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The Effect of Fat Component Quality in Raw-Materials on Fat Quality in the Final Product

BYSTRICKY P, PIPOVA M
Veterinarni Medicina 38, 1993, 441-448

The paper deals with the influence of mechanically deboned poultry meat fat and pork fat on the fat quality of the final product, tender poultry sausage. Three values were estimated: acid value (CKT) of fat as a measure of its hydrolytic breakage, peroxide value (PC) as a degree of oxidative changes in fat, and thiobarbituric acid number (TBA C.) as a value reflecting undesired degradative changes connected with organoleptic changes. Samples were taken from mechanically deboned poultry meat, pork, sausage parts, and fine poultry sausage (60 % of mechanically deboned poultry meat, 25 % of pork) immediately after processing and production, on the third day after processing (which is the last day of the official shelf-life) and on the sixth day after processing. The samples were taken on ten occasions and every sample was estimated in three parallel assays. These ten estimations were made over a period of four months. Acid value and peroxide value were estimated in fat extracted from the samples by the method described by Bodorova (1991). TBA number was estimated using a modified method reported by Bull and Marnett (1985). Malonylaldehyde concentrations (MA) per g of fat were calculated using the molar absorption coefficient of MA-TBA complex epsilon = 149,000 mol/cm. Results were calculated as a mean of three parallels. The composition of fine poultry sausage and the amount of fat are presented in Fig. 1. Average amounts of fat estimated in individual samples are shown in Fig. 2. Average values with their spans of individual estimations are represented in Figs. 3, 4, and 5. Average values from three parallels of CKT, PC and TBA C. estimations taken from the ten tested samples are presented in Figs. 6, 7, and 8. The CKT values for individual samples are characterized by considerable divergence but the percentage of this divergence is almost the same in all samples. The absolute values of CKT in mechanically deboned poultry meat are considerably higher than those in pork, and this fact is reflected in increasing CKT values of sausage parts and sausage which contain equal amounts of poultry and pork fat (Fig. 1). It is evident from Fig. 6 that CKT of sausage parts and sausage relates more closely to CKT of mechanically deboned poultry meat fat than to the value of pork, though correlations are almost the same. All PC values show a broad span. The PC value of mechanically deboned poultry meat fat influences PC of sausage parts and sausage, to the highest degree. This is also evident from Fig. 7. The quality of mechanically deboned poultry meat fat has a primary effect on the quality of fat in sausage part and consequently on fine poultry sausage fat. Mechanically deboned poultry meat is relatively low in fat but its nature (higher amount of unsaturated fatty acids) and the means of its acquisition (microbial contamination, mechanical tissue disintegration) allow higher oxidative and hydrolytic damage than in pork fat. An increase of undesired changes is evident after the processing of sausage parts to final product. During this step thermal treatment causes an increase in sausage fat PC values. During the subsequent six days the PC value is nearly unchanged. Hydrolytic changes in fat after thermal treatment are low, and this is due to elimination of bacteria originally present in raw materials. The absolute CKT values are highly dependent on the sampling season (Fig. 6) and on the origin of fat


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