Delivery emulsions for omega-3 oils: Can they be used as a means to reduce lipid oxidation in foods?

Transcription

1 Delivery emulsions for omega-3 oils: Can they be used as a means to reduce lipid oxidation in foods? Charlotte Jacobsen Research group for Bioactives analysis and application Division of Food Technology chja@food.dtu.dk

2 Outline Introduction Increasing number of omega-3 PUFA enriched foods Factors affecting oxidation in emulsions introduction Why delivery emulsions? Choice of emulsifier Homogenization equipment Homogenization conditions Effect of delivery systems in different foods Conclusions: Yes, delivery emulsions can reduce oxidation But delivery emulsion must be designed for each food system Acknowledgements 2 DTU Food, Technical University of Denmark

3 3 DTU Food, Technical University of Denmark

4 Lipid oxidation Unpleasant flavors, Nutrient loss, Texture, Color, Functionality Food emulsions: Mayonnaise, salads & dressing, yoghurt, milk Bulk oil Fish Lipid oxidation is one of the most important chemical degradation processes Oxidized lipids Rancidity 4 DTU Food, Technical University of Denmark

5 Why delivery emulsions? May be designed to have better oxidative stability than bulk oil increased shelf-life before use May be designed to provide better oxidative stability of omega-3 fatty acids in the food system than addition of neat oil May be easier to handle and mix into food products How to design a good delivery emulsion? 5 DTU Food, Technical University of Denmark

6 Lipid oxidation O 2 1. Initiation 2. Propagation I X XH LH 3. Termination LH L LOO LOOH Me n+ 6 DTU Food, Technical University of Denmark Secondary oxidation products and off flavors

7 Lipid oxidation O 2 Methods for evaluating lipid oxidation I X XH LH LH L LOO Free radicals: ESR LOOH PV, Conjugated dienes Sensory evaluation 7 DTU Food, Technical University of Denmark Me n+ Secondary oxidation products and off flavours TBARS, AV, DHS/SPME GC-MS

8 Factors That Can Affect Lipid Oxidation in emulsions 1. Ingredients (Amount, type and quality) 3. The surface charge Water Oil 4. Viscosity Emulsifier at the interface (Structure/thickness) Emulsifier in the aqueous phase (Antioxidative properties) Fe 2+ Fe ph 5. Oil droplet size / surface area 8 DTU Food, Technical University of Denmark 6. Processing conditions

9 Choosing the right emulsifier 9 DTU Food, Technical University of Denmark

10 70 % fish oil-in-water emulsions Ingredients: 70% fish oil, 1.4 or 2.8% emulsifier & 28.6 or 27.2% 10mM sodium acetate imidazole buffer ph 4.5 ph % CAS 1.4% CAS 2.8% CAS 2.8% WPI 2.8% WPI 2.8% MPL20 2.8% MPL20 Emulsification on a Stephan mixer under cooling and reduced pressure Storage With iron 0 (1) Without iron 0 (1) Days 10 DTU Food, Technical University of Denmark

11 PV [meq peroxides/kg oil] PV [meq peroxides/kg oil] 70% oil-in-water emulsions: Effect of type of Emulsifier (2.8%) at ph 7 20,0 Without iron 2,5 With iron 15,0 2,0 1,5 10,0 1,0 5,0 0,5 0, Days of storage 0, Days of storage Volatiles Neat oil vs data emulsion: supported PV. - Iron: Interfacial barrier protects against Without oxidation iron: CAS WPI Neat oil < MPL20. With + iron: iron: Neat Reactions oil < CAS between < WPI iron and MPL20. LOOH WPI vs. CAS: Antioxidative amino acid residues and their exposure MPL20: Combination of factors/antioxidative potential of pure proteins is higher 11 DTU Food, Technical University of Denmark Without iron Viscosi ty [cp] Zeta potenti al [mv] Droplet size, D2,3 [µm] CAS ~ 9 WPI ~ 21 MPL ~ 8

12 PV [meq peroxides/kg oil] 70% oil-in-water emulsions: Effect of changing ph from 7 to ,0 15,0 10,0 5,0 Without iron WPI_pH4.5 MPL20_pH7 CAS_pH4.5 MPL20_pH4.5 WPI_pH7 CAS_pH7 0, Days of storage At ph 4.5: MPL20, CAS < WPI At ph 7.0: WPI, CAS < MPL20 Maybe due to a preferential adsorption of less oxidatively stabilizing protein components at low ph for CAS and WPI For MPL20 a combination of droplet size, zetapotential and the influence of the phospholipids might be decisive for the results 12 DTU Food, Technical University of Denmark

13 Optimizing emulsification process to obtain optimal stability - Type of equipment - Temperature and pressure 13 DTU Food, Technical University of Denmark

