Search

The interaction between the main protein components of rapeseed, also called canola, was investigated in water as a function of the pH and in the presence of NaCl. Firstly, the solubility of purified cruciferin and napin was determined and the soluble fraction was characterized using light scattering techniques. Napin was found to be soluble over the whole pH range investigated (pH 4–10), whereas cruciferin was only partially soluble at pH ≤ 7. Subsequently, mixtures of the two components were studied as a function of the pH showing that large complexes between the positively charged napin and the negatively charged cruciferin were formed at pH ≥ 7 in water that could be removed by filtration through 0.2 μm pore size filters. It was found that the extent of complexation strongly depended on the fraction of napin in the mixture. Interestingly, in the presence of 0.1 M NaCl much smaller complexes were formed in this pH range that remained in solution. [Display omitted] • The cruciferin has low solubility at pH 4–7, whereas napin remains soluble at pH 4-10. • Large complexes are formed in mixtures of cruciferin and napin at pH ≥ 7. • More napin is needed to form large complexes when the pH is increased from 7 to 9. • Addition of NaCl inhibits complex formation. [ABSTRACT FROM AUTHOR]

Edible protein-based oleogels have garnered extensive attention in food formulation, driven by the desire for enhanced nutritional profiles and improved texture perception. This is facilitated by the nutritional value of the starting ingredient proteins, coupled with high consumer acceptance. However, there exists limited knowledge regarding the connection between the microstructural properties of gels and their macroscopic rheological properties, especially concerning their potential as fat replacers in food products. The present study reveals a simple means of modulating the microstructural properties and macroscopic mechanical features of capillary whey protein oleogels, as well as their aesthetic properties. This is achieved by using whey protein variants with diverse morphologies, such as fibers, particles, and fractal clusters, or by varying the water fraction (s) and the protein concentration (φ) in the formula. Rheological scaling properties and confocal laser scanning microscopy (CLSM) were employed to investigate the structural contribution of protein particles within the gel network. Furthermore, the study explores the practical applications of the derived oleogels, particularly in terms of spreadability or shortening as a potential alternative to margarine, within real food matrices. The spreadability of capillary oleogels with a protein concentration (φ) at 0.16 and 0.18 was comparable to that of commercial margarine. Meanwhile, the capillary oleogel-cake exhibited similarity to the margarine cake in textural parameters and sensory acceptability. This suggests that these capillary whey protein oleogels hold promise for applications in bakery products as margarine alternatives with low levels of saturated/ trans -fat content. [Display omitted] • Capillary oleogels can be formed by using whey protein variants with diverse morphologies. • Capillary oleogels fabricated with different particle shape have diverse mechanical features and aesthetic properties. • The microstructural of capillary oleogels can be tuned by adjusting the water fraction or the protein concentration. • Capillary whey protein oleogels hold promise for applications as margarine alternatives. [ABSTRACT FROM AUTHOR]

The effects of electrostatic repulsion (pH6.5) and attraction (pH4.6) between biopolymers on the physicochemical and foam properties of ovalbumin (OVA)/carboxymethylcellulose (CMC) mixtures subjected to mild heat treatment (60–75 °C) were comparatively investigated. It was found that electrostatic binding between OVA and CMC at pH 4.6 resulted in an increase in the peak temperature of thermal denaturation (T d) of OVA from 71.3 °C to 74.4 °C, while no significant effect was observed at pH 6.5. Thus, 60 and 65 °C below T d were chosen to further investigate the effects of heating on the degree of thermal aggregation, protein conformation and foam properties of OVA/CMC mixtures. Confocal laser scanning microscopy observations and rheological results indicated that electrostatic binding between OVA and CMC at pH 4.6 significantly reduced the degree of protein thermal aggregation, while on the contrary, electrostatic repulsion between proteins and polysaccharides at pH 6.5 promoted OVA thermal aggregation. Raman spectroscopic characterisation indicated that mild heat treatment mainly led to a change in the microenvironment polarity of OVA tyrosine and tryptophan residues, as well as an increase in the content of random coil in the amide III band irrespective of pH. Moreover, after heating at 65 °C for 20 min, The foaming ability of the OVA/CMC mixtures at pH 6.5 and 4.6 increased by approximately 32% and 36% respectively compared to pure OVA. These findings have a positive value for enhancing the heat sterilisation strength of egg white proteins. [Display omitted] • Electrostatic binding enhanced the thermal denaturation temperature of ovalbumin. • Electrostatic binding inhibited thermal aggregation of ovalbumin. • Electrostatic repulsion promoted thermal aggregation of ovalbumin. • Both electrostatic attraction and repulsion enhance the foamability of heated ovalbumin. [ABSTRACT FROM AUTHOR]

Ormosia, as one of the consumer's favorite grains, is rich in protein, but its application is limited by the naturally low solubility of its protein. In order to improve its application capability, the Ormosia protein (OSP) is modified by high-intensity ultrasounds (HIUS), and the effect of ultrasound on the secondary and tertiary structure, as well as the improvement of its foaming property due to the alteration in protein structure, were systematically explored. It has been observed that HIUS greatly reduced the particle size of the OSP, and significantly affected the secondary and tertiary structure. These fundamental changes improved the ability of the OSP to stabilize foam at the water-air interface, and thus the HIUS-treated OSP possessed an excellent foaming property. The results of this study are expected to provide a theoretical basis for expanding the application of the OSP in the food industry. [Display omitted] • HIUS affected the secondary and tertiary structures of OSP. • HIUS enhanced the foam-capacity ability of OSP. • HIUS enhanced the foam-stability ability of OSP. [ABSTRACT FROM AUTHOR]

This research compared effects of heating on the digestion of goat milk proteins in skimmed goat milk model systems with different casein-to-whey protein ratios. The digestion was evaluated both the supernatant and gastric clot part of the digesta. Whey protein concentrates were added in skimmed goat milk (80% casein, C80 sample) to make a 40% casein sample (C40 sample). Heating at 65 °C showed limited influence on digestibility of proteins in supernatant and clot of both model systems. In the supernatant, the C80 sample had a higher soluble protein concentration after 85 °C heating, compared to the C40 sample. After heating at 85 °C for 30 min, the digestibility of proteins in the supernatant of C40 and C80 samples was increased. This heating also increased the casein digestibility of the gastric clot of C80 sample, but resulted in more undigested whey protein aggregates in C40 sample. For the difference between C80 and C40 sample, the proteins in the supernatant of C80 samples showed a higher digestibility than those in the supernatant of C40 samples, both in non-heated and in 85 °C heated samples. The clots of C40 sample showed a relatively higher digestion rate than C80 sample clots, which may be due to their higher water content and looser microstructure. Overall, this study showed that heating induced different digestion kinetics of goat milk model systems with different casein-to-whey ratios. [Display omitted] • Gastric digestion of soluble and coagulated milk proteins were studied. • CaseIn:whey ratio influence reaction of proteins to heating and digestibility. • 85 °C heating increased casein digestion in the clots but induced more whey aggregates. • Whey protein aggregates induced low digestibility in whey-protein rich samples. [ABSTRACT FROM AUTHOR]

Despite the potential benefits of using cellulose ethers and their combination with other polysaccharides and proteins in the creation of reduced-fat water-in-oil (W/O) emulsions, research in this specific area is currently limited. Further studies are needed to explore the optimal combinations and concentrations of these materials to achieve emulsions with desired texture and higher rheological properties. To address this research gap, seven W/O emulsions with a 40 wt% water phase at pH 3.5 are prepared. The water phase consisted of 2 wt% methylcellulose (MC) or hydroxypropyl methylcellulose (HPMC) combined with 10 wt% whey protein isolate (WPI) and/or kappa-carrageenan (kC). The oil phase, comprising 60 wt%, contained 8 wt% polyglycerol polyricinoleate (PGPR) in soybean oil. The emulsions were initially prepared at room temperature and subsequently subjected to a heating process at an elevated temperature of 90 °C for a duration of 30 min. Following this heating step, the emulsions were then cooled back to room temperature. This sequential temperature treatment was employed with the intention of inducing aggregation and gelation within the emulsions. The temperature oscillation measurements (G* versus temperature) provide further evidence for the role of covalent and noncovalent bonding in the rheology and gelation of WPI-based emulsions. The viscosity and moduli of unheated and heated emulsions containing combinations of HPMC were found to be higher compared to those containing MC combinations. This behavior can be attributed to the stronger intermolecular interaction between HPMC, WPI, and/or kC, as well as their attachment with PGPR. These interactions lead to the formation of a more viscous and firmer W–O interface in emulsions. [Display omitted] • W/O emulsions prepared using cellulose ethers, WPI, and/or kappa carrageenan aggregation in the aqueous phase. • They exhibit high viscosity and elasticity and form compact microstructures when undergoing heat treatment. • HPMC combinations showed higher rheological properties compared to the equivalent MC emulsions. [ABSTRACT FROM AUTHOR]

