Different Postharvest Responses of Fresh-Cut Sweet Peppers Related to Quality and Antioxidant and Phenylalanine Ammonia Lyase Activities during Exposure to Light-Emitting Diode Treatments

Abstract

The influence of emitting diode (LED) treatments for 8 h per day on functional quality of three types of fresh-cut sweet peppers (yellow, red, and green) were investigated after 3, 7, 11, and 14 days postharvest storage on the market shelf at 7 °C. Red LED light (660 nm, 150 μmol m−2 s−1) reduced weight loss to commercially acceptable level levels (≤2.0%) in fresh-cuts of yellow and green sweet peppers at 7 and 11 d, respectively. Blue LED light (450 nm, 100 μmol m−2 s−1) maintained weight loss acceptable for marketing in red fresh-cut sweet peppers up to 11 d. Highest marketability with minimum changes in color difference (∆E) and functional compounds (total phenols, ascorbic acid content, and antioxidant activity) were obtained in yellow and green sweet pepper fresh-cuts exposed to red LED light up to 7 and 11 d, respectively, and for red sweet pepper fresh-cuts exposed to blue LED light for 11 d. Red LED light maintained the highest concentrations of β carotene, chlorophyll, and lycopene in yellow, green, and red sweet pepper fresh-cuts up to 7 d. Similarly, blue LED light showed the highest increase in lycopene concentrations for red sweet pepper fresh-cuts up to 7 d. Red LED (yellow and green sweet peppers) and blue LED (red sweet pepper) lights maintained phenolic compounds by increasing phenylalanine ammonia lyase activity. Thus, the results indicate a new approach to improve functional compounds of different types of fresh-cut sweet pepper.

Effects of light‐emitting diode illumination on the quality of fresh‐cut cherry tomatoes during refrigerated storage

“…This difference could be explained by photo‐oxidation under light conditions (Devlin et al ., 2007). The lower lycopene content was also reported in fresh‐cut yellow sweet peppers exposed to white light (Maroga et al ., 2019). In this study, fresh‐cut tomatoes treated with blue and green light had higher lycopene content than the control at the end of storage.…”

Challenges and Opportunities of Light-Emitting Diode (LED) as Key to Modulate Antioxidant Compounds in Plants. A Review

“…Despite the majority of the studies being only focused on the measurement of the TPC, TFC, or of specific phenolic compounds, few of them also reported that these increments after WL, BL, and RL treatments were due to the increased activity of the key enzymes of the shikimate and phenylpropanoid pathways, such as PAL [ 101 , 102 ], chalcone synthase (CHS), chalcone isomerase (CHI), or in flavonoid and anthocyanin synthesis pathways, such as flavonol synthase (FLS), leucoanthocyanidin dioxygenase (LDOX), dihydroflavonol 4-reductase (DFR and stilbene synthase (STS) (for more details, see Figure S2 ) [ 103 , 104 , 105 ]. The synthesis of phenolic compounds is regulated by structural genes, transcriptional activators, and repressors, the latter two acting on putative light regulatory units in gene promoters [ 106 ].…”

“…Generally, higher light intensities were more effective than low intensities in inducing light-responsive genes and increasing the polyphenol content in plants. Nonetheless, results also depend upon plant species [ 15 , 93 ], cultivars [ 101 , 110 ], and timing of LED exposure [ 111 ]. Most importantly, each polyphenolic compound has a specific response to light quality [ 91 ].…”

Extension of Avocado Fruit Postharvest Quality Using Non-Chemical Treatments

“…On thus note use of light-emitting diode (LED) are becoming very poplar and by selecting the appropriate colour lights can be installed in cold storage facility to reduce the postharvest due to decay and disorders. Also, the shelf life of the fruit can help to extended on the shelf life to benefit marketers [81]. In addition, future research may also be focused on active slow release packaging films and coating emulsions that can consistently retain their secondary metabolites the phenolic compounds for prolonged periods.…”