Effect of sous-vide technique on fatty acid and mineral compositions of beef and liver from Bonsmara and non-descript cattle

This study examined the fatty acid and mineral compositions of raw and cooked beef and liver from Bonsmara (BD) and non-descript (ND) cattle, raised on natural pasture. Samples were collected from 80 cows and thermal-processed at 65°C for 120 minutes and 85°C for 60 minutes using sous-vide techniques, and then analysed for fatty acid and mineral compositions. The results did not show differences in individual fatty acid composition of meat samples between the breed (P>0.05). However, the raw beef sample had higher content of monounsaturated fatty acids (MUFA , 40.22% ± 3.79 ND, 42.53% ± 2.39 BD) and lower content of polyunsaturated fatty acids (PUFA , 11.02% ± 5.47 ND, 10.13% ± 6.73 BD) than liver (MUFA , 20.11% ± 4.76 ND, 21.08% ± 2.46 BD; PUFA , 30.73% ± 5.20 ND, 31.11% ± 2.37 BD) (P<0.05). The PUFA /MUFA and n-6/n-3 ratios, atherogenicity and desaturase indices were comparable between breeds, but higher in beef than liver. The total percentage of saturated fatty acid, MUFA and PUFA retained after cooking were numerically higher in liver than in beef (P>0.05). The results further revealed higher contents of Na, Mg, and Zn in raw beef than liver. However, the content of Na, Mg, and Zn in the beef and liver were not significantly (P>0.05) affected after cooking. Based on the PUFA proportion of the total lipids in beef (11.02%) and liver (31.11%) and n-6/n-3 PUFA ratio in beef (2.54) and liver (1.34), consumption of liver and beef from cattle raised on pasture could be beneficial to human health. Additionally, application of sous-vide technique can be used to minimize the nutritional losses in beef and liver.