Evaluation of the Bioaccessibility of Antioxidant Bioactive Compounds and Minerals of Four Genotypes of Brassicaceae Microgreens

Abstract

Microgreens constitute an emerging class of fresh, healthy foods due to their nutritional composition. In this study the content of minerals and antioxidant bioactive compounds, and for the first time bioaccessibility, were evaluated in broccoli (Brassica oleracea L. var. italica Plenck), green curly kale (Brassica oleracea var. sabellica L.), red mustard (Brassica juncea (L.) Czern.) and radish (Raphanus sativus L.) hydroponic microgreens. Macro- (K, Ca, Mg) and oligo-elements (Fe, Zn), ascorbic acid, total soluble polyphenols, total carotenoids, total anthocyanins, total isothiocyanates and total antioxidant capacity (Trolox Equivalent Antioxidant Capacity and Oxygen Radical Absorbance Capacity) were determined before and after the standardized simulated gastrointestinal digestion process. All microgreens provided relevant amounts of vitamin C (31–56 mg/100 g fresh weight) and total carotenoids (162–224 mg β-carotene/100 g dry weight). Mineral content was comparable to that normally found in hydroponic microgreens and the low potassium levels observed would allow their dietetic recommendation for patients with impaired kidney function. Both total soluble polyphenols and total isothiocyanates were the greatest contributors to the total antioxidant capacity after digestion (43–70% and 31–63% bioaccessibility, respectively) while macroelements showed an important bioaccessibility (34–90%). In general, radish and mustard presented the highest bioaccessibility of bioactive compounds and minerals. Overall, the four hydroponic Brassicaceae microgreens present a wide array of antioxidant bioactive compounds.

Microgreen nutrition, food safety, and shelf life: A review

“…Radish and mustard were found to have the highest bioaccessable fraction (BF) for ascorbic acid, total carotenoids, and total isothiocyanates, while broccoli, kale, and radish all had comparable high BF for total polyphenols. Broccoli and mustard showed the lowest and highest BF values, respectively, for potassium and magnesium, while kale had the highest BF value for calcium (de la Fuente et al., ). Pinto et al.…”

“…The rate of accumulation slowed between 7 and 10 days in wheat and between 10 and 13 days in barley, but maximum values were obtained on the last harvesting day. Kale and mustard microgreens were noted to have lower ascorbic acid than their mature counterparts (de la Fuente et al., ). Some researchers reported that microgreens grown in a hydroponic system had lower concentrations of chlorophylls, carotenoids, phenols, and anthocyanins than in baby leaf or mature leaves of the same species (Bulgari, Baldi, Ferrante, & Lenzi, ).…”

“…de la Fuente et al. () evaluated the bioaccessibility of several antioxidant bioactive compounds and minerals in broccoli, kale, mustard, and radish microgreens grown hydroponically. Radish and mustard were found to have the highest bioaccessable fraction (BF) for ascorbic acid, total carotenoids, and total isothiocyanates, while broccoli, kale, and radish all had comparable high BF for total polyphenols.…”

Phenolic Constitution, Phytochemical and Macronutrient Content in Three Species of Microgreens as Modulated by Natural Fiber and Synthetic Substrates

“…Although several studies revealed that variation in microgreens' content of bioactive compounds is based on several pre-harvest factors such as genetic material (i.e., species), conditions of cultivation and light parameters (i.e., spectral quality and intensity), additional variables have also been implicated in shaping microgreens' nutritive and phytochemical composition, including nutrition/biofortification and choice of growth medium [4,10,[12][13][14][15][16][17][18][19][20][21]. Notwithstanding the short crop cycle, special attention must be placed on the selection of growth media for microgreens, which represents one of the most important factors in the production process influencing microgreens quality [22].…”

Setup of an Extraction Method for the Analysis of Carotenoids in Microgreens

“…Traditionally used for garnishing gourmet dishes, microgreens have been reconsidered over the last years as basic ingredients in several types of dishes [1], as well as for their potential in enhancing human diets due to relevant contents in micronutrients and phytochemicals [2][3][4][5]. In this regard, several reviews have been published in the last years [6][7][8][9].…”