Effect of different iron ratios on interaction and thermodynamic stability of bound whey protein isolate.

Whey protein isolates (WPI) are known to have mineral-binding capacity to promote iron absorption. The aim of this study was to investigate the effect of iron ratio on the conformational structure of iron-bound whey protein isolate (WPI-Fe) and its thermodynamic stability. It was shown that the iron to protein ratio affects both the iron binding capacity of WPI and the iron valence state on the surface of WPI-Fe complexes. As the iron content increases, aggregation between protein molecules occurs. In addition, WPI-Fe nanoparticles have thermodynamic stability and Fe2+ has a high affinity with WPI for spontaneous exothermic reactions. This study demonstrates that WPI-Fe complexes can be used to efficiently deliver high-quality iron source (Fe2+) for future iron supplements.

Characterization of coacervation behavior between whey protein isolate and propylene glycol alginate: A morphology, spectroscopy, and thermodynamics study.

The interactions between whey protein isolate (WPI) and propylene glycol alginate (PGA) were investigated as a function of pH and the mass ratio. The results showed that WPI and PGA formed a soluble and uniform complex at a mass ratio of 2:1 and pH 4.0 through forces such as electrostatic attraction and hydrogen bonding. Isothermal titration calorimetry confirmed that the contribution of positive enthalpy (ΔH) and entropy (ΔS) were the beneficial indicator in the process of combining WPI and PGA under the same mass ratio but different pH. Fourier transform infrared spectroscopy, fluorescence spectroscopy and circular dichroism confirmed that hydrogen bonding was also one of the interaction forces in addition to electrostatic interactions between WPI-PGA complex. The freeze-dried WPI-PGA complex showed the same amorphous structure as WPI. These formed WPI-PGA complexes provided insights for interaction mechanism of proteins and polysaccharides as well as a theoretical basis for the food industry.

Salidroside alleviates liver inflammation in furan-induced mice by regulating oxidative stress and endoplasmic reticulum stress.

Furan is a genotoxic and carcinogenic toxicant formed during the food thermal processing. Our previous studies confirmed that salidroside (SAL) displayed excellent protective effects against furan-induced hepatotoxicity and inflammation, whereas the underlying mechanism was still unclear. In the current study, Balb/c mice were divided to the control group (CON), the furan model group (FUR8, 8 mg/kg BW furan for 30 days) and SAL intervention groups (SAL10/20/40, 8 mg/kg BW furan for 30 days + 10/20/40 mg/kg BW SAL from day 16 to day 30). The alleviative effects and the mechanisms of SAL against furan-induced liver inflammation in mice were investigated through oxidative stress (OS) and endoplasmic reticulum stress (ERS). Liver metabonomics data, molecular docking and Western-blotting results implied that SAL suppressed the activity and the high expression of hepatic CYP2E1, and alleviated liver OS induced by furan. Levels of key markers (GRP78, CHOP and Caspase-12) of ERS and proteins in IRE1α pathway of the UPR branch increased by furan were prominently reduced after SAL treatment. Levels of phosphorylated proteins JNK, ERK, p38, IKKα/ß, IκB and p65 in MAPK and NF-κB pathways were also suppressed by SAL. We further confirmed that SAL inhibited furan-induced inflammation by reducing the levels of NLRP3, ASC, Cleaved Caspase-1 and IL-1ß and decreasing the production of pro-inflammatory cytokines. Our results shed light into the alleviating mechanisms behind furan-induced liver inflammation, and suggested that SAL inhibited OS, ERS and related MAPK and NF-κB pathways and therefore inhibited the NLRP3 inflammasome activation, which may be its potential mechanism of alleviating liver inflammation.

Lactoferrin-ginsenoside Rg3 complex ingredients: Study of interaction mechanism and preparation of oil-in-water emulsion.

Revealing the interaction mechanism between bovine lactoferrin (LF) and 20(S)-ginsenoside Rg3 (Rg3), thereby introducing Rg3 to LF and even into stable emulsions will contribute significantly to food valorization and food industry. Adding Rg3 to LF caused slight absorbance increment and static fluorescence quench of LF, implying the successful combination. Synchronous fluorescence, three-dimensional fluorescence and circular dichroism spectroscopy indicated the conformation changing of LF after binding with Rg3. Thermodynamic analysis showed that the binding happened spontaneously to form a LF-Rg3 complex with a molar ratio of 1:1, which was mainly driven by hydrogen bonding and van der Waals force. Molecular docking simulation provided extensive information about the optimized binding sites and the involved interactions. Finally, we prepared stable LF-Rg3 oil-in-water emulsion, showing great potential in foods and beverages. This work prepares all-natural functional ingredients, and also diversifies the effective food molecule-based delivery systems for LF and Rg3.

Effect of reaction temperature on the protein structure and the ability to encapsulate ß-carotene of WPI-dextran conjugates.

In this paper, we studied the effect of glycosylation reaction on the molecular structure and functional properties of whey protein isolate (WPI), and studied the effect of reaction temperature (50 to 90 °C) on the molecular structure and functional properties of WPI-dextran conjugates (WPI-D). The results of the extent of glycation (EG) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirmed the formation of WPI-D. Circular dichroism (CD), Fourier transform infrared spectrum, and fluorescence spectroscopy indicated that the molecular structure of WPI was changed after glycosylation-the ß-sheet content was decreased and the tryptophan content was increased. The emulsifying properties and the ability to encapsulate ß-carotene of WPI-D were improved compared with WPI (P < 0.05). When the reaction temperature was 70 and 80 °C, the EG and the ability to encapsulate ß-carotene of WPI-D were better (P < 0.05), which was related to protein unfolding. However, due to the polymerization between the WPI molecules, the emulsion activity index of WPI-D and the ability to encapsulate ß-carotene were lowered at 90 °C (P < 0.05). Therefore, the glycosylation reaction can change the molecular structure and functional properties of WPI; the emulsifying properties and the ability to encapsulate ß-carotene of WPI-D can be changed by controlling the reaction temperature of glycosylation. PRACTICAL APPLICATION: The glycosylation reaction can change the molecular structure and functional properties of Whey protein isolate; the emulsifying properties and the ability to encapsulate ß-carotene of WPI-dextran conjugates can be changed by controlling the reaction temperature of glycosylation.

Hypolipidemic activity of low-cholesterol ovum oil of Rana chensinensis and phytosterol (stigmasterol) in rats.

The ovum oil of forest frog has various health beneficial functions. In the current research, we evaluated the hypolipidemic effects of the low-cholesterol ovum oil from the forest frog and its combination with stigmasterol in rats.

Polyethylene glycol-stabilized platinum nanoparticles: the efficient and recyclable catalysts for selective hydrogenation of o-chloronitrobenzene to o-chloroaniline.

In the present work, platinum nanoparticles were prepared by in situ reduction with polyethylene glycols (PEGs). The catalytic performance of Pt nanoparticles immobilized in PEGs (Pt-PEGs) is discussed for the hydrogenation of o-chloronitrobenzene (o-CNB). A high selectivity to o-chloroaniline (o-CAN) of about 99.7% was obtained with the Pt-PEGs catalysts at the complete conversion of o-CNB, which is much higher than that (83.4%) obtained over the conventional catalyst of Pt/C. The Pt nanoparticles could be immobilized in PEGs stably and recycled for four times with the same activity and selectivity. It presents a promising performance in the hydrogenation and its wide application in catalytic reactions is expected.