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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]

Abstract: Rice starch gels subjected to repeated freezing and thawing tend to decrease in quality. This study investigated how the addition of sucrose to rice starch gels affects factors commonly used to measure quality. Rice starch gels containing 0–20% sucrose were treated to 5 freeze–thaw cycles. The result showed that sucrose effectively reduced the % syneresis. Scanning electron micrographs of freeze–thaw gels showed that smaller pore size and a thicker surrounding matrix corresponded with increasing sucrose concentration. Furthermore, the amount of freezable water in starch systems decreased with increasing sucrose concentrations, which also corresponded with gel microstructure. These results suggest that re-association of starch chains (retrogradation) induced by freeze–thaw treatment is retarded by sucrose. This study showed that sucrose is an effective agent for preserving the quality of freeze–thawed rice starch gels. [Copyright &y& Elsevier]

Abstract: The pasting properties and freeze–thaw stability of one step combined modifications of rice starch through crosslinking and phosphorylation reactions were studied and compared to those modified by crosslinking or by phosphorylation alone. The native rice starch was mixed with a solution of pH 9.5, containing 1% sodium trimetaphosphate (STMP) and 4% sodium tripolyphosphate (STPP). The starch mixture with approximately 27% moisture content was granulated and heated in a hot air oven at 120°C allowing the gradual evaporation of water to dryness up to 2h reaction time. The combined modifications provided higher peak, breakdown, final and setback viscosities than that of the phosphorylation alone. However, these pasting properties of both combined modifications and phosphorylation were increased in line with the increase of reaction time. In contrast to that of the crosslinking reaction with 1% STMP which provided the decreasing of those pasting properties with the increase of reaction time. The pasting temperature for both the combined modifications and phosphorylation were decreased in line with the reaction time, while those for the crosslinked starch were increased. The freeze–thaw stability of native and modified rice starch pastes for five cycles were studied. The combined modified rice starch provided the highest freeze–thaw stability, and this type of modified rice starch could be used to prepare food products with good freeze–thaw stability. [Copyright &y& Elsevier]

Abstract: Typically following collection biological samples are kept in a freezer for periods ranging from a few days to several months before analysis. Experience has shown that in LC–MS-based metabonomics research the best analytical practice is to store samples as these are collected, complete the sample set and analyse it in a single run. However, this approach is prudent only if the samples stored in the refrigerator or in the freezer are stable. Another important issue is the stability of the samples following the freeze–thaw process. To investigate these matters urine samples were collected from 6 male volunteers and analysed by LC–MS and ultra-performance liquid chromatography (UPLC)–MS [in both positive and negative electrospray ionization (ESI)] on the day of collection or at intervals of up to 6 months storage at −20°C and −80°C. Other sets of these samples underwent a series of up to nine freeze–thaw cycles. The stability of samples kept at 4°C in an autosampler for up to 6 days was also assessed, with clear differences appearing after 48h. Data was analysed using multivariate statistical analysis (principal component analysis). The results show that sample storage at both −20 and −80°C appeared to ensure sample stability. Similarly up to nine freeze thaw cycles were without any apparent effect on the profile. [Copyright &y& Elsevier]

Chicken breast muscle powder (CBMP) and modified waxy cornstarch (MWCS) blends were prepared at different pH conditions (pH 4, 5, 6, 7, 8, and 9). The blends were characterized by light microscopy, frequency sweep, flow analysis, and freeze-thaw stability analysis. Light microscopy showed that the blend structure was coarse at pH conditions close to the isoelectric point of protein and became finer with increasing pH. Frequency sweep demonstrated that the blend was more liquid-like with relatively lower storage ( G′) and loss ( G″) moduli as the pH was increased from pH 4 to pH 9. Flow analysis revealed that thixotropy behavior was evident in samples treated at pHs 4 and 5, whereas antithixotropy was shown by those adjusted to pHs 6, 7, 8, and 9. The CBMP–MWCS blends were found to show better freeze-thaw stability at pH 8 that could be attributed to the formation of a highly interactive network structure of CBMP and MWCS. [ABSTRACT FROM AUTHOR]

