Essential oil antigerminants for prolonged potato storage

During storage, potatoes are at risk of sprouting or rotting due to pathogenic agents such as bacteria and fungi. Currently, Clorprofam (CIPC) is the most commonly used as a sprout suppressant on stored potatoes. However, consumer pressures for healthier and more environmentally-friendly products and possible reductions in permitted dosages are driving the food/agricultural industry to look at alternatives to synthetic products which will meet these needs without affecting the culinary and technological quality of the potatoes.

Agricultural engineer David Gómez Castillo has carried out research for his PhD at the Universidad Pública de Navarra on the possibility of substituting the current chemicals with essential oils of mint, caraway, coriander, eucalyptus and clove.

Gómez 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 with those that had been treated chemically.

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 Gómez, “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 the 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”.