title: The effects of freeze-thaw and sonication on mitochondrial oxygen consumption, electron transport chain-linked metmyoglobin reduction, lipid oxidation, and oxymyoglobin oxidation.
abstract: Mitochondria potentially influence Mb redox stability in meat by (1) decreasing partial oxygen pressure via oxygen consumption, (2) mitochondrial electron transport chain (ETC)-linked reduction of MetMb, and/or (3) oxidation of mitochondrial membrane lipid. The objective of this study was to investigate the effect of freeze-thaw and sonication treatments on mitochondrial oxygen consumption, ETC-dependent MetMb reducing activity, lipid oxidation, and Mb redox stability. Mitochondria were frozen and thawed (-18°C for 2h and 4°C for 0.5h) for 3 cycles, or sonicated for 30s with a sonic dismembrator. State III oxygen consumption rate (OCR) was decreased by both treatments at pH 7.2, and by sonication only at pH 5.6 (P<0.05). There was no effect on state IV OCR (P>0.05). Respiratory control ratio (RCR) was decreased by freeze-thaw and sonication at pH 7.2 and 5.6 (P<0.05). Sonication increased mitochondrial lipid oxidation and MetMb formation (P<0.05); a similar effect was observed in sonicated samples in the presence of ascorbic acid and ferric chloride (P<0.05). Sonication also decreased mitochondrial ETC-dependent MetMb reduction (P<0.05). These results suggested that sonication treatment had the potential to affect Mb stability via mitochondrial lipid oxidation and/or ETC-mediated MetMb reduction, but the effect on myoglobin stability by freeze-thaw treatment was minimal.
authors: Department of Animal Science, University of Connecticut, 3636 Horsebarn Hill Road Ext., Storrs, CT 06269-4040, United States.
authors: Jiali
authors: J
authors: Tang
authors: Cameron
authors: C
authors: Faustman
authors: Richard A
authors: RA
authors: Mancini
authors: Mark
authors: M
authors: Seyfert
authors: Melvin C
authors: MC
authors: Hunt