Broccoli microgreens-apple juice as novel beverages: total phenolic, flavonoids and antioxidant activity

Abstract

Recently, microgreens have been recognized as a potential food of the future, and their application in the formulation of new products has been scarcely investigated. Only a few studies promote the use of microgreens and sprouts in the formulation of novel products, primarily beverages. The most often cultivated, analyzed and used microgreens are from the Brassicaceae family, because they present a good source of bioactive compounds, primarily glucosinolates, isothiocyanates and phenolic compounds. However, products from these microgreens species have a typical flavor, with herbaceous, grassy and sulphurous notes, often repulsive to consumers. Therefore, this study aims to examine total phenolic (TPC) and flavonoids (TFC) content, as well as antioxidant properties (ABTS•+ and FRAP) of novel sensorially acceptable broccoli microgreens-apple juice (BC-AJ). Previously produced coldpressed broccoli microgreens and apple juices were mixed in the ratios 51% and 49% respectively, and further analyzed by well-known spectrophotometric methods such as Folin- Ciocalteu's (TPC) and aluminum chloride (TFC) methods, as well as methods based on radical scavenging (ABTS•+) and ion reducing (FRAP) activities for evaluation of antioxidant properties. Results for the TPC and TFC of BC-AJ were 109.78 ± 1.08 mg GAE/100 mL and 64.68 ± 2.25 mg QE/100 mL, respectively. Furthermore, novel BC-AJ had a good ability to scavenge ABTS•+ radicals (162.90 ± 4.42 mg TE/100 mL) and a tendency to reduce [Fe3+- (TPTZ)2]3+ complexes (258.50 ± 3.26 mg TE/100 mL), probably due to the most diverse of phenolic compounds originated from broccoli and apple. Finally, broccoli microgreens-apple juice has a high content of phenolic compounds and good antioxidant properties, so it can be considered as a potentially functional beverage, but future research that includes additional in vitro and in vivo studies is necessary.