Fat Substitution in Food Miranda Miller Kraft Foods R&D ACCA Seminar Series October 4, 2005
Agenda Why Fat Replacement? Basic Fats and Oils Technology Functions of Fat in Food Fat Mimetic Technology Reduced Calorie Fats and Fat Substitutes Replacing Trans and Saturated Fat
Overweight and Obesity in America Over last 25 years, been a dramatic increase in percent of population in North America who are overweight and obese. Jane Doe is 5’5” and weighed 130 lbs (BMI= 22) in 1980, in 2004 she weighs 160 lbs (BMI=27). How much would Jane have to change her eating behaviors to gain this weight? Decrease in activity level= 10 minutes more commuting/day over 25 years Increase in caloric consumption= 12 calories/day over 25 years 2 Life Savors ¼ cup of skim milk
July is National Hot Dog Month!!! 80 % of the people at a baseball game eat a Hot Dog. 5 Billion Hot Dogs eaten between Memorial Day and Labor Day. 50 million Hot Dogs eaten every day in the US: that’s 80 Hot Dogs/person/year!! 1 Hot Dog has about 150 Calories. Not everyone in the US eats hot dogs. Some people consume LOTS
Comparison of Hot Dogs Beef/Pork Hot Dog:150 Cal; 5 grams Protein; 1 gram CHO; 13 g Fat; 81% Cal from fat 4.8 g Sat Fat; 6.2 g MUFA; 1.2 g PUFA Turkey Hot Dog:102 Cal; 6 g Protein; 1 g CHO; 8 g Fat(71%) 2.4 g Sat Fat; 2.7 g MUFA; 2.1 g PUFA Chicken Hot Dog:115 Cal; 6 g PRO; 3 g CHO; 9 g Fat(70%) 2.5g Sat Fat; 3.8 g MUFA; 2.8 g PUFA What happens when the meat source is changed? Beef Turkey Chicken 81% fat ----71%------70% dec cal---dec cal inc pro--inc pro, inc CHO
Weight Gain 3500 extra Calories = 1 pound of Fat Example: 80 hot dogs per person/year above required Calories 80 dogs x 150 Calories = 12000 Cal/year 12000/3500 = 3.5 # / year Remember, this is if everyone consumed hot dogs.
Why Fat Replacement? High fat diets are linked to obesity and cardiovascular disease There is an epidemic of overweight and obesity in the US About 65% are overweight (BMI 25) (BMI = weight (kg) / Height 2 (m2) About 23% are obese (BMI 30) RDA for fat is 30% of calories Current consumption is somewhere near 38%
Show Obesity Maps
Another example of how changes in fat can influence weight. If you could make a saving every day lilke this one (265 calories) You would lose or keep off 27.5 pounds/year 760-495=265 265 x 365=96,725 96,725/3500=27.6 pounds
Consumers Are Paying Attention to What They Eat “A person should be very cautious serving food with…”
Some Other Consumer Facts Concern about fat peaked in mid 90’s 51% very cautious in 1994 31% very cautious in 2004 Low carb diets may be the diet du jour but 73% consume reduced fat food 78% are trying to cut down fat in their diet 61% trying to avoid trans fat And 70% are concerned with calories
Basic Fats and Oils Technology
Lipids: Definition A family of compounds soluble in organic compounds but not in water 3 classes of food lipids: Triglycerides: 95 % of lipids in foods Phospholipids: e.g..: lecithin Sterols: e.g..: cholesterol Such as, ether, chloroform and acetone Some fats are somewhat soluble in water. Triglycerides - When referring to fat generally mean TG Phospholipids - Fat soluble end and water soluble end example: lecithin major component of cell membreaes Sterols - very different stucturally (rings) Cholesterol - necessary in body but not essential (liver makes it) Needed in cell membranes
Triglycerides Are Esters of Glycerol and Fatty Acids Glycerol "backbone" is a water-soluble alcohol Fatty Acids are chains of carbon atoms with a methyl (-CH3) group at one end and a carboxylic acid (-COOH) group at the other condensation reaction Glycerol + 3 Fatty Acids Triglyceride + 3 water molecules Structures linked by ester bonds (R-COOR') and water is released
Some Basic Facts About Fats Major source plants (soybean, cottonseed, corn, palm) At room temperature, Oil = liquid, Fat = solid (m.p. varies) Calorie-dense (9 Kcal/gram) vs. carbs & protein (4 Kcal/g) Per capita consumption ~80 lb/year (significant inc. since 1980) 38% of dietary calories come from fat (current RDA is 30%) Saturated and trans-fat consumption increase CHD risk Unsaturated oils (olive, fish oils) appear to reduce CHD risk
