Walnut protein isolate (WPI) is a nutritious protein with poor solubility, which severely limits its application. In this study, composite nanoparticles were prepared from WPI and soy protein isolate (SPI) using the pH-cycle technology. The WPI solubility increased from 12.64 to 88.53% with a WPI: SPI ratio increased from 1: 0.01 to 1: 1. Morphological and structural analyses illustrated that interaction forces with hydrogen bonding as the main effect jointly drive the binding of WPI to SPI and that protein co-folding occurs during the neutralization process, resulting in a hydrophilic rigid structure. In addition, the interfacial characterization showed that the composite nanoparticle with a large surface charge enhanced the affinity with water molecules, prevented protein aggregation, and protected the new hydrophilic structure from damage. All these parameters helped to maintain the stability of the composite nanoparticles in a neutral environment. Amino acid analysis, emulsification capacity, foaming, and stability analysis showed that the prepared WPI-based nanoparticles exhibited good nutritional and functional properties. Overall, this study could provide a technical reference for the value-added use of WPI and an alternative strategy for delivering natural food ingredients.

An intricate synergism between multiple biochemical processes and physical conditions determines the formation and function of various biological self-assemblies. Thus, a complex set of variables dictate the far-from-equilibrium nature of these biological assemblies. Mimicking such systems synthetically is a challenging task. We report multi-stimuli responsive transient coacervation of an aldehyde-appended polymer and a short peptide. The coacervates are formed by the disulphide linkages between the peptide molecules and the imine bond between the polymer and the peptide. Imines are susceptible to pH changes and the disulphide bonds can be tuned by oxidation/reduction processes. Thus, the coacervation is operational only under the combined effect of appropriate pH and oxidative conditions. Taking advantage of these facts, the coacervates are transiently formed under a pH cycle (urea-urease/gluconolactone) and a non-equilibrium redox cycle (TCEP/H2 O2 ). Importantly, the system showed high adaptability toward environmental changes. The transient existence of the coacervates can be generated without any apparent change in size and shape within the same system through the sequential application of the above-mentioned nonequilibrium reaction cycles. Additionally, the coacervation allows for efficient encapsulation/stabilisation of proteins. Thus, the system has the potential to be used for protein/drug delivery purposes in the future.

The effects of stirring speed (0, 250, 500, 750, 1000, 1250, and 1500 rpm) on the rice glutelin hydrocolloids (1 %, w/v) during the acidified process were investigated. As the stirring speed was increased to 750 rpm, the hydration diameter of the rice glutelin was significantly decreased, but higher stirring speeds had no significant effect on size. The highest and lowest solubility were recorded for the samples treated at 750 and 0 rpm stirring speeds, respectively. The surface hydrophobicity and molecular weight increased first and then decreased, both the minimum value was recorded at 750 rpm sample. The principal component analysis (PCA) was employed to detect patterns between changes in various properties (solubility, particle size, β-sheet content, surface hydrophobicity, and ζ-potential) and stirring treatment. To conclude, the various properties of rice glutelin refold during acidification are drastically affected by employing different stirring speeds. Choosing a suitable stirring speed is important for quality control in protein hydrocolloid production.