14 Effect of emulsification equipments Microfluidizer vs. two-stage Valve Homogenizer Part 1 and 2 14 DTU Food, Technical University of Denmark

15 Volume (%) Volume (%) Effect of Emulsification Equipment Part 1 Fish oil-in-water emulsion Ingredients: 10% fish oil 1% emulsifier 89% buffer Type of emulsifier Oil droplet size Microfluidizer CAS_M 69 MPa, 3 passes WPI_M Fe 2+ Fe 3+ Transition metal ions Two-stage valve homogenizer CAS_H WPI_H 80 MPa 50 MPa 4 passes 3 passes Processing conditions Storage with iron for 14 days Particle Size Distribution CAS_M 6 5 CAS_H Particle Size (µm) Particle Size Distribution WPI_M WPI_H Particle Size (µm) 15 DTU Food, Technical University of Denmark

16 Scores PC#2 (12.715%) Loadings PC#2 (12.715%) Emulsification Equipment Part 1 Results: PCA Biplot PCA Scores [Model 1] PCA Loadings [Model 1] CAS_Ha CAS_Mb CAS_Hb CAS_Ma WPI_Mb WPI_Ma WPI_Hb WPI_Ha WPI_Ha PV PV_D4 PV_D0 PV_D7 PV_D10 PV_D14 Propanal_D7 1-penten-3-one_D0 t.c-2.4-heptadienal_d0 2-Butenal_D0 t.t-2.4-hexadienal_d0 t.t-2.4-heptadienal_d0 t.t-2.6-nonadienal_d0 4-Heptenal_D7 1-penten-3-one_D7 Hexanal_D0 Propanal_D0 4-Heptenal_D0 t.t-2.6-nonadienal_d14 Heptanal_D0 4-Heptenal_D14 2-Butenal_D7 Pentanal_D7 2-Hexenal_D0 t.t-2.6-nonadienal_d7 t.c-2.4-heptadienal_d7 t.t-2.4-hexadienal_d7 Pentanal_D0 Propanal_D4 2-Hexenal_D7 t.t-2.4-heptadienal_d7 4-Heptenal_D4 2-Butenal_D14 t.c-2.4-heptadienal_d14 Hexanal_D7 4-Heptenal_D10 2-Butenal_D4 Heptanal_D7 Hexanal_D4 1-penten-3-one_D4 2-Hexenal_D4 Heptanal_D14 1-penten-3-one_D10 t.t-2.6-nonadienal_d4 t.t-2.4-hexadienal_d4 t.t-2.4-heptadienal_d10 Pentanal_D4 2-Hexenal_D14 t.t-2.4-heptadienal_d14 t.t-2.4-heptadienal_d4 Hexanal_D14 1-penten-3-one_D14 2-Butenal_D10 t.c-2.4-heptadienal_d10 t.t-2.6-nonadienal_d10 t.c-2.4-heptadienal_d4 Heptanal_D4 t.t-2.4-hexadienal_d14 2-Hexenal_D10 Heptanal_D10 Pentanal_D10 t.t-2.4-hexadienal_d10 Hexanal_D10 Pentanal_D14 Propanal_D10 Propanal_D Scores PC#1 (58.670%) Loadings PC#1 (58.670%) CAS vs WPI: Higher PV in CAS but less increase in volatiles than Protein WPI in Metal chelation aqueous phase: WPI_M vs WPI_H: Protein at the interface WPI_M: 2.86 mg/ml Structure and thickness of interfacial layer WPI_H: 4.96 mg/ml Horn et al. (2012) Food Chemistry. 134, DTU Food, Technical University of Denmark

17 Effect of emulsification equipment part 2 Aims: To study the effect of different types of homogenization equipment on lipid oxidation in emulsions prepared with Tween 20 To study the effect of different emulsifier:lipid ratios on lipid oxidation when produced with different equipments Microfluidizer (Mic) vs Valve homogenizer (H) 17 DTU Food, Technical University of Denmark

18 Part 2: Design Code Equipment Fish oil conc. (%) Tween conc. (%) Droplet size (um) H5:1 H H5:2 H H10:4 H Mic5:1 Mic Mic5:2 Mic Mic10:4 Mic ph 7 Storage at room temperature in darkness PV (IDF method) Volatiles (Dynamic headspace GC-MS) 18 DTU Food, Technical University of Denmark

19 Meq/kg Peroxide values Part H5:1 H5: H10:4 Mic5:1 and 5:2 Mic10: DTU Food, Technical University of Denmark Days

20 Area/g emulsion Volatiles (1-penten-3-one) Part H5:2 H5:1 and H10:4 Mic10:4 Mic5:1 and 5: Days 20 DTU Food, Technical University of Denmark

21 Area/g emulsion Volatiles (4-heptenal) part H5: H5: H10: Mic5:2 and 10:4 Mic5: DTU Food, Technical University of Denmark Days

