| Popis: |
Two studies were conducted to evaluate the influence of packaging and production system (PS) on retail display life color (L*, a*, and b*), fatty acid profile (% of total fatty acids), lipid oxidation (thiobarbituric acid reactive substances; mg malondialdehyde/kg of muscle), vitamin E content (µg/g of muscle), and odor (trained panelists) during storage of LM. Four (or 3) different packaging treatments were applied to LM from steers fattened on grazing systems (Uruguayan) or on high-concentrate diets (U.S.). From fabrication to application of treatments, Uruguayan LM were vacuum packaged for air shipment and U.S. LM were also vacuum packaged and kept in a cooler until Uruguayan samples arrived. Treatments were applied 7 d after slaughter. In Exp. 1, treatments were vacuum packaging (VP), low-oxygen (O) modified atmosphere packaging (MAP) with nitrogen (N2) and carbon dioxide (MAP/CO), low-O MAP with N2 plus CO and carbon monoxide (MAP/CO), and VP plus an application of peroxyacetic acid (VP/PAA). In Exp. 2 block 1, treatments were VP, MAP/CO, and VP with ethyl-arginate HCl incorporated into the film as an antimicrobial agent (VP/AM). In Exp. 2 block 2, treatments were VP, MAP/CO, MAP/CO, and VP/AM. After 35 d storage, steaks were evaluated during simulated retail display for up to 6 d. In Exp. 1, Uruguayan steaks under MAP/CO had greater (0.05) a* values than VP/PAA and MAP/CO on d 6 of display. For U.S. beef, the MAP/CO had the reddest lean color (0.05) compared with the other 3 packaging treatments on d 6 of display in Exp. 1. Packaging × PS × time interaction was significant (0.05) in Exp. 1. In Exp. 2, MAP/CO in Uruguayan steaks also had the greatest a* values on d 6 of display, but no differences (0.05) were detected among both VP and MAP/CO in U.S. steaks at this time. No significant (0.05) packaging × PS × time interaction was observed in Exp. 2. Only PS (both experiments) and time (Exp. 1) affected (0.05) L* values. In both experiments, U.S. steaks had greater (0.05) L* values than Uruguayan steaks. Vitamin E content in Uruguayan steaks was greater (0.05) than in U.S. steaks. Packaging × PS, PS × time, and packaging × PS × time interactions were not significant (0.05) for any of the fatty acids. Beef from Uruguayan had lower (0.05) SFA and MUFA and greater (0.05) PUFA and n-6 and n-3 fatty acid percentages than U.S. beef. Complexity of fresh meat postmortem chemistry warrants a more comprehensive approach to maximize shelf life. |
