Antioxidant Capacity and Shelf Life of Radish Microgreens Affected by Growth Light and Cultivars

Abstract

Microgreens are young, immature vegetables that contain higher concentrations of active compounds compared to mature vegetables and seeds. Radish microgreens are a good source of antioxidants, phenolic compounds, ascorbic acid, carotenoids, and anthocyanins. The production of microgreens is limited by their short shelf life due to higher dark respiration and accelerated senescence. The study was performed on three radish cultivars (Raphanus sativus L.): purple radish (cvP), red radish (cvR), and green radish (cvG). Radish microgreens were grown in chambers with controlled conditions (24 °C and a photoperiod of 16/8 h) under two types of artificial LED light (45 μmol m−2s−1): under white light (B:G:R) and a blue/red light combination (B:2R). The effect of the two types of light was examined on the 3rd, 7th, and 14th day after storage at a low temperature (+4 °C). The physiological status of the three cultivars of radish microgreens was examined by measuring the contents of total soluble phenolics, ascorbic acid, proteins, sugars, dry matter, anthocyanins, carotenoids, and chlorophyll as well as the total antioxidant activity. The results revealed that radish microgreens’ antioxidant capacity and phytochemical profile depend on the radish cultivar and on the type of LED light used for cultivation. It was shown that B:2R and red cultivar were most beneficial for the synthesis of most of the determined phytochemicals compared to B:G:R, or the purple and green cultivar, respectively. Storage at a low temperature in darkness slowed down most of the metabolic reactions during the first seven days, thus preserving most of the antioxidant activity.

Factors Affecting Production, Nutrient Translocation Mechanisms, and LED Emitted Light in Growth of Microgreen Plants in Soilless Culture

“…The agar−agar is mixed with the water, and mixtures of agar−agar + water are sprinkled on seed material containing growth media. 143,144 145 The harvesting period is 2−4 days for rice grass, 146 6−9 days for barley grass, 6−9 days for wheat grass, 147 6−9 days for oat grass, 148 8−12 days for jowar grass, 149 7 days for maize grass, 150 7−14 days for buckwheat, 151 4−6 days for mung bean, 152 6−8 days for chickpea, 153 12−14 days for mint, 154 20 days for basil, 155 18−20 days for sage, 156 16−22 days for oregano, 157 9−12 days for amaranth, 158 10−12 days for beet, 159 8−12 days for chard, 160 12−21 days for red swiss chard, 161 10−17 days for quinoa, 162 4−6 days for spinach, 163 14−25 days for chives, 164 12−14 days for garlic, 165 10−12 days for leeks, 166 12 days for onion, 167 15−25 days for carrot, 168 7− 21 days for dill, 169 21−30 days for celery, 170 10−14 days for fennel, 171 5−10 days for radish, 172 5−20 days for aster cress, 173 8−16 days for mustard, 174 7−12 days for sunflower, 175 7−21 days for linseed, 176 7−21 days for cucumber, 4−20 days for Jute, 177 7−21 days for squash, 178 7−14 days for chicory, 179 8− 16 days for endive, 180 7−16 days for lettuce, 181 7−21 days for beans, <...…”

“…The harvesting period is 2–4 days for rice grass, 6–9 days for barley grass, 6–9 days for wheat grass, 6–9 days for oat grass, 8–12 days for jowar grass, 7 days for maize grass, 7–14 days for buckwheat, 4–6 days for mung bean, 6–8 days for chickpea, 12–14 days for mint, 20 days for basil, 18–20 days for sage, 16–22 days for oregano, 9–12 days for amaranth, 10–12 days for beet, 8–12 days for chard, 12–21 days for red swiss chard, 10–17 days for quinoa, 4–6 days for spinach, 14–25 days for chives, 12–14 days for garlic, 10–12 days for leeks, 12 days for onion, 15–25 days for carrot, 7–21 days for dill, 21–30 days for celery, 10–14 days for fennel, 5–10 days for radish, 5–20 days for aster cress, 8–16 days for mustard, 7–12 days for sunflower, 7–21 days for linseed, 7–21 days for cucumber, 4–20 days for Jute, 7–21 days for squash, 7–14 days for chicory, 8–16 days for endive, 7–16 days for lettuce, 7–21 days for beans, 7–28 days for welsh onion, 9–21 days for long green onion, 7–16 days for coriander, and 6–14 days for fenugreek ( Table ) .…”

A comprehensive review on the antioxidant activities and health benefits of microgreens: current insights and future perspectives

“…The choice of cultivar is essential as different varieties of microgreens can exhibit significant variations in their antioxidant levels. Some cultivars may be specifically bred or selected for their higher concentrations of carotenoids, phenolic compounds, or vitamins, thereby enhancing their antioxidant potential (Martínez‐Ispizua et al ., 2022; Mlinarić et al ., 2023).…”

“…The development of bioactive compounds, flavour profiles, and visual appeal are all influenced by light spectrum, intensity, duration, and growing media (Zhang et al ., 2021). Microgreens have a short shelf life and need research into post‐harvest handling techniques to ensure they retain their nutritional value (Mlinarić et al ., 2023). Finding the best conditions for storing, the right kind of packaging, and the most up‐to‐date approaches to processing are all part of this.…”

“…While antioxidants are found in various plant parts like leaves, stems, and seeds (Sun et al ., 2017; Arumugam et al ., 2022), microgreens are particularly noteworthy for their enhanced nutritional profile. Studies have shown that varieties such as red cabbage, cilantro, garnet amaranth, and green daikon radish have elevated concentrations of essential nutrients and bioactive compounds, including ascorbic acid, carotenoids, phylloquinone, and tocopherols (Pinto et al ., 2015; Choe et al ., 2018; Mlinarić et al ., 2023). These concentrations can be up to 40 times higher than those found in fully mature plants under specific conditions (Xiao et al ., 2012).…”