Controlling Solvent Polarity to Regulate Protein Self-Assembly Morphology and Its Universal Insight for Fibrillation Mechanism.

The mechanism of ethanol-induced fibrillation of ß-lactoglobulin (ß-lg) in the acidic aqueous solution upon heating was investigated using various techniques, mainly thioflavin T fluorescence, atomic force microscopy, nonreducing electrophoresis, mass spectrometry, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy. The results showed that fibrillation occurred with a heating time increase, but high ethanol content slowed down the process. At a low ethanol volume fraction, peptides existed after heating for 2 h, with long and straight fibrils formed after 4-6 h, while at a high ethanol volume fraction, the proteins aggregated with very few peptides appeared at the early stage of heating, and short and curved fibrils formed after heating for 8 h. Ethanol weakened the hydrophobic interactions between proteins in the aqueous solution; therefore the latter could not completely balance the electrostatic repulsion, and thus suppressing the fibrillation process. It is believed that the fibrillation of ß-lg in the acidic solution upon heating is mainly dominated by the polypeptide model; however, ethanol inhibited the hydrolysis of proteins, and the self-assembly mechanism changed to the monomer model.

Influence of Temperatures on Physicochemical Properties and Structural Features of Tamarind Seed Polysaccharide.

Due to the high content of impurities such as proteins in tamarind seed polysaccharide (TSP), they must be separated and purified before it can be used. TSP can disperse in cold water, but a solution can only be obtained by heating the mixture. Therefore, it is important to understand the dispersion and dissolution process of TSP at different temperatures to expand the application of TSP. In this study, pasting behavior and rheological properties as a function of temperature were characterized in comparison with potato starch (PS), and their relationship with TSP molecular features and microstructure was revealed. Pasting behavior showed that TSP had higher peak viscosity and stronger thermal stability than PS. Rheological properties exhibited that G' and G'' of TSP gradually increased with the increase in temperature, without exhibiting typical starch gelatinization behavior. The crystalline or amorphous structure of TSP and starch was disrupted under different temperature treatment conditions. The SEM results show that TSP particles directly transformed into fragments with the temperature increase, while PS granules first expanded and then broken down into fragments. Therefore, TSP and PS underwent different dispersion mechanisms during the dissolution process: As the temperature gradually increased, TSP possibly underwent a straightforward dispersion and was then dissolved in aqueous solution, while PS granules initially expanded, followed by disintegration and dispersion.

Seed gum-based delivery systems and their application in encapsulation of bioactive molecules.

Now-a-days, the food/pharma realm faces with great challenges for the application of bioactive molecules when applying them in free form due to their instability in vitro/in vivo. For promoting the biological and functional properties of bioactive molecules, efficient delivery systems have played a pivotal role offering a controlled delivery and improved bioavailability/solubility of bioactives. Among different carbohydrate-based delivery systems, seed gum-based vehicles (SGVs) have shown great promise, facilitating the delivery of a high concentration of bioactive at the site of action, a controlled payload release, and less bioactive loss. SGVs are potent structures to promote the bioavailability, beneficial properties, and in vitro/in vivo stability of bioactive components. Here, we offer a comprehensive overview of seed gum-based nano- and microdevices as delivery systems for bioactive molecules. We have a focus on structural/functional attributes and health-promoting benefits of seed gums, but also strategies involving modification of these biopolymers are included. Diverse SGVs (nano/microparticles, functional films, hydrogels/nanogels, particles for Pickering nanoemulsions, multilayer carriers, emulsions, and complexes/conjugates) are reviewed and important parameters for bioactive delivery are highlighted (e.g. bioactive-loading capacity, control of bioactive release, (bio)stability, and so on). Future challenges for these biopolymer-based carriers have also been discussed. HighlightsSeed gum-based polymers are promising materials to design different bioactive delivery systems.Seed gum-based delivery systems are particles, fibers, complexes, conjugates, hydrogels, etc.Seed gum-based vehicles are potent structures to promote the bioavailability, beneficial properties, and in vitro/in vivo stability of bioactive components.