The performance of 3D food printing for hydrogels largely depends on the gel spatial structure and water state. However, the mechanism of microstructure and water state that affects the 3D printing performance of hydrogels remains unclear. Our previous studies found that the hydrogel made from honey bee pupae, a rich source of high-quality protein, has good fluidity but poor structural stability, limiting its use in 3D printing. Based on it, honey bee pupa protein (HBPP) added with soybean dietary fiber (SDF) was selected as a case study in this work. The results revealed that HBPP gel had good fluidity but weak mechanical strength, which was guided by the firm immobilization of water molecules and the lack of a rigid three-dimensional network structure. However, upon adding SDF, the rigid network structure of HBPP gel was enhanced and the degree of water immobilization was reduced. HBPP-SDF gel had better structural stability than HBPP gel and lower water migration ability than SDF gel. Additionally, SDF and HBPP complemented each other, thereby improving the 3D printing performance of the gel. Based on the findings, a possible microstructure evolution mechanism of different types of gels during 3D printing was proposed. Out of all the HBPP-SDF gels evaluated, the HBPP-SDF gel with an optimum SDF concentration of 30% demonstrated the best printing performance. [Display omitted] • Addition of SDF enhanced the network structure and mechanical strength of mixed gel. • Immobilized water in network of SDF gel was easily detached under external force. • SDF filling into HBPP matrix enhanced 3D printing adaptability of individual gel. • 30% SDF level yielded best 3D print adaptability compared to other formulations. • Microstructure evolution mechanism of hydrogels during 3D printing was proposed. [ABSTRACT FROM AUTHOR]

The effect and mechanism of four common proteins (egg white powder (EWP), soy protein isolate (SPI), whey protein isolate (WPI) and wheat gluten (WG)) on the short-term retrogradation of wheat starch (WS) gels were investigated in terms of apparent characteristics, structural properties and crystallization (short-range orderliness and long-range orderliness). The recrystallization style of all gel samples were mainly B-type crystal. Compared to the control group, WS gels with EWP, SPI, and WG delayed formation and aggregation of the double helix structure. This delay was accompanied by a reduction in hydrogen bonding, short-range and long-range orderliness, thereby reducing the enthalpy of retrogradation. EWP and SPI reduced the increase rate of hardness during retrogradation. EWP also had the potential to alter the nucleation mode of recrystallization. Thus, EWP, SPI, and WG had the potential to inhibit the retrogradation of WS gels. Conversely, WPI could reduce the short-range orderliness during retrogradation, and WS gels with WPI exhibited higher hardness, long-range orderliness, and enthalpy of retrogradation during storage. [Display omitted] • Effects of four common proteins on wheat starch retrogradation were compared. • EWP, SPI and WG were effective in inhibiting the short-term retrogradation of WS gels. • Formation of hydrogen bonds, short-term and long-term orderliness were reduced by EWP, SPI and WG. • The changes in nanostructures of starch aggregation pattern were characterised. [ABSTRACT FROM AUTHOR]

The increasing number of people around the world suffering from chewing disorders necessitates the design of foods adapted to their needs. Glycation could be considered as one of the possible texturing methods. This chemical reaction alters the texture of food products by changing their macromolecular structure. However, there is no consensus on its effects on food texture. In this study, gelatin is used as a model medium to study the effect of glycation on its texture by considering two different Bloom indices (gel strength) and two different initial water contents. Our results suggest that the initial water content of gelatin, as well as its Bloom index, have an impact on the glycation reaction and on the texture of gelatin gels. The effect of these two factors influences the binding of d -ribose to reactive amino acids, in particular due to a variable amount of gelatin triple helix aggregates. This study shows the importance of controlling the water content and the Bloom index of gelatin to regulate the glycation reaction when used for food texturing. [Display omitted] • d - ribose disrupted the secondary structure of gelatin triple helices. • Initial gelatin water content modulated the production of reaction intermediates. • Aggregates were formed under high-water-content conditions. [ABSTRACT FROM AUTHOR]

The shift from animal-based towards more sustainable plant-based food systems has increased the interest in leguminous protein such as that from the pseudo-cereal quinoa. In spite of the importance of foaming agents in a wide variety of food systems, the foaming properties of quinoa protein are still poorly understood. In this research paper, the air-water (A-W) interfacial and foaming properties of aqueous extracts from defatted quinoa wholemeal were investigated. Foams contained both albumins and 11S globulins, but no 7S globulins, despite the presence of the latter proteins in the extracts. At pH 7.0, both albumins and 11S globulins were soluble and jointly adsorbed at the A-W interface. Closer to the 11S globulin isoelectric point (pH 5.0), only albumins adsorbed at the A-W interface. Cultivar-dependent differences in protein composition and functionality allowed to hypothesize that 11S globulins foam better when present as dissociated acidic and basic subunits rather than as monomers. Heat-induced aggregation of 11S globulins led to enrichment of albumins at the A-W interface. This was associated with an increased surface tension and a decreased surface dilatational modulus. Presumably, quinoa albumins have low tendency to interact at the A-W interface resulting in a weakly elastic interfacial network. At the same time, globulin aggregates formed during heating at pH 5.0 and 7.0 lead to unstable and stable foams, respectively. As protein functional properties are important for the quality of many food products, these insights are valuable when developing novel quinoa-based food products requiring interfacial stability. [Display omitted] • Foams of aqueous quinoa extracts (AQE) contain albumins and 11S globulins. • At pH 7.0, albumins and globulins jointly adsorb at the air-water (A-W) interface. • At pH 5.0, only albumins adsorb at the A-W interface. • 11S Globulin acidic and basic subunits foam better than intact globulin monomers. • Globulin aggregates formed during heating at pH 7.0 provide stability to foam. [ABSTRACT FROM AUTHOR]

The current study investigated the impact of microwave treatment on the physicochemical properties of corn kernels. Three microwave powers (2, 3, 4 W/g) and three treatment times (2, 3, 4 min) were used to treat the corn kernels. The findings indicate that heat treatment increased gelatinization temperature and gelatinization enthalpy. Moreover, relative crystallinity was reduced by 17.89% in the microwave-treated flour in comparison to untreated samples, and alterations were observed in the protein secondary structure, ordered structure, and functional properties of corn flour. Microwave treatment caused the darkening of the sample and a larger particle size distribution. Higher radiation times and microwave powers exhibited more intensive treatment outcomes. Rheological tests indicated that the elastic and viscous moduli of the microwave treated corn gels were higher than those of the control group, and their large-amplitude oscillatory shear curves exhibited a strain-weak strain overshoot (type III). The results of this study suggest that microwave treatment can potentially be utilized as a technique to regulate the technical functional properties and viscoelasticity of corn flour. [Display omitted] • Corn kernels were treated at different microwave treatment powers and times. • Microwave treatment caused gelatinization of starch and reduced crystallinity. • The secondary structure of the protein was changed by microwave treatment. • Microwave treatment altered the viscoelasticity of the corn flour gel. • Microwave treatment enhanced the water uptake ability of the flour. [ABSTRACT FROM AUTHOR]

In this study, the effects of high pressure homogenization (HPH) (0, 20, 40, 60, 80 and 100 MPa) on physicochemical and emulsifying properties of scallop (Chlamys farreri) protein (CFP) solutions were investigated. With the increasing of homogenize pressure, CFP solutions have better solubility. HPH could significantly decrease the particle size, which is distributed mainly in 300–600 nm. Compared with other treatments, HPH at 100 MPa showed highest surface hydrophobicity index (H 0) (131.22 ± 2.22), higher nitrogen soluble index (NSI) (92.72 ± 0.53%) and higher free sulfhydryl group (3.97 ± 0.20 μmol/g protein). Circular dichroism (CD) inspections showed that 100 MPa of high pressure homogenization could make the random coil component decrease and the β-sheet component increase. The adsorbed proteins (AP %) of the emulsions progressively increased from 39.69 ± 0.11% to 61.89 ± 1.01% with the pressure of homogenization increasing from 20 to 100 MPa. Most of the proteins in the emulsions were adsorbed after HPH. Laser scanning confocal microscopy (LSCM) showed stability of the emulsion was increased by HPH. This work showed that HPH treatment has positive effects on physiochemical and emulsifying properties of CFP for innovative technologies for the potential industrial applications. Image 1 • Physicochemical properties of CFP were changed by the combination of shear and cavitation. • HPH did not affect the protein composition of CFP. • A sharp increase of hydrophobicity was found after HPH. • The difference protein distributions between the cream and aqueous phases were clarified. • A uniform dispersion of emulsion was visualized after HPH. [ABSTRACT FROM AUTHOR]

