Effect of Irradiation on Lipid Oxidation and Off-flavor Development in Cooked Pork Products with Different Fatty Acids and Packaging

Irradiated samples had higher thiobarbituric acid reactive substances (TBARS) than nonirradiated at day 0 but the difference disappeared during storage in both packaging types. Storage increased the production of volatiles and changed the composition of volatiles only in aerobic-packaged sausage. Irradiation and the fatty acid composition had significant effects on lipid oxidation, volatile production, and sensory characteristics of cooked pork sausages during storage but that oxygen availability had a stronger effect than irradiation and fatty acid composition. Storage increased the production of volatiles and changed the composition of volatiles only in aerobicpackaged sausage. Among the volatile components, 1-heptene and 1-nonene were influenced most by irradiation dose, and aldehydes by packaging type. The TBARS values and volatiles of vacuum-packaged irradiated cooked sausage had very low correlation. The TBARS, however, had very high correlation with the amount of aldehydes and total volatiles, and ketones and alcohols with long retention times in aerobicpackaged pork sausage. The low correlations of irradiation-dependent volatiles (e.g., 1-heptene and 1-nonene) with TBARS values regardless of packaging and storage conditions indicated that volatile compounds responsible for irradiation odor were different from those of lipid oxidation odor in cooked pork sausages. Irradiation of cooked pork sausage, especially at 4.5 kGy and in aerobic packaging, may result in some diminution of typical meaty aromas and increases in an odor described by the panelists in this study as like wet wool or wet animal hair. The training and controlled test situation used in this study may result in greater discrimination in the panel than would exist in most consumers. Whether the changes caused by irradiation would be noticed by consumers or reduce the acceptability of the product to consumers was not addressed in this study. The data obtained suggest that TBARS values may not be useful in predicting the odor changes in cooked irradiated meat products.