Abstract: This study examines the influence of interfacial composition on the freeze–thaw stability of oil-in-water emulsions. Three 5% w/w oil-in-water emulsions (5mM phosphate buffer, pH 6.0) were prepared using the layer-by-layer electrostatic deposition method that had different interfacial compositions: (i) primary emulsion (β-Lg); secondary emulsion (β-Lg–ι-carrageenan); (iii) tertiary emulsion (β-Lg–ι-carrageenan–gelatin). The primary, secondary and tertiary emulsions were subjected to from one to three freeze–thaw cycles (−20°C for 22h, +40°C for 2h) in the absence or presence of sucrose (10% w/w), and then their stability was assessed by ζ-potential, particle size, microstructure and creaming stability measurements. In the absence of sucrose, the primary and secondary emulsions were highly unstable to droplet aggregation and creaming after three freeze–thaw cycles, whereas the tertiary emulsion was stable, which was attributed to the relatively thick biopolymer layer surrounding the oil droplets. In the presence of 10% w/w sucrose, all of the emulsions were much more stable, which can be attributed to the ability of sucrose to increase the amount of non-frozen aqueous phase in the emulsions. The interfacial engineering technology used in the study could therefore lead to the creation of food emulsions with improved stability to freezing and thawing. [Copyright &y& Elsevier]

The effect of biogenic extra cellular ice nucleators (ECINs) on gel-forming capacity and textural stability of a fish actomyosin (AM) gel system subjected to controlled freeze-thaw (FT) cycles was studied. Stability changes were quantified by measuring the degree of retention of Ca2+ ATPase activity and changes in protein surface hydrophobicity. Results showed that different concentrations of ECIN suppressed Ca2+ ATPase activity loss during FT cycles depended quantitatively on ECIN concentration. After three FT cycles, Ca2+ ATPase activity retention was 76.20% with the highest ECIN concentration and 20.10% without ECIN, and surface hydrophobicity of AM with ECIN was 150.67, whereas the corresponding value of the control sample was 208.70. By measuring changes in surface hydrophobicity, we observed that ECIN significantly reduces denaturation of AM protein caused by FT cycling. Our data show that ECIN contributes a significant protective effect on gel-forming capacity of fish and textural stability of fish AM during FT cycling. This demonstrates for the first time that ECINs have the potential to help stabilise the texture of fish AM and potentially other food products during frozen storage. [ABSTRACT FROM AUTHOR]

Abstract: Effects of pH (3, 7, and 9) and xanthan gum (XG) on freeze-thaw (FT) stability of tapioca starch (TS) pastes (6.0% or 24.0% w/w, total solids) were studied as a function of TS/XG mixing ratios (6.0/0.0, 5.7/0.3, and 5.4/0.6) and FT cycles (−20°C, 22h and 30°C, 1h up to five cycles). Syneresis results showed that xanthan was most effective in reducing the syneresis at pH 7 and this effect increased with increasing gum concentrations. At pH 3, however, xanthan was much less effective reflected by the highest syneresis produced within two FT cycles. DSC data demonstrated that neither transition temperatures nor enthalpies of the FT-TS/XG pastes were affected by pH and xanthan addition. Photographs of stained starch granules exhibited a phase separation between the added xanthan and starch polysaccharides at all pH values tested. SEM micrographs illustrated the largest ice crystals formation in the pH 3 pastes and in the 0.6% xanthan-added pastes of all pH values. Xanthan maintained textural properties of the tapioca starch pastes during FT treatments better at pH 7 and pH 9. Lower starch molecular weight (revealed by HPSEC) and a reduction in viscosity of xanthan solution caused by acid hydrolysis was probably the cause of the lower FT stability of starch pastes at pH 3. [Copyright &y& Elsevier]

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve FIT stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to FIT stability than a fast freezing process; the latter actually preserves suspension stability during freezing. [ABSTRACT FROM AUTHOR]

