Process optimization,texture and microstructure of novel kelp tofu

Laminaria japonica Aresch as an edible and medicine dual-purpose marine algae,has been gradually accepted by people.Tofu was Chinese traditional food,combining kelp function ingredients with tofu has practical value.The extraction-optimization methodology and the sequences of kelp antihypertensive peptide(KAP)were investigated.The sensory,whiteness,water retention ability(WRA)and microstructure of KAP tofu were evaluated.The scanning electron microscope(SEM)results showed KAP addition(20%)significantly improved the tofu texture,with a denser network composed of relatively even pores.Compared with gypsum tofu and glucose-δ-interior fat(GDL)tofu,KAP tofu had significantly higher WRA(94.49±0.49)%and sensory evaluation score value(92.54±0.52),and a significantly lower IC_(50) value at(2.06±0.04)mg/mL(P<0.05).The maximum IC_(50) value(4.14 mg/mL)of kelp enzymatic hydrolysate was observed at enzyme(at an alkaline protease:trypsin ratio of 2:1)concentration 1.5%,temperature 55℃ and time 2 h.The sequences of 8 identified peptides were Lys-Tyr,Phe-Tyr,Gly-Lys-Tyr,Ala-Lys-Tyr,Ser-Lys-Thr-Tyr,Lys-Lys-Phe-Tyr,Lys-Phe-Lys-Tyr and Ala-Lys-Tyr-Ser-Tyr with IC_(50) values of 5.24,4.83,7.94,7.52,20.63,15.33,10.73 and 2.42μmol/L,respectively.These results indicated the potential use of KAP tofu as a valuable resource for development of functional foods.

Core-shell lipid-polymeric nanoparticles for enhanced oral bioavailability and antihypertensive efficacy of KY5 peptide

Hypertension is the leading risk factor for death and disability, and hypertensive patients always need long-term oral antihypertensive drugs. Some bioactive peptides that extracted from animals or plants have shown excellent advantages on antihypertension. However, the oral delivery of these peptides is always failure on account of instability and poor absorption in the gastrointestinal tract. Herein, we developed a core-shell lipid-polymeric nanoparticle for oral delivery of a highly efficient antihypertensive peptide KY5(KY5-CSs). KY5-CSs had a particle size of 216.7 ± 2.5 nm, with a narrow PDI of 0.07 ± 0.01.The zeta potential was-4.1 ± 0.1 m V. It exhibited good stability in 4 ℃ and possessed a controlled release behavior in gastrointestinal tract. The cellular uptake study proved that the lipid shell imparted unique capability of permeation across the mucus layer and internalization by Caco-2/HT-29 cells. In addition, KY5-CSs enhanced in situ intestinal absorption in SD rats. The pharmacokinetic studies and antihypertensive efficacy showed a superior oral absorption and antihypertensive effect of KY5-CSs than KY5-NPs. In conclusion, the core-shell lipid-polymeric nanoparticles will provide attractive potential for oral delivery of antihypertensive peptides.

Semi-elastic core-shell nanoparticles enhanced the oral bioavailability of peptide drugs

The rigidity of nanoparticles was newly reported to influence their oral delivery.Semi-elastic nanoparticles can enhance the penetration in mucus and uptake by epithelial cells.However,it is still challenging and unclear that the semi-elastic core-shell nanoparticles can enhance the oral bioavailability of peptide drugs.This study was for the first time to validate the semi-elastic coreshell poly(lactic-co-glycolic acid)(PLGA)-lipid nanoparticles(LNPs)as the carrier of the oral peptide drug.The antihypertensive peptide Val-Leu-Pro-Val-Pro(VP5)loaded LNPs(VP5-LNPs)were prepared by a modified thin-film ultrasonic dispersion method.Uptake experiment was performed in Caco-2 and HT-29 cells and monito red by high content screening(HCS)and flow cyto metric(FCM).Pharmacokinetics of VP5-LNPs was carried out in Sprague-Dawley(SD)rats and analyzed by DAS 2.0.The optimal VP5-LNPs had an average particle size of 247.3±3.8 nm,zeta potential of-6.57±0.45 mV and excellent entrapment efficiency(EE)of 89.88%±1.23%.Transmission electron microscope(TEM)and Differential scanning calorimeter(DSC)further confirmed the core-shell structure.VP5-LNPs could increase the cellular uptake in vitro and have a 2.55-fold increase in AUC0-72 h,indicating a great promotion of the o ral bioavailability.The semi-elastic LNPs remarkably improved the oral availability of peptide and could be a promising oral peptide delivery system for peptide drugs in the future.