Bioactive compounds and fatty acid composition in raw and cooked beef with two different ageing periods

Abstract

This study investigated the effects of ageing period (5 vs. 90 days) and meat status (raw vs. cooked) in a 2 x 2 factorial design on the concentration of bioactive compounds, intramuscular fat content and fatty acid composition of the longissimus lumborum muscle in beef. Samples were collected from 20 Angus steers finished on pasture. Significant (P < 0.05) interactions between ageing period and meat status were found for L-carnitine, glutathione, and taurine. Taurine and glutathione concentrations were greater (P < 0.05) in raw beef aged for 90 days, while L- carnitine content was lower in cooked meat aged for 5 days than the other treatments. Concentrations of coenzyme Q10, glutathione, L-carnitine, and taurine were higher (P < 0.05), and carnosine and anserine content were lower (P < 0.05) in meat aged for 90 days compared to 5 days. All bioactive compounds presented greater (P < 0.05) concentrations in raw than cooked meat. Beef aged for 90 days presented a greater (P < 0.05) proportion of intramuscular fat (IMF), and concentrations of saturated fatty acids (SFA), monounsaturated (MUFA), n-6 polyunsaturated fatty acids (PUFA)/n-3 PUFA ratio, atherogenic and thrombogenic indices. Cooking increased (P < 0.05) the concentrations of all fatty acids, however the PUFA/SFA ratio was greater (P < 0.05) in raw meat. Our findings show that ageing and cooking affect the bioactive compounds concentrations and fatty acids present in beef, and both factors should be considered to really know what meat provides under the conditions in which it is consumed.