Okara is the byproduct of tofu and soymilk industries. A large amount of okara is produced annually in the world, but only a small amount is fully utilized. The effect of steam explosion (SE) treatment on dietary fiber, protein and physiochemical properties of okara was investigated in this paper. The results showed that untreated okara contained 76.38% total dietary fiber (TDF) and 18.10% protein, but the content of soluble dietary fiber (SDF) was only 1.34%. After SE treatment, SDF content increased significantly. When the SE strength was 1.5 MPa for 30s, SDF content increased to 36.28%, higher by 26 times compared to the control okara. However, the contents of TDF and SDF both decreased when the SE strength enhanced further. Gel filtration chromatography showed that molecular weight of okara polysaccharides were distributed from 55 KDa to 2087 KDa. With the increase of SE strength, the ratio of low molecular weight polysaccharides increased and the molecular weight range of polysaccharides became narrower. Okara protein showed two molecular weight peaks. After SE treatment, the area of high molecular weight peak decreased and low molecular weight peak increased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that okara protein appeared in five bands: 73.7 KDa, 55 KDa, 41.1 KDa, 32.7 KDa and 20.2 KDa. After SE treatment, the bands of 73.7 KDa, 55 KDa and 41.1 KDa weakened markedly, indicating high SE strength can dissociate macromolecular protein aggregates. Water solubility of okara increased significantly, while swelling capacity, oil and water holding capacities decreased after SE treatment. Scanning electron microscopy (SEM) demonstrated that the loose sheet structure of okara surface was destroyed into small fragments after SE treatment and the internal nucleated structure was disintegrated into small particles at high SE strength. The change in morphological structure also produced important influences on physiochemical properties of okara. This study suggested that SE treatment is an effective method for improving SDF content and quality of okara, so as to expand its development and utilization. Image 1 • Steam explosion (SE) can increase significantly soluble dietary fiber content of okara. • Soluble dietary fiber content increased 26 times at SE strength of 1.5 MPa for 30s. • Okara polysaccharides were gradually degraded during SE treatment. • High SE strength can dissociate macromolecular protein aggregates. • Loose sheet structure of okara surface was destroyed into small fragments after SE. [ABSTRACT FROM AUTHOR]

Abstract The rheological behavior of gels prepared from albumin (ALB) and a mixture of ALB and low methoxyl amidated pectin (PEC) with different proportions were studied using oscillatory rheological tests, Fourier transform infrared spectroscopy (FT-IR spectroscopy), zeta potential measurements and confocal microscopy. The mixture was always 5% of the total solute. Assays were performed in two series, one in which all mixtures were adjusted to pH = 8 and another one without pH adjustment. The zeta potential values indicated the presence of a negative net charge on ALB-PEC gels. The rheological tests indicated a frequency dependence of the storage (G′) and loss (G") moduli, with G' > G". The presence of 1% and 2% of pectin in the mixture caused an increase in G'. However, a PEC concentration above 2% led to a decrease in G′, regardless of the pH or frequency. FT-IR spectroscopy indicated that as the PEC content increased, a higher proportion of β-sheet structures was found. Confocal microscopy also confirmed aggregation of ALB particles due to the PEC concentration. Highlights • The interactions between the pectin and albumin have electrostatic feature. • Gels from albumin and pectin are weak regardless of pH. • The increase of G′ was associated with the synergism between the albumin and pectin. • The addition of pectin above the critical concentration led to a decrease in G'. [ABSTRACT FROM AUTHOR]

The 7S and 11S globulins, the main protein fractions found in legumes, may differ in functionality. This study evaluated gel formation and rheological and microstructural properties of gels formed from the 7S and 11S protein fractions of faba bean. The effect of adding sodium chloride (NaCl) was also investigated. In terms of rheological and mechanical properties, NaCl addition appeared to have an opposing effect on 7S and 11S gels. Gels formed from 7S showed increases in storage modulus and peak stress when NaCl was added, whereas gels formed from 11S showed decreases. Microstructural changes were observed only for 7S gels, for which addition of NaCl resulted in transition from a fine-stranded to a coarse-stranded gel network. The 11S gels showed a fine-stranded gel network at all NaCl concentrations investigated. Gels formed from a mixture of 7S and 11S (7S:11S ratio 3:7) showed similar rheological properties and microstructure as the 11S gels. [Display omitted] • 7S and 11S protein fractions were successfully extracted from faba bean. • NaCl had opposing effects on the rheological properties of 7S and 11S gels. • Upon addition of NaCl, microstructural changes were observed only for 7S gels. [ABSTRACT FROM AUTHOR]

Bile salts (BS), as an important biosurfactant, play a vital physiological role in lipid digestion and transport. However, nutrient intake is often not uniform, and the protein-BS interaction may affect the interfacial process of lipolysis and reduce hydrolysis. In this study, an in vitro digestion model was used to explore the digestion behaviours of high-fat and high-protein diets prepared with different protein sources (pork, chicken, casein and soy protein). Interestingly, the final degree of hydrolysis of the same type and level of fat differed in the following order: casein > soy protein > pork protein > chicken protein. This difference was attributed to the findings that the salt-soluble proteins in pork and chicken effectively bound BS during intestinal digestion, reducing its efficiency in participating in fat digestion. Fluorescence spectra demonstrated that myofibrillar proteins of pork and chicken exhibited a strong binding capacity to BS. The addition of BS increased the proportion of random coils in the protein, and hydrophobic interactions played an essential role in the degree of binding. In addition, the rheological characteristics and microstructure of diets differed by protein source. Meat protein diets exhibited stronger aggregation, resulting in a smaller interface area for reaction. This in vitro study could provide a potential mechanism explaining the inhibition of fat digestion by different protein diets and provide more reasonable dietary guidance for obese people. [Display omitted] • The type of protein in the diet affected the rate and degree of lipolysis. • Coagulation of proteins affected the interfacial area of diets in the GIT. • Hydrophobic myofibrillar proteins have stronger interactions with bile salts. • Meat protein in the diet had a more significant effect on lipolysis. [ABSTRACT FROM AUTHOR]

Abstract Edible insects offer a huge potential as a new source of proteins for food and feed and as a promising functional agent. In this regard, our study aimed to evaluate the effect of pH and temperature on aggregation and gelation of honey bee brood (Apis mellifera). Aggregation of soluble proteins was dependent on temperature and pH value and the highest coagulation was reached at 85 °C at pH 5 and 7 (73.7 and 68.4%, respectively). Changes in protein surface hydrophobicity, net charge and amount of available and buried sulfhydryl groups demonstrated the contribution of either covalent or non-covalent intermolecular interactions resulted in aggregation at various pH. The least gelation concentration of raw powder from honey bee brood varied from 5 to 11% on raw powder basis at pH 7 and 3, respectively. Moreover, the effect of pH on rheological and textural properties, as well as gel microstructure from honey bee brood is discussed. Therefore, freeze dried raw powder of honey bee brood has rich nutritional value and demonstrated gelation concentration comparable to conventional protein sources that reveal its potential as an ingredient for insect-based gel product. Graphical abstract Image 1 Highlights • Coagulation of honey bee brood proteins is a pH and temperature-dependent. • Size of coagulated soluble proteins varied as a function of pH and temperature. • Heating induced changes in surface hydrophobicity, charge, SH groups of proteins. • Least gelation concentration of honey bee brood raw powder – 5% on raw basis at pH 7. • Textual properties and gel microstructure were affected by pH alteration. [ABSTRACT FROM AUTHOR]

Abstract The effect of temperature (below denaturation temperature) on protein foam formation and stabilization is potentially large, but has received little attention. This study aims to identify the effect of temperature (15–60 °C) on ovalbumin-stabilized foams at different concentrations (0.05–50 g L−1), and place this in a theoretical perspective. With increasing temperature the initial adsorption rate (dΠ/dt) increased logarithmically from 0.006 mN m−1 s−1 at 5 °C to 0.084 mN m−1 s−1 at 60 °C. A concentration increase resulted in a linear increase of dΠ/dt. This concentration effect was also observed in the foam ability, although the foam ability increased logarithmically rather than linearly with concentration, as expected based on theory and dΠ/dt. The foam ability was hardly affected by temperature (in contrast to theory and dΠ/dt). This was attributed to the strong decrease of foam stability with increasing temperature, which was expected based on theory. At elevated temperatures, the poor foam stability interferes with the foam ability (i.e. foam stability ≈ timescale of foam formation), a situation also happening at low concentrations. When formation was faster than destabilization, the foam ability relates to the effective adsorption rate. The effective adsorption rate includes the decrease in adsorption probability with increasing surface coverage. The observed balance between the effect of adsorption rate and foam stability on foam ability is not quantitatively predictable based on current theoretical models. Graphical abstract Image 1 Highlights • An increase of temperature accelerates adsorption, but hardly affects foam ability. • An increase of temperature strongly decreases foam stability. • When stability ≤ time of formation, low foam ability due to poor foam stability. • When stability > time of formation, foam ability relates to effective adsorption rate. • Combination of foam stability and effective adsorption rate determines foam ability. [ABSTRACT FROM AUTHOR]

