THE INFLUENCE OF LEVEL OF IRRADIATION, TEMPERATURE AND LENGTH OF STORAGE UPON THE LEVEL OF CERTAIN CHEMICAL COMPONENTS AND PANEL SCORES FOR PRECOOKED BEEF, PORK AND VEAL^a,b,c

Abstract

Irradiation of certain meat products produces characteristic objectionable flavors and odors. It has been assumed that the objectionable flavors are due to certain chemical changes, and a number of workers (2,3,6,8,13) have reported values for various chemical components both before and after irradiation. Recently it has been shown that the level of hydrogen sulfide, methyl mercaptan and carbonyls appear to be closely associated with the poor acceptability of irradiated beef, pork and veal (10). However, data are not available in the literature showing the influence of temperature and length of storage upon either the chemical components or panel scores.Consequently, this study was designed to ascertain the effects of length and temperature of storage upon panel scores, carbonyl compounds, hydrogen sulfide, methyl mercaptan, total glutathione, reduced glutathione and the pH of precooked irradiated meats. E X P E R I M E N T A L P R O C E D U R E Preparation and irradiation. The beef, pork and veal were prepared, cooked and irradiated at either 1.86 X 10 6 rads or 2.79 X 10 0 rads as described in a previous publication (10).All samples irradiated at 1.86 X 106 rads were stored at 2" C. in order to prevent the growth of botulinum organisms. The samples irradiated at the higher level (2.79 X 10 6 rads) were stored at 2" C. and 24" C. for the beef and at 2" C., 24" C. and 38" C. for both pork and veal. Storage for both panel and chemical testing was for 0, 1,3 and 6 months. At each of these storage periods, duplicate samples were removed and one was used for taste panel evaluation while the other was used for chemical determinations. Additional samples were available for panel ratings but not for chemical analysis at 12 months for beef and at 9 months for pork.Samples were prepared and presented to a consumer type panel of 18 judges, who rated the samples on the 9-point hedonic scale (12). Although some judges Storage.Panel ratings.

Volatile Sulfur Compounds in Irradiated Precooked Turkey Breast Analyzed with Pulsed Flame Photometric Detection

“…Our results show that all sulfur compounds decreased during storage. Our results seems to be in agreement with earlier observations that storage of products after irradiation generally improves the odor of irradiated meats ( , ). It is not clear whether the decrease in sulfur compounds observed in the present study was due to leakage of volatile sulfur compounds from the vials or to their reaction with other components of cooked turkey breast.…”

Heterocyclic compounds found in cooked meats

“…Around the same time some low boiling point compounds (hydrogen sulfide, acetone, acetaldehyde, methyl mercaptan, etc.) were identified in cooked beef (Pearson et al, 1959;Kramlich and Pearson, 1960; Pippen and Nonaka, 1960).…”

Flavor and aroma problems and their measurement in meat, poultry and fish products

“…They concluded that neither pre-nor post-irradiation storage influenced panel acceptance. In contrast, Pearson et al (1959) found post-irradiation storage of cooked meat resulted in an improvement in flavor, which is probably related to the differences between fresh raw and cooked meat, with heating being necessary to prevent further flavor deterioration caused by the indigenous enzymes during storage of raw irradiated meat. Merritt et al (1959) were able to identify 10 compounds in the volatiles isolated from irradiated beef using a low-temperature vacuum distillation procedure.…”