Answering the Challenge: Label-friendly Emulsifiers and Surfactants for Food Systems Prof. Pete Wilde

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1 2nd annual Clean Label Conference March 31-April 1, 2015, Westin Hotel, Itasca, Ill. Answering the Challenge: Label-friendly Emulsifiers and Surfactants for Food Systems Prof. Pete Wilde

2 Making Emulsions (and foams) How to make a solid from 2 liquids Small droplets m rigid spheres Dilute emulsion Droplets free to move, behaves like a liquid. Viscosity c ( V d ) (Einstein, 1906) Oil droplets Oil droplets Concentrated emulsion V d 0.6, droplets trapped Liquid motion arrested behaves as a solid

Role of Emulsifiers Applies to both emulsions and foams Aid breakup of droplets by reducing interfacial tension Interfacial tension Force acting around the droplet to minimise surface

3 Role of Emulsifiers Applies to both emulsions and foams Aid breakup of droplets by reducing interfacial tension Interfacial tension Force acting around the droplet to minimise surface free energy, and keep droplet spherical F F Droplet shape during emulsification High interfacial tension Stabilise droplets against coalescence Low interfacial tension Stable Unstable

4 Properties of emulsifiers Preferred Interfacial curvature Hydrophobic Oil Hydrophilic Oil Water Low HLB Water in oil emulsions HLB = Hydrophilic:Lipophilic Balance Hydrophobic Low HLB (oil soluble) Hydrophilic High HLB (water soluble) High HLB Foams, Oil in water emulsions Size, structure, charge HLB Use 4-6 W/O emulsifiers 7-9 Wetting agents 8-18 O/W emulsifiers Detergents Solubilizers

5 Interfacial Stability The importance of curvature Hydrophobic High HLB Low HLB Hydrophilic o/w Stable Unstable HLB = Hydrophilic:Lipophilic Balance Hydrophobic Low HLB Hydrophilic High HLB w/o Unstable Stable Size, structure, charge

Food Emulsifiers & Surfactants Ancient Greeks used beeswax in cosmetic products Egg yolk traditionally used as an emulsifier - rich in phospholipids Replaced by phospholipids (lecithin) extracted

modification. Refined / enriched to control HLB and functionality Lecithins Tend to be extracted from plant sources or egg.

6 Food Emulsifiers & Surfactants Ancient Greeks used beeswax in cosmetic products Egg yolk traditionally used as an emulsifier - rich in phospholipids Replaced by phospholipids (lecithin) extracted from soy in 1920 s More effective, synthetic emulsifiers developed based on fatty acid derivatives Mono- and di-glycerides of fatty acids Naturally occurring molecules, but mass produced by chemical modification. Refined / enriched to control HLB and functionality Lecithins Tend to be extracted from plant sources or egg. Can be further refined/enriched to give better control over HLB, and functionality. (Poly)sorbates and sucrose esters Synthetic emulsifiers with highly controlled range of HLB and functionalities. Esters of monoglycerides (Lactylate, citrate, polyglycerol) Chemically modified esters of monoglycerides with specific functionalities.

Prevent splattering, stabilise and control fat crystal network structure.

7 Emulsifiers Uses & Functions Mayonnaise, sauces, soups Emulsify and stabilise fat by adsorbing and reducing interfacial tension and providing stable interfacial layer Margarines & Spreads Emulsify and stabilise water phase. Prevent splattering, stabilise and control fat crystal network structure. Chocolate Emulsify and stabilise different phases, stabilise fat and sugar. Improve consistency during filling and moulding, reduce bloom formation. Fat Sugar Protein Cocoa

Emulsifiers Uses & Functions Bread & Baked products Emulsify and stabilise shortenings, stabilise gas cells. Control starch gluten interactions.

Meat products Emulsify and stabilise water and fat phases, particularly in reduced fat products. Improves texture and taste.