Nonlinear dilatational rheology of different protein aggregates at the oil-water interface.

Proteins tend to self-assemble into different morphological aggregates such as nanoparticles or fibrils during heat treatment depending on the processing conditions. The protein aggregates exhibit excellent interfacial activity and even better ability to stabilize emulsions than native proteins. The interfacial rheological properties at the oil-water interface play a very important role in emulsion stability, among which the interfacial nonlinear rheology is closely related to their ability to resist large perturbation. However, there are very few studies reporting the nonlinear interfacial rheological behavior of protein aggregates at the oil-water interface. In this study, ß-lactoglobulin fibrous aggregates (F) and nanoparticle aggregates (NP) were prepared, and the adsorption kinetics and dilatational nonlinear rheological behavior of ß-lactoglobulin aggregates at the oil-water interface under large amplitude deformation were studied using a pendant drop tensiometer, and compared with those of native proteins. From the adsorption experiments, the adsorption of protein aggregates, especially fibrils, was faster than that of native proteins in the early stage, while in the late stage, the native proteins displayed a significantly higher degree of rearrangement than the fibrils. The surface hydrophobicity and the short fibrils present mainly determine the properties of the fibril interface, while the behavior of the nanoparticle interface was significantly influenced by the size and charge properties of the nanoparticles. From the dilatational experiment, the Lissajous plots revealed that the F interface at all pHs evaluated and the ßlg interface at pH 5.8 displayed strain softening in both expansion and compression processes, while the NP interface at all pHs and ßlg interface at pH 2 and pH 7 displayed strain softening in expansion and strain hardening in compression processes. The nonlinear response of the protein aggregates at the oil-water interface was more obvious at pH 5.8. The modulus change from frequency sweeps revealed that the fibril interface was strong but not very structured in contrast to that formed by the native proteins which displays high structuration although weak in strength, whereas the strength of the interface formed by protein nanoparticles is in between, but more sensitive to the surface charge.

Electrostatic Interaction-Based Fabrication of Calcium Alginate-Zein Core-Shell Microcapsules of Regulable Shapes and Sizes.

Core-shell microcapsules with combined features of hydrophilicity and hydrophobicity have become much popular. However, the assembly of biocompatible and edible materials in hydrophilic-hydrophobic core-shell microcapsules is not easy. In this work, based on electrostatic interactions, we prepared controllable calcium alginate (ALG)-zein core-shell particles of different shapes and sizes using hydrophilic ALG and hydrophobic zein by a two-step extrusion method. Negatively charged hydrogel beads of spherical, ellipsoidal, or fibrous shape were added into a positively charged zein solution (dissolved in 70% (v/v) aqueous ethanol solution) to achieve different-shaped core-shell particles. Interestingly, the size, shape, and shell thickness of the particles can be regulated by the needle diameter, stirring speed, and zein concentration. Moreover, for simplification, the core-shell particles were also synthesized by a one-step extrusion method, in which an ALG solution was added dropwise into a 70% (v/v) aqueous ethanol solution containing zein and CaCl2. The particles synthesized in this work showed controlled digestion of encapsulated medium-chain triglyceride (MCT) and sustained release of encapsulated thiamine and ethyl maltol. Our preparation method is simplistic and can be extended to fabricate a variety of hydrophilic and hydrophobic core-shell structures to encapsulate a broad spectrum of materials.

Interfacial behaviour of ß-lactoglobulin aggregates at the oil-water interface studied using particle tracking and dilatational rheology.

