Effect of microwave cooking or broiling on selected nutrient contents, fatty acid patterns and true retention values in separable lean from lamb rib-loins, with emphasis on conjugated linoleic acid

Proximate composition and fatty acid profiles, conjugated linoleic acid (CLA) isomers included, were determined in separable lean of raw and cooked lamb rib-loins with their subcutaneous and intermuscular fat, prepared as roasts or steaks. Two combinations “cooking method × type of cut” were selected: one is a traditional method for this meat (broiling of steaks), while the other (microwaving followed by final grilling of roasts) is far less widely used. The two methods, similar as regards the short preparation time involved, were also evaluated for cooking yields and true nutrient retention values. The cooking yield in microwaving was markedly higher than in broiling. Significant differences between the two methods were also found in the true retention values of moisture, protein and several fatty acids, again to the advantage of microwaving. On the basis of the retention values obtained, with microwaving there was a minimum migration of lipids into the separable lean, consisting almost exclusively of saturated and monounsaturated fatty acids, while there were small losses of lipids in broiling, almost equally divided between saturated, monounsaturated and ω6 polyunsaturated fatty acids. On the whole, the response to cooking of the class of CLA isomers (including the nutritionally most important isomer cis-9,trans-11) was more similar to that of the monounsaturated than the polyunsaturated fatty acids.