Writing on the Journal of the Science of Food and Agriculture, lead author Korakot Chanjirakul reports that treating blackberries and strawberries with volatile compounds such as ethanol (alcohol), methyl jasmonate, and tea-tree oil significantly boosted their antioxidant activity. The potential health benefits of berries, linked to the antioxidant polyphenol content including anthocyanins, flavonols, flavanols, ellagitannins, galltannins, proanthocyanidins, and phenolic acids, has filtered through to the consumers and resulted in an increase in demand. Indeed, sales of blueberries, for example, are reported to have rocketed by 130 per cent, raspberry sales are said to have grown by 62 per cent in the last two years, a strawberry sales in the UK are reported to have increased by 34 per cent during the last two years. The researchers, from Kasetsart University in Thailand and the US Department of Agriculture's Agricultural Research Service (USDA-ARS), report that treating the berries with naturally volatile compounds such as ethanol (alcohol), methyl jasmonate, and tea-tree oil boosted antioxidant activity, as measured by oxygen radical absorbance capacity (ORAC) assay and the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical assay.
The discovery came about while Chanjirakul and co-workers were exploring ways to help keep strawberries fresh during storage. Commenting independently on the research, Dr Frankie Phillips of the British Dietetic Association said: "This is an interesting piece of research and illustrates that the antioxidant capacity of berries can be enhanced by combining them with volatile substances such as alcohol. It's well known that some preparation of fruit and veg can enhance the availability of nutrients and other plant chemicals including antioxidants. "Whilst this study suggests that consuming strawberries with alcohol increases the antioxidant capacity, there are clearly detrimental effects of consuming alcohol in terms of cell damage. "So any potential antioxidant benefits may be cancelled out by the potential liver damage caused by too much alcohol," she said.
Source: Journal of the Science of Food and Agriculture Published on-line ahead of print, doi: 10.1002/jsfa.2841 "Natural volatile treatments increase free-radical scavenging capacity of strawberries and blackberries"
Authors: K. Chanjirakul, S.Y. Wang, C.Y. Wang, J. Shiriphanich