22 Part 3: Different droplet sizes using a membrane homogenizer P Membrane module P N 2 Continous phase (Aqueous) 22 DTU Food, Technical University of Denmark

23 Part 3: Design Code Membran e size (µm) Fish oil conc. (%) Tween conc. (%) Droplet size (µm) Mem0.5-5:1 0.5 µm Mem0.5-5:2 0.5 µm Mem0.5-10:4 0.5 µm 10 4 Not stable Mem1.1-5:1 1.1 µm Mem1.1-5:2 1.1 µm Mem1.1-10:4 1.1 µm ph 7 Storage at room temperature in darkness PV (IDF method) Volatiles (Dynamic headspace GC-MS) 23 DTU Food, Technical University of Denmark

24 Meq/kg 400 Part 3: Peroxide values 350 Mem1.1-5: Mem0.5-5: DTU Food, Technical University of Denmark Days Mem0.5-5:2 Mem1.1-5:2 & 10:4

25 Area/g emulsion Part 3: Volatiles (1-penten-3-one) Mem1.1-5: Mem0.5-5: Mem0.5-5:2&1.1-5:2 Mem1.1-10:4 Days 25 DTU Food, Technical University of Denmark

26 Comparison of results part 2 and part 3 Two-stage valve homogenizer (H) PV (meq/kg) 1-penten-3-one (area x10 6 /g) 4-heptenal (area x10 6 /g) Microfluidizer Membrane Membrane DTU Food, Technical University of Denmark

27 Effect of emulsification conditions 27 DTU Food, Technical University of Denmark

28 Emulsification Conditions Hypotheses and Study Design Ingredients: 10% fish oil 1% emulsifier 89% buffer Emulsification using a two-stage valve homogenizer Type of emulsifier Oil droplet size ~ 22 C 0.5% WPI 0.5% WPIα 0.1% Lg 0.9% CAS 0.5% WPI 0.5% WPIα 0.1% Lg 0.9% CAS 72 C 0.5% WPI 0.5% WPIα 0.1% Lg 0.9% CAS 0.5% WPI 0.5% WPIα 0.1% Lg 0.9% CAS Processing conditions Low pressure, 5 MPa High pressure, 22.5 MPa Storage without iron for 14 days Horn, A.F., Barouh, N., Nielsen, N.S., Baron, C.P., Jacobsen, C. (2013), J. Am. Oil Chem. Soc. 90, DTU Food, Technical University of Denmark

29 1-penten-3-ol [ng/g sample] PV [meq peroxides/kg oil] WP_low WP_low72 WP_high WP_high72 Emulsification Conditions Results: Whey Protein Emulsions (WP) 5,0 4,0 3,0 2,0 WP_low WP_low72 WP_high WP_high72 1,0 0, Days of storage Days of storage WP_high72 WP_high WP_low WP_low72 β-lg α-lac 49% 51% 52% 48% 46% 54% 43% 57% Radical scavenging effect of β-lg in the aqueous phase 29 DTU Food, Technical University of Denmark

30 1-penten-3-ol [ng/g sample] PV [meq peroxides/kg oil] LgCAS_low LgCAS_low72 LgCAS_high LgCAS_high72 25,0 Emulsification Conditions Results: β-lactoglobulin/caseinate LgCAS) 20,0 15,0 LgCAS_low LgCAS_low72 10,0 LgCAS_high 5,0 LgCAS_high72 0, Days of storage Days of storage LgCAS_low 30 DTU Food, Technical University of Denmark LgCAS_low72 LgCAS_high72 LgCAS_high CAS β-lg α-lac 41% 36% 29% 48% 50% 33% 20% Metal chelating effect of CAS in the aqueous phase Importance of proteins in the aqueous phase 29% 28%

31 Effect of delivery emulsions in omega-3 enriched foods 31 DTU Food, Technical University of Denmark

32 ng/g fish paté Omega-3 enriched fish paté: Bulk oil vs. Emulsion or Powder 1-Penten-3-ol Fish FO oil Storage time (weeks) FO MAP No FO Fish FO emulsion oil emulsion Fish FO powder oil powder Oxidation rate: FO powder < FO emulsion < FO Similar results in fitness bars Nielsen & Jacobsen, J. Food Biochemistry (2013), 37, DTU Food, Technical University of Denmark

33 The Effect of Delivery Systems: Bulk oil vs. Fish Oil Emulsion Milk oxidized much more than both yoghurt and dressing Fishy off-flavour [Intensity 0 18] Days of Dressing Dressing storage Yoghurt Yoghurt Milk + Milk + + bulk FO + FO emulsion + bulk FO + FO emulsion bulk FO FO emulsion Yoghurt and dressing with fish oil-in-water emulsion tend to be more fishy than those with neat fish oil Let, Jacobsen & Meyer (2007) J. Agric. Food Chem. 55: DTU Food, Technical University of Denmark

