Effect of drying conditions on the retention of phenolic compounds, anthocyanins and antioxidant activity of roselle ( Hibiscus sabdariffa L.) added to yogurt

Summary To evaluate the use of lixiviate roselle calyxes as an alternative source of bioactive compounds, they were subjected to dehydration in a vibrofluidised bed dryer after which some chemical parameters such as the retention of monomeric anthocyanins (MA), phenolic compounds, polymeric colour and antioxidant activity were determined. Drying curves showed both a constant drying period and a decreasing falling rate period. The different drying conditions showed significant differences in the chemical parameters. Using the dry residue with the best bioactive compounds content, it was possible to develop a dairy beverage (yogurt). The results confirmed that lixiviated roselle calyxes could be a competitive alternative for traditional products, such as grapes or bilberries, in terms on their antioxidant activity and stability when it is added as a source of bioactive compounds.