In recent years, LED have been used as the sole or auxiliary light source in plant factories or greenhouse crop cultivation, and there have been more and more studies on photosynthesis and light morphology. The agricultural application scenarios of LED have also been expanded. In addition to the process of growing seedlings and cultivation of crops, the role that LED can play in the postharvest storage process has also attracted attention.
How LED keep vegetable and fruit fresh?
The maintenance of postharvest quality of fruits and vegetables is usually achieved by controlling suitable temperature and humidity conditions and gas composition. A large number of studies have shown that light can effectively inhibit postharvest maturity and senescence, maintain appearance quality, extend plants life, and even increase the content of certain nutrients.
The possible mechanism of LED irradiation to regulate the preservation of fruits and vegetables after harvest:
(1) Promote the continued photosynthesis of harvested vegetables and increase the soluble carbohydrates that store respiratory substrates after harvest;
(2) Slow down or inhibit respiration intensity and ethylene release. Light treatment reduces the respiration intensity of harvested vegetables and delays the peak of ethylene release. Ethylene is a key endogenous hormone and signal molecule that mediates and promotes the maturation and aging of fruits and vegetables;
(3) Increase or maintain the level of beneficial compounds, including ascorbic acid (VC), total phenols, soluble sugars, secondary antioxidants, etc., and through the accumulation of pigments (lycopene, carotenoids, anthocyanins) Improve or guarantee the visual appearance quality;
(4) Inhibit the growth of microorganisms on the surface of harvested vegetables. LED irradiation has an inhibitory effect on some food-borne pathogenic bacteria through photodynamic inactivation and photocatalytic inactivation methods, thereby slowing the reproduction of microorganisms and reducing the tissues of fruits and vegetables rot, achieving the purpose of preservation.
If the LED light-controlled fresh-keeping technology is more widely applied to temporary storage and cold chain transportation, it will help to further enhance the supply capacity of high-quality fruits and vegetables, which is worthy of industry attention.