Oil Bodies as a promising source of natural oil in water emulsion. Simone De Chirico, Vincenzo di Bari, David Gray 1
Where is the oil isolated from? Palm fruit oil is a semi-solid fat derived from the mesocarp Oil bodies are the storage organelles of neutral oil in oilseed crops 2
Current manufacturing process of oil extraction and emulsification from oleaginous plants Hexane Cleaning/ Grinding Pressing and solvent extraction High yield High energy input Extensive use of chemicals High environmental impact Surfactants Oil Refining Hexane O/W Emulsion Emulsification Edible Oil 3
Oilseed cotyledon cell: a natural emulsifying system Maturation Germination Fatty acids Oil Body Lipase Phospholipids Oleosins Ribosomes Image adapted from: Roberts, E. H. (2013), SEEDS. PHYSIOLOGY OF DEVELOPMENT AND GERMINATION (Book). 4
Impact of the research: recovery and use of oil bodies in food O/W Emulsion Oil Bodies 5
Our approach: wet milling of oilseeds resulting in a natural emulsion 0.1 M NaHCO 3 (ph9.5) Oilseed Pre-Soaking Grinding High valuable by-product Unit Operation Filtration and centrifugation Cake Washing Protein-rich serum Thermal treatment Oil Body emulsion 6
Enzymatic activity carried over in the extract Well established that enzymes can be more or less tightly associated to the OB Lipase is thought to be bond to the OB through the Lipase Protease Phospholipase oleosin 1 1 Wang, S. M. & Huang, A. H. 1987. Biosynthesis of lipase in the scutellum of maize kernel. J Biol Chem, 262, 2270-4. 7
AIM Test the lipase activity as an indicator of: Purity of recovered oil bodies Effectiveness of thermal treatment STORAGE STUDIES Protein and phospholipid degradation Particle size Oxidative stability
Lipase activity over the recovery process U/g OB (dwb) Lipase activity 1.6 a 1.4 a 1.2 b 1 0.8 0.6 0.4 0.2 0 Crude COB extract WOB 1 st wash I 2WOB nd wash II OB extract sample Crude extract 1 st wash 2 nd wash H2OH 2 O NaHCO 3 NaHCO 3 Lipase activity was assayed over the recovery process Lipase activity was reduced over washing 9
Lipase activity over the recovery process U/g OB (dwb) 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 a Lipase activity c a Crude COB extract WOB 1 st wash I 2WOB nd wash II OB extract sample H2O H 2 O d b NaHCO SB 3 d Lipase activity was assayed over the recovery process Lipase activity was significantly Lipase activity was reduced over the reduced using NaHCO 3 solution first wash of the crude material The enzyme is resistant to further wash NaHCO 3 10
Lipase activity over thermal treatment Relative Activity(A/A0, %) 100 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 7 Time (min) Thermal treatment reduced lipase activity by 90% over the first 6 minutes (95 C). Thermal process could be shortened considerably compared with the one suggested in literature (up to 30 minutes) 11
Other enzymes: Proteases and Phospholipases Relative quantity (%) D0 D30 D30 120 100 80 60 40 20 Phospholipid Content Fresh OB Untr. 6 min Emulsions stored for up to 30 days (20 C) SDS-PAGE analysis to asses protease activity Oleosin 0 0 5 10 15 20 25 30 Storage time (days) Untreated 6 min. 95 C Phospholipids were isolated and quantified over storage No significant changes in phospholipid content in thermally treated emulsion 12
Effect of residual enzymatic activity upon storage (20 C) Volume % 6 5 4 3 2 1 0 0.1 1 10 Particle diameter (µm) (A) Untreated (B) 6 minutes min. 95 C 96C Fresh Day 0 Extended coalescence in untreated emulsions Small coalescence in the 6 minutes treated sample over the first 3 days A B 13
Tocopherols (mg/g oil) MDA, µg/kg oil Effect of thermal treatment on oxidative stability upon storage (40 C) 4 3.5 3 2.5 2 1.5 1 0.5 0 Secondary Products 0 2 4 6 8 10 12 Storage time (days) Untr. 6 min. Thermal treatment significantly improved the oxidative stability of oil body emulsions. Despite tocopherols being susceptible to thermal treatment (6 minutes, 95 C), no changes were registered over storage. Oxidative stability was assessed measuring secondary products over accelerated storage at 40 C. Natural antioxidants (intrinsic components in oil bodies) were measured. 1.4 1.2 1 0.8 0.6 0.4 0.2 0 Total Tocopherols Untr 6 min 0 2 4 6 8 10 12 Storage time (days) 14
Conclusions Heating oilseed rape oil bodies for 6 minutes at 95 C creates a physically stable emulsion This thermal treatment also improves the oxidative stability A reliable method for monitoring the effectiveness of oil body recovery and thermal treatment has been developed using a spectrophotometric assay for lipase activity 15
Thank you for your attention Any question? 16