Instant soluble roselle (Hibiscus sabdariffa L.) powder rich in bioactive compounds: Effect of the production process on volatile compounds

This study investigated the optimum extraction conditions of bioactive compounds from roselle (Hibiscus sabdariffa), the effect of the air inlet temperatures of spray drying on the final product, and variations in the volatile compounds during converting the plant extracts into soluble powder forms. The extraction was conducted at 54 degrees C for 120min to obtain extracts with superior total phenolic content (TPC) (2032.71mg GAE/100g), total anthocyanin content (TAC) (995.37mg Dp-3-sam/100g), DPPH radical scavenging activity (9.48g sample/g DPPH), and ABTS radical scavenging activity (3326.15mg TEAC/100g). The powder forms of the extracts were produced at air inlet temperatures of 165 and 200 degrees C by spray drying and the process was confirmed by FTIR spectroscopy. An increment in air inlet temperature improved the microencapsulation yield (MY) (76.53% for 165 degrees C and 80.83% for 200 degrees C) but adversely affected the solubility (96.86% for 165 degrees C and 90.22% for 200 degrees C). The HPLC results showed that anthocyanins tended to degrade in powders produced at higher temperatures. No interaction was detected between process temperatures and antioxidant properties (p > 0.05). However, there were remarkable changes in the concentration of volatile compounds during the process.