Use of Carbohydrate-Based Fat Substitutes and Emulsifying Agents in Reduced-Fat Shortbread Cookies'

Cereal Chem. 72(l):25-29 Low-fat shortbread cookies were prepared using combinations of carboto analyze the experimental results. Processing modifications were neceshydrate-based fat substitutes (Litesse, N-Flate, Rice*Trin, Stellar, or Trimsary to make low-fat shortbread cookies. The principal effects of fat choice) and emulsifiers (diacetyl-tartaric esters of monoglycerides substitutes on shortbread cookie attributes were higher moisture content, [DATEM], glycerol monostearate [GMS], or sodium stearoyl-2-lactylate greater toughness, and lower specific volume. Fat substitution of 35% [SSL]). The experimental design was an incomplete randomized design had the least negative effects on the physical attributes. The combinations with two factors: fat substitute (at 35, 45, or 55% of shortening weight) N-Flate/ SSL and Litesse/ DATEM showed minimal differences in cookie and emulsifier (at 0.125, 0.25, or 0.5% of flour weight). Response surface breaking strength in comparison with the traditional shortbread cookie methodology and analysis of variance were the statistical techniques used at the three levels of fat substitution and 0.5% emulsifier. The U.S. Public Health Service has recommended that dietary fat consumption be cut to 30% or less of total caloric intake by the year 2000 (McDowell 1994). Preliminary data from the Third National Health and Nutrition Examination Survey (NHANES III) conducted in 1988-91 indicate that Americans currently are consuming about 34% of their total calories as fat, down from 36% in 1976-80 (NHANES II), but still considerably higher than the goal. Modification of the food supply through the use of fat substitutes is one way to achieve this goal. Substitutes are grouped broadly into either lipid-, carbohydrate-, or proteinbased materials. Carbohydrate-based substitutes incorporate water into a gel-type structure, resulting in lubricant or flow properties similar to those of fats in some food systems. It is likely that desirable textures can be achieved using those types of substitutes, and there are few regulatory obstacles regarding any toxicological potential (Hassell 1993). The baking industry has responded to the demands of consumers by developing lowor reduced-fat products, defined as those foods that have at least one-third fewer calories than an equivalent serving of a normal counterpart. The reduced-calorie product also must not be nutritionally inferior to the standard similar product (Vetter 1991). Low-fat products normally contain fat substitutes and are produced using formula or processing modifications. Until now, most cookie products with reduced fat levels have had chewy texture, intermediate final moisture content, and nontraditional snap characteristics (Vetter 1991). Flavor, texture, and appearance of baked products are affected by types and amounts of fat used (Pyler 1988). The primary function of fat is to create more tender products and shorter doughs. Fat lubricates the structure by being dispersed in the dough or batter during mixing and helps prevent the starch and protein from forming a continuous network. The sensation of a fatty mouthfeel is formed by a combination of several poorly defined or quantitated parameters including viscosity, absorption, cohesiveness, adhesiveness, and waxiness (Glicksman 1991). Replacement of the sensory properties of fat is difficult in lowmoisture bakery foods like cookies, with a final moisture between 3-4% (Vetter 1991). Normally, increased levels of water are needed to replace high levels of fat, and a means of stabilizing the extra water is necessary (Jackel 1990). In addition to low moisture 'Contribution 94-372-J of the Kansas Agricultural Experiment Station. 2 Universidad Ezequiel Zamora, Carretera Via Manrique, San Carlos, Estado Cojedes, Venezuela. 3 Department of Grain Science and Industry, Kansas State University, Manhattan. @ 1995 American Association of Cereal Chemists, Inc. contents, cookies are characterized by high levels of sugar. Sugar competes with the starch and gluten for water, so little or no starch gelatinization occurs during baking. Shortbread cookies traditionally contain about 24% fat (USDA/ HNIS 1991). The dough has a very low moisture content, and cohesiveness is the result of fat coating the flour particles. The rotary mold method normally is used to form shortbread cookies. The dough should be well mixed and slightly crumbly but have enough cohesiveness to retain its shape on removal from the mold (Pyler 1988). One option available for reducing fat or calories in this commercial product is to replace part of the fat with carbohydrate-based fat substitutes like maltodextrins, modified food starches, or polydextrose compounds. In addition, the incorporation of emulsifiers has been proposed (Vetter 1991) to reduce interfacial tension and increase the effectiveness of the fat, allowing less to be used. Sodium stearoyl-2-lactylate (SSL) at 0.5% of flour weight effectively improved quality, increased spread, and produced a finer more uniform pattern of surface cracks in sugar snap cookies (Tsen et al 1975). The optimum level for improving the eating quality and permitting shortening reduction was found to be 0.75% (Hutchinson et al 1977). The natural emulsifier lecithin is a complex mixture of phospholipids that provide the majority of its surface-active properties. In some cases, lecithin acts synergistically to improve the functionality of SSL and monoglycerides (Central Soya 1990). In addition, lecithin provides drier doughs that machine better and release well from rotary die faces (Pyler 1988). Monoand diglycerides, including glycerol monostearate (GMS), are the emulsifiers perhaps used most commonly to replace fats in bakery foods. Diacetyl tartaric acid esters of monoand diglycerides (DATEM) have a favorable balance between hydrophilic and lipophilic groups, have a high anionic affinity, and are capable of interacting with the flour protein (Pyler 1988). When shortening in the cookie dough is reduced, the incorporation of these emulsifiers at levels of 0.125 to 0.75% (flour weight) at the first step or creaming phase of mixing results in considerably softer cookies (Hutchinson et al 1977). The objective of this study was to evaluate the effects of reduced fat content in shortbread cookies using combinations of carbohydrate-based fat substitutes and emulsifiers.