Understanding the role of processing and formulation on RBW oleogel microstructure
Vincenzo di Bari Presentation outlook
1. World innovation trends for lipids
2. Oil structuring strategies: Ø TAGs: Fats Ø Non-TAGs: Oleogels
3. Formulation of RBW oleogels: Ø Understanding the thermomechanical behaviour Ø Engineering RBW oleogels
4. Key features of wax oleogels research 1. World innovation trends for lipids
Trend Driver Reduction in trans- & Nutrition – health saturated (≤10%) fats
Reduction in chemically Nutrition – health modified oils Natural Nutrition – health Reduction in animal fats Choices Sustainability
Reduction in palm oil and Sustainability fats in general Nutrition – health
Increase in PUFA content Nutrition – health Natural 2. Edible oil structuring strategies
Molecular Particles mechanisms dispersion
Image taken from: Pernetti et al. Soft Matter (2007) 12, 221-231. Molecular mechanisms to structure edible oils
Traditional: TAGs Fats Solid structure = f(building blocks) Novel: Non-TAGs Oleogels Fats: complex hierarchical structure of TAGs
Image taken from “Structure and functionality of edible fats”, Marangoni et al. Soft Matter, 2012, 8, 1275. Non-TAGs based approach to structure edible oils
Non-TAGs: Oleogels*
Novel routes to structure edible oils
Mechanisms & Functionality = f(building block)
*Organogels are called “Oleogels” when structuring to edible oils Bio-based: • plants • insects • marine animals
2 Image taken from: Patel, A, and Dewettinck, K (2015). Comparative evaluation of structured oil systems: Shellac oleogel, HPMC oleogel, and HIPE gel. Eur. J. Lipid Sci. Technol. 117, 000-000. Plant waxes
• Natural plant hydrophobic compounds deposited outside the epidermal cells
• Complex mixture of fatty alcohols and acids, their esters, hydrocarbons, ketones, etc
• Considered to be among the most promising oleogelators6,7 Plant wax based oleogels
Wax Oil • Candelilla • Olive • Carnauba • Sunflower • Sunflower • Rice bran • Rice Bran • Rapeseed • Berry • Vegetable • Bee • Salad • Fruit Plant wax based oleogels
Wax Oil • Candelilla • Olive • Carnauba • Sunflower • Sunflower • Rice bran • Rice Bran • Rapeseed • Berry • Vegetable • Bee • Salad • Fruit Rice bran wax (RBW)
Rice Bran (7.6 x 107 tons/year)1
Extraction / Hexane
Crude Rice Bran Oil
Degumming
Dewaxing RBW (5-8%) ~700,000 tons Neutralisation
Bleaching De-odorisation Rice Bran Oil
1: Friedman, M., Rice Brans, Rice Bran Oils, and Rice Hulls: Composition, Food and Industrial Uses, and Bioactivities in Humans, Animals, and Cells. J. Agric. Food Chem. 2013, 61, 10626−10641 Rice bran wax (RBW)
• By-product
• Available in large volumes
• Promising gelling agent
• Temperature of phase transition compatible with pasteurisation
• In food applications Rice Bran Wax is EU regulated as a food additive E908. RBW: structural levels
A
Macroscale Mesoscale
Nanoscale
Molecular
Wax ester
A Image taken from reference 8: Characterization of the Nanoscale in Triacylglycerol Crystal Networks Formulation of RBW oleogels Oleogel research landscape at UoN
Characterisation
Functionalisation
Application: cakes & SCP (LMWO) Oleogels: Definition
•Organic liquid entrapped within a thermo- reversible, three-dimensional gel network3
•Network: Thermo-reversible 3D supramolecular structure formed via self-assembly of small molecules in an organic solvent at low concentration4. RBW Oleogels: preparation
Formulation definition
Solubilisation
Crystallisation
Structure Development RBW oleogels: Appearance
RBW concentration (%)
0.0% 0.1% 0.2% 0.5% 1.0% 2.0% 3.0% 5.0% RBW oleogels: microstructure RBW oleogels: microstructure Oleogel research landscape at UoN
Characterisation
Functionalisation
Application: cakes & SCP Microstructure functionalisation: Understanding the thermo-mechanical behaviour
Formulation [RBW] Processing Additives Cooling Thermodynamic/kinetics rate Temperature Shear 100 µm Microstructure = f([RBW])
1.0% 1.5% 2.0%
2.5% 3.0% 5.0% RBW oleogels thermal properties
Liquid oil 3.0 Oleogel 2.5 /g) 2.0 mW 1.5
1.0 Heat Flux ( Heat 0.5
0.0 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Temperature (°C) Gel strength = f(Temperature)
100,000 2% RBW ω = 10 rad/s 10,000
1,000 G' (20C) G'' (20C)
100 G' (30C) G'' (30C) G', G'' (Pa) G' (40C) G'' (40C)
10 G' (50C) G'' (50C)
G' (55C) G'' (55C) 1 0.001 0.01 0.1 1 10 100 1000 γ (%) Engineering the mechanical behaviour= f([RBW], cooling rate)
0.5 °C/min 50 °C/min 240
200
160
120
80 3% RBW Yield Stress (Pa) Stress Yield
40 200 µm 5% RBW 200 µm
0 0.1 1 10 100 Cooling rate (°C/min)
PP50 Sandblasted, ω = 10 rad/s, 40 °C, 0.5 mm gap Engineering the mechanical behaviour= f([RBW], cooling rate)
80% 80% 70% 0.5°C/min 70% 5°C/min 60% 60%
50% 50%
40% 40%
30% 30% % of crystals
20% % of crystals 20%
10% 10%
0% 0% 50 100 150 200 250 >250 50 100 150 >150 Lenght of crystals - classes (µm) Length of crystals - classes (µm)
60%
50% 50°C/min Average number (%) of 40% crystals in each 30% length class
after cooling, at % of crystals 20% 27°C (1%RBW) 10%
0% 25 50 >50 Length of crystals - classes (µm) Role of additives on RBW oleogels Control (0% Emulsifier)
200 µm 1% Span 60 1% Span 65 Crystallisation profile of RBW + Additive (Span 65)
1% Sp65/1% RBW
Heat flow 0.2 (mW) 0.2 flow Heat 0.5% Sp65/1% RBW 0.1% Sp65/1% RBW 1% RBW 20 30 40 50 60 70 80 90 Temperature (°C) Application Pastry re-formulation
Palm oil 20% Replacement with 3% RBW
Images taken by Khatija Nawaz Husain (CIM Nottingham) 4. Key features of wax oleogels research
Reversible physical Increased modification PUFA of oils
Type, origin & recovery Matching strategy fats functionality
Health Sustainability Natural Economical value / by- Functionality Delayed products lipolysis valorisation RBW for oleogelation: Key features
• Low molecular weight gelators
• Unidirectional molecular packing leading to anisotropic platelet shaped crystals with β’ sub-cell structure
• Long range intermolecular interactions
• Self-arrange to form a dispersion of crystals sintered to form an oil-structuring continuous network
• The addition of additives promotes new microstructural arrangement mirrored by different crystallisation profile Many thanks for your attention
Any Questions?