During processing, proteins are easily self-assembled into different aggregates, such as nanoparticles and fibrils. Protein aggregates exhibit a strong interfacial activity due to their morphologies and functional groups on the surface. Their interfacial structure and rheological properties at the oil-water interface have a significant effect on the stability and fat digestion of emulsions in food. In this study, ß-lactoglobulin (ß-lg) aggregates including ß-lg nanoparticles (ß-lg NP) and ß-lg fibrils (ß-lg F) were prepared in solution by controlling the heating temperature and pH, and their surface properties including the electric potential, hydrophobicity, and density of free thiol groups were characterized. The adsorption kinetics, interfacial rheology, and displacement by bile salts (BSs) of native ß-lg and its aggregates at the oil (decane)/water interfaces were studied using particle tracking microrheology and dilatational rheology. From the movement of tracer particles at the interface, ß-lg NP and ß-lg F were found to adsorb faster than native ß-lg, and they were found to form interfacial films with a marginally higher elasticity. During the process of protein adsorption, the films of ß-lg and its aggregates are not uniform. In the process of protein displacement, ß-lg NP has the strongest ability while native ß-lg has the weakest ability to resist BS substitution, which is consistent with the results from in vitro digestion experiments. The present study reveals the microrheological behaviour of protein aggregates at the oil-water interface and demonstrates that ß-lg thermal aggregates exhibit an excellent emulsification ability and can be used to control fat digestion. The study also illustrates the applicability of microrheological methods to the study of interfacial rheology and its complementarity with dilatational rheological methods.

Molar mass effect in food and health.

It is demanded to supply foods with good quality for all the humans. With the advent of aging society, palatable and healthy foods are required to improve the quality of life and reduce the burden of finance for medical expenditure. Food hydrocolloids can contribute to this demand by versatile functions such as thickening, gelling, stabilising, and emulsifying, controlling texture and flavour release in food processing. Molar mass effects on viscosity and diffusion in liquid foods, and on mechanical and other physical properties of solid and semi-solid foods and films are overviewed. In these functions, the molar mass is one of the key factors, and therefore, the effects of molar mass on various health problems related to noncommunicable diseases or symptoms such as cancer, hyperlipidemia, hyperglycemia, constipation, high blood pressure, knee pain, osteoporosis, cystic fibrosis and dysphagia are described. Understanding these problems only from the viewpoint of molar mass is limited since other structural characteristics, conformation, branching, blockiness in copolymers such as pectin and alginate, degree of substitution as well as the position of the substituents are sometimes the determining factor rather than the molar mass. Nevertheless, comparison of different behaviours and functions in different polymers from the viewpoint of molar mass is expected to be useful to find a common characteristics, which may be helpful to understand the mechanism in other problems.

Microencapsulation of probiotic lactobacilli with shellac as moisture barrier and to allow controlled release.

BACKGROUND: Rapid dissolution in digestive tract and moisture sorption during ambient storage are the two challenges of dry probiotic preparations. To solve these problems, microcapsules with shellac (LAC) addition containing Limosilactobacillus reuteri TMW 1.656 were designed in this work to provide a good moisture barrier and to provide controlled release in digestive tract, based on the hydrophobicity and acid-resistance of LAC. Four microcapsules were prepared using the method of emulsification/external gelation based on the crosslinking reaction between alginate or LAC with calcium ion, including alginate/sucrose (ALG), alginate/shellac/sucrose (ALG/LAC), alginate/whey protein isolate/sucrose (ALG/WPI) and alginate/whey protein isolate/shellac/sucrose (ALG/WPI/LAC). RESULTS: Measurements of physical properties showed that microcapsules with LAC addition (ALG/WPI/LAC and ALG/LAC) had larger particle size, much denser structure, lower hygroscopicity and slower solubilization in water, which agreed with the primary microcapsule design. Probiotic survivals in digestive juices followed the order of ALG/WPI/LAC ≥ ALG/WPI ≥ ALG/LAC > ALG. Probiotic stability after heating and ambient storage both exhibited the order of ALG/WPI/LAC > ALG/LAC ≈ ALG/WPI > ALG, which can be explained by the decreased hygroscopicity with adding LAC. CONCLUSION: LAC addition contributed to better probiotic survivals after freeze drying, simulated digestion, heating and ambient storage, and whey protein isolate (WPI) addition had a synergistic effect. Microcapsule hygroscopicity was closely related with probiotic survivals after heating and ambient storage, while microcapsule solubilization was closely related with probiotic survivals in simulated juices. Within our knowledge, this is the first report to improve probiotic stability during ambient storage based on LAC hydrophobicity. © 2020 Society of Chemical Industry.

