Table 2.
Postharvest UV and visible spectrum lighting as elicitors of phytochemicals and preservative techniques for sprouts, microgreens, and baby leaves.
| Light Stimuli | Light Conditions | Species | Shelf Life | Major Findings | Ref. |
|---|---|---|---|---|---|
| Sprouts | |||||
| B (465 nm), R (660 nm), FR (730 nm) | 35 μmol m−2 s−1 | Broccoli | 15 d 5 °C 90% RH |
R and FR increased the sprout length and decreased the microbial load. | [87] |
| W (610 nm), G (517 nm), Y (600 nm) |
35 μmol m−2 s−1 | Broccoli | 15 d 5 °C 90% RH |
W and Y increased phenolic accumulation (+86%). Y increased glucosinolate accumulation (+84%). G slightly increased the accumulation of glucosinolates. | [88] |
| UV-B (394 nm), UV-C (245 nm) | 2 doses of 7.5 W m−2 UV-B and/or 4.5 W m−2 UV-C | Broccoli Radish |
10 d 4 °C 90% RH |
UV-B increased glucosinolate (+38%) and isothyocyanate (+72%) contents in broccoli and radish sprouts, and maintained it during their shelf life. | [10] |
| UV-A (360 nm), UV-B (300 nm) | 9.47 W m−2 UV-A or 7.16 W m−2 UV-B | Broccoli | 1 d at room temperature | UV-A and UV-B increased the accumulation of phenolics, flavonoids, carotenoids, chlorophylls, and glucosinolates. | [9] |
| UV-A (360 nm), UV-B (300 nm) | 3.16 and 4.05 W m−2 UV-A or 2.28 and 3.34 W m−2 UV-B | Broccoli | 1 d at room temperature | High doses of UV-A and UV-B increased the accumulation of phenolics, flavonoids, and glucosinolates. | [2] |
| Microgreens | |||||
| UV-B (300 nm) |
0.18 and 0.36 W m−2 | Broccoli | 21 d 4 °C 90% RH |
UV-B + CaCl2 increased glucoerucin and glucosinolates. | [89] |
| Fl (400–780 nm) |
30 μmol m−2 s−1 | Daikon radish | 16 d 5 °C |
Light exposure increased and mantained the ascorbic acid content. | [90] |
| Baby Leaves | |||||
| W (610 nm), B (465 nm), G (517 nm), Y (600 nm), R (660 nm), and FR (730 nm) |
35 μmol m−2 s−1 | Red chard and rocket | 10 d 5 °C 95% RH |
B and Y reduced the microbial load, whereas G and W kept the colour and enhanced the pigment concentration. R and B increased the antioxidant activity. |
[91] |
| W (400–780 nm) |
5–20 μmol m−2 s−1 | Pak choi | 7 d 20 °C 90% RH |
10 μmol m−2 s−1 delayed senescence by reducing respiration and accumulation of MDA and stimulating antioxidant gene expression. | [92] |
| B (400–499 nm), R (600–699 nm), and FR (700–780 nm) |
10–70 μmol m−2 s−1 0–24 h light/24–0 h darkness | Pak choi | 5 d 20 °C |
35 μmol m−2 s−1 for 8 h R per day inhibited senescence. | [93] |
| W (400–700 nm) |
91 μmol m−2 s−1 | Pak choi | 5 d 20 °C |
Chlorophyll and glucosinolate biosynthesis were induced by W. | [94] |
| B (460 nm) |
10, 20, 30 μmol m−2 s−1 | Amaranth | 12 d 4 °C 90% RH |
Sensory scores and antioxidant capacity were increased, whereas spoilage bacteria Pseudomonas was reduced. | [95] |
| Fl (400–780 nm) |
36 μmol m−2 s−1 12 or 24 h/12 or 0 h darkness | Mustard | 6 d 20 °C 75% RH |
24 h light maintained sensory quality, avoided deterioration, and retarded losses of sugars, vitamins, antioxidants, and glucosinolates. | [96] |
UV-A: ultraviolet-A; UV-B: ultraviolet-B; UV-C: ultraviolet-C; Fl: fluorescent lights; B: blue LED; G: green LED; Y: yellow LED; R: red LED; FR: far-red LED; W: white LED. MDA: Malondialdehyde.