Physical and oxidative stability of high fat omega-3 PUFA delivery oil-in-water emulsions - PowerPoint Presentation

1. Physical and oxidative stability of high fat omega-3 PUFA delivery oil-in-water emulsions stabilized with modified phosphatidylcholine and oil-water interface characteristics of a model emulsion system using small angle scattering techniques. Betül YesiltasResearcher, betye@food.dtu.dkNational Food Institute, Technical University of DenmarkCo-authors: Ann-Dorit M. Sørensen, Pedro J. García-Moreno, Mika Torkkeli, László Almásy, Zoltán Dudás, András Ferenc Wacha, Robert Dalgliesh, Sampson Anankanbil, Zheng Guo, Matti Knaapila, and Charlotte Jacobsen Technician: Lis BernerJune 2020, AOCS

2. 2Study AStudy BJune 2020, AOCS

3. LC omega-3 PUFAs and their health benefits3Health benefits reduce the risk of CVDimprove mental healthdecrease inflammation and blood triglyceridesLow consumption of omega-3 rich foods; fish, seeds, etc.~40 mg/ day in children & teens; ~90 mg/day in adults Necessity for increasing the intake of omega-3 PUFAs to meet RDI RDI: 250 mg /dayLC omega-3 PUFAs: Long chain omega-3 polyunsaturated fatty acidsJune 2020, AOCS

4. LC omega-3 PUFAs enrichment4Food enrichment strategiesadding neat fish oilomega-3 delivery systemsoil-in-water emulsionsLC omega-3 PUFAs are prone to oxidationloss of nutritional valueformation of undesired off-flavoursrancid or fishy tasteLC omega-3 PUFAs: Long chain omega-3 polyunsaturated fatty acidsJune 2020, AOCS

5. High fat oil-in-water emulsions as omega-3 delivery systemsDelivery systems opportunity to prevent physical instability and lipid oxidationAdvantages of high fat emulsionseasiness in the enrichment of highly viscous food systems similar textural propertieslower amount of delivery system needed for enrichment5high fat oil-in-water emulsionwateroilJune 2020, AOCS

6. Emulsifiers, their distribution and interfacial structureChallenges in obtaining oxidative stability in high fat emulsionsSeveral factors affecting lipid oxidationingredients (e.g., emulsifiers, oil type and quality)compositionhomogenizer typephysical characteristics (e.g., droplet size, viscosity) …Importance of oil-water interface; contact area between prooxidants and lipidsPhysical stability  uniform layer or heterogeneous lateral domainsThickness & permeability  physical barrier for the diffusion of prooxidantsSmall angle X-ray and neutron scattering techniques can be used 6LC omega-3 PUFAsprooxidantsAffects oil-water interface characteristicsJune 2020, AOCS

7. Emulsifiers; amphiphilic molecules, adsorb at the oil-water interfaceProtein; Sodium caseinate, CASSurfactants; phosphatidylcholine (PC) and mod.PCCombined use of emulsifiers…Advantages: decreasing interfacial tension compared to single emulsifier use, interaction between emulsifiers leading to thicker interface, etc.Emulsifiers, their distribution and interfacial structure7Phosphatidylcholine, PCModified phosphatidylcholine, mod. PCJune 2020, AOCS

8. Aim of the study AInvestigating the impact of modified PC in combination with CAS and PCon emulsifier distribution and oil-water interfacial structure on physical and oxidative stability of high-fat fish oil-in-water emulsionsto develop stable high-fat omega-3 delivery emulsions 8June 2020, AOCS

9. Experimental setup9Modified PC with caffeic acid and various lipophilicities (C14 and C16)Dose-response effect of modified PC in 70% fish o/w emulsionsStored at RT, in darkness for 12 daysCAS+PC+Caffeic acid(CA)CAS+PC+PC C14CAS+PC+PC C16CAS+PC-Low CA-High CA-Low CA-Medium CA-High CA-Low CA-Medium CA-High CACASwateroil12345678910caffeic acid (antioxidant group)June 2020, AOCS

10. Methods – Physical parametersViscosity: Stress-controlled rheometer equipped with a standard bob (CC25) cup system Droplet size: Laser diffraction technique: D[4,3]=Ʃnidi4/Ʃnidi3Zeta potential: Surface charge of the emulsion droplets was determined using Zetasizer Nano 2SCreaming: Creaming index (%) = b/a*100Protein content in the water phase: Centrifugation  ultracentrifugation  DUMAS method was used for quantification of Nitrogen. Crude protein was estimated using 6.25 conversion factor.ab10June 2020, AOCS

11. Primary Oxidation Products - Peroxide ValueIDF Fe2+ oxidation based spectrophotometric methodTocopherol Contenta-tocopherol content was determined by HPLC (AOCS method ’98) Secondary Oxidation products - Volatile compoundsCollected using dynamic headspace followed by GC-MSWaterbath T=60˚C SampleN2N2150 ml/min for 30 min Methods – Oxidative parameters11June 2020, AOCS

12. Physical stability – Creaming and viscosity12<6% creaming instability, lower viscosity compared to only CAS emulsion20µmJune 2020, AOCS

13. Physical stability – Droplet size13PC C14, 360PC C16, 360PC C14, 1080PC C16, 1080PC C14, 2160PC C16, 216020µmJune 2020, AOCS

14. Physical stability – non-adsorbed protein1420µmmod PCs decreased the interfacial tension; PC C16 > PC C14PC C16 had less non-adsorbed CAS, but higher protein surface load than PC C14PC C16 had thicker interface than PC C14 – protein surface loadJune 2020, AOCS

