61A-20 |
Effect of moisture and CMC concentration on the physico-chemical properties of masa-water mixtures |
Y. GAO and Y. Vodovotz. Dept. of Food Science & Technology, Ohio State Univ., 110 Parker FS&T Bldg., 2015 Fyfee Rd., Columbus, OH 43210 Carboxymethyl Cellulose (CMC) is a widely used hydrocolloid. In corn tortillas it helps maintain softness, thus increasing the shelf life of the product. CMC changes the rheological and thermal properties of the masa (dough) and the resulting tortillas. It increases the viscosity of the masa and during thermal processing, it is hypothesized to compete with the masa constituents for the water. Also during storage, the gum may inhibit retrogradation of gelatinized starch granules, influencing the flexibility of tortilla. Little is known about the interaction of the different components in the masa system at the super-structural level. The objective of this study was to better understand the effect of CMC concentration on the physico-chemical properties of masa-water mixtures during storage using thermal analysis techniques. Four different type of CMC with different viscosity were added at 0.125%, 0.25% and 0.5% levels to a masa/water system with 55% and 65% moisture, and heated in the Differential Scanning Calorimeter (DSC) pans to 210~{!c~}C. Samples were stored at 4~{!c~}C for 0, 1, 3, 5, 7, 14 days and analyzed by DSC after storage. The type and amount of CMC influenced the % ~{!0~}freezable~{!1~} water and amylopectin recrystallization found in the sample during storage. Increased CMC quantity and higher CMC viscosity resulted in a lower % ~{!0~}freezable~{!1~} water and amylopectin recrystallization after 14 days of storage. Additionally, water loss detected by Thermogravimetric Analysis (TGA) occurred at higher temperatures as CMC concentrations increased. It appeared that CMC was acting on the amorphous components in the system by competing for the water.
Session 61A, Carbohydrate
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