Key Takeaways
- MIT researchers developed biodegradable microneedles that inject melatonin into crops to extend shelf life.
- Pak choy treated with melatonin lasted four days longer at room temperature and ten days more in refrigeration.
- This innovative method could significantly reduce food waste, especially in regions without reliable refrigeration.
Researchers at the Massachusetts Institute of Technology (MIT) and the Singapore-MIT Alliance for Research and Technology (SMART) have introduced a novel method for extending the shelf life of perishable crops using biodegradable microneedles. These microneedles, constructed from silk, are designed to inject melatonin—a hormone known for regulating sleep—directly into harvested plants without causing stress.
Benedetto Marelli, the study’s senior author and an associate professor at MIT, noted this technique is the first successful application of microneedles to enhance the longevity of fresh produce. The research primarily focused on pak choy, a highly perishable leafy green that is significant in Asian cuisine. By injecting melatonin into the plant’s base, the team managed to prolong the crop’s freshness, allowing it to remain market-ready for an additional four days at room temperature and ten days when refrigerated.
The use of melatonin benefits not only human sleep but also plays a crucial role in plant growth and aging processes. The researchers discovered that small doses of melatonin could effectively slow down the natural aging of crops, or senescence. Marelli explained that the low dosage used in their experiments does not significantly raise melatonin levels in the food.
Using fluorescent dye, the research team demonstrated that the melatonin reached all parts of the treated plants. While initial applications of melatonin via sprays and dips were ineffective, the microneedle method yielded promising results. Untreated pak choy displayed yellowing within two to three days, while those treated with melatonin retained their green color well into eight days.
Interestingly, refrigeration enhanced the results further, permitting treated vegetables to maintain their quality and color for up to 25 days—five days longer than untreated varieties. Spectrophotometric analyses indicated increased antioxidant activity in melatonin-treated plants, supported by gene analysis that showed protective metabolic responses preserving both chlorophyll and hormonal balance.
The implications of this technique could significantly reduce post-harvest waste, especially in areas with inadequate refrigeration, like parts of Africa and Southeast Asia, where crops often spoil before reaching markets. Marelli emphasized that a shift towards automation—potentially using tractors or drones—could further streamline the melatonin application process, assuming it becomes cost-effective for farmers.
Future research will explore the application of other plant hormones and different types of fresh produce. The ultimate goal is to not only extend shelf life but also improve the overall quality, texture, and nutritional value of crops.
With continued innovation, these small silk needles might represent a major advance in the effort to minimize food waste, making fresh produce more accessible to a wider audience.
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