Abstract: This study was designed to investigate the effect of a thermostable α-glucanotransferase (TSαGT) originated from Thermus scotoductus on the rheological properties, molecular weight distribution, thermo-reversibility, and freeze-thaw stability of rice starch paste. Rice starch paste samples (5%) were incubated at 70°C with TSαGT and a commercial α-amylase, respectively, until reduction of moduli leveled off. The TSαGT-modified rice starch paste showed a yield stress. After the enzymatic treatment, both enzyme-treated pastes showed considerably low moduli with higher G″ than G′, indicating a significant liquefaction. However, when stored at 4°C, both moduli of a TSαGT-treated sample dramatically increased with significantly higher G′ than G″, confirming that a solid gel structure formed. This transition was found to be reversible, when temperature fluctuated between 70 and 4°C. The control starch gel did not show thermo-reversibility, and α-amylase-treated starch paste was incapable of forming a solid gel. The size distribution of the starch polymers, as measured by MALLS, revealed that average M w reduced to about 5×105 after the TSαGT treatment, which was a significant decrease, but possibly high enough to form a solid gel matrix at low temperatures. The TsαGT-treated gel demonstrated highly improved freeze-thaw stability. [Copyright &y& Elsevier]

Flour and starch from mechanically and field dried peas of two cultivars were evaluated for physico-chemical and functional properties. The noodle making properties of pea starch were also compared with potato starch. Field dried pea flour from both the cultivars showed higher starch content than mechanically dried peas. The field dried pea starch, showed lower water binding capacity, swelling power, and solubility as compared to those from mechanically dried pea starch. The mechanically dried pea starches showed lower retrogradation and higher freeze thaw stabilities compared to field dried pea starches. Pea starch noodles showed significantly lower cooking weight and cooking loss than potato starch noodles. Overall acceptability scores for pea and potato starch noodles did not differ significantly. [ABSTRACT FROM AUTHOR]

The influence of aqueous phase composition (0–40wt.% sucrose, 0 and 150mmolkg-1 sodium chloride, NaCl) on the stability of 20wt.% hydrogenated palm oil-in-water emulsions stabilized by 0.9wt.% whey protein isolate (WPI) to chilling and freezing was studied. Emulsion stability was measured after emulsions had been cooled to temperatures where (i) only the oil phase crystallized or (ii) both the oil and aqueous phases crystallized. Emulsion stability was assessed by DSC measurements of fat destabilization after cool–heat cycles (-40 to 40°C or -10 to 40°C), and by measurements of mean particle size, free oil, gravitational separation, and shear viscosity after isothermal storage (-40 to 37°C). Sucrose improved emulsion stability to droplet coalescence and gravitational separation, particularly at temperatures where part of the aqueous phase froze. The cryo-protective affect of sucrose was attributed to its ability to increase the amount of unfrozen water (UW), modify ice crystal structure, alter interfacial protein structure, and/or reduce the frequency of droplet–droplet collisions. NaCl promoted emulsion instability, particularly at holding temperatures where the oil was partially crystalline, which was attributed to its ability to facilitate the close approach of droplets by screening the electrostatic repulsion between them. These results have important implications for the formulation of emulsions that are stable to chilling and freezing. [Copyright &y& Elsevier]

Nine polysaccharide gums (sodium alginate, carboxymethyl cellulose, curdlan, gellan, guar gum, gum arabic, κ-carrageenan, locust bean, and xanthan) were compared for their stabilizing effects in sweet potato starch gel against repeated freeze–thawing (FT) treatments. The gums were added in starch gel at 0.3 or 0.6% (w/w, based on total gel weight), and total solid content in the gel was adjusted to 7% (w/w) with starch. The gels containing starch and gum were repeatedly freeze–thawed up to five times by storing at −18 °C for 20 h and then at 25 °C for 4 h. Water release (syneresis) was measured by vacuum-filtering the freeze–thawed gels. Among the gums tested, alginate, guar gum, and xanthan were highly effective in reducing the syneresis. For example, guar gum, at 0.6%, showed the least syneresis (33.0%, w/w based on initial water content) after five FT cycles, which was less than half that of pure starch gel. At 0.3%, however, xanthan was more effective than guar gum in reducing syneresis. Xanthan reduced paste viscosity significantly, whereas guar gum and alginate increased the viscosity, but there was little relation between pasting viscosity and syneresis. The gums remained in the gel matrix during the syneresis without a significant loss. Recrystallization of starch (retrogradation) induced by FT treatment was also retarded by the presence of gums, and sodium alginate was more effective in retarding the retrogradation than xanthan or guar gum. [Copyright &y& Elsevier]

