Ingredient Functionality & Characterization - Home | UMass Amherst PDF
Preview Ingredient Functionality & Characterization - Home | UMass Amherst
Ingredient Functionality & Characterization David Julian McClements Biopolymers and Colloids Laboratory Department of Food Science • Emulsifiers • Texture Modifiers – Thickening Agents – Gelling Agents • Weighting Agents Emulsifiers: Major Functions in Food Emulsions Functional Properties • Emulsion Formation • Emulsion Stabilization • Modification of Interfacial Properties • Modification of Crystallization • Interaction with Biopolymers Displacement – Crystal modification – Polymer interaction – ice cream manufacture margarine manufacture Bread manufacture Emulsifiers: Formation Emulsifier Factors Affecting Formation: Microfluidics • Concentration and Surface Load – sufficient present to cover all surfaces formed • Adsorption Kinetics – adsorbs fast enough to form protective coating • Interfacial Tension – lower γgives smaller droplets • Protective Coating – Emulsifier layer should protect against aggregation Film Movement Incorporation Formation − to surface − In surface − − − − − − − − − − Emulsifiers: Stability Emulsifier Factors Affecting Stability: • Colloidal Interactions - Interfacial Thickness, Charge & Hydrophobicity • Resistance of membrane to disruption - Interfacial rheology Hydrophobicity Charge + + + + Thickness Environmental Responsiveness: pH, I, T Common Food Emulsifiers Small Molecule Surfactants – Tweens, Spans, fatty acids, DATEM – Sucrose esters, polyglycerol esters, monoglycerides Phospholipids – Egg, soybean, milk − Biopolymers − − − − − − − − – whey, casein, egg, gelatin, soy – modified starch, gum arabic, modified cellulose Emulsifier Applications in Foods Salad Dressings – Tweens Soft Drinks – PGA – Gum Arabic – Proteins – Modified Starch Mayonnaise – Proteins Ice Cream – Phospholipids – Proteins – Yolk particles – Phospholipids Sauces & Dips – (Surfactants) – Mono/diglycerides Nutritional Beverages Milk & Cream – Proteins – Proteins – Phospholipids – Phospholipids Specifying Emulsifier Functionality Choosing the most appropriate emulsifier Physicochemical Factors • Emulsion type (O/W or W/O) • Minimum amount needed (C ) min • Minimum droplet size achievable (r ) min • Ingredient compatibility • Sensitivity to environmental stresses (pH, I, T) Practical Factors • Ease of utilization • Reliability/Consistency of source • Long term stability • Sensory properties Currently no standard method of Economic & Marketing Factors specifying emulsifier • Cost functionality • Label friendliness Surfactants: Molecular Structure − + Head Group • Electrical charge (non-ionic/ionic) • Chemical groups • Length and cross-section Tail Group • Number of chains • Length of chains − − − • Saturation of chains Industrial Manufacture of Surfactants Tween 20 Structure: ChemBlink Commercial surfactants are actually a complex mixture of many different molecules Danisco Self Assembly of Surfactants Non-spherical Micelle Micelle Reverse Micelle Vesicle Surfactants can form a variety of structures, with different functional properties, depending on their molecular structure
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