Abstract In this study, different ultrasound powers, namely, 0, 200, 400, 600, 800 and 950 W with intensities of 0, 707.71, 1415.43, 2123.14, 2830.86 and 3361.64 W cm−2, respectively, were applied to treat proteins from scallops. Proteins from scallops (C. farreri) (ScP) were obtained by alkali dissolution and acid deposition. Changes in the particle size, surface hydrophobicity, sulfhydryl group content, and emulsifying properties were investigated. With the increasing ultrasonic power, ScP has better disposability. Compared with other treatments, ScP treated by a 950 W ultrasound had smaller particles, a higher surface hydrophobicity index (H 0) (476.73 ± 3.52), a higher free SH group (2.19 ± 0.05 μmol/g protein) and a higher nitrogen solubility index (NSI) (93.96 ± 0.52%). SDS-PAGE showed that the ultrasound could not change the molecular weight distribution of ScP. Secondary structural analysis by circular dichroism indicated that a high power ultrasound treatment could decrease the random coil and α-helix constituents and increase the β-sheet constituent of ScP. Confocal laser scanning microscopy (CLSM) showed that the emulsion stability was increased by the ultrasound treatment. It was concluded that the ultrasound treatment has beneficial effects with respect to the physiochemical and emulsifying properties of ScP and promotes its potential industrial applications. Graphical abstract Image 1 Highlights • Ultrasound treatment could reduce the particle size of CFP molecules. • A sharp increase of H 0 was found after ultrasound treatment. • A uniform dispersion of CFP emulsion was visualized after ultrasound treatment. • The protein distributions between the cream and aqueous phase were different. [ABSTRACT FROM AUTHOR]

Abstract Bambara groundnut is a protein-rich legume of African origin. This study investigated the influence of fractionation pH on degree of complexation of bambara protein isolate (BPI) with gum arabic (GA). BPI extracted at pH 2, pH 7, pH 9 and by the traditional salt solubilisation method were complexed with GA. BPI-GA complexes appeared as spherical particles (average size: 100–200 nm) that were aggregated. Optimal pHs of biopolymer interactions decreased (pH opt : 4.8 to 2.9) as protein extraction pH became more acidic. pH 2 fraction had the lowest coacervates yield (41%). ζ-potential profiles of protein fractions displayed similar pH dependent patterns, but with different pHs of net neutrality. The pH 2 fraction showed a high molecular weight protein (100 kDa), which was absent in other fractions. It also contained the highest content of basic amino acids. Protein extraction pH could be manipulated to produce better acid-stable structures on complexation with polysaccharides. Graphical abstract Image Highlights • Extraction pH significantly affected the degree of protein complexation with gum arabic. • Bambara protein –gum arabic coacervates appeared as spherical structures (100–200 nm). • High content of basic amino acids in protein fractions seems to lower coacervates yields. • PH opt of biopolymer interactions decreased as protein extraction pH become more acidic. [ABSTRACT FROM AUTHOR]

Fat rendering is a common process in the meat industry, whereby fatty or oily materials are melted away or cooked from the solid portion of the animal tissue. Once the fat, and more solid protein in the form of greaves, has been removed a co-product called glue water or stick water is produced which in generally considered a waste product. This study was established to investigate ways to revalorise this product and reduce the economic and environmental impact of this waste material. Proximate characterisation shows it contains 1.1–1.3% w/w of protein along with similar concentration of ashes (1.3% w/w). While low in protein this is a key pollutant if the product is disposed of, and could also represent an interesting protein source for downstream applications. In order to recover these proteins the salt has to be removed. Therefore, after the techno-functional properties of the raw material and of the recovered proteins were evaluated, especially those related to gelling formation, a new demineralizing method based on the excellent gelling properties of these proteins was developed and results compared with those obtained from three different ultrafiltration membranes (10, 3 and 1 kDa MWCO). Protein recovery was greater for the new method (79–90%) (50–77%); however, the amount of salt removed was higher when ultrafiltration was employed (90% compared to 81%). [ABSTRACT FROM AUTHOR]

Starch digestibility strongly depends on the food composition and microstructure formed during food processing. Identifying the interplay among food ingredients is vital to design starch-based foods with low digestibility. In this work, the effects of native and enzymatic (pepsin and pancreatin) hydrolyzed rice proteins on structural features, enzyme activity and digestibility of cooked rice starch were systematically investigated. All protein and its hydrolysates showed potent abilities in mitigating starch digestion. Native and pepsin hydrolyzed proteins increased starch retrogradation extent and thus increased ordered and aggregated structures of cooked starch. Pepsin-pancreatin hydrolyzed proteins displayed anti-retrogradation activity and decreased starch ordered structures, however, increased V-type inclusion complexes and displayed a potent mixed-type (competitive and non-competitive) inhibitory activity against α-amylase. Based on these findings, it can be concluded that native and pepsin hydrolyzed proteins decreased starch digestibility via increasing ordered structures of cooked starch, while pepsin-pancreatin hydrolyzed proteins mitigated starch digestion by the synergistic effects of V-type structures enhancement and mixed-type suppression activity against α-amylase. The data is of significant to formulate low glycemic health-promoting food products via native or proteolytic proteins complexation. [ABSTRACT FROM AUTHOR]

Natural emulsifiers have become of increasing interest within the food and beverage industry. Oat bran is a natural side-stream product produced during oat refinement that may be used to obtain amphiphilic extracts. Our hypothesis was that the oat bran extract is rich in surface-active and amphiphilic oat saponins and proteins that can form and stabilize emulsions. For this, we examined the surface activity of oat bran extract at oil-water and air-water interfaces, its ability to form oil-in-water emulsions and their stability against various stress tests. The highly surface-active oat bran extract acted as an ionic emulsifier, forming highly negatively charged submicron-sized emulsion droplets. These emulsions were stable over a wide range of pH (4–9), heat treatment (≤50 °C), and during storage at ≤25 °C up to 42 days. However, the emulsions showed instability at pH 2–3, at high ionic strengths, and during freeze-thawing. The formation and stability of the emulsions is related to interfaces containing oat saponins or oat saponin-protein complexes rather than a protein layer. These findings show that oat bran extract is a highly promising natural emulsifier, providing the food and beverage industry with a viable substitute to traditional emulsifiers. [ABSTRACT FROM AUTHOR]

The emulsification capacity of process-induced tomato and broccoli sera, containing proteins and pectin with distinct molecular structures, was investigated. Targeted pectin molecular modifications were induced by applying combinations of treatments to prepare the purées, and subsequently, the serum pectin-protein mixtures were isolated and assessed in terms of their capacity to stabilize oil-in-water (o/w) emulsions at different pH conditions (pH 3.5 or 6.0). Regardless of the processing applied, broccoli sera presented a better emulsion stabilizing capacity than tomato sera due to the higher protein content and probably the presence of more acetylated and branched pectin. In tomato sera, where a low amount of protein was detected, differences in emulsification capacity were identified depending on pectin molecular structure. Tomato sera, obtained from purées treated at low temperature for the stimulation of pectin-related enzymes which led to pectin with a high molecular weight, low degree of methyl-esterification and relatively high degree of acetylation, formed stable o/w emulsions. The vegetable sera exhibited higher capacity to form stable emulsions at pH 3.5 compared to pH 6.0, which can be attributed to a lower dissociation of the pectin carboxylic groups at low pH leading to less intramolecular repulsions resulting in a more compact conformation of the adsorbed species at the oil-water interface and better electrostatic interactions with positively-charged proteins. Thus, selective processing of vegetable purées is a promising strategy to induce molecular changes in water-soluble biopolymers with potential use as natural emulsifiers in acid/acidified foods. [ABSTRACT FROM AUTHOR]

