Fabrication And Functional Evaluation Of Bovine Serum Albumin/Carboxymethyl Inulin Complex-stabilized Pickering Emulsion

Increasing attentions among humans regarding the healthy lifestyle stimulate the research interests on novel functional food delivery systems.Pickering emulsion,which consists of food-grade biomacromolecules(lipids,polysaccharid and protein)has potential application value in food area as a delivery vehicle for nature nutrients or bacteriostatic components.As a functional polysaccharide,inulin was carboxymethylated and formed complexes with bovine serumalbumin(BSA).The success of obtaining carboxymethyl inulin(CMI)was confirmed by a combination of Fourier transform Infrared(FT-IR),Raman spectroscopy,gel permeation chromatography(GPC),and titration.The effects of pH and ionic strength on the formation of BSA/CMI complexes were investigated.Our results showed that the formation of complex coacervate(pH?1)and dissolution of BSA/CMI insoluble complexes(PH?2)appeared in pH near 4.85 and 2.00 respectively.The sodium chloride suppression effect on BSA/CMI complexes was confirmed by the decrease of incipient pH for soluble complex formation(or pHc)and pH?1 under different sodium chloride concentrations BSA/CMI complexes formed at pH 4.00 were further analysis.FT-IR and Raman data confirmed the existence of electrostatic interaction and hydrogen bonding between CMI and BSA at pH 4.00.The isothermal titration calorimetry(ITC)results suggested that the process of complex formation was spontaneous and exothermic at pH 4.00.The complexation was dominated by enthalpy changes(?H<0,?S<0).Laser scanning confocal microscope(CLSM)suggested that irregularly shaped complexes were observed in CMI/BSA complexes at pH 4.00.The rheometer analysis indicated that BSA/CMI complexes formed a compact structure at the ratio of 5:1 and pH 4 00A novel delivery vehicle oil in water BSA/CMI complexes-stabilized Pickering emulsion(BSA/CMI-PE)was designed.Microscope images and rheological measurement suggested that the emulsion's oil droplets size was dependence on particles concentration.The oil droplets size decreased,homogeneity in size distribution increased,and the impact structure strengthened with the increase of BSA concentration from 0.2%to 0.4%.Furthermore,rheological measurement suggested that a gel-like structures and shear thinning were observed in different ratio of particles concentration to oil content.The same trend existed in distrinct NaCl concentration.Accordingly,optimum BSA/CMI-PE was formed at ratio,BSA concentration,pH,oil content,NaCl concentration of 5:1,0.4%,4.0,60%and 0 mM respectively.And its droplets size was around 33 ?mIn vitro lipolysis digestion model and in vivo animal model were used to mechanistically evaluate the effect of oral bioavailability of nobiletin encapsulated in BSA/CMI-PE.In vitro lipolysis digestion experiment revealed that emulsified nobiletin was digested and became bioaccessible much faster than unprocessed tangeretin oil suspension.In vivo pharmacokinetics analysis on rat again confirmed that the oral bioavailability of nobiletin increased 1.9 fold when incorporated in BSA/CMI-PE than unformulated oil suspension.By using the combination of in vitro and in vivo models,the mechanism that underlied the effect of BSA/CMI-PE on the oral bioavailability of nobiletin was well-elucidatedMeanwhile,antibacterial camosic acid(CA)loaded in BSA/CMI-PE coating was developed.It is assessed for inhibition of Escherichia coli,Staphylococcus aureus,and Bacillus subtilis.inhibition zone diameters of CA BSA/CMI-PE were around 1 mm larger than that of CA MCT suspension in the same condition.Minimum inhibitory concentration(MIC)of CA BSA/CMI-PE was significant lower than that of CA MCT suspension in the same condition.CA BSA/CMI-PE was used for the preservation experiment of chilled pigeon leat.Compared with CA MCT suspension,chilled pigeon meat coated with CA BSA/CMI-PE exhibited the slower change in the total number of colonies,TVB-N and pH value,and water retention rate within 8 days shelflife.A significant concentration dependence of the effect was observed.Therefore,edible CA BSA/CMI-PE improved the storage and preservation of chilled pigeon meat.