Upgrading materials & minimising waste. Functionality at interfaces. Bettina Wolf University of Nottingham

Transcription

1 Upgrading materials & minimising waste Functionality at interfaces Bettina Wolf University of Nottingham

2 Outline Emulsifier for chocolate Oleogels at oil-in-water emulsion interfaces Lignin-based Pickering particles Figure 2 in DOI: /ind Process functionalisation of native starch

3 Emulsifier for chocolate Green leaf lipid extract as alternative emulsifier in chocolate? Nizaha Juhaida Mohamad *, David Gray, Bettina Wolf * Department of Food Sciences, School of Food Science and Technology, Universiti Malaysia Terengganu, Kuala Nerus, Terengganu, Malaysia

4 Spinach lipid extract lecithin PGPR Ricinoleic acid Spinach lipid extract (SPLIP)

5 Prior art Oat lipid has comparable performance to PGPR * Dark Chocolate (31.9% fat) Viscosity (Pa s) at 40 o C and at shear rates s -1 No emulsifier Soya lecithin PGPR Oat Lipid Fraction Functionality due to digalactosyl diacylglycerol (DGDG) in oat * Monogalactosyl diacylglycerol (MGDG) and DGDG major polar lipids in photosynthetic tissues, e.g. spinach (36% MGDG, 20% DGDG of total lipids) * Evans et al (1991) United States Patent No

6 Molecular structure PGPR

7 Preparation of SPLIP Blend with preheated (80ºC) isopropanol Filter & re-extract with chloroform:methanol (2:1) Wash with 0.9% NaCl to a ratio of chloroform:methanol:nacl (8:4:3) to remove non-lipid contaminant Evaporate (40ºC) & reconstitute with chloroform:methanol (2:1) Collect the bottom layer & evaporate (40ºC) to dry for lipid recovery Re-dissolve the lipid with chloroform before mixing with a known amount of sunflower oil SPLIP Evaporate (40ºC) to remove chloroform

8 Yield and composition

9 Sugar/oil suspensions Surface active impurities removed from sunflower oil Icing sugar dried PSD dry icing sugar on the right 9

10 Viscosity 50% sugar

11 Bars: Apparent Viscosity, η40 (Pa.s) Characteristic parameters % Surfactant a a b c d d b a c c bc c bc b c a a c bc b c b ab b c a b bc a c CONTROL SPLIP CH.SPLIP LEC PGPR 40% sugar 45% sugar 50% sugar Symbols: Yield Stress, τ (Pa) Letters indicate statistically significant difference (P<0.05) between samples of same sugar content. Bold letters refer to yield stress. Yield stress comparable to PGPR Viscosity reduced further than by lecithin

12 Application to chocolate 0.3% emulsifier 0.6% emulsifier 0.6% emulsifier 4g of cocoa butter and cocoa butter containing emulsifier was mixed with 96 g of chocolate (32% fat, no added emulsifiers, donated by Barry-Callebaut) 0.3% w/w or 0.6% w/w emulsifier on total chocolate Analysed at 40ºC Suspension yield stress data low higher concentration: viscosity reduction but higher yield Building further understanding of PGPR functionality first (i-case Case with Nestle PTC York)

13 Oleogels at oil-in-water emulsion interfaces Oil phase structuring with rice bran wax: A concept to enhance the nutritional value of aqueous continuous emulsions? Hui Zhang, Vincenzo di Bari, Tim Foster, Bettina Wolf

14 Rice bran wax oleogels

15 Emulsion development (10% o)

16 Crystallisation inside oil drop 1% RBW oleogel 5% GA/1% RBW emulsion Crystals Cryo-SEM images 100µ m SFO emulsions 20µ m 5% GA/20% RBW emulsion Structured internal phase 2µm 2µm

17 Forcing interfacial nucleation 3%SP/5%RBW/SFO 1 C/min 100µ m 20µ m 2 nd peak 1 st peak Sample 3% Span 3%Span & 5%RBW 5%RBW Cooling 1 st peak 2 nd peak 1 st peak 2 nd peak Onset ( C) Peak ( C) End ( C) Heat flow (J) nd crystallization peak: narrower temperature range - SP was involved into RBW crystallization SP may act as nucleation site for RBW

18 Lignin-based Pickering particles Holly Cuthill, James Huscroft, Khatija Nawaz Husain, Jo Gould, Andrew Bosman *, Paulina Garcia Macias #, Ellie Binner, Bettina Wolf * Campden BRI Ltd, Chipping Campden, GL55 6LD, UK # Reading Science Centre, Mondelēz International, Reading RG6 6LA, UK

19 Why particle stabilisation? Long term stability against coalescence Complex emulsion formulation Modified rheology Triggered release through responsive particle design from particle or droplet volume Delayed lipolysis 100 µm Mezzenga et al (2004) Langmuir 20,

20 Emulsifying and foaming with cocoa particles Emulsions Expectorated dark chocolate 200 μm Cocoa particle s Water Hand shaken emulsion Sunflower oil 200 µm Foams Low fat cocoa particle stabilised foam Onset of collapse after 2 hours Wet foam structure (isolated spherical bubbles) at low solids Some polyhedral structure at high solids and at stages of advanced drainage

21 Water-in-oil emulsions 0.5% Cocoa concentration 3% Cocoa concentration 6% Cocoa concentration Unstable with time Day 0 100µm 100µm 100µm Cocoa particles accumulate in the droplet volume predominantly hydrophilic surface characteristics? Day 1 100µm 100µm 100µm Day 2 100µm 100µm 100µm

22 Lignin re-location Donohoe et al (2008) Biotechnology and Bioengineering, 101(5), Steel reactor (d i 22mm, l 173mm)

23 2 PhD projects James Huscroft Develop fundamental understanding enabling transferable process design (Time, Temperature, Pressure, ph) Use conventional thermal processing and/or microwave processing Create a food particle with functional properties such as emulsion stability Holly Cuthill Extraction of lignin and conversion into functional microparticles Gould et al (2016) Materials 9(9): 14

24 Process functionalisation of native starch Miroslaw Kasprzak, William Macnaughtan, Stephen Harding, Peter Wilde *, Bettina Wolf * Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, NR4 7UA, UK

25 Stabilising o/w emulsions 4 % waxy rice starch (high T, high PGPR) 100µm Kasprzak et al (2018) Food Hydrocolloids 81,

26 Mechanism Starch Moisture (%) Amylose (%) Protein (%) ΔH (J/g) T onset ( C) T peak ( C) T endset ( C) (OSA-starch) 6.0 ± ± ± High amylose maize 11.6 ± ± ± ± ± ± ± 3.0 Non-waxy rice 11.1 ± ± ± ± ± ± ± 0.2 Pea starch 12.3 ± ± ± ± ± ± ± 1.1 Potato 13.2 Gelatinise ± ± 1.2starch 0.14 ± oil ± ± ± ± 0.2 Regular rice 10.5 ± ± ± ± ± ± ± 0.1 Tapioca 11.8 ± ± ± ± ± ± ± 0.4 Waxy maize AMIOCA TF ± 0.3 oil while 6.4 ± 0.2 gelatinising 0.24 ± starch ± ± ± ± 0.2 Waxy maize PRIMA ± ± ± ± ± ± ± 0.0 Waxy rice 13.0 ± ± ± ± ± ± ± 0.3 Wheat 11.4 ± ± ± ± ± ± ± 0.2 Gelatinise starch cool (freeze dry ) + oil Kasprzak et al (2018) Food Hydrocolloids 81,

27 That s all