Effects of drying conditions on total phenolic content and other parameters of soursop jelly (Annona muricata L.)

Abstract

Annona muricata Linn. (soursop) belongs to the family Annonaceae. This plant had been traditionally used for treatment of various infectious and inflammatory diseases. This study aimed to determine the effects of convection drying on the nutrient composition of the plant. Measured indicators included protein content, ash content, fat, total ascorbic acid content (TAA), total phenolic content (TPC), color and sensory level of soursop. At different temperatures of 40°C, 50° and 60°C, the evaluation criteria change significantly when supplemented with °Brix at 10%, 15% and 20%. Highest protein content achieved at 20% soluble solids concentration was 2.71 ± 0.09 and 2.68 ± 0.01 at 40 and 60°C, respectively. Most of the percentage of ash of the sample was unaffected and the change of the fat content is negligible. Moreover, TAA and TPC were found to decline after the process. About 68.62% TAA was retained when drying at 40°C (20% Brix) and the figure for TPC was 38.46% (60°C, 10% Brix). Typically, in the L* color space, all samples exhibited the value of higher than than 55 and there is a tendency to give a white color. In addition, the a* and b* values increased after drying. Optimal parameters are selected based on the commercial nature of the product and the retention of nutritional value. Final results consisted of the addition of 10% syrup sugar (60 ° Brix) in the sample under the temperature of 40 ° C for 390 minutes.