a dash of methyl jasmonate in your daiquiri might leave you healthier

Antioxidants in Berries Increased by Ethanol (but Are Daiquiris Healthy?)

Category: Chemistry
Posted on: April 24, 2007 9:10 AM, by Shelley Batts

From the BBC on down, in the past few days the headline "Alchohol Makes Fruit Healthier" has been highlighted in nearly every news venue.

The fruit contains compounds [antioxidants] that can protect against cancer, heart disease and arthritis.

But having them with alcohol, such as in a daiquiri, boosts these
antioxidant properties, the Journal of the Science of Food and
Agriculture says.

Nutritionists said the "detrimental effects" of such drinks could cancel out such benefits.

As a college student, no one takes this sort of study more seriously than I. Alcohol as health food? Surely you jest!

This deserved a bit more investigation.

The study that all these 'blurby' news briefs are referring to is a
brand-spankin'-new paper published in the Journal of the Science of
Food and Agriculture entitled 'Natural volatile treatments increase free-radical scavenging capacity of strawberries and blackberries'
by Chanjirakul et al. Quite the mouthful (forgive the pun). The paper
was a collaboration between the USDA Fruit Labs and Produce Quality
Labs, and the Dept of Horticulture in Thailand.

As many people know, certain fruits contain large amounts of
healthful compounds called antioxidants which "scavenge" cell-damaging
free-radicals in our bodies. Strawberries and blackberries fall into
this category, both naturally containing high amounts of antioxidants
such as anthocyanin and phenolic acid. These compounds interact with
reactive oxygen species (ROS), which are byproducts of metabolic
processes, and prevent them from damaging DNA and cells.

The other side of this is that improving the antioxidant levels in
fruit not only increases healthful benefits to the people that ingest
them, it increases the shelf life of fruit by slowing down decay. So
obviously there is interest in getting fruit to last longer and
reducing waste and allowing increases in transit time.

So the researchers tested whether treating strawberries and
blackberries with natural volatile compounds (methyl jasmonate, allyl
isothiocyanate, ethanol, and tea tree oil) would be effective in
reducing decay in the berries. Natural volatiles occur naturally in
some fruits, and were thought to have evolved as an antimicrobial and
antifungal defense mechanism. But would they increase antioxidant
activity as well?

The method was simple. Include a piece of soaked blot paper
(saturated with a natural volatile) within a closed container of
berries and wait 7 and 14 days at 4 degrees C. Antioxidant levels were
examined before and after, and decay was measured visually. Results of
treatment conditions and decay are below.

Compared to controls, allyl isotholcyanate treatment resulted in
the least decay in both berry types. Ethanol treatment provided the
least protection against decay.

As for antioxidant activity, that was measured by 'ORAC' test
(Oxygen Radical Absorbance Capacity, no not Orac). Results are below,
which show that compared to controls, all the natural volatiles except
the allyl isotholcyanate provided modest increases in antioxidant
activity. Methyl jasmonate treatment provided the largest increase in
antioxidant activity (see below).

The group tested the quantities of specific reactive oxygen species
and, overall, consistently found that methyl jasmonate treatment
provided the best protection against ROS but that the other natural
volatiles (ethanol included) provided some beneficial effect too. Take
home message was that a combination of methyl jasmonate (to increase
antioxidants) and allyl isotholcyanate (to reduce decay) would maximize
shelf life.

So really, a dash of methyl jasmonate in your daiquiri might leave
you healthier, but I can't say what that would do for the taste and fun
of your beverage.