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Agriculture 2011
Fig. 3: Semi-commercial application of mint essential oil on stored potato tubers.
there is considerable interest in finding effective potato
sprout suppressants that have negligible environmental
impact. Previous research has concentrated on such
compounds as ethylene, ozone, hydrogen peroxide,
volatile monoterpenes, aromatic aldehydes and
alcohols. To date, only one monoterpene, (S)-(+)-
carvone (S-5-isopropenyl-2-methyl-2-cyclohexenone),
a chemical produced from caraway (Carum carvi) seeds
and described as a volatile sprout suppressant more
than 30 years ago, has been developed commercially.
Higher production and application costs compared
to such traditional sprout suppressants as CIPC have
limited its use primarily in the Netherlands.
Research objectives are to develop an alternative,
environmental friendly, method for sprout suppression
in order to (1) inhibit potato sprouting during storage
and shelf life; (2) maintain tuber quality parameters; (3)
delay diseases of potato tubers during storage, and (4)
regulate sprouting in potato seeds.
Methods: We tested the efficiency of mint essential
oil (MEO, Biox-M®, Xeda International, Saint Andiol,
France) on the sprout inhibition of eight potato cultivars
that are commonly grown in Israel and differ in their
length of dormancy. Tubers were treated in the lab and
semi commercial scale by monthly thermal fogging
(Electro-fogger, Xeda International). Treated tubers
were analyzed for preserving their quality parameters,
such as weight, turgidity, texture and taste. The effect
of MEO was analyzed by microscopic and biochemical
means.
Results: A scalable method to inhibit potato tuber
sprouting by fogging with a raw material extracted from
natural spearmint oil (70% R-carvone) was developed
(Fig. 1) (Eshel et al. 2008, Orenstein et al. 2008, Teper-
Bamnolker et al. 2010). Experiments were conducted on
8 potato cultivars that differ in their length of dormancy
(Fig. 2). Tubers were treated with MEO using an applicator
that creates a thermal fog circulated by the ventilation
system. Monthly thermal fogging with MEO inhibited
sprouting for 9 months in all treated cultivars. Purified
R-carvone produced the same effect. Treatment with
MEO reduced weight loss during storage by up to 4% and
reduced softening; both these changes were associated
with sprouting inhibition. Thermal fogging of potato
tubers with MEO resulted in highly efficient penetration
to bulk of commercial Dolev containers (Fig. 3). Cooking
of treated potatoes showed no taste, color or texture
changes.
Conclusions and recommendations for MEO application:
Since mint oil was found as an efficient way for sprout
inhibition of potato tubers under semi commercial
storage conditions, we should consider a controlled
translocation to commercial storage rooms. Mint
esential oil way action is reversible and can be tested to
control sprouting of potato tuber seeds.
Literature
Eshel, D., J. Orenstein, M. Hazanovsky, and L. Tsror. 2008.
Control of sprouting and tuber-borne diseases of stored
potato by environment-friendly method. Acta Hort 830:363-
368.
Orenstein, J., M. Michaeli, and D. Eshel. 2008. Sprouting
retard in potatoes, whilst quality assurence during sorage, by
using mint oil. Gan Vayerek (in hebrew) 5:59-62.
Teper-Bamnolker, P., N. Dudai, R. Fischer, E. Belausov, H.
Zemach, O. Shoseyov, and D. Eshel. 2010. Mint essential oil
can induce or inhibit potato sprouting by differential alteration
of apical meristem. Planta 232:179-186.
dani@agri.gov.il
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