The Effect of Different Induction Methods on the Structure and Physicochemical Properties of Glycosylated Soybean Isolate Gels

Inhibitory effect of chlorogenic acid on tannase-mediated astringency removal and its mechanism

BACKGROUND

Phenolic acids, such as chlorogenic acid (CGA) and rosmarinic acid (RA), are added to plant-based beverages as nutritional supplements to enhance their health benefits. However, these compounds can also interfere with the astringency-reducing effect of tannase. This study employed electronic tongue analysis, enzyme inhibition kinetics, spectroscopy, molecular docking and molecular dynamics simulations to investigate the inhibitory mechanisms of CGA and RA on tannase-mediated deastringency.

RESULTS

Our research results indicate that CGA can inhibit tannase-mediated deastringency. It, along with RA, inhibits tannase activity in a non-competitive manner and quenches its intrinsic fluorescence through static quenching. The binding of CGA and RA to tannase led to the exposure of aromatic amino acid residues and a more polar microenvironment. Fourier transform infrared spectroscopy showed that CGA and RA reduced the α-helix and β-turn content in tannase, while increasing the unordered coil content. Molecular docking and dynamics simulations revealed that CGA and RA bind tightly to tannase primarily through hydrogen bonds and van der Waals interactions, occupying the substrate-binding site and thus inhibiting tannase's astringency-reducing activity. Additionally, other polyphenols, such as epicatechin, hesperidin and naringin, were also found to inhibit tannase activity.

CONCLUSION

The study demonstrated that CGA and RA inhibit the astringency-removal activity of tannase, offering important mechanistic insights for the development of plant-based beverages and deastringency techniques. © 2025 Society of Chemical Industry.

Preparation, structural changes and functional properties of the covalent complexes of almond protein and phloretin

Proteins and polyphenols exhibit distinct biological activities and functional properties. A comprehensive investigation into the formation mechanisms, structures, and functional properties of protein-polyphenol complexes will deepen our understanding of their interactions and establish a theoretical foundation and technical support for development of novel functional foods and pharmaceutical products. The almond protein-phloretin (AP-PHL) covalent complex was synthesized through the covalent binding of hydroxyl radicals to phloretin (PHL), utilizing almond protein (AP) as the raw material. Ultraviolet absorption spectroscopy (UV), fluorescence spectroscopy (FS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (RS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were employed to characterize the AP-PHL complex. Additionally, its properties, including emulsification characteristics and antioxidant activity, were analyzed. The results indicated that the hydrophobic groups in hydroxyl radical-treated AP relocated to a hydrophilic environment and interacted with PHL, thereby forming a stable complex. TEM results indicated that AP formed clusters within the central region of PHL. Additionally, UV and FS analyses revealed that the maximum absorption wavelength of AP-PHL shifted from 287.5 nm to 258 nm and 280 nm, respectively. As the PHL concentration increased, the fluorescence intensity gradually decreased, accompanied by a slight redshift. FTIR and RS analyses revealed that modifications in functional groups (e.g., -CH3, =CH2, CO, CC, CO) were implicated in the interaction between AP and PHL. Such structural modifications, along with other changes, enhanced the functional properties of AP-PHL, including thermal stability, water solubility, and emulsification, thereby indicating its substantial potential for applications in food and pharmaceuticals.

Natural protein-polysaccharide-phenol complex particles from rice bran as novel food-grade Pickering emulsion stabilizers

To develop novel food-grade Pickering emulsion stabilizers, insoluble rice bran protein-polysaccharide-phenol natural complex (IRBPPP) was prepared into Pickering emulsion stabilizers after different mechanical pretreatments (shear, high-pressure homogenization, ultrasonic, and combined mechanical pretreatment). With the increase in mechanical pretreatment types, the covalent binding of proteins and polysaccharides in IRBPPP gradually enhanced, the breakage efficiency of IRBPPP gradually increased (IRBPPP particle size decreased from 220.54 to 67.89 μm, the specific surface area of IRBPPP particle increased from 993.47 to 2033.86 cm-1/g), and the microstructure of IRBPPP gradually showed an orderly network structure, which enhanced the IRBPPP dispersion stability and the Pickering emulsion stability. Pickering emulsion stability was highly correlated (P < 0.01) with the breakage efficiency of IRBPPP particles. Overall, the combined mechanical pretreatment improved the stability of the IRBPPP-stabilized Pickering emulsion. The study added value to rice bran products and offered a new way to create stable food-grade Pickering emulsions for functional foods using natural protein-polysaccharide-phenol complex particles.

