Influence of feeding systems on selected beef quality and sensory attributes

Feeding systems and other factors associated with processing influence meat quality, and therefore sensory attributes. This study was conducted to assess the meat quality attributes of young grain-fed and older grass-fed steers that mostly affect consumer acceptability of beef. Eighty Bonsmara steers consisting of 20 each of A-age (0-tooth) grain-fed (AC) and grain-fed supplemented with zilpaterol (AZ), 20 each of grass-fed AB (1-2 teeth) and B-age (3 - 6 teeth) animals were used. This combination represented the typical feeding systems of South Africa and other countries using similar classification systems, therefore describes the typical feeding systems of the South African beef industry. The longissimus lumborum (LL), semitendinosus (ST), and biceps femoris (BF) muscles were tested for colour, moisture properties, lipid oxidation and sensory attributes. It was found that diet in combination with animal age influenced meat colour. Muscles of the older grass-fed steers were generally darker and duller (darker red) compared to muscles of young grain-fed animals. Moisture loss was consistently higher in zilpaterol supplemented meat samples compared to the feedlot controls, while muscles of the grass-fed animals had lower moisture loss. A sensory panel clearly distinguished between cuts of grain-fed (AZ and AC) and grass-fed carcasses (AB and B) on the grounds of flavour characteristic. The AB and B cuts scored higher for grassy, animal-like and rancid flavour overtones and lower for roasted flavour and sourness than AZ and AC grain-fed cuts. This indicated that typical flavours related to diet define expected eating quality.