In this study, the effects of the addition of pectin (PEC) on the physicochemical properties and freeze-thaw stability of waxy rice starch (WRS) were investigated. As PEC content increased, the pasting viscosity and pasting temperature of WRS significantly increased (p < 0.05), whereas its breakdown value and setback value decreased. Differential scanning calorimetry showed that the addition of PEC increased the gelatinization temperature of WRS, but decreased its gelatinization enthalpy. Rheological measurements indicated that the addition of PEC did not change the shear-thinning behavior of WRS–PEC blends, and the storage modulus and loss modulus were positively correlated with PEC content. Moreover, the textural parameter of WRS decreased with the increase in PEC content. Furthermore, the addition of PEC decreased the transmittance of starch paste, but enhanced the freeze-thaw stability of WRS to some extent. These results may contribute to the development of WRS-based food products. [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]

The current interest in personalized food through the application of surface-active biopolymers and additive manufacturing has identified a requirement to tailor a 3D printed healthy diet with well-defined geometries. In this study, a reduced-fat casein-based Pickering emulsion was stabilized via different ratios of acetylated microcrystalline cellulose, and then it was printed through an extrusion-based printer. The micro-biosurfactant contents led to differences in the printing performance and resolution of printed architectures. The original compact and uneven structures of 3D printed objects were reduced in presence of micro-biosurfactant, providing a uniform and porous matrix. Thermal investigation indicated that oil and aqueous phases in the reduced-fat 3D printed systems were less readily frozen. Proton molecular mobility became less mobile and moved to the populations with a shorter relaxation time upon micro-biosurfactant addition. Oral tribology was shown to depend on micro-biosurfactant content, where less deformable (firmer) 3D printed objects decreased surface-surface contact and reduced friction coefficients, improving lubrication property. The dynamic sensory evaluation by temporal dominance of sensations showed promising results regarding creaminess and mouth-coating, which was correlated well with instrumental readings. This work established an integrated attitude, from fundamental and practical viewpoints, supporting the application of Pickering emulsions in the 3D printing process to develop functional foods, broadening the micro-biosurfactant utilization in food printing. [Display omitted] • A highly porous 3D structure was fabricated in presence of micro-biosurfactant. • Reduced-fat 3D printed objects formed a structured and stable network. • Reduced-fat 3D printed objects presented greater stability against freezing. • The presence of micro-biosurfactant offered a better lubrication effect in 3D printed constructs. • Reduced-fat 3D printed samples showed a desired sensory profile with a higher creamy sensation. [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]

The study investigates the role of pectin and heat-moisture treatment in modifying the physicochemical and structural properties of corn starch. The structural features and morphological, thermal and rheological properties of samples were characterized using techniques including microscope, SEM, DSC, FTIR, NMR, and rheometer. Results reveal that the pectin-starch mixture with the heat-moisture treatment shows an improved paste stability and a modified structure with a lowest value of retrogradation degree (39.7%), syneresis rate (6.33%), double helices content (26.5%), and leaching amylose content (22.7%). All of these can be ascribed to a fact that the heat-moisture treatment could enable a strong interaction of hydrogen bonds between pectin and starch molecules (amylose/amylopectin). The current findings suggest a potential use of the heat-moisture-treated pectin-starch paste in food industry. [Display omitted] • The pectin and heat moisture treatment affected starch's structure and property. • Retrogradation of both amylose and amylopectin was inhibited by pectin. • Some new double helices were formed due to the presence of pectin. • The influence of pectin was improved further by heat moisture treatment. • The starchy paste showed a great stability. [ABSTRACT FROM AUTHOR]

