ABSTRACT
Light has several fundamental roles in many chemical, biochemical and physical processes. Light has an electromagnetic spectrum ranging from long radio waves (less energy) to gamma rays (high energy). The most suitable light spectrum for postharvest decay control is the ultraviolet (UV) light, which has less energy as compared with the others and is the closest spectrum to the visible light from the left side. The highest energy sources of the spectrum, X-rays and gamma rays, may also be used for several purposes but damage the fresh produce if exposed too much. Moreover, low-pressure mercury lamps, excimer lamps, light-emitting diodes (LEDs) and pulsed light (PL) are important technologies for the postharvest use of light, which can be used to produce narrow bandwidths of wavelengths, including UV (100–400 nm) and blue-light (400–500 nm). Light may control postharvest decay at the fresh produce by two general mechanisms: (1) by inducing the tolerance of the fresh produce against fungal pathogens and (2) by inhibiting fungal growth and/or development. In this chapter, the role and mechanisms of UV and blue-light in controlling fungal pathogens are discussed, and several examples are provided for the use of light in commercial postharvest applications.
