Effect of drying method on volatile compounds, phenolic profile and antioxidant capacity of guava powders

We studied the chemical composition of oven and freeze dried guava powders for future use as antioxidant-rich flavour enhancers. Among thirty-one volatiles in guava powders, terpenes were predominant, even after both drying processes. In contrast, esters and aldehydes, volatiles characteristic of fresh guava fruit, appeared to have been decreased by drying. Insoluble phenolics were predominant and among the sixteen compounds identified, quercetin-3-O-rutinoside and naringenin corresponded to 56% of total phenolics. Drying processes decreased total phenolics contents by up to 44%. Oven drying promoted the release of insoluble flavonoids, generating mainly quercetin. Antioxidant capacity also decreased due to both drying processes, but guava powders still presented similar antioxidant capacity in comparison to other tropical fruit powders. Our results suggest that oven drying is a viable option for the production of a functional ingredient that would improve the phenolic content of cereal foods while adding desirable guava flavour.