A clay film developed by a team of researchers from the National Institute of Materials Science Japan (NIMS), the University of Queensland and National Taiwan University reportedly ensures the long-term storage of fresh produce.
By adjusting the size of the particles in the clay nanosheets, the researchers achieved gas permeability similar to that of plastic bags, wherein the bag’s minute pores reduce the oxygen supply to the produce, thereby preventing rapid ripening. Composed of clay nanosheets with particle sizes within the range of several dozen nanometers, the clay film demonstrated relatively high permeability to gas molecules, which can travel through gaps between the particles.
In the lab, the researchers applied the clay film to apples, oranges and bananas and compared its performance to produce left untreated or sealed in cling wrap.
Following a monitoring period, the untreated and cling-wrapped produce reportedly showed signs of both mold and decay. Meanwhile, the clay film-wrapped produce was unaffected, according to the researchers. This was due in part to the film’s ability to keep the respiration rates of the produce low without depriving it of oxygen, thereby preventing decay.
Additionally, the researchers determined that because the clay film was in such tight contact with the produce, it prevented ethylene — a phytohormone — diffusion into the atmosphere, which induces the ripening of fruit.
The research is detailed in the article, Highly adhesive and disposable inorganic barrier films: made from 2D silicate nanosheets and water, which appears in the Journal of Materials Chemistry A.