Effect of Heat Treatment on Chilling Injury in Nang Klangwan Mongo Fruits
Warangkana Katawatcharakul
Thesis (M.Sc. Postharvest Technology) King Mongkut's University of Technology Thonburi, 2000. 94 p
2000
บทคัดย่อ
Effect of Heat Treatment on Chilling Injury in Nang Klangwan Mongo Fruits
Mango is climacteric fruit thus it inhibits various changes rapidly after harvesting. Low temperature could delay ripening of mangoes, though later, this technology was found to cause chilling injury. There are reports however, that subjecting fruits to high temperature prior to sufficient low temperature reduces chilling injury. Such technology has already been applied to various fruits. Hence a study the effect of heat treatment on chilling injury in Nang Klangwans mango fruits was conducted. Mangoes harvested at 110 days after full blooms were subjected to various heat treatment as follows: 5, 10 and 15 min at 46°C and 2, 5 and 8 min at 50 °C. The fruits were then incubated further at 5 °C for 35 days under 80-85 %relative humidity. Symptoms of chilling injury observed includes pitting and browning on the skin.In addition, hardening of some area in the pulp and abnormal ripening were also observed. Mangoes treated at 46 °C for 15 min prior to cold storage showed significant reduction in the chilling injury (CI) index compared to non-heated fruits. Accumulation of a protein with molecular mass of approximately 75 kDa, which might be heat shock protein was found. Moreover, the heated mangoes delayed fruit ripening, decreased soluble solids, respiration rate, ethylene production, pectinmethylesterase activity and polygalacturonase activity. on the other hand, the heat treatment did not affect fruit weight loss, firmness, color changes, titratable acidity and water soluble pectin at 5 °C. The results obtained demonstrate that heat treatment prior storage at low temperature reduces chilling injury in mangoes significantly, leading to the implication for mango and other fruits storage and exportation