Canning Process Increases Antioxidant Levels in Blueberries
Blueberries owe their nutritional dynamite to high levels of naturally occurring antioxidant phytonutrients, particularly, flavonoids. Blueberries' valuable nutrients offer protection from oxidative damage - a key link to many age-related diseases such as cancer, diabetes and rheumatoid arthritis, among others.
A study commissioned recently by the Canned Food Alliance with the Oregon Health Sciences University and the U.S. Department of Agriculture (USDA) -- to determine the affect of commercial canning on the flavonoid content of blueberries compared with fresh blueberries -- found that the antioxidant level and flavonoid activity in canned blueberries actually is higher than that of fresh and frozen blueberries.
"Not only did this study prove that commercial canning does not diminish the levels of any flavonoid measured, it actually increases the abundance of some antioxidants," said Dr. Daniel Hatton, associate professor at OHSU. "Since canned fruit is processed immediately after harvest, canned blueberries offer a year-round source of antioxidants with higher levels than fresh or frozen blueberries."
A New Canvas for Nutrition
With both consumers and media interested in the health benefits of phytonutrients, very little information has been available about the effects of food processing (canning) on flavonoid values. With the USDA, the Oregon Health Sciences University compared flavonoids in fresh, frozen, canned, heated and refrigerated blueberries -- from the same harvested sample to determine the effects of commercial canning on the flavonoid (with antioxidant functions) content of blueberries as compared to fresh blueberries.
"Consumers today are more interested in positive nutrition -- adding, not avoiding, foods that may enhance fitness, boost immunity, slow aging and prevent or slow the chance for chronic disease," said Roberta Duyff, MS, RD, and author of the American Dietetic Association Complete Food and Nutrition Guide. "Research on phytonutrients is the new frontier in nutrition, and is as exciting today as vitamin discoveries were a hundred years ago."
Since 1995, the Canned Food Alliance has commissioned research studies to test the nutritional values of canned foods. The University of Illinois conducted a study in 1997 that found, among other things, that canned fruits and vegetables provide as much dietary fiber as their cooked fresh and frozen counterparts, and are a convenient weapon in helping to combat the risk of heart disease and some types of cancer. In 2000, the University of Massachusetts executed a study in three separate phases, which found that recipes using canned ingredients are similar in taste and nutritional value to those made with fresh or frozen items. For more information on these studies visit http://www.mealtime.org .
About the Canned Food Alliance
The Canned Food Alliance (CFA) is a partnership of the American Iron and Steel Institute's Steel Packaging Council, the Can Manufacturers Institute and selected food processors. The primary mission of CFA is to serve as a resource for information on the convenience, contemporary appeal, nutrition and versatility of canned food, more than 90 percent of which is packaged in recyclable steel cans. For hundreds of mealtime solutions, visit http://www.mealtime.org .