They Have Less Starch, More Protein Than White Corn Tortillas, Researchers Say
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Reviewed By Louise Chang, MD
July 30, 2007 -- Fare at your local taco joint may be getting a bit more colorful. A new study shows blue's best when it comes to packing the most nutrition into a taco shell or bowl of tortilla chips.
Researchers from the home of the tortilla, Mexico, found blue corn tortillas contain 20% more protein than their white corn counterparts. They also have less starch and a lower glycemic index (GI), which may be good news for dieters and people with diabetes.
Foods with a lower glycemic index are considered healthier because the sugar content is taken into the blood more slowly and provide a steady source of energy, while sugars in high-glycemic index foods are more likely to cause spikes in blood sugar and energy levels.
Blue Corn Better
Researcher Juan Pablo Hernández-Uribe of the Centro de Desarrole de Productos Bióticos del IPN in Morelos, Mexico, and colleagues say the blue color of the tortillas comes from anthocyanins in the corn, which are the same healthy compounds found in berries and red wine.
The study, published in the Journal of the Science of Food and Agriculture, analyzed the chemical composition of blue and white corn tortillas.
The results showed that white corn tortillas contained an average of about 75% total starch compared with 68% starch in blue corn tortillas. Blue corn tortillas also had a lower concentration of resistant or undigestible starch than white, although resistant starch increased with greater storage time among both types of tortillas compared with fresh.
Finally, researchers found blue corn tortillas had a lower glycemic index value that did not change over time, while white corn tortillas had a higher glycemic index value that also increased with storage.
SOURCES: Hernández-Uribe, J. Journal of the Science of Food and Agriculture. News release, Society of Chemical Industry.
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