Food-grade polymers such as proteins and polysaccharides have attracted great interest in recent years as excellent stabilisers for emulsion gels due to their good biocompatibility, environmental friendliness, and low cost. The obtained emulsion gels with specific properties can be used as extrudable inks in 3D printing. To further understand the application of food-grade polymers in emulsion gels construction, the interaction between proteins and polysaccharides as well as their mechanisms of stabilizing emulsion gels were reviewed. Besides, the feasibility of applying emulsion gels to 3D printing systems is discussed. Finally, this paper provides a brief outlook on using 3D-printed emulsion gels as practical foods. Proteins after the physical, chemical, and enzyme modifications are allowed to obtain emulsion gels by emulsion filling and particle aggregation. The mechanism of polysaccharide-based emulsion gels construction can be mainly distinguished as single stabilizing, bulk gelling, polysaccharide complexion stabilizing and dual-layer stabilizing, respectively. When used together, proteins and polysaccharides mainly stabilize emulsion gels by polysaccharide thickening, multilayer wrapping, or complex stabilizing. The emulsion gels with properties of shear-thinning, smooth flowability, and powerful stability can be successfully used as 3D printing inks. This review gathers and analyses mechanisms of applying food-grade polymers like proteins and polysaccharides to stabilize emulsion gels and summarizes the feasibility of emulsion gel application for 3D printing. This work can provide basic guidance for the development and application of low-fat and healthy fat-substitutes. [Display omitted] • Modifications of proteins for preparing emulsion gels are reviewed. • Polysaccharides used for emulsion gel stabilization are summarized. • Extrudability, flowability and stability are keys to emulsion gel 3D printing. • The limitations and prospects of emulsion gel 3D printing are discussed. [ABSTRACT FROM AUTHOR]

Starch and protein are major components in many foods, contributing to nutritional and textural properties. Understanding how the behaviour and interactions of these components contribute to different textures is important. In this study, mixed gel systems were created with different ratios of starch to protein (constant solid content 12%) extracted from faba bean, a promising crop for locally produced plant-based foods in cold climate regions. The mixed starch-protein gels were characterised in terms of pasting, texture and microstructure. Starch-rich mixtures showed higher water binding and water absorption than samples with higher protein content. A tendency for more efficient hydration in starch-rich samples was confirmed by NMR. Iodine affinity appeared to be lower for high-protein samples, particularly at higher temperatures. Mixtures with high starch content also showed higher viscosity during pasting, higher storage modulus throughout gelation, lower tan δ and lower frequency dependence of the final gel. Characterisation by compression tests showed stronger and more elastic gels with increasing starch content. Light microscopy revealed that starch granules were tightly packed, especially at higher starch content, with protein filling the spaces between starch granules. SEM micrographs revealed a network structure with larger pores and thicker strands in samples with higher starch content. Overall, increasing protein content reduced viscosity during pasting and caused softer gels, likely owing to different gelation and hydration properties of starch and protein. [Display omitted] • Pasting temperature increased and viscosity decreased as protein replaced starch. • Gels became softer as protein replaced starch. • Water binding and textural/rheological properties improved with starch content. • NMR revealed better hydration in starch-rich samples, affecting granule swelling. • LM and SEM revealed different microstructures in starch and protein networks. [ABSTRACT FROM AUTHOR]

To satisfy consumer demand for healthier food formulations, and to improve the performance, functionality and application of oil–in–water (O/W) emulsions, researchers have focused on the design of oil–water interfaces. However, the complexity of emulsion systems poses significant challenges for interface design. This review discusses the impacts of interface design based on monomeric (chemical modification of antioxidants), binary (polysaccharide–antioxidant and protein–antioxidant combinations) and ternary (polysaccharide–protein–antioxidant combinations) systems to enhance the oxidative stability of emulsions. We summarized the factors influencing the antioxidant efficiency of the combinations. In addition to inhibition of lipid oxidation, the impacts of interface design on other functional properties of the emulsions were highlighted. The high antioxidant and interfacial activity of monomeric, binary and ternary systems facilitated their effective inhibition of lipid oxidation. The antioxidant activity was influenced by the binding mode, grafting efficiency, conformational hindrance, and intermolecular distances. In real food systems, the antioxidant efficiency of the combinations needs to be further evaluated. In addition to antioxidant efficiency, interface design enhanced several functional properties of emulsions, including retention of nutrients, improved bioavailability of antioxidants, inhibition of harmful microbial growth, reduction of cytotoxicity, and stimulation of cell growth. This finding serves as an inspiration for expanding the application of interface design in emulsion systems. [Display omitted] • Advances in the design of monomeric, binary and ternary interfaces were presented. • Interfacial design contributed to the inhibition of lipid oxidation in emulsions. • Interface design facilitated nutrient retention and antioxidant bioaccessibility. • The role of interface design on microbial growth and cytotoxicity was described. [ABSTRACT FROM AUTHOR]

Oleosins are unique proteins that are crucial for the stabilization of the oil droplets, that nature designed to store and protect triacylgycerols in seeds. To better understand and possibly replicate the role of oleosins in the stability of oil droplets, an efficient extraction for oleosins is necessary, which has not been achieved yet. Oleosins consist of a long central hydrophobic hairpin that is attached to two hydrophilic arms. This high amphiphilicity makes their extraction a challenging task. The aim of the present work was to develop a scalable method to extract oleosins from rapeseed oleosomes using washing steps with methanol, hexane, and ethanol (MHE). Following this method, we obtained oleosins with a recovery of 94 ± 1.4 wt% and a purity of 87.1 ± 1.9 wt%. The recovery was significantly higher (p < 0.005) compared to the commonly applied Folch extraction (recovery of 57.2 ± 5.5 wt%). Oleosins formed micro- and nanosized aggregates when dispersed in aqueous solutions, because of their long hydrophobic moiety. The fraction of nanosized aggregates was 6-fold higher for the oleosins obtained with the MHE method in comparison to those obtained using the Folch method. Due to the smaller aggregates, oleosins obtained using the MHE method were more efficient in reducing the oil-water interfacial pressure and formed a stronger interfacial film in comparison to those obtained with the Folch method. The highly efficient and scalable oleosin extraction, paves the way for elucidating the stabilizing role of oleosins and the way towards industrial oleosin extraction. [Display omitted] • A new scalable method to extract oleosins was developed. • This method recovers ∼95% of oleosins from oleosomes with a purity of 87%. • Oleosins formed micro- and nanosized aggregates in aqueous solutions. • Oleosins form solid-like layer at oil-water interface. [ABSTRACT FROM AUTHOR]

Some research activities at Phillips Hydrocolloids Research Centre in Wrexham, Wales and in Wuhan, China have been overviewed. Historical development in both laboratories is described. Most extensively studied topics, the relation between structure and physico-chemical properties of gum Arabic, alginates, konjac glucomannan, carrageenans, beta-lactoglobulins, protein-polysaccharide interactions have been highlighted. [ABSTRACT FROM AUTHOR]

Dietary proteins and polyphenols contribute both nutritive and extra-nutritional (disease-preventing and metabolism-enhancing) benefits, and can participate in food structure formation and stabilization. There is a desire to increase consumption of proteins and polyphenols based on health considerations, and one approach is to form protein-polyphenol particles that combine both health and structural functionality in food products. The roles of proteins and polyphenols individually, or when bound together, are discussed in terms of health benefits (nutrition, disease prevention, satiety, allergy alleviation) and impact on food structure. The overall goal should be a rational design of protein-polyphenol particles to ensure a positive contribution to food quality, protein nutrition, and delivery of a health-relevant dose of polyphenols to the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of inorganic salt and protein in the aqueous phase on the dilational rheology properties of interfacial film stabilized by the hydrophobic emulsifier polyglycerol polyricinoleate (PGPR). The interfacial behavior was investigated using the oscillating drop method. With increased PGPR concentration, the interfacial tension tended to decrease and reached an equilibrium value of 3.3 mN m −1 , at 1.0% (w/w) PGPR. With 0.01% (w/w) PGPR in the oil phase, the presence of whey protein isolate (WPI) increased the dilational elasticity modulus of PGPR, but the addition of bovine serum albumin (BSA) decreased the elasticity modulus. This was likely due to competitive adsorption of BSA and PGPR at the soy oil/water interface, resulting in the desorption of BSA from the interface. At 1.0% (w/w) PGPR, both WPI and BSA increased the interfacial dilational elastic modulus and the reason might be that the presence of protein could suppress the diffusion-exchange process of PGPR between bulk phase and interface. The addition of MgCl 2 may enhance the adsorption of PGPR molecules at the interface and therefore increased the dilational modulus. [ABSTRACT FROM AUTHOR]

