Foam Mat Drying of Jujube (Ziziphus mauritiana) Juice: Process Optimisation, Physico-Functional, Phenolic Content and Antioxidant Analysis

Indian Jujube (Ziziphus mauritiana) is rich in minerals, vitamin C and amino acids. Jujube juice was converted into a powder by foam mat drying (FMD) using a minimum amount of maltodextrin. For FMD, drying temperature (Td; 45 °C, 55 °C, 65 °C), egg albumin (EA; 5, 10, and 15%) and maltodextrin (7%) were used as process parameters and optimized by RSM coupled with FFD. Solubility (84–79.7%) and L* (82.3–75.4) value of product decreased on increasing process parameters. Flowability decreased on increasing the EA concentration and drying temperature (≤ 55 °C) and thereafter increased. Total phenolic content (TPC) decreased with Td and increased with EA (≤ 11%) and thereafter decreased. Solubility, flowability, TPC, colour, aroma and taste showed a quadratic model. Models were validated by re-experimenting at optimum conditions which were found to 54.91 °C (Td), 11.563% (EA) with solubility (86.66%), flowability (1.109), TPC (20.769 mgGAE)/100 g), colour (ΔE; 11.7), aroma (6.565) and taste (6.717) having 81.3% desirability.