Impact of maltodextrin concentration on the properties of freeze-dried roselle (Hibiscus sabdariffa L.) powder and its effervescent tablet characteristics

Abstract

The potentially high therapeutic properties of roselle (Hibiscus sabdariffa L.) are limited by its poor stability during storage without additional preservation. To preserve roselle calyxes into shelf-stable powder, a problem arose due to the hygroscopicity of the powder, which drives the development of roselle powder into effervescent roselle tablets. This study first investigated the impact of varying maltodextrin concentrations as an encapsulation material on the physicochemical properties of freeze-dried roselle powder. Roselle calyxes were freeze-dried with the addition of maltodextrin at concentrations of 10%, 20%, and 30%. The powder properties, including analysis of moisture content, water activity, colour, bulk density, tapped density, particle size, and flowability, were analysed. This study observed that the concentration of carrier increased with bulk density (0.52 ± 0.02 - 0.67 ± 0.02), tapped density (0.71 ± 0.00 - 0.83 ± 0.01), and L* value (32.27 ± 0.56 - 45.03 ± 0.48) of colour. The optimum concentration of the carrier was 20% MD, as the powder had slightly poor flowability while retaining the colour. Then, this study aimed to produce effervescent roselle tablets using different percentages (60%, 70%, and 80%) of roselle powder with 20% MD and investigated the effect of different tablet formulations on the tablet characteristics. The tablet with 80% roselle powder was selected as the best tablet due to the high vitamin C content (6.600± 0.000), hardness value (2.649 ± 0.222), and pH of less than 6 (5.403 ± 0.015), and also received higher scores in terms of aroma (4.8 ± 1.0), flavour (4.4 ± 1.5), sourness (4.4 ± 1.3), and overall acceptability (4.8 ± 1.3) as compared to tablets with 60% and 70% roselle powder. Overall, the results confirm that incorporating freeze-dried roselle powder enables the efficient production of roselle tablets with enhanced quality and health-promoting potential.