8 Emulsifiers Uses & Functions Bread & Baked products Emulsify and stabilise shortenings, stabilise gas cells. Control starch gluten interactions. Controls dough strength, loaf volume, crumb structure and shelf life. Meat products Emulsify and stabilise water and fat phases, particularly in reduced fat products. Improves texture and taste. Fat Air bubble Gluten/Starch Matrix Thin aqueous film Ice cream and whipping cream Emulsify and stabilise fat droplets. Destabilise interfaces to promote partial coalescence to develop structure formation. Stabilise ice crystals to maintain texture.

9 Clean label solutions Direct Replacements Natural alternatives Additional or Alternative Functionalities Modifications & Processing Aids

Natural Emulsifiers Quillaja extract - from inner

Rich in saponin natural surfactant Bile salts

excellent emulsifiers, aid digestion of fats.

10 Natural Emulsifiers Quillaja extract - from inner bark of the soapbark (Quillaja saponaria, Molina). Rich in saponin natural surfactant Bile salts derived from cholesterol, secreted by gall bladder, excellent emulsifiers, aid digestion of fats. Used a supplement in bile deficiency. Potential Food Emulsifier?

Natural Emulsifiers Lipoproteins, Nature s own emulsions.

tissues. Highly stable, energy efficient.

etc) Assembled on an individual basis, slow manufacture.

11 Natural Emulsifiers Lipoproteins, Nature s own emulsions. Energy store Egg yolk, soy, sunflower etc Oil bodies in plants and animal tissues. Highly stable, energy efficient. Phosholipids, surface active proteins (oleosins, apolipoproteins, hydrophobins etc) Assembled on an individual basis, slow manufacture. Tend to be locked into structures, eg fat globule membranes poor solubility Hence, purification / refinement required no longer clean label? Oil body Iipoprotein

enzyme section). Galactolipids may also modulate fat digestion and may help reduce appetite.

12 Natural Emulsifiers Chloroplasts, thylakoid membranes packed with galactolipids. Bound up in structure, but free galactolipids linked with improved functionality in breadmaking (see enzyme section). Galactolipids may also modulate fat digestion and may help reduce appetite. Need targeted processing to help develop as a natural ingredient. Chloroplast MonoGalactosylDiacylGlycerol (MGDG) MonoGalactosylMonoacylGlycerol (MGMG)

13 Natural Emulsifiers Hydrophobins secreted by filamentous fungi to help hyphae break through water surface Excellent long term stability of bubbles in ice cream, and responsible for gushing in beer. But Food or Additive? Froghopper cuckoospit froth. Natural, but not tasty

14 Emerging Research Grape seed and apple tannins: Emulsifying and antioxidant properties. Figueroa-Espinoza, Maria Cruz; Zafimahova, Andrea; Alvarado, Pedro G Maldonado; et al. Food chemistry Volume: 178 (2015) Pages: Emulsions stabilised by grape and apple tannins Optimization of extraction conditions and fatty acid characterization of Lactobacillus pentosus cell-bound biosurfactant/bioemulsifier Vecino, Xanel; Barbosa-Pereira, Letricia; Devesa-Rey, Rosa; et al. Journal of the Science of Food and Agriculture Volume: 95 (2015) Issue: 2 Pages: Using biosurfactants produced by lactic acid bacteria. Efficient as surfactants, but clean label? Production of exopolysaccharides by Lactobacillus helveticus MB2-1 and its functional characteristics in vitro Li, Wei; Ji, Juan; Rui, Xin; et al. LWT- Food Science and Technology Volume: 59 (2014) Issue: 2 Pages: Exopolysaccharides produced by lactic acid bacteria with emulsifying properties. Interesting properties but clean label?