Improved effects of okara atomized by a water jet system on α-amylase inhibition and butyrate production by Roseburia intestinalis.

Improving the physicochemical properties of okara for various applications in foods is of great importance. Here, okara and microcrystalline cellulose (MCC) were atomized using a water jet (WJ) system. The WJ-treated okara and MCC dispersed homogeneously in water, and their median sizes in particle size distribution were 6.6 µm and 9.5 µm, respectively. The dispersions of WJ-treated okara and MCC showed high apparent viscosity and shear thinning behavior. Moreover, the inhibition of α-amylase activities by WJ-treated okara was more effective than that by untreated MCC and cellulose. Furthermore, the production of short-chain fatty acids by 32 dominant species of human gut microbes was determined. An increase in butyrate production by Roseburia intestinalis was observed in the presence of WJ-treated okara, but not in untreated okara or WJ-treated MCC. These results demonstrate that WJ system can be used on okara to increase inhibited α-amylase activities and butyrate production by gut microbiota.

Electrostatic complexation of ß-lactoglobulin aggregates with κ-carrageenan and the resulting emulsifying and foaming properties.

The electrostatic complexation of protein and polysaccharide and the functional properties of the complexes are significantly affected by the structure of protein aggregates and are important in the development of new food ingredients. In this work, natural globular ß-lactoglobulin (NGBLG), ß-lactoglobulin nanoparticles (BLGNP), and ß-lactoglobulin fibrils (BLGF) were prepared and complexed with κ-carrageenan (κ-car). Phase diagrams of the NGBLG-, BLGNP-, and BLGF-κ-car systems were established and divided into 4 regions: mixed soluble polymers (I), intramolecular soluble complex (II), intermolecular soluble complex (III), and intermolecular insoluble complex (IV). Aggregation shifted the boundaries of regions III and IV of BLGF- or BLGNP-κ-car to lower pH and higher protein aggregates/κ-car weight ratio (r), especially for BLGF-κ-car. The emulsifying and foaming properties of the 3 mixed systems were investigated in regions I and II. Complexes in region II had significantly better emulsifying properties than the corresponding mixtures in region I and the pure protein aggregates. Interestingly, phase separation resulted in different effects on the foaming properties of the 3 BLG-κ-car complexes, in which BLGF-κ-car complexation in region II decreased the foaming properties in region I but the complexation of NGBLG-κ-car and BLGNP-κ-car in region II increased the foaming properties. The BLGF-κ-car complex in regions I and II provided the best emulsifying and foaming properties. Interfacial data both on oil-water and air-water interfaces overall explained the emulsifying and foaming properties of the complexes.

Co-gelation of gluten and gelatin as a novel functional material formation method.

Gelatin solution was added to the gluten dispersion to obtain 25% protein from gluten and 0, 0.3, 0.6 and 1.0% of gelatin. Heat-induced gels were formed. The gelatin was leached by immersing the gel straps in distilled water at 45 °C for 2 h. Incorporation of gelatin into the gluten gel matrix resulted in its strengthening. Increase in elastic properties with the increasing amount of gelatin was also found for the macerated gels. The tangent delta showed the minimum for the leached gel with the initial concentration of gelatin 0.6%, so probably at this concentration there was some reinforcement of gluten, or the structure of gluten matrix was formed with the best ability to include gelatin inside. FTIR (Fourier transform infrared spectroscopy) results showed, that at the 0.6% gelatin concentration more gelatin was present in the leached samples than in the 1% gelatin added samples. Gelatin gels can act as an active filler reinforcing the gluten microstructure. Leaching of gelatin from the mixed gel matrix resulted in the microstructure with visible phase separation. Generally gelatin addition gave a surface smoothing effect and lower surface roughness of the obtained gels. Pure gluten gels soaking in hot water resulted in the decreased roughness. Possibility of manipulation with gluten gels surface roughness by co-gelling with gelatin can have an influence on the application of such gels as matrices for active ingredients.