In this study, stability and in vitro digestion of sesame oil-based high purity diacylglycerol (DAG) oil-in-water emulsions were investigated. Firstly, the effects of DAG content and the freeze-thaw process on the physical properties of emulsions were assessed. The fresh DAG emulsions exhibited high absolute ζ-potential values (>40 mV), small d 4,3 (<0.94 μm), and good stability during 14 days storage. However, DAG promoted partial coalescence of fat globules and the creaming index increased after the freeze-thaw process. Subsequently, the in vitro digestion of DAG emulsions was studied. The d 4,3 of emulsions increased from 0.942 μm, 0.754 μm and 0.489 μm to 33 μm (0 g/kg DAG), 30 μm (50 g/kg DAG) and 25 μm (100 g/kg DAG) respectively after digestion in the simulated saliva and stomach, and then decreased to 8 μm, 7 μm and 5 μm respectively in the simulated small intestine. Notably, the variation tendency of ζ-potential was opposite to the d 4,3 of emulsions during the simulated digestion. Finally, the free fatty acid release was monitored under simulated intestine digestion and it revealed that higher DAG content favored higher lipolysis. This work sheds light on employing DAG oil to prepare food emulsions. • Diacylglycerol (DAG) oil was obtained through enzymatic glycerolysis of sesame oil. • Protein-stabilized DAG oil-in-water emulsions had good stability in 14 days storage. • DAG promoted partial coalescence of fat in emulsions during the freeze-thaw process. • Emulsions with higher DAG content favored higher lipolysis. [ABSTRACT FROM AUTHOR]

This research aimed to evaluate effects of starch source, sucrose at high concentration and coconut milk on physical properties of chilled and frozen starch gels, considered as traditional Thai dessert models. Gel containing 15% w/w of starch was prepared from rice starch, tapioca starch or blended rice starch/tapioca starch (1:0.85 w/w) mixed with water, 45oBx sucrose solution or coconut milk. The result showed that rice starch gel stored at 4 °C had highest hardness, degree of syneresis and melting enthalpy of the retrograded structure (ΔH ret). Degree of syneresis of frozen rice starch gels subjected to several freezing-thawing cycles was also highest. Under chilled temperature storage, starch gels containing sucrose or coconut milk had higher hardness and denser gel structure, comparing to the starch gels in water. This textural change was due to greater degree of starch retrogradation, sucrose recrystallization and/or formation of amylose-lipid complex crystallites shown in X-ray diffractograms. However, addition of highly concentrated sucrose or coconut milk increased freeze-thaw stability of the frozen starch gels, as shown by decreasing degree of syneresis. Results from this study could be applied to formulate starch-based dessert with improved quality during chilled or frozen storage. [Display omitted] • Blending of tapioca starch to rice starch retarded hardening of the aged gels. • Hardening of chilled starch gels rich in sucrose were related to sucrose recrystallization. • Fat recrystallization increased hardness of aged starch-coconut milk gels at 4 °C. • Freeze-thaw stability of starch gels was enhanced by sucrose and coconut milk. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structure of TSPs determined their effects on physicochemical properties of CS. • HPH changed M w , conformational structure, and Gal/Glc ratio of TSP. • Different structural TSP had different effects on physicochemical properties of CS. • M w and Gal/Glc ratio of TSP influenced CS retrogradation and water distribution. In this work, structural characteristics of TSPs treated by high-pressure homogenization (HPH) and their effects on physicochemical properties of corn starch were analyzed. HPH induced monosaccharides change, Gal/Glc ratio decrease from 0.32 to 0.25, and molecular weight (M w) decrease from 10.55 to 4.47 × 105 Da through damaging glycosidic linkages in the backbone and side-chain of TSPs. Furthermore, 90 MPa homogenized TSP (higher Gal removal) showed inhibitory effects on starch paste retrogradation, and TSPs with a lower M w (homogenized at 60 and 90 MPa) could limit water precipitation during the long-term storage. Moreover, M w and Gal/Glc ratio were the major factors for the determined effects of TSPs on physicochemical properties of corn starch. The results could provide new insights into the relationship between TSP structure and their effects on the physicochemical properties of starch. [ABSTRACT FROM AUTHOR]

