Flavor and Texture Characteristics of Foods Containing Z-Trim Corn and Oat Fibers as Fat and Flour Replacers!

To detennine the effects of panial replacement of fat and flour in foods with Z·Trim corn and oat fibers, brownies and ground beef patties containing Z·Trim were evaluated for flavor and texture characteristics. A cake·like brownie formulation containing 26% fat (control) was pre· pared with 0, 25, 50, 75, and 100% fat replacement using ·four levels of Z·Trim corn fiber at 0.18, 0.36, 0.55, and 0.73% by weight of total ingredients. In samples containing fat replacer, the flour level was half that of the control. The calories per gram of brownie for the full-fat product was 3.4 compared to 1.6 for the brownie with 100% fat replacement and 50% flour replacement. A trained sensory panel reponed that replacing either 50. 75. or 100% of the fat in addition to 50% of the flour with the addition of Z·Trim corn fiber significantly increased moistness. density, and cohesiveness compared to the control. The fat content of 89% fat-free ground beef was reduced to 93% fat·free with Z·Trim oat fiber or a Z-Trimloatrim blend at I and 1.5% addition by weight with 10% water. Sensory analySIS of flavor and texture of the beef patties showed slight decreases in beef and fatty flavors and increases in texture characteristics of tenderness and juiciness. In many foods, fat content directly relates to palatability. For example, fat creates more tender baked products, and in ground beef. fat is essential for beefy flavor, juiciness, and tenderness (I). The mouthfeel characteristics attributed to fat are a combination of several parameters including viscosity, absorption, cohesive· ness, adhesiveness, and waxiness (2). Americans currently consume approxi· mately 34% of their calories as fat; however, recommendations state that total daily fat intake should not be more than 30% of total caloric intake (3). Taste is generally the number one reason people select a I Names are necessary to repon factually on avail· able data; however. the USDA neither guarantees nor warrants the standard of the product. and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. 2 Food Quality and Safety Research and Biopoly. mer Research. respectively. National Center For Agncultural Utilizauon Research. Agncultural Research Service. U.S. Department of Agriculture. Peoria, IL 61604. 3 To whom correspondence should be addressed: National Center For Agricultural Utilization Research. 1815 Nonh University Street. Peoria. IL 61604; 309/681-6584/-6555; Fax 309/6816679; E·mail [email protected]. Publlcallon no. W·1997·0905-03R. This article is in the public domain and not coPyrillhl' able. II may be freely repnnted with customary credrtlng 01 the source. Amencan Assoclallon 01 Cereal Chem· iSIS. Inc.. 1997. panicular food; the poorer flavor quality associated with a reduced fat diet may help explain consumers' inability to adhere to this type of diet (4). To help alleviate this problem, researchers have attempted a variety of methods to decrease fat in foods while preserving flavor. Previous research showed that panial or complete fat replace· ment caused foods to have unfavorable characteristics such as loss of or imbalance of flavor (5). For example, Sanchez and coworkers (6) found that reduced fat cookies had a chewy texture and low moisture content, whereas Brewer and coworkers (I) reponed that ground beef panies with only 8% fat were more rubbery and less juicy than were panies with 20% fat. Flavor, texture, and appearance of baked products are affected by types and amounts of fat used; therefore, fat replacers in baked products need to be able to act as fat does by aerating the batter, maintaining flavor, and providing a moist mouthfeel. The ideal fat replacer would duplicate all of the funcllonal features of fats without contributing any calones. Of the cammer· cial fat replacers available, 50% are carbohydrate based. According to Bath and coworkers (7), processed (swollen) starches that remain intact could duplicate the mouth sensation of fat. Deis (8) reponed that carbohydrates imitate fat by binding water to proVide lubrication, slipperiness, body, and mouthfeel. Research has been published on effects of carbohydrate fat replacers in a variety of food products. Inglett and coworkers (9) replaced shonening in oatmeal raisin cookies with oatrim gel at 50, 75, and 100% levels. An analytical sensory panel did not find significant differences in flavor and texture between cookies with 50% fat substitution and the control (0% fat replacement) cookies; however, differences were observed between the control and cookies with 75 and 100% levels of fat substitution. Hipple· heuser and coworkers (10) used a carbohydrate-based fat replacer in muffins to compare a commercial full·fat (27%) control with muffins containing only 5% fat (low. fat control) and 5% fat muffins with either I or 2% pregelatinized dull waxy corn starch. Results from sensory evaluations indicated that the low-fat muffin formula· tion with 2% starch was preferred overall to the full-fat control. Crumb structure of the sample with 1% pregelatinized starch was preferred over the 5% fat (low·fat control) muffin, and moistness/softness of the full·fat control was preferred over the muffin with I% starch. In research on starch-based fat replacers in high-ratio layer cakes. Bath and coworkers (7) found that cakes baked without any shonening had low volume and dense internal structure, but acceptable cakes were made with complete fat replacement using corn or rice starch with or without the addition of protein, guar gum, or emulsifiers. Research has shown that consumers prefer ground beef containing 15-20% fat for palatability (II). As fat content of ground beef decreases, there is a corresponding decrease in beef flavor intensity, juiciness, and tenderness (1,12,13). Giese (13) reo poned that textural propenies of meat (cohesiveness, hardness, and density) were influenced by fat level for all cooking techniques. Less hardness, lower density, and decreased cohesiveness during initial biting of the samples accounted for the increased tenderness associated with higher fat levels. According to Berry's (12) observations, shear force increased with de· creasing fat content; however, more pro· nounced differences were noted at lower CEREAL FOODS WORLD 1821 Table I. Compositions< and Fonnulations of Brownies With and Without z.Trim Corn Fiber Table II, Compositions and Fonnulations of Ground Beef Patties With and Without Z.Trim Oat Fiber or Z·Trim Oat Fiber:Oatrim 5 (1:1) Fig,!. Flavor/taste intensity scores for brownies with 0-100% fat replacement, 50% flour replacement, and 0-2.8% Z·Trim addition. MATERIALS AND METHODS