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The formation of aggregates was studied in arginine aqueous solutions using light scattering. The main driving force for aggregate formation is hydrogen bonding between the arginine (Arg) amino acids, which is partially verified using density functional theory calculations. The measurement of energy loss during this process, coupled with Cryo-EM morphology data, indicates that these aggregates are in the solid state. The aggregation occurs in two steps, with a liquid intermediate stage. The investigation of the effect of pH and solute concentration on aggregate formation for other amino acid aqueous solutions verifies that aggregate formation is amino-acid specific, while small-sized clusters formed by weak interactions lead to large-sized aggregation. The water structure around amino acid molecules sheds light on the prediction of their aggregate formation. Homochirality is observed in the aggregates; its existence sheds light on the origin of protein homochirality. [ABSTRACT FROM AUTHOR]

BACKGROUND: In order to study the effect of adsorption of surfactant at the two interfacial layers on emulsion stability, the kinetically stable water‐in‐oil‐in‐water (W/O/W) emulsion carriers were prepared using polyglycerol polyricinoleate (PGPR) and gum arabic (GA) as emulsifiers. The relationship between the adsorption of the surfactant and the stability mechanism of the emulsions was elucidated. RESULTS: When the contents of PGPR and GA were low, the interfaces between oil and the inner and outer water phases, respectively, could not be completely covered. However, when the concentration of PGPR was higher than 60 g kg−1, the excess PGPR was adsorbed on the interface between the oil phase and the outer water phase. When the concentration of GA reached 80 g kg−1, more GA was adsorbed to the oil‐in‐water interface. Moreover, the presence of PGPR on the interface could reduce the adsorption capacity of GA. Two types of kinetically stable emulsions were obtained by optimizing the interface composition (60 g kg−1 GA/80 g kg−1 PGPR and 60 g kg−1 PGPR/80 g kg−1 GA). The kinetically stable W/O/W emulsions prepared in this study were successfully used to encapsulate a hydrophilic vitamin (vitamin B12) with an encapsulation efficiency (EE) of 80% and release efficiency (RE) of 95%. The interfacial adsorption GA can accelerate the hydrolysis of fat. CONCLUSION: Overall, this study provides a new strategy for the preparation of W/O/W emulsions, which might be beneficial for application in food, cosmetic, chemical, and pharmaceutical industries. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The thyme oil emulsion was prepared using a novel type of nanocellulose obtained under different hydrolysis durations. The effect of different cellulose structures on interfacial adsorption properties of emulsion and loading efficiency of thyme oil were analyzed. The results showed that the cellulose particles became more homogeneous and hydrophilic after hydrolysis duration for 10 h. The loading efficiency of thyme oil for all emulsions reached about 80%. The retention rate of thyme oil decreased during the storage period, and rising temperatures will exacerbate the loss of thyme oil. Compared to Hd2, emulsions stabilized by Hd10 exhibited better stability and higher retention at all storage conditions. Cellulose emulsion can increase the dispersion and improve the stability of thyme oil. A smaller cellulose particle could make the emulsion become more stable. The experimental results confirmed that cellulose can be used as a stabilizer to encapsulate and transport hydrophobic active ingredient. Practical Application: The study results demonstrated that the emulsion transport system was developed using cellulose nanoparticles prepared by hydrolysis. The system can be used to load hydrophobic active substances (active peptides, curcumin, β‐carotene, essential oils, etc.). It can protect the active substance from environmental damage, enhance water solubility and stability, and improve the bioavailability of the active substance. [ABSTRACT FROM AUTHOR]

After formation of the ovalbumin (OVA)-gum arabic (GA) complex coacervates, a more ordered crystal structure was obtained, and the protein denaturation temperature increased from 72 to 96 °C. GA can reduce the pH-induced conformational perturbations of ovalbumin. The presence of GA improved the stability of the α-helix and β-turn regions against pH, but showed less influence on the random coil and β-sheet domains. The complex coacervates showed the highest viscosity value at pH 3.7 compared with the other pH values tested (4.0, 3.4, 3.0, 2.7) due to the stronger interactions of OVA and GA. A large thixotropic loop was observed for the coacervate obtained at pH 3.7 compared with that obtained at pH 4.0. Moreover, the salt concentration and OVA:GA ratio influenced the rheological properties by affecting the structure and composition of the complexes. A stronger interaction between OVA and GA led to greater viscoelastic properties. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of limited hydrolysis on conformational and antioxidant properties of soy protein isolate-maltodextrin (SPI-Md) conjugates. Extrinsic fluorescence analysis showed unfolding of the protein molecule and exposure of hydrophobic groups in SPI-Md conjugate hydrolysates. Free amino acid analysis showed that, the contents of hydrophobic amino acids in SPI-Md conjugates increased after hydrolysis. The contents of leucine, isoleucine, phenylalanine increased from 0.32, 0.30 and 0.54 to 1.36, 1.86 and 2.60, respectively, when the hydrolysis degree (DH) gradually increased from 0% to 5.7%. The FT-IR spectrum showed that C = O absorption of the amide group formed by glycosylation continued unabated after limited hydrolysis (DH 2.9%). The glycated SPI products showed good reducing power and superior resistance to lipid oxidation (34%, 12 mg mL−1), whereas the limit hydrolysates (DH 2.9%) of SPI-Md conjugates showed more efficient radical-scavenging capacity (89.5%, at 12 mg mL−1) and iron-chelation activity (91.3%, at 12 mg mL−1). Results of this study indicated that, slight enzymatic hydrolysis (DH 0-2.9%) could help partially unfolding the globular structure of SPI-Md conjugates without deteriorating amide bonds and had a positive effect on their antioxidant properties. [ABSTRACT FROM AUTHOR]