Dietary proteins and polyphenols contribute both nutritive and extra-nutritional (disease-preventing and metabolism-enhancing) benefits, and can participate in food structure formation and stabilization. There is a desire to increase consumption of proteins and polyphenols based on health considerations, and one approach is to form protein-polyphenol particles that combine both health and structural functionality in food products. The roles of proteins and polyphenols individually, or when bound together, are discussed in terms of health benefits (nutrition, disease prevention, satiety, allergy alleviation) and impact on food structure. The overall goal should be a rational design of protein-polyphenol particles to ensure a positive contribution to food quality, protein nutrition, and delivery of a health-relevant dose of polyphenols to the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Casein and soy soluble polysaccharide formed compacted complex aggregates in pH 3–4.5 aqueous solutions by electrostatic and hydrophobic interactions. The diameters of the complex aggregates were about 133 nm. The oil in water emulsion produced from the complex at pH 4 was stable after 500 days of storage in pH 2–6.8 media at 4 °C due to the compacted complex interfacial film. The curcumin loading efficiency of the emulsion was 99.9% and diameter of the droplets was about 324 nm. Only 3% of the loaded curcumin degraded when the emulsion was stored at 4 °C for 40 days. About 73% of the curcumin was released after 2 h digestion of the emulsion in simulated gastric fluid followed by 2 h digestion in simulated intestinal fluid. The curcumin pharmacokinetics in mice was analyzed after oral administration. The curcumin absorption of the emulsion treatment group was more rapid and effective than the absorption of curcumin/Tween 20 suspension treatment group. The curcumin oral bioavailability of the emulsion group was 11-fold higher than the bioavailability of curcumin/Tween 20 suspension group. This study demonstrated that casein and soy polysaccharide complex emulsion is an applicable system for oral delivery of lipophilic nutrients and drugs. [ABSTRACT FROM AUTHOR]

Liquid-liquid phase separation is a phenomenon occurring spontaneously upon changing the physico-chemical conditions of (bio-)polymers mixtures such as pH, ionic strength, total concentration, mixing ratio or temperature. The establishment of a phase diagram is a useful approach to highlight interactions and phase separation conditions of a mixture. Such approach generally performed in bulk is highly time and raw material consuming. In the present work, we developed a droplets-based millifluidic device for rapid phase diagram determination of liquid-liquid phase separated system. The proof of concept was first performed using a colloidal suspension of titanium dioxide (TiO 2 ). The developed millifluidic device was then applied to a model protein-polysaccharide mixture made of β-lactoglobulin (BLG) and Gum Arabic (GA) in water and at pH 4.2. In this model, a specific type of liquid-liquid phase separation occurs: complex coacervation. Biopolymers droplets of about 2.5 μL of various compositions were generated to investigate the impact of total biopolymers concentration (0.1–5 wt %) and protein-polysaccharide mixing ratio (1:8 to 8:1). Initiation and suppression of phase separation were then evidenced through turbidity measurements within the droplets using image analysis. High similarities between cloud points probed using the millifluidic device and the binodal curve determined in bulk were found in the total biopolymers concentration range explored. Droplets-based millifluidic represents an efficient and highly versatile tool to probe liquid-liquid phase separation of various biopolymers mixtures. [ABSTRACT FROM AUTHOR]

Thermal aggregation and gelation of soy protein isolate (SPI) was studied at fixed charge density over a wide range of protein concentrations (1–95 g/L), NaCl concentrations (0–0.5 M) and temperatures (30–85 °C). Gelation was studied with oscillatory shear measurements and aggregation with light scattering. At all conditions, self-similar aggregates were formed by random association of elementary units consisting of dense SPI particles with radii between 30 nm and 50 nm that were formed in a first step of the thermal aggregation process. Two distinct irreversible aggregation processes were identified: one dominating between 30 and 45 °C and one dominating above 65 °C. Addition of salt led to faster aggregation and gelation, but did not influence the gel stiffness at steady state. The size and density of the elementary units of the aggregates increased with increasing NaCl concentration and confocal laser scanning microscopy images showed increasingly heterogeneous gels structures. The effect of varying the ionic strength on thermal aggregation is compared with that of varying the net charge density of the proteins. [ABSTRACT FROM AUTHOR]

Cinnamaldehyde (CA), a common hydrophobic flavor, was encapsulated in oil-in-water emulsions that were stabilized by whey protein isolate (WPI). The impact of CA content and pH on the physical stability and lipolysis of the emulsions was then investigated. The presence of CA gave the emulsions a creamy yellow color, which became darker during storage. Emulsions formed using only CA as the oil phase contained large droplets that were physically unstable to particle growth and phase separation. The addition of medium chain triglyceride oil (MCT) improved the stability of emulsions containing CA, which was attributed to inhibition of Ostwald ripening effects. Fluorescent microscopy indicated that the adsorption of the protein to the droplet surfaces led to a thicker adsorbed layer in the presence of CA. The stability of the emulsions to droplet flocculation and coalescence depended on the CA level in the oil phase and the pH of the aqueous phase. An in vitro model was used to assess the impact of oil phase composition and pH on lipid hydrolysis and emulsion microstructure under simulated gastrointestinal tract conditions. The rate of lipid hydrolysis was highly dependent on CA level and pH. These results may facilitate the fabrication of emulsions with controlled GIT fate that are suitable for use in functional foods and beverages. [ABSTRACT FROM AUTHOR]

Proteins as natural amphiphilic biopolymers can stabilize emulsions and are attracting intensive interest due to their abundant resource, good emulsifying properties, biocompatibility, biodegradability, nutritional benefits, and high acceptance as food ingredients. Relying on the rational design of protein-polysaccharide interactions and their differences in physicochemical properties, the interfacial structure and properties of protein-based emulsions can be effectively improved. This review summarizes the influence of various types of cellulose (i.e., nanocellulose, microcrystalline cellulose (MCC), cellulose derivatives and regenerated cellulose (RC)) on the stabilization and interaction mechanism of protein-based emulsions. The key role of cellulose in protein-based emulsions can be summarized as the following points, namely strengthening network stabilization, improving emulsifying property, adjusting emulsion structure, enhancing environmental stability and regulating lipid digestion. The application potential of protein-based emulsions focusing on fat replacer, 3D printed food, delivery vehicle, and material design can also be improved by introducing various types of cellulose. [Display omitted] • Introducing cellulose improves structure and properties of protein-based emulsions. • Rational combination of protein and cellulose allows designing tailor-made emulsions. • Various types of cellulose have varied effects on protein-based emulsions. • Key role of cellulose on protein emulsions and their applications are summarized. [ABSTRACT FROM AUTHOR]

Stickiness is a major factor determining the eating quality of cooked rice, but the molecular mechanisms governing this property are not fully understood. In the present study, two different starch structures were examined: that in the uncooked grain, and that of starch leached out of the grain during cooking, and these results were parameterized by fitting to biosynthesis-based models. Protein content and stickiness were measured using a Kjeldahl apparatus and texture analyzer, respectively. In addition to protein content, the spatial distribution of the protein in the grain was obtained by microscopy after fluorescence labelling. Results showed that the extra-long amylose (ELA) chains were largely leached out during cooking. The amount of leached ELA chains was positively correlated with the amylose content in rice grain and negatively correlated with the stickiness of cooked rice, respectively. The difference in average chain length of ELA between parent and leached starch was negatively correlated with protein content. This implied that the protein network was wholly or partially entangled with ELA chains, which could retard ELA-chain leaching and consequently influence the stickiness of cooked rice. This suggests that stickiness, a quality important to consumers, could be managed by rice breeders through manipulating genes controlling the chain-length distribution. [Display omitted] • Both short and extra-long amylose (ELA) chains leach out during rice cooking. • ELA chains influence the stickiness of cooked rice. • Protein network retards ELA-chains leaching by entanglement. • The higher density protein network and longer ELA chains make entanglement stronger. [ABSTRACT FROM AUTHOR]

