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Grapes
Researchers at the University of Adelaide have discovered how grapes breathe… and the negative impact on wine when they are ‘short of breath’.
"In 2008 we discovered the phenomenon of cell death in grapes, which can be implicated where there are problems with ripening. We've since been trying to establish what causes cell death," says Professor Steve Tyerman, Chair of Viticulture at the University of Adelaide.
"Although there were hints that oxygen was involved, until now we've not known of the role of oxygen and how it enters the berry.”
Tyerman and PhD student Zeyu Xiao discovered that while grapes are ripening they may suffer an internal shortage of oxygen. The research team inserted a tiny oxygen detection probe into Chardonnay and Shiraz wine grapes, and Ruby seedless table grapes.
They found that the level of oxygen correlates very closely to cell death in grapes, which in turn can lessen the quality of the wine made from those grapes.
"By manipulating oxygen supply we discovered that small pores on the surface of the berry stem were vital for oxygen supply, and if they were blocked this caused increased cell death within the berry of Chardonnay, essentially suffocating the berry,” said Xiao.
The pair also found that higher temperatures can cause the pores of grapes to be blocked, leading to oxygen deprivation and cell death. The ARC Training Centre for Innovative Wine Production - an offshoot of the University of Adelaide - says the discovery will lead to more research on how to adapt viticulture to a warming climate.
The study was published in the Journal of Experimental Botany on March 6.