Analysis of structural changes and anti-inflammatory capacity in soybean protein isolates conjugated with anthocyanins

Abstract

This study investigated the covalent cross-link at alkaline (pH 9.0) between different concentrations of anthocyanins and soybean protein isolate (SPI). The structure of the product was analyzed by SDS-PAGE, fluorescence spectrum, and circular dichroism. In order to test the effects of SPI on the anti-inflammatory ability of anthocyanins, in vitro inflammatory cell model was set by RAW264.7 cell line. Results showed that fluorescence quenching of soybean protein isolates was static strengthened. The α-helix content of the secondary structure gradually decreased with the content of the β-sheet and random coil increasing. A super molecular weight subunit was observed, and the complex of soybean protein and anthocyanins can markedly reduce the secretion of TNF-α and NO at the dose of 200 μg/mL when the concentration of anthocyanins is greater than 0.167 mg/mL.

Effects of high hydrostatic pressure on physicochemical and functional properties of soybean protein isolate

“…The fluorescence of SPI samples (0.2 mg/mL) were measured with fluorescence spectrometer (Lumina, Thermo Fisher, America) at 290 nm excitation wavelength (slit = 5 nm) and 300-500 nm emission wavelength (slit = 5 nm). The sample solutions were prepared in 10 mM phosphate buffer (pH 7.0) (Zhao et al, 2019;Wang et al, 2022).…”

“…If more positively charged amino acids are present than negatively charged amino acids, the ζ-potential of a protein solution is positive (Bouzid et al, 2008). SPI is a representative ampholyte with a bunch of non-polar and polar (Amino, carboxyl, hydroxyl) groups on the side chain (Wang et al, 2022). As shown in Figure 5, the highest ζ-potential (13.65 mV) was got at 200 MPa (30 min), due to the exposure of the positively charged groups containing lysine and histidine on the SPI surface.…”

Effect of protein oxidation on the structural characteristics of hazelnut protein isolate

“…The intrinsic fluorescence spectrum can reflect the changes in protein tertiary structure and conformation, and an intensity decrease can partly reflect tryptophan and tyrosine oxidation (Wang et al, 2022). In the folded state, tryptophan residues were generally located within the hydrophobic environment of the protein, having a high quantum yield and, therefore, a high fluorescence intensity.…”

Inherent molecular characteristics and effect of garlic polysaccharides on dough micro- and mesoscopic properties

“…The properties of garlic polysaccharides-enriched dough significantly depend on the contents of the polysaccharide fractions and cross-linking effects between the components induced by the polysaccharides fractions in the dough, predominantly gluten protein. For example, the addition of excessive garlic polysaccharide fractions can reduce the appearance, flavour and texture of flour products, which is a key challenge when manufacturing non-starch polysaccharides-enriched foods ( Wang et al, 2022 ). As a result, it is imperative to explore the complex cross-linking effects of ingredients in garlic polysaccharide-based food systems and the influences of their impact on the processing, adaptability and properties of the final flour-based products.…”