30C-15 |
Influence of glycerol on water mobility and textural changes in intermediate moisture (IM) turkey |
A. P. P. YANG1, Y. Kou2, Y. Kim1, and I. A. Taub1. (1) Defense Department, U. S. Army Natick Soldier Systems Center, Kansas Street, Natick, MA 01760-5018, (2) Food Science Department, University of Massachusetts, Amherst, MA 01003 Glycerol is known to be an effective humectant. However, the influence of this humectant on the food matrix and specifically on the water mobility is not clearly understood. Our objective was to study the relationship among moisture content (MC), water mobility (T1), water self-diffusion coefficients (D), and textural changes in intermediate moisture (IM) turkey of differing water activities with and without glycerol. Turkey roll containing either no glycerol (control) or glycerol was prepared. They were then dried to a water activity (Aw) of 0.96, 0.94, 0.92, 0.90, 0.88, 0.86, and 0.84 using a microwave-assisted freeze dryer. Moisture content was measured by AOAC method. A PCT20/20 NMR analyzer with a pulsed-field gradient (PFG) probe was employed to measure water mobility T1 at -20°C to 45°C and water self-diffusion coefficient (D) at 35°C. The operating frequency for 1H was 20MHz. Texture analyzer was used to measure the texture of the (IM) meats. For the same Aw, glycerol samples contained 5-7% more moisture than control samples. Both glycerol and control samples with higher Aw contained higher T1 values, whereas the former was more sensitive to temperature change than the latter. D values were sensitive to the Aw changes when Aw is higher than 0.90 for both glycerol and control meats. Texture became harder when the Aw was lowered, but appeared softer when glycerol was added. Glycerol, as a humectant, helps to hold the moisture in IM meats and therefore provides softer texture and better acceptance. Meat samples containing glycerol exhibit higher D values as compared to the control samples at the same water activity level.
Session 30C, Muscle Foods: Tenderness, Quality, Processing, Marination, Oxidation, and Shelf-Life
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