title: Impact of extraneous proteins on the gastrointestinal fate of sunflower seed (Helianthus annuus) oil bodies: a simulated gastrointestinal tract study.
abstract: In this study, we examined the physicochemical nature of sunflower seed oil bodies (in the absence and presence of added protein) exposed to gastrointestinal conditions in vitro: crude oil bodies (COB); washed oil bodies (WOB); whey protein isolate-enriched oil bodies (WOB-WPI); and, sodium caseinate enriched-oil bodies (WOB-SC). All oil body emulsions were passed through an in vitro digestion model that mimicked the stomach and duodenal environments, and their physicochemical properties were measured before, during, and after digestion. Oil bodies had a positive charge under gastric conditions because the pH was below the isoelectric point of the adsorbed protein layer, but they had a negative charge under duodenal conditions which was attributed to changes in interfacial composition resulting from adsorption of bile salts. Oil bodies were highly susceptible to flocculation and coalescence in both gastric and duodenal conditions. SDS-PAGE analysis indicated degradation of oleosin proteins (ca. 18-21 kDa) to a greater or lesser extent (dependent on the emulsion) during the gastric phase in all emulsions tested; there is evidence that some oleosin remained intact in the crude oil body preparation during this phase of the digestion process. Measurements of protein displacement from the surface of COBs during direct exposure to bile salts, without inclusion of a gastric phase, indicated the removal of intact oleosin from native oil bodies.
authors.affiliation: University of Phayao, Division of Food Science and Technology, School of Agriculture and Natural Resources, Muang, Phayao, 56000 Thailand.
authors.forename: Sakunkhun
authors.initials: S
authors.lastname: Makkhun
authors.forename: Amit
authors.initials: A
authors.lastname: Khosla
authors.forename: Tim
authors.initials: T
authors.lastname: Foster
authors.forename: David Julian
authors.initials: DJ
authors.lastname: McClements
authors.forename: Myriam M L
authors.initials: MM
authors.lastname: Grundy
authors.forename: David A
authors.initials: DA
authors.lastname: Gray
mesh_terms: D000327:Adsorption; D000818:Animals; D001647:Bile Acids and Salts / Q000737:chemistry; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D055598:Chemical Phenomena; D004063:Digestion; D004386:Duodenum / Q000378:metabolism*; D004655:Emulsions; D005750:Gastric Juice / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D006368:Helianthus / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007419:Intestinal Secretions / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D007526:Isoelectric Point; D008894:Milk Proteins / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D010938:Plant Oils / Q000737:chemistry / Q000378:metabolism*; D012639:Seeds / Q000737:chemistry; D000074242:Sunflower Oil; D013499:Surface Properties; D000067816:Whey Proteins
chemical_list: D001647:Bile Acids and Salts; D002364:Caseins; D004655:Emulsions; D008894:Milk Proteins; D010938:Plant Oils; D000074242:Sunflower Oil; D000067816:Whey Proteins