Degradation of inosine-5′-monophosphate (IMP) in aqueous and in layering chicken muscle fibre systems: Effect of pH and temperature

Studies were carried out to assess the effect of pH and temperature on the degradation of major meat flavour precursor inosine mono-phosphate (IMP) in model systems. Breast and leg muscles from Indian domesticated layer chicken (Gallus gallus) were washed repeatedly with 0.1 M phosphate buffer of pH 6 to obtain pigment-free muscle fibres. Degradation of IMP in water and in muscle fibre-IMP systems were studied at 80, 100, and 120 °C under three pH (2, 7 and 11) conditions. The pH of muscle fibres was 6.2-6.4. The IMP content (mg/100 g) of fresh breast muscle (188.5) and its fibre (7.9) were higher (P?0.05) than fresh leg muscle (135.2) and its fibre (1.9). Inosine and hypoxanthine contents were also higher in breast than in leg muscles and their fibres. Degradation of IMP in both model systems was significantly influenced by pH and thermal treatment. In water systems, the degradation of IMP increased with temperature. Acidic pH caused greater degree of degradation than neutral or alkaline pH.