In this study, we investigated the influence of Chinese quince seed gum (CQSG) on the functional and rheological features of tigernut tuber starch using a rapid visco-analyzer (RVA), differential scanning calorimetry (DSC), scanning electron microscopy, and rheometry. The addition of CQSG markedly increased the pasting temperature, peak, breakdown, final viscosities, and the setback value. The freeze-thaw stability of the gum/starch blends significantly (p < 0.05) increased as the gum concentration increased, thus suggesting the importance of CQSG in controlling the syneresis of the gel. The addition of CQSG decreased the gelatinization enthalpy, ranging from 16.57 J/g to 12.98 J/g, and the solubility at 75 °C and 85 °C. Structure measurements revealed CQSG decreased the recrystallization of the gel, thus suggesting that it prevented starch gel retrogradation by likely coating the granules of starch and/or influencing the interactions of the amylose. Behavior index values (n) indicated pseudoplastic flow increased ranging from 0.46 to 0.29 as the CQSG content increased. Overall, CQSG improved the properties of the tigernut starches, in particular by increasing freeze-thaw stability, viscosity, and pseudoplasticity and by preventing retrogradation in the starch gel. CQSG is promising to improving the properties of starch-based products in the food industry. • Chinese quince seed gum increased the viscosity of the starch. • The gum obviously improved the freeze-thaw stability of the starch. • The gum decreased the swelling power and solubility at 75 °C and 85 °C. • The gum prevented retrogradation and recrystallization of the starch gels. • The flow behavior index (n) of starch gels decreased with the addition of the gum. [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]

The aim of this work was to develop a food-grade emulsion that stabilized by the by-product proteins in the head of giant freshwater prawn. The physicochemical properties of protein particles were characterized, and the stability of proteins-stabilized emulsions under different environmental stresses was evaluated. Results showed that the proteins were relatively hydrophilic and preferentially resided in the aqueous phase to form oil/water emulsions. On this basis, the proteins exhibited superior ability to stabilize the emulsions, and remarkably, the emulsions stabilized by 2% proteins and 3:7 oil/water ratio efficiently resisted the freeze-thaw treatment and the change of pH (3-9), salt addition (NaCl, 50-400 mM), and storage temperatures (4-60°C). Furthermore, the emulsions showed a matched long-term stability with the existing biopolymers-stabilized emulsions. Consequently, this is the first finding of the by-product proteins in the head of giant freshwater prawn as an excellent emulsifier to stabilize emulsions, which help to improve the stability of food-grade emulsions and the added value of aquatic products., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wu, Li, Wang, Zhao, Liu and Wang.)

• DAG in combination with PGPR was applied to stabilize HPO-based W/O emulsion. • DAG can promote HPO to form typical interfacial crystals at the water–oil interface. • DAG-PGPR-HPO emulsion had smaller droplet size and higher freeze–thaw stability. • DAG-PGPR-HPO emulsion had remarkably higher textural and rheology properties. The influence of diacylglycerol (DAG) combined with polyglycerol polyricinoleate (PGPR) on the stability of water-in-oil (W/O) emulsions containing hydrogenated palm oil (HPO) was studied. Polarized light microscope revealed that DAG promoted HPO to crystallize at the water–oil interface, providing the combination of Pickering and network stabilization effects. It was proposed that the molecular compatibility of fatty acids in DAG with HPO accounted for the promotional effect. The interfacial crystallization of DAG together with the surface activity of PGPR led to the formation of emulsions with uniform small droplets and high freeze–thaw stability. Further exploration of physical properties indicated that the combination of DAG and PGPR dramatically improved the emulsion's viscoelasticity and obtained a larger deformation yield. Water droplets in DAG-based emulsions acted as active fillers to improve the network rigidity. Therefore, DAG is a promising material to be used as emulsifier to enhance the physical stability of W/O emulsions. [ABSTRACT FROM AUTHOR]

For the first time, the irradiation technology combined with Maillard reaction were used to improve the freeze - thaw stability of soybean protein emulsion. The freeze-thaw stability of emulsions prepared with soy protein isolate (SPI), soy protein isolate and maltose mixture (SPI + M) or glycosylated soy protein isolate with maltose formed by irradiation of 7.5 kGy and 12.5 kGy (named SPI-M 7.5 and SPI-M 12.5 , respectively) was compared. Fourier transform infrared spectroscopy, fluorescence spectroscopy and ultraviolet spectroscopy confirmed the change of the structure of soy protein isolate, indicating that maltose was covalently linked to soybean protein isolate. Scanning electron microscopy showed that the modified protein particles were more loose, uniform in size, and significantly reduced in molecular aggregation than untreated protein. The freeze-thaw stability of SPI, SPI + M, and SPI-M 7.5 and SPI-M 12.5 emulsions was evaluated. It was found that after three freeze-thaw cycles, the creaming index, oiling off, particle size, coalescence degree and flocculation degree of emulsions prepared with irradiated SPI samples were all lower than those prepared with SPI and SPI + M. Zeta potential, laser confocal and optical microscopy showed that the emulsion was still in a relatively stable state, and the SPI-M 7.5 emulsion after freeze-thaw treatment was more stable than the SPI-M 12.5 emulsion. Image 10726 • For the first time, the irradiation technology was used to promote Maillard reaction. • The irradiated glycosylated soy emulsion could be used as the effective stabilizer. • The SPI-M 7.5 emulsion was more stable than the SPI-M 12.5 emulsion after freeze-thaw treatment. • This study could promote the practical application of irradiation technology and Maillard reaction in SPI modification. [ABSTRACT FROM AUTHOR]

