Effects of diets supplemented with sunflower or flax seeds on quality and fatty acid profile of hamburgers made with perirenal or subcutaneous fat

Steers were fed grass hay or red clover silage based diets containing flaxseed or sunflower seed as sources of 18:3n - 3 and 18:2n - 6 respectively. Hamburgers were made from triceps brachii and perirenal or subcutaneous fat. Perirenal-hamburgers contained more polyunsaturated fatty acids (PUFA), several PUFA biohydrogenation intermediates (BHI), and 18:0 (P < 0.05). Oxidative stability was similar across hamburgers (P > 0.05). Sensory differences were found due to hamburger fat source, but were < one panel unit. Within perirenal-hamburgers, feeding flaxseed increased 18:3n - 3 and its BHI (P < 0.05), and feeding sunflower seed increased 18:2n - 6 and its BHI (P < 0.05). Feeding flaxseed increased off-flavour intensity and oxidation in perirenal-hamburgers (P < 0.05). Feeding oilseeds in forage based diets while using perirenal fat to make hamburgers provides opportunities to increase PUFA and BHI with potential to impact human health, but control measures need to be explored to limit oxidation and off-flavours when feeding flaxseed. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.