One of the critical moments in the final quality of the potato occurs during its storage, as there exists the risk of sprouting or rotting due to pathogenic agents such as bacteria and fungi.

In order to avoid this, agricultural engineer David Gomez Castillo carried out research for his PhD on the possibility of substituting the current use of chemical products by treating the tuber with essential oils of mint, caraway, coriander, eucalyptus and clove, "which have proved to be great potential inhibitors in the main problems detected".

The chemical product Clorprofam (CIPC) is the most commonly used as a sprout suppressant on stored potatoes. Nevertheless, possible reductions in permitted dosages, market and consumer pressures seeking healthier and, moreover, more environmentally-friendly products, have made it necessary to find alternatives to these synthetic products, with the market, culinary and technological quality of the potato remaining unaltered.

This is the context of the research by David Gomez Castillo, who has evaluated alternative treatment using essential oils of mint, caraway, coriander, eucalyptus and clove.

In concrete, he studied the effect of applying these oils with table-stock varieties of the potato (Agata and Monalisa) and industrial ones (Agria and Kennebec), and compared the results thereof with those that had been treated chemically.

A good alternative
The research analysed two parameters: the commercial quality (germination, texture and colour of the tuber) and the culinary and technological quality (colour and texture of slices of the potato, dry material, total soluble solids, reductor sugars and sensorial analysis). Evaluations at 10, 25, 40, 55 and 70 days in storage were also undertaken, the antimicrobial effect of essential oils being assessed for the principal phytopathogens (fungi and bacteria).

According to Mr Gomez, "we found a high antigerminant capacity with treatment using the essential oil of coriander for industrial crops, and with the essential oil of mint for both industrial and table-stock crops. These showed great inhibitory potential on the principal phytopathogenic problems studied and all this makes a good alternative to CPIC use for storage of potatoes".

It was also shown that the essential oil of eucalyptus, for its high antigerminant capacity with table-stock potatoes, "could be another alternative for reducing post-harvest losses due to phytopathogenic problems, obtaining even better results if the treatment is accompanied by the essential oil of clove".

In the opinion of this researcher, the use of treatment with essential oils in the storage of potatoes "can provide added value in the application of antigerminant treatment, due to its efficacy in controlling the progress of important phytopathogens".