Tumor-targeted nano-assemblies for energy-blocking cocktail therapy in cancer

Starvation therapy aims to "starve" tumor cells by cutting off their nutritional supply. However, due to the complex and varied energy metabolism of tumors, targeting a single nutrient supply often fails to yield significant therapeutic benefits. This study proposes a tumor energy cocktail therapy that combines metformin, an oxidative phosphorylation inhibitor, with 2-deoxy-d-glucose (2-DG), a glycolysis inhibitor, to target tumor cells. To minimize the dosage of both drugs, we have developed a drug delivery strategy that prepared metformin as a nanoderivative, denoted as MA-dots. These MA-dots not only preserve the antitumor properties of metformin but also serve as a targeted delivery platform for 2-DG, ensuring its direct reach to the tumor site. Upon reaching the acidic tumor environment, the composite disintegrates, releasing 2-DG to inhibit glycolysis by targeting hexokinase 2 (HK2), the key enzyme in glycolysis, while MA-dots inhibit mitochondrial OXPHOS. This dual action significantly reduces ATP production in tumor cells, leading to apoptosis. In human lung tumor cells, the half-maximal inhibitory concentration (IC50) of 2-DG@MA-dots was significantly lower than that of either metformin or 2-DG alone, showing a nearly 100-fold and 30-fold reduction in IC50 values to 11.78 µg mL-1, from 1159 µg mL-1 and 351.20 µg mL-1, respectively. In studies with A549 tumor-bearing mice, the combination of low-dose 2-DG and metformin did not impede tumor growth, whereas 2-DG@MA-dots markedly decreased tumor volume, with the mean final tumor volume in the combination treatment group being approximately 89 times greater than that in the 2-DG@MA-dot group. STATEMENT OF SIGNIFICANCE: Metformin is a promising antitumor agent capable of modulating mitochondrial oxidative phosphorylation to inhibit cancer growth. However, its antitumor efficacy is limited when used alone due to compensatory energy mechanisms. Hence, we introduced glycolysis inhibitor 2-deoxy-d-glucose (2-DG) to inhibit an alternative tumor energy pathway. In our study, we developed a drug delivery strategy using metformin-derived nanomedicine (MA-dots) to load 2-DG. This approach enables the co-delivery of both drugs and their synergistic effect at the tumor site, disrupting both energy pathways and introducing an innovative "energy cocktail therapy".

Effect of succinylation-assisted glycosylation on the structural characteristics, emulsifying, and gel properties of walnut glutenin

In this study, we examined the effects of various sodium alginate (ALG) concentrations (0.2%-0.8%) on the functional and physicochemical characteristics of succinylated walnut glutenin (GLU-SA). The results showed that acylation decreased the particle size and zeta potential of walnut glutenin (GLU) by 122- and 0.27-fold, respectively. In addition, the protein structure unfolded, providing conditions for glycosylation. After GLU-SA was combined with ALG, the surface hydrophobicity decreased and the net negative charge and disulfide bond content increased. The protein structure was analyzed by FTIR, Endogenous fluorescence spectroscopy, and SEM, and ALG prompted GLU-SA cross-linking to form a stable three-dimensional network structure. The results indicated that dual modification improved the functional properties of the complex, especially its potential protein gel and emulsifying properties. This research provide theoretical support and a technical reference for expanding the application of GLU in the processing of protein and oil products.

Effects of Germination on the Structure, Functional Properties, and In Vitro Digestibility of a Black Bean (Glycine max (L.) Merr.) Protein Isolate

The utilization of black beans as a protein-rich ingredient presents remarkable prospects in the protein food industry. The objective of this study was to assess the impact of germination treatment on the physicochemical, structural, and functional characteristics of a black bean protein isolate. The findings indicate that germination resulted in an increase in both the total and soluble protein contents of black beans, while SDS-PAGE demonstrated an increase in the proportion of 11S and 7S globulin subunits. After germination, the particle size of the black bean protein isolate decreased in the solution, while the absolute value of the zeta potential increased. The above results show that the stability of the solution was improved. The contents of β-sheet and β-turn gradually decreased, while the content of α-helix increased, and the fluorescence spectrum of the black bean protein isolate showed a red shift phenomenon, indicating that the structure of the protein isolate and its polypeptide chain were prolonged, and the foaming property, emulsification property and in vitro digestibility were significantly improved after germination. Therefore, germination not only improves functional properties, but also nutritional content.