A Comparison of the Antioxidant Activity and pH Adjustment Properties Pyrophosphate and Carnosine in Meat Model Products
Ewa Biazik, Wiesław Kopeć, Teresa Skiba, Łukasz Bobak  
Department of Animal Products Technology and Quality Management, Wrocław University of Environmental and Life Sciences, Wrocław, Poland

	This study investigated influence of  the level pyrophosphates and carnosine on oxidation processes and pH adjustment properties in model meat products. Model meat batters, i.e. raw chicken breast muscles ground and emulsified with fat were prepared with pyrophosphate or carnosine addition of 0,25%;0,5% and 0,75%. Then, samples were thermally treated and cold stored for 3 days. 
	The level of lipid peroxidation in the samples was determined as the concentration of substances reacting with thiobarbituric acid (TBARS). Fatty acid composition was monitored using the GC-MS technique. The total antioxidant capacity of the hydrophilic fraction of model dispersion systems was monitored with the ABTS method . pH values were measured before and after thermal treatment.
 	The highest level of both additives caused pH change  from 5,8 up to about 6,4 before cooking. In samples with pyrophosphate and carnosine addition thermal treatment had no effect on ph value. Rising pyrophosphate and carnosine addition led to the increase in total antioxidant capacity of the hydrophilic fraction of model meat products. After cold storage for 3 days decreased in ABTS+ radical scavenging ability was observed in samples prepared with 0,25% carnosine addition. However, storage time had no effect in samples with added pyrophosphate.  The trend to decrease TBARS with increasing pyrophosphate content was observed after 3 days and when supplement was applied. Addition of carnosine did not lead to reduction of TBARS amount.