UV-B irradiation for modulating the quality parameters during postharvest in green basil (Ocimum basilicum L.)

UV-B irradiation is a potential approach to modulate and enhance the antioxidant compounds in plants. This study was carried out to investigate the postharvest response of green basil exposed to UV-B treatments during cultivation to record the effects in the quality determinants of the produce. In an indoor UV-B chamber, a single wavelength of 315 nm light treatment was used on green basil at two different intensities of 43.2 and 86.4 kJ m‑2 for varying time span respectively. Analytical determination included chlorophyll a and b, carotenoids, phenolic index, anthocyanins, nitrates, total sugars contents, reducing sugars as well as sucrose. These parameters have been performed at 4 different stages with the first readings being recorded at harvesting stage (T0), then after three days (T3), 6 days (T6) and 9 days (T9) of cold storage. Interestingly, an increase was observed for total sugars as well as phenolic index of UV-B treated plants at T0 which gradually decline with the later time points, however, reducing sugars, sucrose, anthocyanins, nitrates, chlorophyll as well as carotenoids exhibited lower values compared to the control at this stage. Although UV-B treated basil for both treatments exhibited less accumulation of chlorophyll and carotenoids at T0 in comparison to control, yet at T3, T7 and T10 sustained a higher concentrations of these pigments, expressing a huge potential of UV-B for postharvest management. Additionally at T10, 86.4 kJ m‑2 UV-B treated basil maintained higher total sugars, reducing sugars, sucrose as well as phenolic index among all the studied treatments. Furthermore, anthocyanins accumulation under 43.2 kJ m‑2 showed a remarkable increased values throughout the experiment with a slight decreased values in T0 compared to the control. However nitrate contents remained lower in UV-B treated plants compared to the control at T0 and T3 but exhibited higher values at later time points of postharvest.