Fatty Acids Vary in Chain Length and Saturation Add Double Bonds Lower Melting Point saturated stearic acid m.p. 73 oC “cis” monounsaturated oleic acid m.p. 5.5 oC Longer Chain Higher Melting Point
Poly-Unsaturation Confers Liquidity (And Reactivity Toward Oxygen) “cis, cis” linoleic acid m.p. –13 oC “cis, cis, cis” linolenic acid m.p. –24 oC More Double Bonds Lower Oxidative and Thermal Stability
Hydrogenation Improves Stability BUT… “sat” stearic acid m.p. 73 oC “trans” elaidic acid m.p. 42 oC “cis” oleic acid m.p. 5.5 oC H2 Trans fats behave more like saturated fat
Functions of Fat in Food
Nutritional Role Source of essential fatty acids Linoleic and linolenic Carriers for fat soluble vitamins A, D, E and K Important source of energy 9 Kcal/g vs. 4 Kcal/g for carbs or protein
Physical and Chemical Functions Physical Properties of Foods Rheological properties: viscosity, plasticity, yield stress, thixotropy, gelation, spreadability, lubricity, hardness, stringiness Thermal properties: melting characteristics, heat transfer coefficient, solid fat index, softening point, polymorphism Processing behavior: heat stability, viscosity, crystallization, aeration Post-processing and shelf stability: shear sensitivity, tackiness, migration, dispersion, and stability (physical, chemical, microbiological) Chemical Properties of Fat or Oil Length of carbon chain Degree of unsaturation Distribution of fatty acids Cis-trans configuration Crystal state of fat
Sensory Functions of Fat in Products Appearance Gloss, translucency, color, surface uniformity, crystallinity Texture Viscosity, elasticity, hardness Flavor Intensity of flavors, flavor and aroma release, flavor profile, flavor development, time intensity relationships Mouthfeel Meltability, creaminess, lubricity, thickness, degree of mouthcoating, mouth warming or cooling
Many Fats and Oils in Food Exist As Emulsions Discontinuous phase Internal phase Dispersed phase Continuous phase External phase Dispersion Medium
Emulsion Types O/W EMULSION W/O EMULSION Examples: Mayonnaise WATER OIL OIL WATER Examples: Mayonnaise Milk Salad Dressing Coffee Whiteners Examples: Margarine Tablespread Butter
Microstructure of Mayonnaise
Fat Replacers
Historical Context Consumers became aware of impact of diet on health in 80’s Proposed energy from fat in diet reduced to 30% (from 40-49%) Began affecting consumer attitudes Challenge was to produce low-fat products with physical and sensory characteristics as close as possible to full-fat quality “Breakthrough” came with introduction of a microparticulated protein ingredient called “Simplesse” The search for the next magic bullet ingredient followed Subsequent development effort revealed consequences of removing fat from a product Alternative ingredients or processes had to be developed as all the attributes of fat became recognized
Classification Over 200 commercial fat replacement ingredients Carbohydrate-based Starch and starch hydrolysis products Fiber based (gums, gels, thickeners, bulking agents) Protein-based Specially processed proteins Protein/fiber combinations Lipid-based Synthetic fat substitutes Low-calorie fats Emulsifiers
Approach to Fat Replacement Has Changed Late 80’s to Mid 90’s Fat free products with full fat quality using magic bullet technologies 21st Century Healthy products with balanced macronutrients Fat is a necessary part of diet Need to cut down bad fats: saturated and trans Good tasting calorie-reduced light products
Some Basic Terminology Fat Replacer Blanket term for any ingredient used to replace fat Fat Substitute Synthetic compound used as direct 1-for-1 replacement Similar chemical structure to fat but resist digestion Fat Mimetic Non-fat substance requiring high water content Replace some (not all) functions of fat in products Low-calorie fat Synthetic triglyceride combining unconventional fatty acids resulting in reduced calorie content Fat Extender System of ingredients used in combination with standard fats or oils to achieve fat reduction
