Characteristics and antioxidant activity of Maillard reaction products from ß-lactoglobulin and isomaltooligosaccharide.

Starch-derived isomaltooligosaccharide (IMO) is potentially used as prebiotics in infant formulas. Given that they are non-digestible carbohydrates rich in reducing substrates, it's crucial to understand if they can interact with ß-lactoglobulin (ß-LG) to produce Maillard reaction products (MRPs) and how these MRPs might influence the nutritional properties of ß-LG. In our investigation, we conjugated ß-LG with IMO to generate MRPs. Using a spectrophotometer, we identified the intermediates and assessed browning. We also evaluated changes in free amino groups and structural alterations. The antioxidative activity of the resulting compounds was assessed using DPPH and the ferric reducing/antioxidant power (FRAP) assay. Our data revealed increased visible absorption and fluorescence intensity, suggesting the formation of intermediate and browning products. The content of free amino groups diminished by 33%, supporting the conjugation of IMO with ß-LG. However, circular dichroism results indicated no significant alterations in the secondary structure of ß-LG. Notably, the ß-LG-IMO MRPs exhibited enhanced 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and ferric reducing/antioxidant power (FRAP). The findings provide insights into the characteristics and antioxidant activities of the conjugates derived from IMO and dairy protein in infant formula.

Characteristics and Functional Properties of Maillard Reaction Products from α-Lactalbumin and Polydextrose.

The characteristics and the functions of Maillard reaction products (MRPs) produced by polydextrose (PD), a new type of prebiotic, and α-lactalbumin (α-LA) were valued. PD and α-LA were incubated at 60 °C and 79% relative humidity for up to 72 h to prepare MRPs. The results showed that the absorbance and fluorescence intensity of heated α-LA-PD increased, and the amount of free amino groups reduced as the reaction progressed, which confirmed the formation of different stages of MRPs. Electrophoresis revealed an increase in molecular mass and the degree of covalent cross-linking. The secondary structure of MRPs experienced no significant changes with the measurement of circular dichroism (CD), while the tertiary structure gradually unfolded, exposing hydrophobic groups. Furthermore, a significant increase was detected in the radical-scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the ferric reducing/antioxidant power (FRAP) of MRPs. The findings offer a foundation for understanding the structural and functional features of MRPs in formula milk powder.

Characterization and functional properties of Maillard reaction products of ß-lactoglobulin and polydextrose.

The Maillard reaction products (MRPs) between polydextrose (PDX), a popular polysaccharide in formula powder, and ß-lactoglobulin (ß-LG), a major whey protein, were studied in aggregation degree, structure, hydrophobic, antigenic and antioxidant activity changes of ß-LG. Incubation of PDX and ß-LG (60 ℃, 79% relative humidity) for up to 72 h yielded MRPs with increases in furosine, UV absorbance, fluorescence intensity and loss of free amino groups. High molecular weight ß-LG-PDX MRPs were observed by SDS-PAGE. Circular dichroism spectroscopy revealed negligible change in ß-LG secondary structure. Changes in the tertiary structure of ß-LG were detected by tryptophan fluorescence spectroscopy consistent with an increase in surface hydrophobicity of heated ß-LG-PDX. Antigenicity reduction of ß-LG in ß-LG-PDX reached its peak when heated for 24 h. After heating for 72 h, DPPH radical-scavenging activity of ß-LG-PDX increased by 7.4-fold, and the ferric reducing antioxidant power reached 61.1 µmol ascorbic acid/g protein.

Stretchable distributed fiber-optic sensors.

Silica-based distributed fiber-optic sensor (DFOS) systems have been a powerful tool for sensing strain, pressure, vibration, acceleration, temperature, and humidity in inextensible structures. DFOS systems, however, are incompatible with the large strains associated with soft robotics and stretchable electronics. We develop a sensor composed of parallel assemblies of elastomeric lightguides that incorporate continuum or discrete chromatic patterns. By exploiting a combination of frustrated total internal reflection and absorption, stretchable DFOSs can distinguish and measure the locations, magnitudes, and modes (stretch, bend, or press) of mechanical deformation. We further demonstrate multilocation decoupling and multimodal deformation decoupling through a stretchable DFOS-integrated wireless glove that can reconfigure all types of finger joint movements and external presses simultaneously, with only a single sensor in real time.

Characteristics and antioxidant activity of Maillard reaction products from α-lactalbumin and 2'-fucosyllactose.

The characteristics and antioxidant activity of Maillard reaction products (MRPs) from 2'-fucosyllactose (2'-FL), a human milk oligosaccharide, and α-lactalbumin (α-LA) were investigated. MRPs were prepared by reacting 2'-FL with α-LA at 60 °C and 79% relative humidity for up to 72 h. The absorbance and fluorescence intensity of heated α-LA-2'-FL increased as the heating time increased, while the free amino group content decreased, confirming that 2'-FL reacted with α-LA and produced various MRPs at different incubation stages. Conjugates of 2'-FL and α-LA and aggregation of α-LA were observed by SDS-PAGE. The secondary structure of α-LA did not change significantly after reacting with 2'-FL. In terms of antioxidant activity, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and reducing power of α-LA-2'-FL increased significantly when compared with the protein only sample (p < 0.05). The findings provide a foundation for the characterization and functional analysis of MRPs in dairy products.

Simple Synthesis of Elastomeric Photomechanical Switches That Self-Heal.

This article introduces a simple two-stage method to synthesize and program a photomechanical elastomer (PME) for light-driven artificial muscle-like actuations in soft robotics. First, photochromic azobenzene molecules are covalently attached to a polyurethane backbone via a two-part step-growth polymerization. Next, mechanical alignment is applied to induce anisotropic deformations in the PME-actuating films. Cross-linked through dynamic hydrogen bonds, the PMEs also possess autonomic self-healing properties without external energy input. This self-healing allows for a single alignment step of the PME film and subsequent "cut and paste" assembly for multi-axis actuation of a self-folded soft-robotic gripper from a single degree of freedom optical input.

Self-Assembly of One-Dimensional Nanocrystal Superlattice Chains Mediated by Molecular Clusters.

Self-assembly of nanocrystal (NC) building blocks into mesoscopic superstructures with well-defined symmetry and geometry is essential for creating new materials with rationally designed properties. Despite the tremendous progress in colloidal assembly, it remains a fundamental challenge to assemble isotropic spherical NCs into one-dimensional (1D) ordered superstructures. Here, we report a new and general methodology that utilizes molecular clusters to induce the anisotropic assembly of NCs in solution, yielding polymer-like, single-NC-wide linear chains comprising as many as ∼1000 close-packed NCs. This cluster-assisted assembly process is applicable to various metallic, semiconductor, and magnetic NCs of different sizes and shapes. Mechanistic investigation reveals that the solvent-induced association of clusters plays a key role in driving the anisotropic assembly of NCs. Our work opens a solution-based route for linearly assembling NCs and represents an important step toward the bottom-up construction of 1D ordered NC superstructures.