34 Fish Oil Enriched Milk study 2 Study Design Milk Addition of 0.5% fish oil = 250 mg EPA+DHA/glass REF FO WP Lg CAS Ingredients in delivery emulsions: 10% fish oil 1% emulsifier 89% water Storage: 11 days, 2 C, darkness. 34 DTU Food, Technical University of Denmark

35 1-penten-3-ol [ng/g sample] Results: Milk study 2 18 Neat fish oil CAS WP 12 Lg 10 FO % delivery emulsion REF + Days of storage Oxidative stability: FO < CAS, WP, Lg In contrast to Let et al., J. Agric Food Chem, 2007 Difference in oil droplet size 50% delivery emulsion 35 DTU Food, Technical University of Denmark

36 Fish Oil Enriched Milk Study 3 Experimental Design Total fat: 1.5% Addition of 0.5% fish oil = 250 mg EPA+DHA/glass of 250 ml Oil CAS50 CAS10 WPN50 WPN10 Storage: 11 days, 5 C, darkness. 36 DTU Food, Technical University of Denmark

37 Peroxide value [meq LOOH/kg oil] 1-penten-3-ol [ng/g sample] Fish Oil Enriched Milk Study 2 20, CAS10 15,00 10,00 5,00 CAS10 CAS50 Oil WPN50 WPN CAS50 WPN50 Oil WPN10 0, Days of storage Days of storage Neat CAS 10% vs oil (microfluidizer) WPN vs delivery emulsion: emulsions: vs 50% (two-stage valve homogenizer) fish Milk CAS10 oil-in-water with oxidizes CAS emulsions: more than oxidized WPN10. more, and WPN emulsions equally or less CAS50 CAS10 than oxidizes has milk a higher with more neat PV than than oil. CAS50, WPN50, whereas but no the differences differences in volatiles between Whether concentrations WPN10 and it increases WPN50 were were observed. the oxidative less clear. stability of fish oil-enriched milk to add a Metal A delivery combined chelating emulsion effect effect between instead of CAS oil of in neat concentration the oil, aqueous depends phase and on type of the an of choice homogenizer? emulsion of is lost emulsifier. when dispersed in milk. 37 DTU Food, Technical University of Denmark

38 Fish Oil Enriched Milk Study 3 Experimental design Total fat: 1.5% Addition of 0.5% fish oil = 250 mg EPA+DHA/glass of 250 ml Oil WPN10 C-phase W-phase Storage: 11 days, 5 C, darkness. 38 DTU Food, Technical University of Denmark

39 Peroxide value [meq LOOH/kg oil] 1-penten-3-ol [ng/g sample] Fish Oil Enriched Milk study 3 Results on the addition of different emulsion fractions 6, ,00 4,00 W-phase Oil W-phase Oil 3,00 2,00 WPN10 C-phase WPN10 1,00 10 C-phase 0, Days of storage Days of storage Effect of different fractions: Milk with neat oil + water-phase (W-phase) = Milk with oil alone (Oil) > Milk with 10% DE with Nutrilac (WPN10) > Milk with cream phase (Cphase). 39 DTU Food, Technical University of Denmark

40 Fish Oil Enriched Cream Cheese Experimental Design Cream Cheese Addition of 1.3% fish oil = 82 mg EPA+DHA/30 g REF FO CAS WPI MPL20 Ingredients in delivery emulsions: 70% fish oil 2.8% emulsifier 27.2% water Storage: 20 weeks, 5 C, darkness. 40 DTU Food, Technical University of Denmark

41 t-2-hexenal [ng/g sample] Results: Cream Cheese Weeks of storage CAS FO WPI MPL20 REF Fish oil addition increased oxidation Oxidative stability: MPL20, Neat oil > WPI > CAS Horn,et al. (2012) Agriculture, 2, REF FO MPL20 WPI CAS 41 DTU Food, Technical University of Denmark

42 Conclusions The type of emulsifier affects oxidative stability of delivery emulsions Emulsification conditions must be optimised to minimise oxidation of the delivery emulsions Type of emulsification equipment can affect oxidation of delivery emulsion and depends on emulsifier type Yes, delivery emulsions can be used as a means to reduce lipid oxidation But delivery emulsions for omega-3 oils must be optimised for different foods Better understanding of the effect of delivery emulsions on oxidative stability and physical structure is needed 42 DTU Food, Technical University of Denmark

43 Acknowledgements Nina Skall Nielsen Mette Bruni Let Anna F. Horn Anne S. Meyer Lis Berner Inge Holmberg Trang Vu Jane Jørgensen 43 DTU Food, Technical University of Denmark