High internal phase emulsions (HIPEs) have recently been investigated for applications in food areas: plant proteins, polysaccharides, and commercial surfactants have been used as emulsifiers, but meat proteins have rarely been reported as emulsifiers for HIPEs. In this report, we describe an outstanding HIPE stabilized solely by meat protein particles. The natural stabilizer was prepared by a one-pot centrifugation process (3000× g , 20 min), and the HIPEs were fabricated by a simple one-pot homogenization process (5000 rpm/min, 1 min). The meat proteins could form homogeneous and stable HIPEs in the continuous phase over a wide pH range of 3–11. In this state, the HIPEs exhibited excellent stability in three conditions: heat, freeze-thaw, and storage (60 days). Interestingly, these natural stabilizers were also perfect combinations of soybean oil, corn oil, sunflower oil, and n-hexane, and they exhibit the potential to act as nutrition delivery systems, animal fat replacements, partially hydrogenated oils, and other functional materials. Image 1 • High internal phase emulsions (HIPEs) were formed by meat protein particles through one-pot homogenization. • The meat protein was produced by single-step centrifugation and the particles were prepared through one-pot homogenization. • The meat proteins particles could form stable HIPEs regardless the pH in continuous phase. • HIPEs stabilized by meat protein particles exhibited excellent freeze-thaw, heated, and storage stabilities. [ABSTRACT FROM AUTHOR]

In order to interpret the mechanism underlying the changes in rice flour (RF), rice starch (RS), and their gels after green tea polyphenols (GTPs) addition, the pasting, thermodynamic, gel rheological attributes, and freeze-thaw stability of brown, refined RF, and RS were studied. GTPs reduced all pasting attributes of brown, refined RF, and RS mainly due to the building of the cross-linking between starch granule and GTPs. It also decreased the peak temperature and gelatinization enthalpy of RF and RS by facilitating the hydration of starch granules. The retrogradation degree after storage was reduced as well by GTPs, showing the inhibition on the long-term retrogradation of RF and RS. GTPs induced more reductions in G ′ than in G ″, and greater changes in RS than in RF. Moreover, GTPs improved the freeze-thaw stability of RF and RS gel. The addition of NaCl or sucrose showed certain impacts on these physical properties of rice flour or gel by interfering the cross-linking between GTPs and starch chain. Briefly, apart from starch, GTPs could remarkably influenced the pasting and thermodynamic attributes of brown and refined RF, it was proven a promising alternative in inhibiting the retrogradation and enhancing the freeze-thaw stability in rice-based products. • The physical properties of rice flour (RF) and rice starch (RS) were investigated. • Green tea polyphenols (GTPs) reduced all pasting attributes of RF and RS. • GTPs decreased gelatinization enthalpy and retrogradation degree of RF and RS. • GTPs induced more reductions in G ′ than G ″ and greater changes in RS than RF. • The freeze-thaw stability of rice gel was improved by GTPs addition. [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]

