Effect of dietary unsaturated fats on the flavour, and on oxidative and colour stability, of Suffolk, Friesland and Soay sheep meats

Abstract

Nutritional recommendations to improve the human diet are to increase the P:S ratio and to decrease the n-6:n-3 ratio of food (Department of Health 1994). However, increasing the degree of unsaturation of meat lipids may alter the flavour of the cooked meat and can increase its susceptibility to oxidative changes such as lipid rancidity and colour deterioration. We have studied these quality aspects in meat from three breeds of lambs fed different fats.Seventy two entire ram lambs of three genotypes were used in a 3x4 factorial design: Suffolk x Lleyn, Frieslands x Lleyn and Soay lambs were fed diets, for an average of 80 days, containing one of four fats at 50g/kg supplemented with 200 IU/kg vitamin E: 1, control, 2, linseed, 3, fish oil and 4, fish oil plus linseed (50:50). Sensory assessment was performed on loin chops grilled to an internal temperature of 74°C which were rated using 100mm unstructured line scales. For colour and lipid oxidation measurements, 10mm thick leg steaks were aged for 10 days in vacuum at 1°C then repacked in modified atmosphere (O2:CO2,75:25) and displayed under light at 4°C for 6 days.