15. Oxidative stability15Increasing caffeic acid concentration increased the oxidative stability for PC C14 June 2020June 2020, AOCS

16. Oxidative stability16Increasing caffeic acid concentration increased the oxidative stability for PC C16 June 2020June 2020, AOCS

17. Oxidative stability17Increasing caffeic acid concentration increased the oxidative stability for PC + CA June 2020June 2020, AOCS

18. Oxidative stability18No advantage of having mod PC on lowering the formation of peroxides compared to PC + CAProoxidant effect of mod PCsJune 2020June 2020, AOCS

19. Oxidative stability19At low caffeic acid concentration; mod. PCs compared to PC+ CA prooxidant effect for the formation volatilesNo advantage of covalently attached caffeic acid to PC compared to PC + caffeic acidJune 2020June 2020, AOCS

20. Oxidative stability20At high caffeic acid concentration; mod. PCs compared to PC + CA antioxidant effect on decreasing the formation of volatilesPC C16 > PC C14  effects of the thicker interface and antioxidant activity at the interfaceJune 2020June 2020, AOCS

21. Conclusions of the Study AViscosity of the emulsions were decreased with the addition of PCsDroplet size was decreased with the addition of mod. PCs Physical stability was decreased with the use of PC in combination with CAS addition of mod. PCs improved physical stability Alkyl chain length had an influence on the distribution of modified emulsifiersPC C16 provided a thicker interfacial layer and better oxidative stability compared to PC C14 High concentration of PC C16 improved oxidative stability compared to PC + CA in high fat emulsions21June 2020June 2020, AOCS

22. Aim of the study BInvestigating the structural characteristics of a model high-fat omega-3 delivery emulsions stabilized with CAS and PC using small angle scattering techniques,emulsifier self-assemblies in bulk phasesoil-water interfacial structure22June 2020, AOCS

23. Methods – Small Angle X-ray/neutron scattering (SAXS/SANS)23SAXS CREDO apparatus of the Research Centre for Natural Sciences, Hungarian Academy of Sciences. SANS  Yellow Submarine instrument at the BNC in Budapest, Hungary and ISIS Larmor instrument in Chilton, England.Scattering length densities across the interfaceNeutronX-raydeuteratednon-deuteratedX-rays hit the electrons and neutrons hit the nuclei of the moleculesBéchade et al., 2015, DOI: 10.1051/epjconf/201510401008June 2020, AOCS

24. CAS structure in D2O or H2O24Intensity and q2 scaled intensity curves for SAXS (solid lines) and SANS (circles) of employed CAS in D2O/H2O for various concentrations. Dashed vertical lines mark positions of 1st and 2nd order maxima for periodicity D = 20.4 nm.20µmJune 2020, AOCS

25. PC multilayers in D2O or H2O25SAXS (solid lines) and SANS (circles) patterns of employed PC in D2O/H2O for various concentrations Each SAXS intensity normalized to agree with respective SANS curve. Intensity is divided by PC concentration.6.32 nm bilayer thickness100 nm multilayer structure~15 bilayers20µmJune 2020, AOCS

26. SAXS pattern of 70% oil-in-water emulsions26PC peak shifted significantly to the higher q values with the increasing concentration of CAS (0 to 1.05%) indicating the interaction between CAS and PCWhen concentration of CAS is stable, we don’t observe any change in the peak location of PC crystals. 20µmJune 2020, AOCS

27. SANS pattern of 70% oil-in-water emulsions27CAS featurePC peaks, 1st and 2nd orderIn d-/n-hex-in-D2O emulsion, we see a -2 slope, which indicates a thin monolayer of PC at the interface. However, we do not see a clear -2 slope for emulsions with fish oil-4 slope in fish oil emulsions indicated a tail contribution of globular structures 20µmThe black dashed curve – contribution of CAS aggregates (40%) alone. The blue dashed line gives the contribution of a single monolayer film in the contrast matched oil and water phases.June 2020, AOCSCASPC

28. CAS contribution in 70% oil-in-water emulsions28CAS in D2O/H2O location shown with dashed vertical lineCAS/PC 1.05/1.75 gives significantly different peak position for CAS in deuterated oil/water emulsion(d) than the same emulsion with fishoil/H2O(h)CAS are more closely packed in CAS/PC 1.05/1.75 compared to CAS/PC 1.05/0.3520µmSAXS (solid line) PC 1.75% emulsion subtracted from CAS/PC 1.05/1.75, SANS (circles) subtracted contribution from the PC monolayer as a power law background, and SANS (symbols) CAS 4%. June 2020, AOCS

29. Model of the interface in 70 % oil emulsions with CAS and PC29laterally heterogeneous oil-water interfacelateral domains may imply fragmentation of emulsifier film at the interface and uncovered surfaces  physical instability potential in thicker interface and interaction between molecules  oxidative stability20µmJune 2020, AOCS

30. Conclusions of the Study BSize and CMC of the CAS aggregates were investigated, PC peaks were obtained and bilayer thickness was calculated. Multilayer structure sizes were also obtained. There was an indication of a PC monolayer at the interface in hexadecane emulsions. Periodic repeat distance of the PC bilayers decreased with increased CAS concentration.CAS aggregates were more closely packed when there was more PC involved in the emulsion.As perspectives: Use SANS and SAXS on food emulsions to study: How different concentrations and combinations of emulsifiers affect interfacial structure and colloidal structures in the aqueous phase, interactions between antioxidants and emulsifiers, changes in structure over time or even effects of various conditions on emulsion formation during homogenization30June 2020, AOCS

31. Acknowledgements32Please don’t hesitate to ask your questions via email.betye@food.dtu.dkJune 2020, AOCS