author(s)
Shoba S, Pandiarajan T, Shashidhar KC, Ganapathy S, Shylaja S and Gautham S

abstract
Mango fruit fly (B. dorsalis) is a major pest in mango, which causes a substantial economic loss to the tune of 27 – 80 percent at the pre-harvest and post-harvest stage of mango production. Mango varieties such as ‘Banganpalli’, ‘Alphonso’ and ‘Totapuri’ are most susceptible to fruit fly infestation. Therefore, mango fruit fly is considered as a pest of quarantine importance in the mango trade. The engineering properties of foods invariably influence the quality of food products in terms of visual characteristics and basic functionality. The internal and external characteristics such as size, shape, colour, weight, specific gravity, % T A, pH, TSS, volatile compounds, carotenoids, vitamins and volatile compounds determine the quality of mango fruits. Emissivity is one of the thermal property which attribute the quality of food materials. Emissivity is defined as the ratio of energy emitted from an object to that of a black body at the same temperature. The thermal emissivity of healthy and fruit fly infested mango fruits of the varieties ‘Alphonso’ and ‘Totapuri’ was determined using thermal imaging technique. It was found that there was significant difference in the thermal emissivity of healthy and fruit fly infested fruits at the same heating conditions due to the changes in internal structure and composition of fruit fly infested mango fruits. It was also observed that, there was variation in thermal emissivity between the varieties which may attributed to the difference in the varietal characteristics such as peel thickness and pulp content of ‘Alphonso’ and ‘Totapuri’ mango fruits.