ARS | Publication request: Nutrient Retention of Vitamins and Minerals in Cooked Whole Grains

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 11, 2008
Publication Date: September 21, 2008
Citation: Gebhardt, S.E., Thomas, R.G. 2008. Nutrient Retention of Vitamins and Minerals in Cooked Whole Grains. AACC International, Sept. 21-24, 2008 Honolulu, HI.

Technical Abstract: Recipe calculations are used in many applications, such as food consumption surveys and food service, to estimate the nutrient content of multi-ingredient foods when analytical data are not available. When using uncooked foods as ingredients in recipes, retention factors are needed to account for loss of nutrients in cooking. Samples of amaranth, quinoa, and spelt were analyzed to provide nutrient values for these whole grains. The analytical nutrient data for both the uncooked and cooked forms of these grains, in conjunction with food weights before and after cooking, provided the opportunity to calculate nutrient retention factors for the vitamins and minerals. Three different brands of each type of grain were purchased from retail outlets. Samples were prepared at the Food Analysis Laboratory Control Center at Virginia Polytechnic Institute and State University. Standardized cooking procedures based on package directions were developed for each type of grain. Weights of the samples before and after cooking were recorded. Uncooked and cooked samples for each composite along with appropriate control and reference materials were shipped to analytical laboratories. Composites were analyzed for proximates, ten minerals, six vitamins, and other components using validated methods as part of USDA’s National Food and Nutrient Analysis Program. The nutrient data are presented in the USDA National Nutrient Database for Standard Reference at http//:www.ars.usda.gov/nutrientdata. Percent true retentions were calculated via the USDA Nutrient Data Bank System for each of the cereals using the following algorithm: percent true retention = (nutrient content per g of cooked food x g of cooked food) / (nutrient content per g of raw food x g of food before cooking) x 100. This method accounts for the loss or gain of moisture from food that occurs during preparation and cooking. Retention of iron, magnesium, phosphorus, copper, and manganese ranged from a low of 85% in quinoa to 100% in spelt. Selenium had 100% retention in all three grains. Retention of vitamins was more variable, ranging from a low of 45% for riboflavin in amaranth to 100% for niacin and vitamin B6 in spelt. This research provides retention factors that can be used to calculate nutrient content when uncooked grains are used as ingredients in recipe calculations or when there are no nutrient values available for other cooked whole grains such as wheat berries.