Improving the Stability of Oil Body Emulsions from Diverse Plant Seeds Using Sodium Alginate.

In this study, peanut, sesame, and rapeseed oil bodies (OBs) were extracted by the aqueous medium method. The surface protein composition, microstructure, average particle size d 4 ,   3 , ζ-potential of the extracted OBs in aqueous emulsion were characterized. The stability of the OB emulsions was investigated. It was found that different OB emulsions contained different types and contents of endogenous and exogenous proteins. Aggregation at low pHs (<6) and creaming at high pHs (7 and 8) both occurred for all of three OB emulsions. Sodium alginate (ALG) was used to solve the instability of OB emulsions under different conditions-low concentration of ALG improved the stability of OB emulsions below and near the isoelectric point of the OBs, through electrostatic interaction. While a high concentration of ALG improved the OB emulsion stability through the viscosity effect at pH 7. The OB emulsions stabilized by ALG were salt-tolerant and freeze-thaw resistant.

Conformational Transition of Polyelectrolyte As Influenced by Electrostatic Complexation with Protein.

Conformation and conformational transitions are essential for the biological and technological functions of natural polyelectrolytes, for example, DNA. This study aims to clarify how the conformational transition of natural polyelectrolyte is affected and tuned by electrostatic complexation with protein as encountered in many biological processes. A model protein/polyelectrolyte system, ß-lactoglobulin (ß-lg) and κ-carrageenan (κ-car), was used for the investigation. The effect was found to be determined by the molecular state of ß-lg/κ-car electrostatic complexation and the molecular weight of protein. ß-lg/κ-car complexation in soluble state had a subtle effect on the coil-to-helix transition of κ-car, while that in insoluble state greatly suppressed it. On the basis of the McGhee-Hippel theory, a quantitative model was successfully developed to describe the effect of protein/polyelectrolyte electrostatic complexation on the conformational transition of polyelectrolyte. The model can also provide additional information on the change of tertiary structure of ß-lg upon electrostatic complexation with κ-car. Moreover, it was found that ß-lg or its hydrolysates with a molecular weight larger than 2000 Da hindered the conformational transition of κ-car, while those with a molecular weight lower than 1000 Da promoted it. The observations offer a promising approach to control the conformational transition and related properties of polyelectrolytes for technological applications.

Effect of acidification on the protection of alginate-encapsulated probiotic based on emulsification/internal gelation.

BACKGROUND: The method of emulsification/internal gelation is commonly used to prepare alginate microspheres for lactic acid bacteria (LAB). This paper focused on the influence of acidification parameters, i.e. acid/Ca molar ratio and acidification time, on the physical properties and cell protection efficiency of microspheres and their correlations. RESULTS: With increasing acid/Ca molar ratio and acidification time, the average diameter of microspheres decreased and their mechanical strength increased. Interestingly, wet alginate microspheres shrank in simulated gastric juice (SGJ) while they swelled in bile salts solution (BS). The shrinkage or swelling ratio decreased with increasing mechanical strength. Correlation analysis showed that the encapsulated cell survivals in both SGJ and BS were positively correlated with the mechanical strength of microspheres but negatively with the shrinkage or swelling ratio. BacLight LIVE/DEAD assay suggested that the viability of encapsulated cells in fresh, SGJ-treated and BS-treated microspheres was closely related to cell membrane integrity. CONCLUSION: Acidification is a key step during microsphere preparation, which strongly affected the physical properties of alginate microspheres, resulting in different cell protection efficiency. The resulting well-protected LAB can be applied in probiotics foods. © 2016 Society of Chemical Industry.

