No abstract

Whey protein isolate (WPI) has a variety of nutritional benefits. The stability of WPI beverages has attracted a large amount of attention. In this study, Flammulina velutipes polysaccharides (FVPs) interacted with WPI to improve the stability via noncovalent interactions. Multiple light scattering studies showed that FVPs can improve the stability of WPI solutions, with results of radical scavenging activity assays demonstrating that the solutions of the complex had antioxidant activity. The addition of FVPs significantly altered the secondary structures of WPI, including its α-helix and random coil. The results of bio-layer interferometry (BLI) analysis indicated that FVPs interacted with the WPI, and the equilibrium dissociation constant (KD) was calculated as 1.736 × 10−4 M in this study. The in vitro digestibility studies showed that the FVPs protected WPI from pepsin digestion, increasing the satiety. Therefore, FVPs effectively interact with WPI through noncovalent interactions and improve the stability of WPI, with this method expected to be used in protein-enriched and functional beverages.

Here, we characterize the activities of two depeptidyl peptidase-IV (DPP-IV) inhibitory peptides, VLATSGPG and LDKVFER, using the Caco-2 monolayer model for the intestine. VLATSGPG and LDKVFR inhibited the DPP-IV in the cells via a mixed-type inhibition mode, with in situ IC50 values of 207.3 and 148.5 μM, respectively. Furthermore, VLATSGPG and LDKVFR were transported intact across the cells, with P app values of 2.41 ± 0.16 and 4.23 ± 0.29 × 10–7 cm/s, respectively. Fragmented peptides were identified in the basolateral side of the membrane. Two of these, GPG and VLA, exhibited high inhibitory activities of 83.6 ± 3.3 and 58.5 ± 2.5%, respectively, at 100 μM concentration. Although 3 mM VLATSGPG and LDKVFR were transported across the epithelium in a concentration-dependent manner, their transport did not damage the tight junction proteins, ZO-1 and occludin. This study demonstrates that the two peptides potentially regulate DPP-IV activity in the intestine.

Summary In order to improve the utilisation of the common carp (Cyprinus carpio), the effects of deodorising agents [NaCl, β‐CD, malic acid (MA) and hawthorn extract (HE)] on the volatile compounds of common carp mince and its surimi gel properties were investigated. In total, thirty‐two volatile compounds were identified, seven of which were considered the main compounds of off‐odour, using HS‐SPME‐GC‐MS and OVA analyses. HS‐SPME‐GC‐MS analysis showed that MA and HE removed 84.51% and 77.18% off‐odour compounds, respectively. Three relaxation components (T21, T22, T23) were found in surimi, and their amounts were not affected by deodorising; however, the relaxation time of major component T22 was significantly increased. Surimi deodorised by HE had the highest gel strength because of its increased breaking displacement; however, a slight decrease in whiteness was observed. Thus, appropriate levels of HE could improve the palatability of surimi.

Whey protein isolate (WPI) is unstable near isoelectric point with simultaneous precipitation or phase separation, which negatively affects its application. In the current study, four kinds of edible fungal polysaccharides were selected to improve the WPI stability through non-covalent interaction. The addition of edible fungal polysaccharides significantly improved the WPI stability. Zeta potential analysis showed that edible fungal polysaccharides reduced the zeta potential of WPI. The analysis of rheological properties showed that complex solutions exhibited higher viscosity and behaved as pseudoplastic fluids. Bio-layer interferometry demonstrated the interactions between edible fungal polysaccharides and WPI, and the K D between Tremella fuciformis (TFP) and WPI was the lowest. LC-MS/MS results indicated that the peptide fragments "VGINYWLAHK" and "TPEVDDEALEKFDK" in α-lactalbumin and β-lactoglobulin were probably binding regions interacted with the four kinds of edible fungal polysaccharides. Furthermore, molecular docking results inferred GLN43 and GLU127 were the major residues in the α-lactalbumin and β-lactoglobulin.

No abstract

The peptide VLATSGPG (VLA) is known to inhibit dipeptidyl peptidase IV (DPP-IV), although its mechanism in relieving endoplasmic reticulum (ER) stress is unclear. In this study, we found that treating...

Inhibition of dipeptidyl peptidase IV (DPP-IV) was considered to be a crucial target for type 2 diabetes, and food-derived peptides were superior source of DPP-IV inhibitory peptides. The purpose of this investigation was to identify inhibitory peptides from salmon skin collagen using simulated digestion combined with Caco-2 cell monolayer membrane model. The analysis in silico showed that TKLPAVF and YLNF were potential inhibitory peptides. Determination of the inhibition activity showed that the IC 50 values of TKLPVAF and YLNF were 242.10 AE 3.40 and 146.90 AE 4.40 µM, respectively. Molecular docking results showed that seven hydrogen bonds were formed between YLNF and key residues of DPP-IV. YLNF may be considered a novel DPP-IV inhibitory peptide. In addition, YLNF could be transported by Caco-2 cell monolayer membrane in intact, and the apparent permeability coefficient value was (3.54 AE 0.34) × 10 -6 cm s −1 at 5 mM.