The objective of this work was to effectively migrate gallic acid (GA) to the oil–water interface and inhibit the lipid oxidation in water–in–oil (W/O) emulsions by combining GA with a natural emulsifier (pea protein isolate, PPI). The results showed that the conjugate induced by ultrasound–assisted alkali treatment exhibited superior binding efficiency (17.27 mg/g) and stability (9.01 mg/g retained after 30 days). Such conjugate showed a decrease in particle size, ζ–potential and sulfhydryl content. The secondary and tertiary structure of the PPI were altered. The cross–linking sites for PPI and GA binding included Glu, Asp, His, Lys, Arg and Trp. The functional properties of the conjugates were enhanced with their structural changes, including antioxidant and interfacial properties. The improvement of interfacial properties (2.13 mN/m for interfacial tension and 95.51% for interfacial protein adsorption) was attributed to the increase in surface hydrophobicity and the decrease in particle size. When added to the W/O emulsion, the conjugate provided the emulsion with the highest physical stability (droplet size of 198.10 nm and ζ–potential of −110.97 mV). In terms of oxidative stability, conjugate significantly reduced the production of primary and secondary oxidation products of lipid oxidation (64.62 and 92.34% respectively). Compared with the antioxidant (octyl gallate, C8) with high interfacial activity, the combination of PPI and GA provided emulsions with equivalent or higher oxidative stability. This is instructive for improving the oxidative stability of W/O emulsion through interface engineering. [Display omitted] • Ultrasound assisted–alkali treatment increased binding efficiency of PPI and GA. • Covalent cross–linking sites included Glu, ASP, His, Lys, Arg and Trp. • Conjugates had stronger antioxidant and interfacial properties than complexes. • Physicochemical stability of W/O emulsions was significantly improved. [ABSTRACT FROM AUTHOR]

Lactose is a disaccharide and has many uses in food and non-food formulations. Its anomeric form, β-lactose, is a natural inhibitor of the galectin-3 protein, which is responsible for several pathological effects (e.g., colon cancer cell proliferation). However, lactose cannot be orally administered since it is rapidly hydrolyzed by intestinal lactases. Therefore, the development of nanosystems from food hydrocolloids is of particular interest as oral delivery systems for β-lactose to enhance its chemical stability, bioaccessibility, and bioavailability. This report describes a new proof-of-concept assembling of high methoxyl pectin (HMP) and lysozyme (Ly) complexes loaded with β-lactose produced under appropriate solution conditions (ratio, pH, and temperature) without toxic solvents. Under optimized conditions, the prepared nanoparticles had a spherical shape (81.20 ± 0.34 nm), negative surface charge (∼−30 mV), homogeneous size distribution (PDI <0.2), and smooth surface, as evidenced by dynamic light scattering, scanning, and transmission electron microscopes. The encapsulation efficiency of β-lactose was greater than 96%. The particle size and morphology of the nanoparticles hardly changed with the incorporation of β-lactose. The interaction between the compounds was evidenced by Fourier transform infrared spectroscopy and differential scanning calorimetry, indicating that intermolecular electrostatic interactions and hydrogen bonds were the driving forces to form nanoparticles and suggesting the absence of free β-lactose on the surface of nanoparticles. Colorectal cancer cells treated with the nanocomplexes showed time-dependent incorporation of nanocomplexes. The results demonstrate a newly proof-of-concept pectin/lysozyme nanocomplexes loaded with β-lactose, with acid galacturonans covering the nanoparticles and maintaining the thermal stability, being relevant for future application of these complexes as potential oral delivery vehicles in food matrices for low molecular weight sugars. [Display omitted] • Assembly of high methoxyl pectin (HMP) and lysozyme (Ly) complexes were developed for the encapsulation of β-lactose. • Electrostatic interactions and hydrogen bonds were the primary mechanisms for forming the HMP/Ly complexes after heating. • β-lactose was entrapped inside the nanocomplex. • Nanocomplex entered colorectal cancer cells in a time-dependent manner. • These nanocomplexes can be used to protect and deliver bioactive ingredients. [ABSTRACT FROM AUTHOR]

A comparative study of both the bulk and air/liquid interfacial rheological responses was carried out by using four kinds of representative high molecular weight and highly branched polysaccharide emulsifiers, (a) corn fiber gum (CFG), (b) octenyl succinate anhydride-modified starch (OSA-s), (c) gum arabic (GA) and (d) soybean soluble polysaccharides (SSPS), spanning the concentration range of 1–15 wt%. We found that the bulk and interfacial rheological properties of their aqueous solutions were significantly different. While both CFG and OSA-s showed Newtonian flow behavior at higher concentrations, both GA and SSPS exhibited obviously shear thinning behavior or thixotropy even at a low concentration of 1 wt%. The time-dependent flow behavior for CFG, GA and SSPS reflected microstructural breakdown and rebuilding in solutions under shear, indicated that their proteinaceous portion was strongly bound to their polysaccharide part. This phenomenon was not observed for the almost protein-free OSA-s. The interfacial rheology responses showed that the layers formed by CFG and OSA-s were viscously predominant with faster formation kinetics while they were elastically predominant for GA and SSPS with slower formation kinetics. Interfacial viscoelastic responses of CFG and OSA-s were weaker than those of GA and SSPS. By comparison, the interfacial layer for OSA-s showed pure viscous responses whereas SSPS showed the highest elastic responses. These significant disparities in bulk and interfacial viscoelasticity of the four polysaccharide emulsifiers reflect the influence of different fine chain structures on the dissimilarity in the intermolecular associations and the architectures of the interfacial layers. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the possibility of stabilising foam bubbles in water by adsorption of calcium carbonate (CaCO 3 ) particles. Because CaCO 3 is hydrophilic and not surface-active, particles were hydrophobised in situ with several emulsifiers. The used emulsifiers were food-grade and negatively charged at the pH employed. The effect of particle addition on foamability and foam stability of solutions containing either β-lactoglobulin, sodium caseinate, Quillaja, sodium dodecanoate (SD) or sodium stearoyl-2-lactylate (SSL) was studied. It was found that the ability of the emulsifiers to induce surface activity such that the particles are able to adsorb to the air-water interface is related to their structure. The structure needs to consist of a well-defined hydrophobic part and a charged part. Large emulsifiers with a complex structure, such as β-lactoglobulin, sodium caseinate and Quillaja, were able to partially hydrophobise the particles but were not able to act synergistically with the particles to increase the foam stability. Low molecular weight emulsifiers, however, consisting of a single tail with one charged group, such as SD and SSL, adsorbed at the particle surface rendering the particles partially hydrophobic such that they adsorb to the air-water interface. In a subsequent investigation, the pH was changed to a value typical for food products (pH 6–7) and the addition of milk salts on the foamability and foam stability was assessed. Based on these results, the use of food-grade CaCO 3 particles hydrophobised in situ with food-grade surfactants (SD or SSL) to prepare ultra-stable aqueous foams is demonstrated. [ABSTRACT FROM AUTHOR]

In this study, BSA-dextran conjugate, produced by Maillard reaction, was used as emulsifier and stabilizer to produce curcumin-loaded oil in water emulsions. At fixed pH and BSA-dextran concentration in aqueous phase, the increases of curcumin concentration in oil phase from 12 to 15 mg/mL and oil volume fraction from 20% to 40% did not influence curcumin loading efficiency, but the oil-water interfacial films became imperfect, which were observed by transmission electron microscopy. The emulsion with integrated and cross-linked interfacial film formed on a heat treatment was long-term stable at various temperature and pH conditions, including physical stability of the emulsion and chemical stability of the loaded curcumin. Ex vivo fluorescence images of mice by means of hydrophobic fluorescence probe-loaded BSA-dextran emulsion revealed that the emulsion and/or released probe were mainly in gastrointestinal tract after oral administration and almost disappeared at 24 h post-administration. The pharmacokinetics analysis demonstrated that curcumin-loaded BSA-dextran emulsion could increase curcumin oral bioavailability in mice by 4.8-fold compared with curcumin/Tween 20 suspension. This study verifies that the emulsion can protect loaded curcumin from decomposition and also can promote curcumin absorption in gastrointestinal tract, indicating that protein-polysaccharide emulsions are good oral delivery systems for hydrophobic drugs and nutrients. [ABSTRACT FROM AUTHOR]

The rate of enzymic digestion of the three major macronutrients (protein, triglyceride and starch) in the human diet has a controlling influence on physiological and hormonal responses underpinning many of the risk factors for major non-communicable diseases. Previously, the interactions among macronutrients and the inter-dependence of individual macronutrient enzymic hydrolysis processes have been largely ignored. We now report a comprehensive study of component interactions in the enzymic hydrolysis of starch, protein and lipids representing both gastric and small intestinal digestion using wheat flour as an exemplar. Enzymic susceptibility of individual macronutrients in wheat flour was affected by each of a range of interactions among constituents as well as interactions of enzymes with non-substrate macronutrients. The results show the importance of food structure in attenuating the rate and extent of hydrolysis of starch, protein, and lipids, and highlight the fact that studies performed on isolated macronutrient/enzyme systems may not represent the complexities of real digestion. [ABSTRACT FROM AUTHOR]

