Light Emitting Diodes for Agriculture by S Dutta Gupta

Author:S Dutta Gupta
Language: eng
Format: epub
Publisher: Springer Singapore, Singapore

8.3 Carotenoids

Carotenoids are lipophilic isoprenoid and are broadly presented in fruits and vegetables (Botella-Pavia and Rodriguez-Concepcion 2006; Kopsell and Kopsell 2006; Maiani et al. 2009; Cuttriss et al. 2011; Flores-Perez and Rodriguez-Concepcion 2012). According to various sources in the literature, 500–700 carotenoids have been known in nature. People regularly uses 40 of them (Stahl and Sies 2005; Kopsell and Kopsell 2006). Generally, carotenoids have such functions as free radical scavenging, improving the immune response, repressing cancer development and defending eye tissues. α-Carotene (AC), β-carotene (BC) and β-cryptoxanthin, lycopene are mostly related to decrease of cardiovascular diseases. Zeaxanthin (ZEA) and lutein (LU) protect eyes from light-induced damage. (Botella-Pavia and Rodriguez-Concepcion 2006; Kopsell and Kopsell 2006). In plants, carotenoids are light-harvesting pigments in chloroplasts and protect plants from photo-oxidative damage (Botella-Pavia and Rodriguez-Concepcion 2006; Lefsrud et al. 2007; Cuttriss et al. 2011). Generally, carotenoids are characterised by such functions as free radical scavenging, enhancing the immune response, suppressing cancer development and protecting eye tissues, but individual carotenoids differ in their protective roles. α-Carotene (AC), β-carotene (BC) and β-cryptoxanthin, which are provitamin A carotenoids, are mostly associated with cardiovascular disease reduction. Zeaxanthin (ZEA) and lutein (LU) are components of the macular pigment in the eye and protect the macula from light-induced damage. Lycopene prevents cardiovascular diseases and prostate cancer (Botella-Pavia and Rodriguez-Concepcion 2006; Kopsell and Kopsell 2006). In plants, carotenoids are light-harvesting pigments in chloroplasts and are important in the protection of plants against photo-oxidative damage (Botella-Pavia and Rodriguez-Concepcion 2006; Lefsrud et al. 2007; Cuttriss et al. 2011). Generally, carotenoids protect plants from photo-oxidative damage through thermal dissipation by means of the xanthophyll cycle (converting violaxanthin (VIO) to ZEA) (Stange and Flores 2012). Chlorophyll molecules, in addition to their participation in photosynthesis, are the precursors of tocopherols (Zhang et al. 2015a, b), which are also distinguished by antioxidant properties. The changes of mentioned compounds accumulation depend on the environmental conditions during growth and show different results for different plant species (Kopsell and Kopsell 2006). Since carotenoids are closely related to photosynthesis, the most important factors influencing carotenoid content changes are light quality and quantity. Properly chosen light spectra and intensity, which, with current technology of LEDs, allows the possibility to use specific light wavelengths in the range from ultraviolet to infrared, can lead to higher carotenoid content in vegetables grown in greenhouses and indoors (Tamulaitis et al. 2005; Morrow 2008). Many scientific experiments regarding effects of light spectra on carotenoid content changes associated with blue, red and their combinations as well as supplementation of other lamp spectra using LED illumination of these wavelengths have been performed. It is known that chlorophylls and carotenoids have high light absorption at 400–500 and at 630–680 nm (Lin et al. 2013). In addition, the absorption peaks of various carotenoids differ: LU absorbs at 448 nm, BC at 454 nm and, generally, xanthophylls (XA) at 446 nm (Lefsrud et al. 2008; Li and Kubota 2009). However, some researchers determined two peaks of maximum LU and BC in kale

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.