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?.