30G-9 |
Modification of minimally processed texture of mango cubes |
P. BANJONGSINSIRI, Department of Food Science and Technology, The University of Georgia, Food Science Building, Athens, GA 30602 and L. Wicker. Softening and loss of texture is a problem in fresh cut and minimally processed fruits and vegetables. To minimize softening, calcium infiltration, low temperature blanching and stepwise blanching increases firmness. However, low temperature blanching also activates detrimental enzymes. Infusion of exogenous pectinmethylesterase (PME) firms some fruits but it is not effective with others due to structure and presence of PME inhibitors. Our objectives were to test for a PME inhibitor in mango and optimize the process to improve the texture of mango cubes using external PME. To test for inhibitor, PME was extracted from mango (cv. Tommy Atkins), heated at 100 C between 1 and 2.5 min, mixed with Valencia PME, with residual activity determined by titration. Ripe mangoes were peeled and cut into 1.5 cm cubes. The first process: unblanched mango cubes were infused with Valencia PME (13-16 Unit/ml) under vacuum (84.65 kPa) for 10 min at room temperature. Pulsing infusion was the second experiment. Third, mango cubes were blanched for 2.5 min at 100 C and immediately submerged in Valencia PME with and without CaCl2 (100 or 1000ppm) at 4 C for 2 hr. Water treated mangoes were used as controls. Texture profile analysis (TPA) and puncture test were measured with Texture Analyzer. Mango extracts, heated for more than 1 min, did not affect on Valencia PME activity, whereas unheated mango decreased activity. TPA provided less variation and more characteristic information on texture. Unblanched, infused mango cubes were not significantly different from control, water infused. Pulsing infusion did not increase firmness. Temperature gradient infusion with Valencia PME increased firmness from 8.02 °¾ 3.29N to 13.25 °¾ 3.65N. A heat labile PME inhibitor was found in mango. CaCl2 did not enhance firmness. A large variation in texture between cubes was observed and firmness increase was greatest by temperature gradient infusion.
Session 30G, Fruit & Vegetable Product: Processed Fruits and Vegetables
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