Characterization of amaranth (Amaranthus tricolor L.) microgreens juice encapsulated within inulin and maltodextrin

Abstract

Amaranth microgreens represent a rich source of betalains and phenolic compounds, which show a broad range of positive effects on human health. However, these biocompounds are very sensitive and easily degraded, which often limits their application and bioaccessibility. For the above reasons, natural extracts and juices are most often encapsulated using different carriers, which protect and control the release of bioactive compounds. The aim of this study was to encapsulate cold-pressed amaranth (Amaranthus tricolor L.) microgreens juice using maltodextrin (AMD) and inulin (AIN) as carriers and to investigate total phenolic content (TPC), total flavonoid content (TFC) and antioxidant properties (ABTS•+ and FRAP) of obtained spray-dried powders. To the best of our knowledge, this is the first report on the encapsulation of amaranth microgreens juice. Before analysis, both powders were reconstituted in Milli-Q water (5% solutions) and analyzed using well-known spectrophotometric methods. The results are expressed in mg equivalents (gallic acid, quercetin, Trolox) per 100 g encapsulates. The obtained values for TPC and TFC for AMD were 291.7 ± 3.0 mg GAE/100 g and 291.3 ± 2.5 mg QE/100 g, while values for AIN were 356.9 ± 1.0 mg GAE/100 g and 289.6 ± 3.8 mg QE/100 g. The results of antioxidant activity were as follows: 546.3 ± 12.6 mg TE/100 g (AMD) and 745.2 ± 3.1 mg TE/100 g (AIN) for ABTS•+ and 713.3 ± 8.4 mg TE/100 g (AMD) and 905.1 ± 4.5 mg TE/100 g (AIN) for FRAP. Finally, maltodextrin and inulin can be successfully used for the encapsulation of bioactive compounds of amaranth microgreens. In addition, both powders show good antioxidant properties and can be used in the food industry as potentially novel additives or supplements.