14A-17 |
Effect of fat substitutes of different chemical nature on texture and microstructure of low-fat yogurt |
O. SANDOVAL-CASTILLA, Departamento de Preparatoria Agrícola, Universidad Autonoma Chapingo, Km 38.5 México- Texcoco, Texcoco, 56230, Mexico, E. Aguirre-Mandujano, Departamento de Preparatoria Agrícola, Universidad Autónoma Chapingo, Texcoco, 56230, Mexico, C. Lobato-Calleros, Preparatoria Agrícola, Universidad Autónoma Chapingo, Texcoco, Edo. Méx., 56230, Mexico, and E. J. Vernon-Carter, IPH, Universidad Autonoma Metropolitana-Iztapalapa, Mexico City, 09340, Mexico. The reduction of fat in the yogurt can alter microstructure, rate of syneresis, and therefore the texture properties. Little information is available on the impact of partially substituting fat by fat substitutes on the microstructure and texture of the systems where they are incorporated. The objective of this work was study the effect of the incorporation of fat replacers of different nature on their own and blended on the microstructure and texture characteristics of low-fat yogurt. Microparticulate whey protein (MWP), whey protein concentrate (WPC), and modified tapioca starch (MTS) were added individually and in blends to milk with 15 g/ L of milk- fat in concentrations recommended by the manufacturer. A yogurt control was elaborated with 30 g/ L of milk- fat (FFY). The microstructure of the different treatments was observed with Scanning Electron Microscopy (SEM), while the texture characteristics were evaluated instrumentally with a TATXT2i texturometer and sensorily with a trained panel. The decrease of the 50% of the milk-fat and the addition of the fat replacers affected the microestructure arrangement and texture of the low-fat yogurts. The incorporation of pure WCP or in combination with MWP yielded low-fat yogurts exhibiting a protein network similar to the FFY, whereas MWP gave way to a relaxed protein network, softer yogurt, and more prone to syneresis. MTS yogurts showed large void spaces where water was held in-between the casein micelle network. The mixture of WPC and MWP imparted sensory and instrument texture characteristics comparable to those exhibited by FFY. It is possible to effectively substitute milk-fat by fat replacers and attain a yogurt microstructure such that the instrumental and sensory texture perception are similar.
Session 14A, Dairy Foods: General developments in dairy technology I
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