Preparation and drug release performance of different gelation type polysaccharide/ß-lactoglobulin fiber composite gels.

Self-assembled protein fibers have attracted much attention in the fields of medicine and food because of their high aspect ratio, polymorphic structure and strong surface hydrophobicity. In this study, three different gelation types of polysaccharides/ß-lactoglobulin fiber (Fblg) composite gels, including ionic alginate-Fblg gels, synergistic xanthan-Fblg gels, and double network agar-Fblg gels, were first prepared. The interactions between the polysaccharides and the Fblgs, the microstructure and mechanical properties of the composite gels were investigated using the light scattering, scanning electron microscopy, rheology and texture analysis in order to reveal their formation mechanisms. Then the loading and release properties of the water-soluble drug 5-fluorouracil (5-FU) and the hydrophobic drug curcumin (Cur) through these composite gels were further studied with release mechanisms determined by fitting different release models. It was found that the mechanical properties of the composite gels were determined by the mesh density of the three-dimensional networks formed inside the gels. The network structure and mechanical strength of the alginate-Fblg gels became weaker with the increase of Fblg content at pH 4 due to their attractive interaction which hindered the binding of Ca2+ to ALG, while the network and the strength of the alginate-Fblg gels didn't change much at pH 7 due to the repulsion between Alg and Fblg. The xanthan-Fblg gels formed lamellar structures with enhanced gel network and mechanical strength due to the hydrogen bonding and the electrostatic interaction with Fblg. The Agar-Fblg composite gel formed at 60 °C (above the gelation temperature of agar of 40 °C) had a denser double network structure and higher mechanical strength than that formed at 0 °C due to inhibition of diffusion of Ca2+ as salt bridges for Fblg. The hydrophilic drugs were loaded in the meshes of the composite gels and their release was determined by the structure of the composite gel networks, whereas the hydrophobic drugs were loaded by attaching to the Fblgs in the composite gels and their release was determined by the loading ability and strength of the gels. The study not only provided a new idea for the preparation and application of polysaccharide-protein fiber composite hydrogels, but also provided insights for improving the efficiency of drug carriers.

Effect of emulsifiers on the properties of corn starch films incorporated with Zanthoxylum bungeanum essential oil.

The use of natural and safe ingredients in green food packaging material is a hot research topic. This study investigated the effect of different emulsifiers on starch film properties. Three types of emulsifiers, including Tween 80 as a small-molecule surfactant, sodium caseinate (CAS), whey protein isolate (WPI), and gelatin (GE) as macromolecule emulsifiers, whey protein isolate fibril (WPIF) as a particle emulsifier, were utilized to prepare Zanthoxylum bungeanum essential oil (ZBO) emulsions. The mechanical, physical, thermal, antibacterial properties, microstructure and essential oil release of starch films were investigated. CAS-ZBO nanoemulsion exhibited the smallest particle size of 198.6 ± 2.2 nm. The film properties changed with different emulsifiers. CAS-ZBO film showed the highest tensile strength value. CAS-ZBO and WPIF-ZBO films exhibited lower water vapor permeability than Tween-ZBO. CAS-ZBO film showed good dispersion of essential oil, the slowest release rate of essential oils in all food simulants, and the best antibacterial effect against Staphylococcus aureus and Listeria monocytogenes. The films composed of CAS-ZBO nanoemulsion, corn starch, and glycerol are considered more suitable for food packaging. This work indicated that natural macromolecule emulsifiers of CAS and WPIF are expected to be used in green food packaging material to offer better film properties.

Effect of mixture microstructure/compatibility on the properties of type-A gelatin-dextran edible films.

