Research recently presented at the Federation of American Societies for Experimental Biology conference in Boston, MA shows that resistant starch content of potatoes is similar across potato varieties; but can be altered significantly by the cooking and serving methods. Resistant starch is starch that is resistant to enzymatic digestion and, thus, is not absorbed in the small intestine.
Researchers from the USDA Agricultural Research Service (ARS) Grand Forks Human Nutrition Research Center in North Dakota and the University of Minnesota developed a standardized protocol to examine the amount of resistant starch in three different potato varieties (Yukon Gold, Red Norland and Russet Burbank) subjected to two methods of preparation (baking or boiling) and served at three service temperatures (hot, chilled for 6 days and chilled followed by reheating). Results show that the resistant starch content of potatoes varied significantly by method of preparation and service temperature but not variety (p > 0.05). More specifically, regardless of potato variety, the baked potatoes had significantly higher resistant starch at 3.6 grams of starch per 100 grams of food (3.6/100g on average) than boiled potatoes (2.4/100g). Also on average, chilled potatoes (whether originally baked or boiled) contained the most resistant starch (4.3/100g ) followed by chilled-and-reheated potatoes (3.5/100g) and potatoes served hot (3.1/100g).
Thirty years of research in human models suggests that the consumption of resistant starch may help regulate blood glucose levels and favorably alter bacteria in the colon. Emerging research in animals has linked resistant starch fermentation to satiety.
“This research adds important information to the growing database of resistant starch contents of foods,” explained Susan Raatz, lead investigator on the study. “Resistant starch is garnering more interest among the scientific community and consumers. Identifying foods that are high in resistant starch, and preparation methods that can increase the content of resistant starch in a particular food, has valuable practical applications.”
This study was funded by the United States Potato Board and the USDA-ARS. For Quick & Healthy potato recipes, videos and nutrition information please visit: http://www.potatogoodness.com.
US Potato Board