A small bag of clay can prevent fruit from rotting quickly

Scientists have proposed a seemingly simple solution to the problem: using a special type of clay that absorbs ethylene. In future, this material could be placed alongside fruit and vegetables in the form of small sachets or inserts — much like the silica gel sachets that absorb moisture in packaging for shoes or electronic devices.

The study has been published in *Applied Surface Science Advances*.

The researchers investigated smectite clays as stable materials for trapping ethylene — a plant hormone that accelerates fruit ripening.

Details

Ordinary clay does not trap ethylene very well on its own. The researchers therefore modified its structure to create more suitable voids and surfaces within the clay where gas molecules can be trapped.

The study compared several variants of montmorillonite – a clay mineral from the smectite group: the original clay, acid-activated clay and choline-modified clay. It turned out that chemical treatment alters the way ethylene is captured: acid activation enhances overall gas capture by creating new pores, whilst choline modification is more effective at trapping molecules within the interlayer spaces.

Put simply, the scientists did not just ‘sprinkle clay on the fruit’. They sought to understand how to structure the clay so that it would act as a trap for ripening gas.

Why this is important

Fruit and vegetables continue to live after harvest: they breathe, change, ripen and release ethylene. This gas can accelerate the ripening, softening and ageing of fruit, and when it accumulates in packaging or storage, it can increase post-harvest losses.

The scientists’ idea is to remove some of the ethylene from the air surrounding the produce. If there is less of the gas, the fruit may overripe more slowly. This is particularly important during long-distance transport: avocados, bananas, tomatoes, mangoes and other produce often travel across countries and continents.

If the technology reaches industrial-scale application, it could help reduce food waste. Another potential benefit is that fruit could be harvested slightly later, once it has developed better flavour and aroma, rather than too early simply to ensure it survives the journey.

What this might look like

The simplest option would be a small sachet or insert containing clay powder inside the fruit packaging. It would not be mixed in with the food, but would sit alongside it and absorb ethylene from the air.

Shoppers are already familiar with a similar principle: boxes often contain sachets of silica gel, which absorb moisture. Here, however, the aim is different – it is not moisture but ripening gas that needs to be controlled.

Reviews of active packaging show that clay films, sachets, liners and granules are already regarded as a promising format for controlling ethylene and preserving fresh produce. This new research is significant in that it clarifies the mechanism: exactly where in the clay ethylene is trapped and how chemical treatment can enhance this process.

Why this is not a ‘magic protection against rotting’

Rotting and spoilage do not depend solely on ethylene. Produce is affected by temperature, humidity, microbes, damage during transport, oxygen, packaging and storage conditions.

Therefore, such a sachet will not make fruit last forever. It can only solve one part of the problem — reducing the concentration of the gas that accelerates the ripening and ageing of certain fruits.

Furthermore, the technology has not yet become a common feature in supermarkets. Researchers have demonstrated how the material can be tailored and how it traps ethylene. The next step is to conduct trials using real packaging with produce, where humidity, temperature fluctuations and different types of fruit are present.

Background

Ethylene has long been used and controlled in food logistics. It is necessary for fruit to ripen, but an excess of it can accelerate spoilage. Therefore, various methods of ethylene management are used in the storage and transport of fruit: ventilation, segregation of produce, gas scavengers, controlled atmosphere and other techniques.

Clay is interesting because it is cheap, widely available and potentially safe. Smectites have a layered structure that can be chemically modified. This allows spaces to be created within the material where small gas molecules can be trapped.

Source

Research: K. Kovalchuk, L. Michels, W. P. Gates, M. L. Martins, G. W. Greene, H. N. Bordallo — “Disentangling interlayer confinement and pore surface adsorption in functionalised smectites for tunable ethylene gas capture”, Applied Surface Science Advances, 2026.