Isopropanol was used to sequentially precipitate sugar beet pectin (SBP) and generate six fractions that varied in galacturonic acid, protein, ferulic acid and other physic–chemical characteristics. Protein was high in Fractions 1 and 2 at 209 and 154 μg/mg alcohol insoluble solids (AIS), respectively. Fractions 3, 4, and 5 had lower protein values of 77–106 μg/mg AIS; the protein content was 87 μg/mg AIS in unfractionated control. Ferulic acid content in Fraction 1 was 93 μg/mg AIS and at least three times higher than measured in other fractions. The degree of esterification in Fraction 1 was 11% and ranged from 46 to 74% in later precipitating fractions. The relative fluorescence with an external probe for hydrophobicity ranged from 159 to 254 in F1, F2 and F3 compared to negligible values in later fractions. The ζ-potential ranged from −25 to −33 mV and was not different between fractions or control. Molecular weight analysis indicated highly heterogenous pectin (Mw/Mn greater than 2.5) with MW values of 398,630, 543,900, and 442,330 g/mol for F1, F4 and control, respectively. FTIR analysis confirmed that F1 and F2 were richer in protein. SBP that precipitated at the lowest isopropanol addition had the greatest protein, ferulic acid content, particle size, relative fluorescence intensity and lowest uronic acid content and degree of esterification. The type and/or nature of protein in F1 and F4 is likely different. Isopropanol fractionation resulted in SBP fractions with unique physico–chemical properties. [ABSTRACT FROM AUTHOR]

Fining treatment is an important step in winemaking but its mechanism is still not well known. To have a better understanding of the protein fining process, the influence of polysaccharides and glycerol, major compounds in wine, on proanthocyanidin precipitation was studied. A wine and a model wine obtained from its polyphenol fraction were analyzed before and after fining by a gelatin and a plant protein, a hydrolyzed gluten HG. The results showed that polysaccharides and glycerol modify quantitatively proanthocyanidin precipitation, but not much the nature of the precipitated proanthocyanidins. The nature of the remaining proanthocyanidins in the treated model wines after protein fining was not much modified neither. All proanthocyanidins were not recovered after the fining treatments when polysaccharides and glycerol were added to the model wines. These results suggested the creation of soluble complexes between proanthocyanidins, fining proteins and polysaccharides. The efficiency of the fining treatment could be thus modified by the content of the wines. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the water distribution in maize starch (MS) and pea protein isolate (PPI) composite gels and understand how the separate contributions of MS and PPI affect the mechanical properties of composite gels with varying MS/PPI ratios. A series of MS gels with increasing PPI contents and a series of PPI gels with increasing MS contents were prepared. The water distribution was evaluated with a novel image analysis method using confocal laser scanning microscopy (CLSM). This method was used to quantify the volume fraction of each phase, from which the water distribution between the starch phase and the protein phase within the gels was estimated. Depending on the MS/PPI ratios, either a dispersed or a bicontinuous gel was formed. The estimated stiffness of each phase was used to estimate the gel stiffness using models for either dispersed or bicontinuous structures. These predictions were shown to be in good agreement with experimental data obtained from compression tests. The determination of the properties of each phase separately allowed us to determine which phase dominated the properties of the composite gel. In filled gels, the MS network dominated the gel properties, unless the stiffness of PPI fillers was remarkably higher than that of the MS network. In bicontinuous gels, the stiffness of the composite gels was determined by the network with the highest stiffness. Dispersing pea protein aggregates (PPA) with different size into MS gels resulted in minor differences in mechanical properties compared to PPI-MS gel. These results show that this new analysis method can be used to predict water distribution within gels, and how this leads to changes in the stiffness, hardness and brittleness of the gels. [Display omitted] • Water distribution can be estimated with a CLSM imaging analysis method. • Uneven water distribution was observed in all studied starch-protein gels. • Stiffness estimated based on theoretical models was in good agreement with experimental data. • In composite gels, the stiffer component dominates the gel properties. [ABSTRACT FROM AUTHOR]

The upsurging global population, along with the increasing cost of traditional sources of food proteins, provides an opportunity to directly utilize plant-derived proteins in human diets. Recently, the utilization of agro-industrial-generated raw byproducts has attracted the attention of modern food industries toward the production of sustainable, nutritious, and biofriendly products. Plant-derived proteins are among the promising materials being investigated. In particular, cottonseed protein, an important byproduct generated during the processing of cottonseed, is abundant in basic amino acids linked with several bioactivities. The suitability of using cottonseed protein products in terms of functional attributes and nutritional value in food systems will ultimately determine the magnitude of their application in the food industry. Techniques used for the most effective extraction of cottonseed protein with an esculent gossypol concentration have been comprehensively discussed. The bioactivities of enzymatically obtained cottonseed protein hydrolysates can be employed for fabricating bioactive packaging materials. Cottonseed proteins exhibit a plethora of bioactivities, such as antioxidant, antimicrobial, immunomodulatory, and angiotensin-converting enzyme inhibitory activities. Their superior functional food properties and relatively lower cost than other plant proteins make them suitable candidates for various food and nonfood applications. In this review, recent developments regarding the extraction, hydrolysate preparation, bioactivities, and industrial applications of cottonseed protein are thoroughly discussed. [Display omitted] • First review considering extraction of cotton seed protein and preparation of its hydrolysates. • Bifunctionalities associated with bioactive peptides from cottonseed are discussed. • Bioactive peptides exhibit antioxidant, antimicrobial and immunomodulatory activities. • Cottonseed protein have multifaceted food and non-food industrial applications. [ABSTRACT FROM AUTHOR]

Soybean oleosome-associated protein (SOP) plays a vital role in stabilizing soy oleosomes owing to its unique amphipathic topological structure. Inspired by the structure of natural oleosomes, in the current study, SOP-decorated liposomes (SOP-Lips) were proposed as a vehicle for improving phospholipid bilayer membrane stability. The micro morphology, size, encapsulation efficiency, and retention rate of SOP-Lips were characterized, the interactions between SOP and the phospholipid bilayer and their effects on the protein and lipid bilayer structures were evaluated. When the liposomes/SOP mass ratio was 1: 0.2 and 1: 0.4, the SOP-Lips exhibited spherical morphology and favorable dispersibility. The quartz crystal microbalance with dissipation monitoring (QCM-D) result suggested that most of SOP bound to liposomes in a tightly integrated way. Spectroscopy analysis indicated that the aromatic amino acids in the protein were exposed to a more hydrophobic microenvironment due to the interactions between the SOP and liposomes. There was an increase in α-helix and decrease in β-sheet and random curl contents in SOP upon exposure to liposomes. The decoration of SOP to liposomes could decrease membrane fluidity and enhance lateral packing of the phospholipid fatty acyl chain. The SOP coating increased the pH, ionic strength and temperature stability of luteolin liposomes (LUT-Lips). In the simulated digestion, SOP-decorated luteolin liposomes (SOP-LUT-Lips) showed a delayed release effect compared with LUT-Lips, suggesting that the inclusion of SOP resulted in a more digestion-resistant structure. This work provides a viable strategy for using SOP-Lips as a delivery system for nutraceuticals in functional food, dietary supplements and pharmaceuticals. [Display omitted] • Soybean oleosome-associated protein (SOP) decorated liposomes were constructed. • SOP interacted with liposomes through hydrogen bonding and hydrophobic interaction. • SOP decreased phospholipid membrane fluidity and enhanced the bilayer orderness. • Inclusion of SOP increased the load efficiency of luteolin in liposomes. • SOP modified liposomes exhibited sustained luteolin release profile. [ABSTRACT FROM AUTHOR]

The destabilization of water-in-oil (W/O) emulsions greatly restricts their application. Converting the inner water droplets into soft solid-like gelled particles is an appealing strategy to improve the stability of W/O emulsions. In the present communication, we propose a novel method for preparing stable W/O emulsions containing gelled water droplets. In this method, the 3% (w/v) casein dispersions containing 0.9% (w/v) glucono-δ-lactone (GDL) and soybean oil with 2% or 6% lipophilic emulsifier polyglycerol polyricinoleate (PGPR) were homogenized to form W/O emulsions. Three hours later, the GDL-induced gelation of caseins in the inner aqueous phase occurred; thus, the W/O emulsions containing gelled water droplets were formed. The stability of the emulsions was characterized by Turbiscan analysis, particle size changes and visual inspection of phase separation. It was found that the W/O emulsions containing GDL-induced casein gels in the inner aqueous phase showed higher resistance to destabilization than the non-gelled W/O emulsions. In addition, the stability of the emulsions formulated by the gelled aqueous phase and 2% PGPR was even higher than emulsions with 6% PGPR in the absence of the gelled aqueous phase. These findings suggested that this method is an effective strategy for improving the long-term stability of W/O emulsions. [ABSTRACT FROM AUTHOR]