Effects of Core/Wall Ratio and Inlet Temperature on the Retention of Antioxidant Compounds during the Spray Drying of Sim (Rhodomyrtus tomentosa) Juice

Sim (Rhodomyrtus tomentosa) fruit is rich in antioxidants including phenolics and ascorbic acid. In this study, maltodextrin was used as encapsulating agent in spray drying of sim juice to yield the powder. The effects of core/wall ratio and inlet temperature of drying agent on the retention of antioxidants during the spray drying of sim juice were investigated. Decrease in core/wall ratio from 1:1 to 1:4 led to lower moisture content of the powder and higher retention of phenolics and ascorbic acid. Further decrease in core/wall ratio from 1:4 to 1:5 reduced the antioxidant retention due to high viscosity of the feed solution. When the inlet temperature of drying agent augmented from 150 to 180C, the moisture content of the powder decreased and the retention of antioxidants increased. Increase in inlet temperature from 180 to 190C had detrimental effect on the antioxidant retention during the spray drying of sim juice. PRACTICAL APPLICATIONS: Sim juice is a significant source of antioxidants. The present study investigated the preparation of sim powder from sim juice by spray drying. The effects of two technical parameters, core/wall ratio and inlet temperature of drying agent, on the retention of antioxidants in the sim powder during the drying process were presented. Moreover, the effects of these parameters on the powder moisture content and the storage stability of powder were also studied. These results would be useful for food researchers on the field of drying technology and for food manufacturers who look for new inexpensive source of antioxidants.