Natural biopolymer stabilized oil-in-water emulsions were formulated using ovalbumin (OVA), gum arabic (GA) solutions and their complexes. The influence of interfacial structure of emulsion (OVA-GA bilayer and OVA/GA complexes emulsions) on the physical properties and antimicrobial activity of thyme oil (TO) emulsion against Escherichia coli ( E. coli ) was evaluated. The results revealed that the two types of emulsions with different oil phase compositions remained stable during a long storage period. The oil phase composition had an appreciable influence on the mean particle diameter and retention of the TO emulsions. The stable emulsion showed a higher minimum inhibitory concentration (MIC), and the TO emulsions showed an improved long-term antimicrobial activity compared to the pure thyme oil, especially complexes emulsion at pH 4.0. These results provided useful information for developing protection and delivery systems for essential oil using biopolymer. [ABSTRACT FROM AUTHOR]

BACKGROUND The aim of this work was to evaluate the effects of egg freshness on baking properties and final qualities in batter systems. Batters were made with eggs of different freshness, and the properties of batter systems were studied through rheological analysis, rapid viscosity analysis ( RVA), differential scanning calorimetry ( DSC), batter density and expansion rate during the baking and cooling processes. Moreover, the qualities of final baked systems were investigated, including specific volume and texture profile analysis ( TPA). RESULTS The flow behavior of batters showed that the consistency index ( K) decreased as the Haugh unit ( HU) value decreased, while the flow behavior index ( n) increased. Both the storage modulus ( G′) and loss modulus ( G″) determined by mechanical spectra at 20 °C decreased with decreasing HU. RVA and DSC determinations revealed that lower- HU samples had a lower viscosity in the baking process and a shorter time for starch gelatinization and egg protein denaturation. Observation of the batter density revealed an increasing change, which was reflected by a decrease in the specific volume of final models. TPA showed significant differences in hardness and chewiness, but no significant differences in springiness and cohesiveness were found. CONCLUSION The egg freshness affected the properties of batter systems. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Because of the low stoichiometry from enzymatic hydrolysis of casein, purification of casein phosphopeptides ( CPPs) is necessary prior to application in infant formula or nutritional foods. In this study, functional zirconia-modified magnetic nanoparticles ( Fe3O4@ ZrO2) were prepared and applied for purification of CPPs. The physical shape, crystalline structures and chemical groups were characterized by transmission electron microscopy, X-ray diffraction and Fourier transform infrared. Fe3O4@ ZrO2 nanoparticles had nano-dimension and good dispersion. The purification studies showed that the high selectivity of Fe3O4@ ZrO2 was obtained at pH 4.5. Then the structures of reused Fe3O4@ ZrO2 were characterized to study the stability of material. The purity of CPPs isolated by Fe3O4@ ZrO2 was analyzed to study the affinity force of material. All results confirmed that Fe3O4@ ZrO2 nanoparticles had good stability and high affinity force for CPPs after 15 repeated cycles, and the maximum loading amount of material was 105.53 mg/g with lower N/P (5.94) of CPPs. Practical Applications Casein phosphopeptides can enhance the absorption and utilization of calcium, but it needs to be purified before used as calcium nutritional supplements. Most of existing purification methods are two-step methods, which have limitations in food application. Compared with traditional methods, the separation method using Fe3O4@ ZrO2 nanoparticles can one-step purify phosphopeptides from real samples, and shows good performance. The purification process using Fe3O4@ ZrO2 nanoparticles has the simpler procedures, higher enrichment efficiency and shorter production cycle. It means that the purification process is easy to expand the scale of production for improving the yield and quality of phosphopeptides, which can satisfy the demand of market. The results demonstrate that Fe3O4@ ZrO2, which has good stability and high affinity force for metal oxide affinity peptides, is one new type of extraction materials and possesses wide application prospects in food industry. [ABSTRACT FROM AUTHOR]