We aimed to purify polyphenols from distiller’s grain extract using macroporous resins and to identify its polyphenolic components. The influence of operational parameters on purification efficiency was investigated. The polyphenolic composition was analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) and then quantified by UPLC-MS using authenticated standards. The results showed that the optimal purifying conditions were D101 resin with a dosage of 3 g, four hours adsorption, three hours desorption time, and 60% ethanol as the eluent, producing the highest purification rate of 51%. The purified distiller’s grain extract exhibited stronger antioxidant activity than the unpurified extracts, which was assessed using DPPH and ABTS methods (IC₅₀ DPPH = 34.03 and 16.21 μg/mL, respectively; IC₅₀ ABTS = 20.31 and 5.73 μg/mL, respectively). UPLC-MS results indicated that (−)-epicatechin is the major compound found in distiller’s grain extract which was quantified as 562.7 μg/g extract, followed by ferulic acid (518.2 μg/g), p-hydroxybenzoic acid (417.7 μg/g), caffeic acid (217.1 μg/g), syringic acid (158.0 μg/g) and quercetin (147.8 μg/g). Two compounds, vanillic acid (66.5 μg/g) and gallic acid (41.4 μg/g), were found in lower concentrations. The findings of this study suggest that purification of polyphenolic compounds from distiller’s grain by macroporous resins is feasible, providing a new and effective method for the secondary use of distiller’s grain resources.

This study investigates the mechanism of phosphorylation in the regulation of apoptosis-mediated meat tenderization during postmortem aging. The results found that the pork muscle exhibited apoptotic potential at early postmortem (48 h) and showed more tenderness at late postmortem, as evidenced by the increase in mitochondrial membrane permeability (MMP), Ca²⁺ level, reactive oxygen species (ROS) content, and caspases activity at 0 h to 48 h, and decreases in ATP level at 0 h to 24 h and shear force at 12 h to 120 h (p < 0.05). Phosphoproteomic analysis revealed that phosphorylation regulated apoptosis by modulating ATP and calcium bindings as well as apoptotic signaling, which occurred within early 12 h and mainly occurred at 12 h to 48 h postmortem. Moreover, differential expression of phosphoproteins demonstrated that phosphorylation regulated oxidative stress-induced apoptosis and rigor mortis, thereby promoting the development of meat tenderness. Our results provide insights into the roles of phosphorylation in various physiological processes that affect meat tenderness.

The effect of Astragalus polysaccharide (APS) on the formation and physicochemical properties of whey protein isolate (WPI) gel was systematically evaluated. It was found that visual appearance, gel strength, water-holding capacity, and swelling ratio of the APS-WPI gels were enhanced with increasing APS concentration. APS addition also notably promoted the enhancement in the absolute value of zeta potential with a simultaneous increase in size. Rheological results exhibited that APS-WPI gels had higher apparent viscosities, loss modulus, and storage modulus than native WPI. Scanning electron microscopy demonstrated that the water cavity structure of the gel network was denser when 1.2 g/100 mL APS was used. Additionally, disulfide bonds and hydrogen-bonding interactions between WPI and APS were considered the major contributing forces affecting the formation of APS-WPI gels, as confirmed by Fourier transform infrared spectroscopy and molecular forces. These results indicated that APS is effective in improving the gelling properties of WPI, which provides a reference for the potential application of a gelling agent in functional foods.