Agriculture Reference
In-Depth Information
“old-fashioned”. The combination of more dis-
posable income and a much greater variety of
readily available fresh produce than in the past
creates more choices for shoppers and little in-
centive to purchase anything regarded as “bor-
ing”. Feeding into this attitude is the perception
by some that potatoes are “empty calories”.
Consumers with more income tend to be better
educated, and more likely to be aware of the
negative comments made by some nutrition-
ists about potatoes. Moreover, consumers with
higher disposable income are also more likely to
actively pursue a healthy diet. Baby potatoes are
perceived as a more gourmet, exciting product
and are thus more likely to appeal to affluent
consumers. Likewise, as the public becomes
more aware of the phytonutrient content of
baby potatoes, this should influence perception
positively.
Another advantage of baby potatoes is that
they are cooked and eaten with their skin,
thereby retaining all of the phytonutrients in the
skin and reducing leaching of phytonutrients
during cooking. Another benefit is that, because
of their small size, baby potatoes cook faster,
which, along with not having to be peeled, con-
tributes to faster and less laborious preparation.
With changing lifestyles such as both couples
working full-time jobs and fewer family sit-down
dinners, ease of preparation is more important
than it once was. Thus, “baby” or “new” potatoes
are a good example of a product with consumer-
oriented traits, namely, superior taste, visually
appealing, faster preparation, and more phyto-
nutrients.
the amount of chlorogenic acid, rutin, or vita-
min C (Navarre
et al
., 2010). In fact, compared
to uncooked potatoes, there was a trend for
amounts of these compounds to increase after
cooking, especially after baking. This was likely
due to the phytonutrients becoming more
extractable from the food matrix after cooking.
A slight decrease occurred in chlorogenic acid
and vitamin C in potatoes overcooked by baking
for
15
additional minutes. Similar results were
seen with mature cooked potatoes, where mul-
tiple cooking methods resulted in an increase in
various polyphenols (Blessington
et al
., 2010).
Conversely, a different study reported a marked
decrease in polyphenols and antioxidant activity
in potatoes cooked by various methods (Perla
et al
.,
2012). The reasons for such different findings
between studies are not clear, but such conflict-
ing results are common among the great many
published studies of the effect of cooking on
phytonutrients (Navarre
et al
., 2010). Whatever
the reason for the discrepancies, it is clear that
cooking can decrease the phytonutrient content
of potatoes, but it is equally clear that it need not
if leaching and overcooking are avoided. Also
clear is that heating alone does not necessarily
decrease amounts, so additional degradative
mechanisms must be at play.
Efforts have been made to assess the effect
on phytonutrients of different commercial pro-
cessing methods. The effect of freeze drying
(FD), drum drying (DD), and refractive window
(RW) drying on a purée of purple potatoes
showed no significant loss of total phenolics or
total antioxidant capacity by any method, but a
23-
45% loss of anthocyanins (Nayak
et al
.,
2011). The authors suggested purple potato flour
could be used as an ingredient in nutritionally
enhanced food products and snack foods high in
antioxidants. Similar results were reported in
another study using these three drying methods
(Kaspar
et al
., 2012). Unlike the previous study
where FD caused the most loss of anthocya-
nins, FD resulted in less loss of anthocyanins
and carotenoids in processed potatoes than DD
or RW drying. Drum drying caused up to a 48%
loss of anthocyanins and 30% loss of caroten-
oids. Despite the better results, FD may not be
cost-effective on a commercial scale. Curiously,
both studies showed little or no loss in total anti-
oxidant capacity by the different methods, des-
pite the significant decreases in anthocyanins.
Effect of cooking on potato
phytonutrients
Research directed towards increasing potato
phytonutrients should focus on those that sur-
vive cooking. The effect of multiple cooking
methods on new potatoes was measured to see
how well selected phytonutrients survive cook-
ing. Baby potatoes from the cultivars, Piccolo,
Bintje, and Purple Majesty, were baked, boiled,
microwaved, steamed, or stir-fried.
Figure 18.5
shows the effect of cooking on chlorogenic acid
in Bintje, Piccolo, and Purple Majesty. None of
the four cooking methods significantly decreased
