To study the role of glutathione peroxidase for lipid oxidation in meat, chicken and duck muscle were heated to an internal temperature of 60, 70 or 80 degrees C and the meats were then stored at 8 degrees C for up to 6 days. Thiobarbituric-acid-reactive substances (TBARS) and glutathione peroxidase (GSHPx) activity were measured on days 0, 1, 3 and 6. In heated muscle samples, TBARS increased during 6 days of storage. GSHPx activity was diminished with increasing temperature and was much more affected by the internal temperature than by the length of the subsequent cold storage, whereas the formation of TBARS was affected by both the final temperature and storage time. Meat samples, which had been heated to 80 degrees C, were also used to investigate the effect of added GSHPx on lipid oxidation. GSHPx (2 or 4 U) was added per I g meat after cooking, and the concentration of TBARS and GSHPx activity were measured on day 0 and 6. Chicken muscle samples with added GSHPx had a lower TBARS concentration on day 6 (2 U/g meat: 58% and 4 U/g meat: 54%) compared to the control without added GSHPx. In contrast, GSHPx addition had no effect on lipid oxidation in heated duck muscle. The study shows that there was a reciprocal relationship between TBARS formation and GSHPx activity and that addition of GSHPx could decrease lipid oxidation. (c) 2006 Elsevier Ltd. All rights reserved.
- Biokemi och molekylärbiologi