cycles. Overall, our results showed that novel viscoelastic food materials with good freeze-thaw stability can be produced by controlling the electrostatic interactions between the emulsion droplets and the gelation of emulsion gels. These materials may be useful for application in frozen food products. [ABSTRACT FROM AUTHOR]