Antioxidant behaviour of products resulting from beef sarcoplasmic proteins‐malondialdehyde reaction

The antioxidant properties of the soluble fraction of a Maillard reaction product (MRP) model generated from sarcoplasmic protein/malondialdehyde (MDA) were evaluated. The dry extract colour values showed that it has a pale brown colour appearance, and the carbonyl content of isolated protein increased from 2474 nmol/mg protein to 3904 nmol/mg protein, before and after reaction with MDA, respectively. Reducing power (82.34%) and 1,1-diphenyl-2-picryl hydrazyl radical scavenging (35.20%) were very good, while superoxide anion scavenging showed poor inhibition (324 equivalent SOD units/g). Antioxidant activity in the fused lard system was stronger than in the emulsion system, on all parameters tested, exerting 89% reduction on hydroperoxides, 78% on thiobarbituric acid-reactive substances (TBARS) and 69% on conjugated dienes (CD) at 80 °C. In the linoleic acid/water emulsion system, the antioxidant activity, measured as peroxide formation inhibition at 37 °C, at the higher concentration assayed was 81%, whereas on CD and on TBARS, it exerted a moderate inhibition (45% and 58%). At 80 °C, the antioxidant activity, for the same concentration, was less effective (37% on CD; 75% on peroxide values, and 40% on TBARS). In conclusion, the sarcoplasmic protein/MDA reaction products showed an excellent antioxidant activity in fused lard and a good performance in the linoleic/water emulsion system.