30G-35 |
Inhibiting irradiation induced softening in diced tomatoes using a calcium treatment |
R. L. MAGEE1, F. Caporaso, and A. Prakash. (1) Dept. of Food Science and Nutrition, Chapman University, One University Drive, Orange, CA 92866 Although irradiation can improve safety and extend the shelf-life of fresh produce, solubilization of pectic substances can cause textural softening due to loss of structural integrity of the fruit and vegetable tissue. Calcium treatments have been shown to reduce solubilization of pectic substances, thus maintaining firmness. Research on combining irradiation with a calcium treatment is limited. The objective of our study was to determine the effects of calcification prior to irradiation on the firmness and pectic substances of diced tomatoes. Diced tomatoes were dipped into either 0.2% CaCl2, 1% CaCl2, or 2% calcium lactate solution for 1 minute, drained, and exposed to gamma irradiation at 1.25 kGy from a Co60 source. The diced tomatoes were analyzed for water soluble pectin (WSP), oxalate soluble pectin (OSP), and total pectin and firmness was measured using a texture analyzer with a Kramer Shear probe. Calcification of diced tomatoes increased the firmness in all samples. Calcium lactate had the greatest impact on firmness, increasing firmness by 48% as compared with the control. Irradiation at 1.25 kGy decreased firmness in all samples with the greatest loss in the control (35%), where as, 1% CaCl2 and 2% calcium lactate remained significantly firmer than the control following irradiation. After 8 days of storage at 4 °C, diced tomatoes dipped in 1 or 2% calcium salts maintained firmness, while the 0.2% CaCl2 and control samples were considerably softer. Yields of WSP decreased and OSP increased with increasing calcium dip concentration. Irradiation decreased WSP slightly and had no effect on OSP. Loss of texture, the limiting factor in acceptability of irradiated-diced tomatoes, can be prevented by using calcium dips.
Session 30G, Fruit & Vegetable Product: Processed Fruits and Vegetables
|