I bet your stroke hospital will never do this.
http://www.alphagalileo.org/ViewItem.aspx?ItemId=160177&CultureCode=en
Researchers from the University of Granada (UGR) have proven that
frying in Extra Virgin Olive Oil (EVOO) is the cooking method that
increases the phenolic fraction present in raw vegetables used in
Mediterranean diet (potato, pumpkin, tomato and eggplant) the most. This
means an improvement to this foods in the cooking process.
In an article published in Food Chemistry magazine, researchers have
proven that vegetables fried in EVOO improved their antioxidant capacity
and the amount of phenolic compounds, which prevent chronic
degenerative pathologies such as cancer, diabetes or macular
degeneration.
The aim of this research was to determine the effect of applying
various cooking methods on the antioxidant capacity and the amount of
phenolic compounds (total and individual concentrations) present in
vegetables consumed in the Mediterranean diet.
The Mediterranean diet of the Spanish population is characterized by a
high intake of vegetables and EVOO. These are both an important source
of dietary phenols, whose consumption has been associated with the
prevention of chronic degenerative pathologies. This kind of
antioxidants can be modified during the processing of the foods,
increasing or decreasing their concentrations.
With this goal in mind, the researchers conceived an experiment in
which they cooked 120 grams cubes of potato (Solanumtuberosum), pumpkin
(Cucurbitamoschata), tomato (Licopersicumesculentum) and eggplant
(Solanummelongena), all of them without seeds or skin.
Fried, boiled, or with a mix of water and EVOO
The vegetables were fried and sautéed in EVOO, boiled in water, and
boiled in a mix of water and EVOO. The experiments were controlled so
the processing conditions were guaranteed. The ratio between vegetable
and cooking element was constant, following traditional Spanish recipes.
Processed vegetables were kept in right conditions for the
measurement of moisture, fat, dry matter and total number of phenols, as
well as the measurement of the antioxidant capacity, by various
methods. Parallel to this, the research was completed with the
determination of the content in individual phenolic compounds typical of
each vegetable, using high-performance liquid chromatography (HPLC).
The results showed that using EVOO for frying vegetables increases
their fat content and reduces their moisture, while this is not observed
in other cooking methods.
"Comparing the content of phenols with that of raw vegetables we
found increases and reductions alike, depending on the chosen method.
Oil as a mean of heat transfer increases the amount of phenolic
compounds in vegetables, opposite to other cooking methods such as
boiling, where heat transfer is done through the water", explains one of
the authors of this paper, professor Cristina Samaniego Sánchez from
UGR.
EVOO transfers phenols to the vegetables
This is due to a transfer of phenols from EVOO to the vegetables,
enhancing the latter with oil-exclusive phenolic compounds which are not
naturally present in raw vegetables.
"Therefore, we can confirm that frying is the method that produces
the greatest associated increases in the phenolic fraction, which means
an improvement in the cooking process although it increases the energy
density by means of the absorbed oil", says Samaniego.
All the cooking methods increased the antioxidant capacity of all
four vegetables. It was a reduction of it or an absence of significant
changes after boiling them in water, in certain cases.
Samaniego stresses that each cooked vegetable developed a specific
profile of phenols, moisture, fat, dry matter and antioxidant activity
determined by the original characteristics of the raw vegetables and the
cooking method applied.
"When the phenolic content of the raw vegetable is high, the total
content of phenols is increased even more if EVOO is used in the
process, and boiling doesn't affect the final concentration. Therefore,
we must stress that frying and sautéing conserve and enhance the
phenolic composition. Hydrothermal cooking methods can be recommended
when the food is consumed together with the cooking water, as the
addition of EVOO improves the phenolic profile and compensates for the
deficiencies of the raw food", the researcher stresses.
The results of this research are part of Jessica del Pilar Ramírez
Anaya's doctoral thesis, done under the direction of UGR professors
Cristina Samaniego Sánchez, Marina Villalón Mir and Herminia
López-García de la Serrana, from the Department of Nutrition and
Bromatology of the Faculty of Pharmacy (UGR), and also with support from
the programme PROMEP/SEP, Mexico UDG-598.
http://canal.ugr.es/index.php/food-and-agriculture/item/80229
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