Fat Replacement Strategies Direct Fat Removal First strategy to evolve in rush to comply with nutritional recommendations in 80’s Worked well for milk, some dairy products, some processed meat… but not much else Formulation Optimization Water replaces fat in higher fat products Optimization with functional ingredients to stabilize product Processing Technology Vary processing conditions (time, temp, pressure, etc.) to cause interactions in ingredients or change functionalities Holistic Approach No single replacer can do it all
Fat Mimetic Technology
Fat Reduction Success Story Miracle Whip brand salad dressing was one of Kraft's earliest successes at fat reduction, being introduced in the 1930's Miracle Whip was formulated to provide about half the fat of conventional mayonnaise using a starch gel at about one tenth the level of the fat that it was replacing Miracle Whip’s success over its 70+ year lifetime is in part due to the fact that it did not try to duplicate the product that it was replacing, but rather developed its own unique flavor and mouthfeel which is a function of the new macronutrient composition of the product
Spoonable Dressings Example
Full Fat Emulsion Products Have Multiple Phases (80%) (20%) (80%) (20%)
Something Needs to Replace Fat in Lower Fat Foods Passive Active
Fat Mimetic Mechanisms for Emulsion Products There are at least 5 mechanisms by which fat mimetic ingredients act to provide fat texture: Entanglement Network Gels Particle Gels Aggregates Non-interacting Particles Each provides different rheological properties to a product that the mimic dispersed or continuous phase of an emulsion product such as mayonnaise
Entanglement and Gelation Mimic Continuous Phase Long non-gelling, non-interacting polymers that have large spheres of hydration Provide slipperiness and viscosity Mimic the continuous phase of mayonnaise Examples are xanthan gum, carrageenan, polydextrose Network Gels Polymers interact with each other to form more or less permanent junction zones Provide yield stress and gel structure Mimic the “cut” of a mayonnaise Examples are pectin, alginates, gelatin
Particle Gels Mimic Dispersed Phase Network forms between polymers but is not continuous throughout the system Simplesse, “breakthrough” fat mimetic, is particle gel made by microparticulation of whey protein Mimic the dispersed phase of mayonnaise Performance affected by size, shape, surface properties, and rigidity (or deformability) of the particle Examples: colloidal cellulose and small particle starch Can also be formed by shearing network gels Provide creaminess and body
Interactions Between Particles (or Not) Particle Gel Aggregates Discrete crystalline or gel particles that reassociate with each other to form aggregate Similar in functionality and constraints to particle gels If aggregate is continuous, can mimic both dispersed and continuous phases Examples include starch gel, starch hydrolysates or microcrystalline cellulose (cellulose gel/cellulose gum) Non-Interacting Particles Inert particles Provide opacity and reduce cohesiveness Examples include uncooked or retrograded starch, crystalline cellulose
Microbiological Considerations Regardless of the mechanism, water is the main ingredient that replaces fat Fat mimetics hold water so that it builds texture like fat Shelf life and microbiological safety are affected by combination of water activity, acidity, salt, preservatives, heat treatment Addition of water requires increasing other safety measures Typically acidity of aqueous phase is increased Control of pH is critical Strong acidic notes affect overall sensory quality
Fat Mimetic Systems - KFM Ingredients: Water, modified food starch, sugar, high fructose corn starch, vinegar, soybean oil*, salt, cellulose gel, natural flavor, artificial flavor, egg yolks*, xanthan gum, mustard flour, lactic acid, cellulose gum, phosphoric acid, vitamin E acetate, lemon juice concentrate, dried garlic, dried onions spice, yellow 6, beta carotene, blue 1, with potassium sorbate and calcium disodium EDTA as preservatives *Trivial source of fat and cholesterol
Current Fat Mimetics Cannot Supply Full Fat Quality
Approach to Fat Mimetics Has Evolved Because of “missing attributes”, most food manufacturers have taken a step back from fat free The learnings from fat free days have allowed creation of more and better light, low-fat and reduced-fat products
Reduced Calorie Fat Substitutes
