Drying Kinetics of Bilimbi (Averrhoa bilimbi L.) with Osmotic Dehydration Pretreatment Using Different Types of Sugar
La Choviya Hawa*, Aprillia Cahyani Putri, Salma Meidina Putri, Nabila Intan Milania

Department of Biosystem Engineering, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia
Email: *la_choviya[at]ub.ac.id

Abstract

Averrhoa bilimbi L., commonly known as bilimbi, is a fruit rich in vitamins and nutrients, frequently utilized as a culinary ingredient, beverage component, food additive, and traditional medicine. Its high moisture content renders it highly perishable. To extend its shelf life, a drying process employing osmotic dehydration pretreatment was applied to reduce moisture content. This study aimed to evaluate the effect of sugar type on mass transfer, as well as the influence of osmotic dehydration treatment and drying temperature variations on moisture content, drying rate, and physicochemical characteristics of bilimbi. Three types of sugar, namely glucose, sucrose, and maltodextrin, were used at a concentration of 40 percent, with three drying temperatures set at 50, 60, and 70 degrees Celsius using a forced convection drying method. The results indicated that sucrose was the most effective sugar, yielding the highest water loss and weight reduction, along with the lowest solid gain. Increasing the drying temperature resulted in lower final moisture content and higher drying rates. Samples pretreated with sucrose exhibited color values of L* = 38.78 to 41.15, a* = 14.48 to 16.11, b* = 70.30 to 71.06. The vitamin C content after osmotic dehydration with sucrose ranged from 21.99 to 48.68 mg per 100 g, with more pronounced cellular shrinkage. The Modified Page model best described the drying kinetics.

Keywords: Bilimbi- Drying- Osmotic dehydration

Topic: Agricultural and bioprocess engineering