Oil bodies as a source of naturally preemulsified oil: novel methodologies for extraction and stabilization.

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1 Oil bodies as a source of naturally preemulsified oil: novel methodologies for extraction and stabilization. Simone De Chirico, Vincenzo di Bari, David Gray 1

2 Oil body structure and composition µm Surface proteins: Oleosin Caleolosin Stereolosin PL: Phospholipid TAG: Triacylglycerol (Oil) 1 Source: Huang, A.H.C., Oleosins and Oil Bodies in Seeds and Other Organs. Plant Physiology, 110:

3 Current manufacturing process of oil extraction and emulsification from oleaginous plants Hexane Cleaning/ Grinding Pressing and solvent extraction Mayonnaise Bakery products Surfactants Oil Refining Hexane Salad dressing Emulsification Edible Oil Ice-cream Spreads 3

4 Our approach: extraction of oil bodies to be used in food application Oilseed Pre-Soaking High valuable by-product Unit Operation Grinding Filtration and centrifugation Cake Washing Protein-rich serum Thermal treatment Oil Body emulsion 4

5 Advantages of the process* Oilseed Pre-Soaking Grinding Filtration and centrifugation Washing Thermal treatment The aqueous media maintains intact the oil bodies and removes the majority of exogenous seed proteins The oil body cream is a versatile O/W emulsion (72% oil) that can be further processed according the end use More environmental-friendly process from the current manufacturing extraction and emulsification of oil No need of additional emulsifiers Natural product Oil Body emulsion *Manuscript in preparation 5

6 Volume % Limitations: carry over of active enzymes Removal of exogenous seed proteins Lipase Protease Phospholipase Final protein content Urea (no food-grade) 2.6±0.05 (% dry matter) Optimised aqueous media Storage at 20 C 2.69±0.21 (% dry matter) Fresh Day 0 Day Particle diameter 6

7 Aim of our current research Stabilize the emulsion using thermal treatment Lipase Protease Phospholipase 7

8 Enzyme activity as a marker of thermal process effectiveness Current literature approach: T= C t= minutes Effect of thermal treatment on oil body characteristics Particle size Zeta potential Imaging Our approach: Effect of thermal treatment (95 C) on enzymatic activity Effect of thermal treatment on oil body characteristics (on fresh sample) Effect of residual enzymatic activity over storage Particle size Zeta potential Imaging Minimal condition for stabilization of the emulsion suggested 8

9 ζ-potential (mv) Volume % Effect of thermal treatment on oil body emulsion (day 0) Particle size Untreated 6 minutes Diameter (µm) 60 Zeta-potential gives information of the charged components on the surface No changes upon thermal treatment (95 C) Treated No size increase upon thermal treatment (95 C) Zeta-potential Untreated Treated Treated 6 minutes ph 9

10 Volume % Effect of enzymatic activity upon storage (20 C) on untreated emulsions Fresh Day 7 Day Diameter (µm) Rapid destabilization of the emulsion 10 µm 10

11 Volume % Effect of residual enzymatic activity upon storage (20 C): particle size 7 6 Fresh Day 7 Day Thermally treated (95 C) Small increase after 7 days, then stable for the rest of the trial Diameter (µm) 10 µm 11

12 ζ-potential/mv ζ-potential/mv Effect of residual enzymatic activity upon storage (20 C): zeta potential Small changes in the thermally treated sample Untreated Day Fresh Day 7 Day ph Decay of zeta-potential is due to changes of the charged components at the surface Thermally treated Day Fresh 0 Day 7 Day ph

13 Conclusions Oil body emulsions are resistant to thermal treatment The length of thermal treatments of oil body emulsions could be remarkably shorter than the one suggested by literature The use of enzymes as a marker of thermal treatment is a novel methodology and effective for the stabilization of oil body emulsions 13

14 Future work Recovery of high valuable protein isolates from the extraction process Development of a low-fat vegan mayonnaise based on oil body preparation 14

15 Thank you Any question? 15