"Enhanced bioaccessibility of encapsulated red mizuna microgreens: A phytochemical profile approach"

Abstract

Microgreens of the Brassicaceae family have garnered considerable interest due to their higher phytochemical content compared to their mature counterparts. These bioactive compounds include phenolic compounds, glucosinolates, and isothiocyanates. This study evaluated their bioaccessibility and antioxidant capacity in red mizuna microgreens, sodium alginate-encapsulated microgreens, and an aqueous reference standard mixture using the standardized INFOGEST digestion model.

Alginate capsules exhibited significantly higher bioaccessible antioxidant activity by TPC assay (83.64% ± 9.02%) than raw microgreens (46.28% ± 1.35%, p < 0.005) and aqueous mixture (0%). The DPPH assay showed a bioaccessibility of 19.69% ± 2.26% in raw mizuna and 0% in the aqueous mixture. However, individual phenolic compounds were more bioaccessible in raw microgreens (98.39 ± 3.60 mg 100 g⁻¹ DW) compared to alginate capsules (60.54 ± 1.56 mg 100 g⁻¹ DW) and aqueous mixture (0%), with flavanols predominating. Glucosinolates were 22% bioaccessible in alginate capsules but undetectable in raw red mizuna's intestinal phase and aqueous mixture. Isothiocyanate concentrations were significantly higher in encapsulated microgreens (248.53 ± 15.57 μg g⁻¹) than in raw microgreens (163.51 ± 4.28 μg g⁻¹, p < 0.005), while none were detected in the aqueous mixture. The reference standard mixture showed no bioaccessible compounds in any assay, highlighting the food matrix's protective role.

These findings suggest alginate encapsulation enhances glucosinolate and isothiocyanate bioaccessibility while protecting compounds during digestion. However, it may not favor the release of certain phenolics. This research provides insights into functional food development, indicating that encapsulation strategies could optimize the bioavailability of microgreen derived phytochemicals.