Response surface optimization of time and pressure for freeze-drying mango slices

Abstract

Mango is the second most-produced fruit in Indonesia, and the quantity of mangoes produced reached 2,624,791 tons at the end of 2018. This fruit is prone to rotting and getting wasted. Therefore, innovation is required to preserve mangoes by processing them into dehydrated food products using drying techniques. Freeze drying is still considered an efficient method to de-hydrate the water content in a product under mild process conditions, and it is mostly applicable to highly sensitive products. This study aims to determine the optimum processing parameters of drying time (13, 15, 17 hrs) and pressure (25 Pa, 30 Pa, and 35 Pa) to maintain the product quality of mango slices by using a response surface methodology. The results showed that the moisture contents are in accordance with SNI standards (less than 31%) with optimum moisture content (MC) values of 6.574%, total phenolic content (TPC) of 10.476 mg GAE/g, rehydration capacity (RC) of 2.852, colour (∆E) of 87.373, hardness of 1312.959, the cohesiveness of 0.549, and Springiness of 3.446 unit. This study also revealed that the optimum conditions of freeze-drying were at the time (t) 13 hrs and pressure (P) 25 Pa. It can, therefore, be concluded that freeze-drying can prevent changes in the structure of mango and help retain its good quality.