What Is the Logic Behind Fat Substitutes? Think like a lipase… ...what would make a triglyceride less appealing? C | H2- - H -O-C-(CH2)n-CH3 CH3-(CH2)n-C-O- O Change the backbone Change the fatty acid Change the linkage
Olestra Is Only FDA-approved Noncaloric Fat Substitute Chemistry: Different Backbone Sucrose: a disaccharide from glucose and fructose 8 hydroxyl groups for esterification Fatty acid esters at 6 to 8 sites Typical triglyceride Sucrose Octaoleate
Olestra Approved for Savory Snacks Current approval only in prepackaged ready-to-eat savory (i.e. salty or piquant but not sweet) snacks and prepackaged, un-popped popcorn kernels that are ready-to-heat Approved as food additive for savory snacks (chips, crackers, etc) in 1996 Ruling expanded in 2004 to include popcorn In 2003, FDA removed requirement for advisory label warning on products made with olestra
Absorption Decreases With More Esters Mattson and Volpenhein, J. Nutr. 1972
Does Olestra Function the Same As Triglyceride? Melting properties vary with fatty acid comp Composition limited to C16-C22, specified degree of unsaturation Physiological stability (measured by stiffness) requires incomplete melting Crystallinity, and polymorphic behavior of crystals, are not the same as TG Properties of certain fats (e.g. Cocoa butter) rely on specific crystal structures Emulsion properties (e.g. Size of droplet) partially dependent on viscosity
Triglycerides Can Be Low Calorie Too! Commercial options: Salatrim or Caprenin TG containing mixed long chain saturated fatty acid (LCFA, C18-22) with short or medium chain fatty acids (SCFA, C2-4 or MCFA, C6-10) Preferred Comp: 1 LCFA: 2 S/MCFA Approximate Caloric Content: 5 cal/g Low Cal due to poor absorption of LCFA
Salatrim/Caprenin Functionality Melting properties controlled primarily by length of short or medium chain fatty acid Melting Point (°C)
Replacing Trans and Saturated Fat
Trans Fatty Acids in Shortening Most difficult challenge has been to replace trans fat in shortening Solid fats are desirable in baked products Saturated fats were replaced by hydrogenated (trans) fats when health issues surrounding sat fat became known Science supports the link between trans fatty acids heart disease risk Trans fats elevate LDL cholesterol levels, lower HDL Major source of dietary trans-fat is partially hydrogenated vegetable oils
Trans Fat Replacement in Reduced Fat Snacks In the case of baked snacks (crackers and cookies) reformulation to reduce trans fat has been a multi-year research and development effort Liquid vegetable oils would be ideal ingredients because of their inherently low levels of trans-fat and saturated fat A non-hydrogenated, RBD (refined, bleached and deodorized) soybean oil was found to perform “adequately” in Nabisco’s SnackWells crackers and cookies owing to their low fat and reduced fat formulas (generally 2-3 grams of total fat per serving)
Trans Fat Replacement in Full Fat Snacks In comparable “full fat” products that contained > 4 fat grams per serving, the food matrix was insufficient to hold the liquid oil in place, Liquid soybean oil “drained” out of such a product by the action of gravity, and failed to deliver the buttery, signature flavor and light open texture expected by Ritz cracker consumers.
Trans Fat Replacement Solution First practical, low trans-fat solution involved the use of high melting point mono- and di-glyceride emulsifiers as minor components in liquid oils Used with Triscuit crackers, a product with a high surface area provided by a woven wheat structure The oil blend containing 4-8% emulsifier was topically applied to this product immediately upon its exit from the oven Worked with Triscuit and Wheat Thins, but not Ritz Needed to change the fat in the dough, as well as that brushed on top of the cracker
Fat Reduction/ Replacement: Summary Fat mimetics replace the fat in a product, though often sacrificing texture and/or flavor. For this reason, partial fat replacement is generally a more consumer acceptable approach Trans fatty acids can be replaced , though it is very difficult to remove these fats from baked foods. However, with investment of significant research efforts, success is possible and in fact can drive sales growth