Optimization of drum drying parameters for gac powder

Food Engineering Department, Faculty of Engineering, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand

^* Corresponding author: maradee.ph@kmitl.ac.th

Abstract

Gac (Momordica cochinchinensis Spreng.) is a tropical fruit which contains a rich nutrient source, especially lycopene. However, fresh gac fruit can spoil rapidly due to its high moisture content. Drum drying is a process to remove moisture from food in order to preserve nutrients and extend shelf life. In this study, gac fruit powder was produced by using drum drying technique. The present research was aimed to determine the optimum drum drying condition for gac powder. Response Surface Methodology was employed with three processing variables, including drum surface drying temperature (115, 125, 135˚C) maltodextrin content (100, 150, 200%) and gum arabic content (10, 20, 30%). The response variables were moisture content, solubility, hygroscopicity, total phenolic content and lycopene content of gac fruit powder. Regression analysis was then performed to obtain the mathematical relation between the processing variables and the responses in the form of second-order polynomial equations.. The results showed that optimum conditions for drum drying of gac fruit was at 135˚C of drum surface drying temperature, 138% of added maltodextrin and 10% of added gum arabic, which provided the highest amount of total phenolic and lycopene content.