The Optimum Conditions for the Production of Dried Osmotic Dehydrated Karanda (Carissa carandas L.)

Abstract

         The aim of this research was to produce osmo-dried Karanda (Carissa carandas L.). The Karanda fruits at half-ripened stage were soaked in calcium chloride solutions of 0, 0.2, 0.4, 0.6 and 0.8 % (w/v) for pretreatment before osmotic dehydration process. After pretreatment, Karanda fruit juice at fully-ripened stage was added to osmotic solutions of 0, 10, 15, 20 and 25 % (w/v) during a fast osmotic dehydration process. Next, fruits samples were dried at a temperature of 60°C with a tray dryer at an air velocity of 4.2 m/s for 6 h. It was found that the use of 0.6 % calcium chloride could improve the appearance of the finished products compared to control treatment, resulting in a higher sensory score (9-point hedonic score) as evaluated in terms of overall acceptability (p≤0.05). The addition of 25 % of Karanda juice could improve the colour of the finished products, resulting in a higher sensory score as evaluated in terms of colour (score 8.15±0.87) and overall acceptability (p≤0.05). The addition of Karanda juice at fully-ripened stage can increase the amount of anthocyanin contents in finished products. Total microbial count values were less than 25 CFU/g and yeast and mould levels were less than 10 CFU/g. This study suggested that the addition of Karanda juice can increase the amount of anthocyanin contents and improve the osmo-dried Karanda sensory quality.