Mangoes exposed to blue light over several days were redder and sweeter (left) than those placed in the dark (right). Credit: Adapted from the Journal of Agricultural and Food Chemistry, 2022, DOI: 10.1021/acs.jafc.2c07137
Key Points:
- A study reveals blue light might help fruits such as mangoes become redder, sweeter and riper.
- Researchers wanted to see how the various light wavelengths could have different effects on fruit growth.
- This work could help shed light on the complex relationship behind colored light and the internal quality of fruit.
Harsh blue light emitted from computer screens and tablets can be harmful to humans, hence the warning to limit our “screen time.” Plants also react to blue light, but instead of wreaking havoc on their sleep, it could help make their fruits taste richer. Researchers recently reported in ACS’ Journal of Agricultural and Food Chemistry that mangoes can actually become more vibrant, sweeter and ripen faster when exposed to blue light over several days.
Plants rely on sunlight for photosynthesis and to ripen their fruits. Studies have shown that exposure to light can affect the appearance of certain fruits’ peels and can increase the amount of sugar and pigments found in fruits including tomatoes, which contain an abundance of chlorophyll in their flesh. The same light can affect the flesh of other fruits such as mangoes, which only contain this type of pigment deeper within their thick peels.
Natural sunlight also contains a variety of colors, so different wavelengths could have different effects. This phenomenon is what led Yuanwen Teng and his colleagues to investigate how blue light impacts the quality and ripeness of mangoes.
To understand this phenomenon, the researchers placed a group of mangoes in blue light and another group in darkness for nine days. They found that mangoes in blue light contained far more anthocyanins in their peels, making them redder than those left in the dark. The flesh of these mangoes was also softer, sweeter and more yellow, and had more sucrose and carotenoids than the other group.
Researchers also found that light-responsive genes involved in the photosynthesis pathway, and genes involved in producing sucrose, anthocyanin and carotenoids, were enhanced by the blue light. This meant that the mangoes could directly perceive this light and trigger an internal genetic signaling pathway.
The researchers feel this work could help shed light on the complex relationship behind colored light and the internal quality of fruit.