The influence of phase separation behavior on bio-based film properties has attracted more and more attention. This work investigated the effects of microstructure and compatibility of the type-A gelatin (GE)-dextran (DE) mixtures on GE-DE edible film properties. Three kinds of GE-DE edible films with different textures were prepared via modulating the microstructure and compatibility of film-forming mixtures using the method of gelation-drying, e.g., homogeneous films, microphase separated films with relatively homogeneous texture, and microphase separated films with uneven texture. The optical, mechanical, water barrier, and thermal properties of films were characterized. Results showed that microstructure and compatibility significantly affected the film properties. In general, films with DE-in-GE microstructure exhibited the best film properties, followed by films with water-in-water-in-water/bicontinuous microstructure, and then films with GE-in-DE microstructure. And homogeneous films showed the best film properties, followed by films with relatively homogeneous texture, and then films with uneven texture. The weight loss results suggested the potential of GE-DE edible films for application in cherry tomato preservation. This work provided interesting information for the design of film with fabricated microstructure and properties.

Formation and application of edible oleogels prepared by dispersing soy fiber particles in oil phase.

Oleogels containing less saturated and trans-fats were considered as an ideal option to replace the solid fats in foods. In this research, oleogel was fabricated by dispersing soy fiber particles (SFP) in soy oil, and further it was used in bread preparation. Effect of the particle size, particle content and the second fluid content on the formation of oleogels were evaluated, based on the appearance and rheological properties. Results showed that the suspension of SFP in soy oil (24%, w/w) could be transformed into gel-like state, upon the addition of the second fluid. The SFP based networks were dominated by the capillary force which was originated from the second fluid. The rheological properties and yield stress of the oleogels could be modulated by particle size and particle content of SFP in oil phase, as well as the second fluid content in the system. When the oleogels were applicated in bread preparation, a layered structure could be formed in the bread, indicating the possibility of replacing the solid fats in bakery products by our oleogels. Our results offered a feasibility approach for oil structuring with natural raw materials, and developed a new approach to replace the solid fats in foods.

Chewing gum base: A comprehensive review of composition, production, and assessment methods: Advances and approaches in biodegradability.

The gum base mass is a colloidal system and the main component of chewing gum; which is an inert, non-nutritious, indigestible, and insoluble part of chewing gum, therefore this substance does not dissolve in the mouth when chewed. The gum base plays the most crucial role in determining the mechanical properties, flexibility, and overall quality of chewing gum. Moreover, it acts as a delivery system to transport sweeteners, flavorings, and other ingredients in chewing gum. Despite the massive market for chewing gum and the provision of a list of the main ingredients in gum base by the Code of Federal Regulations and some international organizations, there is a lack of information about chewing gum base and its compositions in the literature. Therefore, the purpose of this review is to present an overview of the characteristics, ingredients and applications, production process, assessment, and modification methods of the gum base along with the advances and approaches in biodegradability. Biodegradability concerns play a promoting role in the research and development of chewing gum and its applications in the food industry, medical and dental sectors. Reviewing previous studies can surely help for faster development of this path.

Influence of interfacial properties/structure on oxygen diffusion in oil-in-water emulsions.

Oxygen diffusion played an important role in the lipid oxidation of food emulsions. In this study, a simple method was developed to quantitatively observe the oxygen diffusion in the oil-water biphasic system, and it was further applied to investigate the relationship between the oxygen diffusion and lipid oxidation in O/W emulsions. Various factors that related to the emulsion oxidation were considered, from their influence on the oxygen diffusion and lipid oxidation in the emulsions. Results showed that there was obvious correlation between the oxygen diffusion and lipid oxidation in O/W emulsions, which reveals the inhibition of oxygen diffusion could apparently slow down the lipid oxidation. Moreover, the changes of oil phase, water phase and interfacial layer of the emulsions, which were related to the oxygen diffusion, could improve the oxidative stability of the emulsions effectively. Our findings are helpful for deep understanding the mechanisms of the lipid oxidation in food emulsions.