15 Proteins and Polymeric Emulsifiers Interactions Unfolding to expose hydrophobic groups to surface Oil / Air Phase Aqueous Phase Hydrophobic groups at core of molecule

16 Foam & Emulsion Stability Proteins vs Surfactants Short range Protein Mixed Surfactants Thin film Strong interactions Weak interactions Restricted mobility High mobility

Perceived Fat Content (Score) Polymers and Emulsion Stability Proteins and polymers can confer excellent long term stability Some proteins, eg hydrophobins create strong, elastic interfaces which

17 Perceived Fat Content (Score) Polymers and Emulsion Stability Proteins and polymers can confer excellent long term stability Some proteins, eg hydrophobins create strong, elastic interfaces which prolong stability and can improve texture and mouthfeel Sensory perception Protein 3 2 Surfactant Natural carbohydrate protein complexes (eg gum arabic, sugar beet pectins) form thick, bulky structures at surface, conferring excellent long term steric stabilisation Fat Content (vol %) However, high molecular weight, not efficient during emulsification, so high concentrations / high energy required Carbohydrate Protein

18 Pickering Stabilisation Emulsions stabilised by particles with defined surface hydrophobicity. Some small starch granules (quinoa, rice) can form stable emulsions. Fat crystals can also be used, but sensitive to heat treatment. Large size warrants high energy required to form emulsions initially. Surface modification improves functionality

Modification & Processing Aids There are many natural, clean label

already in an emulsified form Adams et al.

19 Modification & Processing Aids There are many natural, clean label emulsifiers, but often not in a functional form Oil bodies are already in an emulsified form Adams et al. Extraction, isolation and characterisation of oil bodies from pumpkin seeds for therapeutic use. Food Chemistry 2012 Volume 134, Issue 4, Pages Could their natural emulsifying properties be exploited by in situ use of oil bodies

Loaf volume (ml) Modification & Processing Aids Lipases in

Addition of emulsifiers such as DATEM and SSL improve

20 Loaf volume (ml) Modification & Processing Aids Lipases in breadmaking Gas cell in bread are stabilised primarily be polar lipids. Lipid composition of bread affects loaf volume and quality Addition of emulsifiers such as DATEM and SSL improve baking quality. Flour polar lipids C16:0 - FA Flour total lipids C14:0 - FA Flour non-polar lipids C18:2 - FA

21 Gas cell development Lamellae Gluten starch matrix Gas cells Coalescence Sponge transition Mixing Proofing Baking CO 2 production bubble expansion during proofing and oven spring Bubbles in contact rely on interfacial stability Early coalescence loss of loaf volume

22 Dough liquor foam and lipid composition Flour Dough Liquor Foam 50 %mol Total Lipids Polar Lipids TAG FFA DAG Type of Lipids Fatty acids concentrate in foam TAG do not accumulate in foam, but some present which may cause instability

DGMG MGMG PC LPC Conversion of polar lipids from di-acyl to Mono-Acyl

23 Loaf Volume (ml) Using lipase to alter lipid profile Control YieldMAX Lipolase Lecitase Lipopan Lipase FFA DGDG MGDG DGMG MGMG PC LPC Conversion of polar lipids from di-acyl to Mono-Acyl Strong correlation with loaf volume Gerits LR. et al. Food Chemistry 156 (2014)

24 Summary Emulsifiers and surfactants have been developed and optimised for functional performance adsorption, emulsification, stabilisation, texture modification etc. Natural, clean label alternatives becoming will probably never match bespoke emulsifiers for performance. Understanding the structure function performance relationships of conventional ingredients is key to developing viable replacements. Emerging research is revealing new sources of active ingredients, but not all will be clean label. Process modification and addition functionalities of some clean label solutions do make them viable alternatives.

25 Acknowledgements Louise Salt, Fiona Husband, Mike Ridout Irene Gonzalez-Thuillier, Byoung Min Peter Shewry, Richard Haslam, Paola Tosi Simon Penson, Gemma Chope Thank you 2nd annual Clean Label Conference March 31-April 1, 2015, Westin Hotel, Itasca, Ill.

Figure: 11.1 Working of Emulsifier

Figure: 11.1 Working of Emulsifier Paper No.: 13 Paper Title: FOOD ADDITIVES Module 11: Emulsifiers for the food industry 11.1 Introduction Emulsifiers are additives that allow normally immiscible liquids, such as oil and water, to form