Controlling crystallization of water phase and interfacial engineering is an effective strategy for improving freeze-thaw stability of protein-based emulsions. In this study, we prepared high freeze-thaw stability of wheat gluten (WG)-based emulsions by incorporated deep eutectic solvents (DES). Low melting point DES (−32.76 °C) with glycerol/choline chloride molar ratio of 2:1 were firstly achieved, and then water-diluted DES as solvent to dissolve WG, which was used to prepare emulsions. The results of interfacial property, confocal laser scanning microscopy (CLSM), and rheology showed that with increasing DES concentrations, WG exhibited thick interfacial membranes surrounding dispersed droplets, positively reflected in forming elastic gel-like emulsion with smaller droplet size. The freeze-thaw stability was characterized by monitoring the changes in their emulsion droplet size, stability against coalescence, as well as microstructure and thermal events. Higher concentrations of glycerol-based DES as "cryoprotectants agents" in the bulk phase and strong interfacial network of WG could prevent formation of the ice crystals and damage to the interface during the freezing process, resulting in formation of freeze-thaw stable emulsions even after three cycles of treatment (−40 °C, 24 h; 25 °C, 2 h). This finding provides a novel technical platform for the development and application of protein-based emulsions in frozen foods. Image 1 • High freeze-thaw stable wheat gluten-based emulsions were prepared by incorporated deep eutectic solvents. • Wheat gluten in higher concentrations of deep eutectic solvents exhibited elastic gel-like emulsions with smaller droplet size. • Wheat gluten-based emulsions showed extraordinary freeze-thaw stability against coalescence after 3 cycles of freeze-thaw treatment (−40 °C, 24 h; 25 °C, 2 h). [ABSTRACT FROM AUTHOR]

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.

The aim of this work was to compare the composition and physicochemical properties (SEM, XRD, solubility, swelling power, paste clarity, retrogradation, freeze–thaw stability, thermal property, and pasting property) of three Chinese yam (Dioscorea opposita Thunb.) starches (CYYS-1, CYYS-2, and CYYS-3) in Yunlong town, Haikou, Hainan Province, China. Our results show that all the CYYS gave a typical C-type X-ray diffraction pattern. The swelling power of CYYS varied from 10.79% to 30.34%, whereas solubility index was in the range of 7.84–4.55%. The freeze–thaw stability of each CYYS showed a contrary tendency with its amylose content. In addition, CYYS-3 showed the highest To (81.1 °C), Tp (84.8 °C), Tc (91.2 °C), and ΔH (14.1 J/g). The pasting temperature of CYYS-1 increased significantly with sucrose addition. NaCl could inhibit the swelling power of CYYS. There were significant decreases in pasting temperature and pasting time of CYYS when pH decreased. [ABSTRACT FROM AUTHOR]

In this study, the effects of the addition of inulin and konjac glucomannan (KGM) on the freeze‐thaw stability, retrogradation, and pasting viscosity of starches isolated from different botanical sources are investigated. The isolated starches complexed with inulin and KGM show significant differences (p < 0.05) in the freeze‐thaw stability, degree of retrogradation, and pasting properties. For example, the addition of inulin (5–50%) and KGM (0.2–1.0%) to the starches, enhance the inhibition of retrogradation of all starches as well as reduce their syneresis rates. Inulin shows higher effects than KGM on the functional characteristics of isolated starches. Both inulin and KGM noticeably effect the viscosity of starches. The addition of inulin at 0–50% greatly reduces the peak, trough, breakdown, final, and setback viscosities of the starches; however, the addition of KGM at 0–10% increase these viscosities, whereas that at 10–50% decrease the viscosities. In addition, the pasting temperature increases gradually with the addition of inulin from 0 to 50%; however, the pasting temperature first increases with the addition of KGM from 0 to 20% and then decreases with further increase in KGM up to 50%. Thus, this study provides useful information for the development of functional starch foods with longer shelf life by the addition of dietary fibers, such as inulin and KGM. [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 freeze-thaw 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.

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.

Three types of inulin with different degree of polymerization (average DP < 10, DP ≥ 10, and DP > 23) were used to improve the freeze-thaw stability of rice starch gel. The gels with or without addition of inulin were subjected to seven freeze-thaw cycles (FTC). Inulin enhanced the water holding capacity and reduced the amount of freezable water of the gels, thereby decreasing the syneresis of the gels during seven FTC. In addition, the amylose and amylopectin retrogradation of the gels were retarded. By adding inulin, the microstructure of gel network was stabilized, and the deterioration in viscoelastic properties of the gels during seven FTC was reversed. Therefore, inulin was an effective additive for preserving the quality of freeze-thawed rice starch gels. Furthermore, low DP inulin had higher water holding capacity than high DP one, as a result the inulin with lower DP was more effective., (Copyright © 2018 Elsevier Ltd. All rights reserved.)