Lipid content of beef and lamb cuts--grass- or grain-fed--including the impact of cooking, from USDA research studies

Authors: ROSELAND, JANET - US Department Of Agriculture (USDA); NGUYEN, QUYNHANH - University Of Maryland; PATTERSON, KRISTINE - University Of Maryland; Pehrsson, Pamela; WOERNER, DALE - Colorado State University; GIFFORD, CODY - Colorado State University; LEHESKA, JENNIFER - Consultant

Submitted to: Northeast Pasture Consortium Annual Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/15/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The Nutrient Data Laboratory (NDL) at the USDA/ARS conducts food composition research for meats and other foods to develop nutrient data which are publicly released in the USDA food composition database. NDL studies adhere to research study protocols which include representative sampling plans, validated analytical laboratories using official standardized methods, and data evaluation procedures to obtain results that are publicly disseminated. This report highlights the content of lipids and other nutrients and the effect of cooking on these nutrients in grass- and grain-finished lamb and beef. A study conducted with Colorado State University examined the nutrient content of 11 raw and cooked retail lamb cuts from representative samples of grass- and grain-finished lamb. The fatty acid profile for both grass- and grain-finished lamb was composed primarily of polyunsaturated fatty acids, monounsaturated fatty acids, and stearic acid; the total fat content varied among cuts. A study of grass-fed beef was done in collaboration with the Beef Checkoff Program, America’s Beef Producers and Texas Tech University. Representative samples of grass-fed and control ground beef and strip steaks were analyzed using quality control protocols. Grass-fed beef samples compared to control were lower in total fat and monounsaturated fat, and were higher in saturated fat, omega-3 fatty acids, total conjugated linoleic acid (CLA), and total trans fatty acid. In another NDL study, representative samples of conventionally-raised beef were obtained and the effects of cooking on cuts from three different primals were examined. Chuck eye and tenderloin roasts had higher cooking yields than ribeye roasts, while grilled ribeye steak had a higher cooking yield than grilled chuck or tenderloin (p<0.05). Furthermore, grilled chuck and tenderloin had higher fat concentrations than their roasted counterparts. In an NDL ground beef study, representative retail samples were analyzed for proximates, cholesterol, fatty acids, vitamins and minerals. The data were statistically evaluated to obtain prediction equations for estimated mean values for ground beef from 3 to 30% labeled fat, based on the relationship between analytical raw fat levels and analytical nutrient values. As analytical raw fat increased, nutrient values in ground beef increased in saturated, polyunsaturated, and monounsaturated fatty acid classes, as positive linear relationships (p<0.05). In an NDL study of cooking yields, data for six different cuts were evaluated; results varied according to cooking method, with broiling having the highest and braising having the lowest cooking yields (p<0.0001). These data provide researchers, agriculture industry members, nutritionists, and consumers with important information to apply to policy, health research, labeling, and food selection or preparation decisions.