Potential bioactive ingredient from elderberry fruit: Process optimization for a maximum phenolic recovery, physicochemical characterization, and bioaccesibility

BACKGROUND: Dark-skin berries constitute a polyphenol-rich source of interest for the development of functional ingredients. OBJECTIVE: To develop an elderberry powder, addressing technological aspects for maximum bioactive recovery, including physical quality and bioaccesibility of the antioxidant compounds. METHODS: An optimization of the combined process of enzyme-assisted extraction and freeze-drying was undertaken. Polyphenols and anthocyanins were quantified by spectrophotometric and HPLC-DAD analysis along processing stages and an in vitro digestion model was used to study the antioxidant compound activity through gastrointestinal tract and after transepithelial transport across a Caco-2 cell monolayer. Powder physical properties were also evaluated. RESULTS: The best extraction conditions were 45 degrees C and 160 ppm enzyme. 10% maltodextrin was the minimum carrier concentration needed to get a freeze-dried powder with good physical properties and maximum bioactive content. The phenolic compounds identified in fruits (mainly cyanidin-based anthocyanins, quercetin-3-rutinoside, catechin and, in smaller amounts, gallic and chlorogenic acids) were also present in the optimum extract and the powder. High bioaccesibility of bioactive compounds and antioxidant activity were obtained after in vitro digestion and transepithelial transport. CONCLUSION: The designed elderberry powder showed great potential as functional ingredient to be used in berry juice-based beverages or other products formulated with fruit powders.