30B-17 |
Heat shock proteins in refrigerated heat pre-treated mango |
D. M. LEON1, H. S. Garcia1, and M. A. Gomez-Lim2. (1) UNIDA, Instituto Tecnologico de Veracruz, M.A. de Quevedo # 2779, Col. Formando Hogar, Veracruz, Ver., 91897, Mexico, (2) CINVESTAV-Irapuato Tropical fruits like mango develop chilling injury at low temperatures. It has been found that a heat shock before refrigerated storage of mango reduced the severity of chilling symptoms in mango peel. It has been reported that after a heat shock new proteins are translated. These new proteins are known as heat shock proteins (HSP), HSP have been correlated with and increase in thermotolerance of plant cells and it has also been reported that HSP can protect cells against low temperature stress. The objective of this work was to evaluate if any changes in protein synthesis occur in mango after a heat treatment. Manila mangoes were harvested at Cotaxtla research station (INIFAP). Fruits were placed at 23, 12 or 6 ºC or heated at 38ºC for 12, 24 and 36 h and then stored at 6 or 12ºC for 20 days. Proteins from the pulp were extracted with Tris-HCl (pH 8) buffer and after centrifugation proteins in the supernatant were separated by SDS-PAGE. Total protein content was evaluated by Bradford. The protein content in Manila mango mesocarp increased during ripening. Eleven proteins were found in mango extracts 9 days post-harvest. Three proteins were detected in mesocarp extracts from mangoes that were preheated 36 h and refrigerated at 6ºC. These proteins were also present in control fruits. The protein pattern of mesocarp extracts from preheated mangoes that were refrigerated and then ripened was different. One protein of 73 kda was not present in gels and six new proteins 64,62,32,26,24 and 19 kda were found in treated fruits. In this study inhibition of normal proteins and production of new protein bands were found in mango mesocarp after heat treatment and refrigerated storage. These new proteins might be related to increased chilling tolerance that we have reported previously in Manila mangoes.
Session 30B, Fruit & Vegetable Products: Sensory, Product Development, Fresh-Cut, and Storage
|