乳酸对牛心线粒体氧消耗及肌肉色泽变深的影响。

Effects of lactate on beef heart mitochondrial oxygen consumption and muscle darkening.

作者信息

Ramanathan Ranjith, Mancini Richard A, Konda Muralikrishna Reddy

机构信息

Department of Animal Science, University of Connecticut, Storrs, Connecticut 06269-4040, USA.

出版信息

J Agric Food Chem. 2009 Feb 25;57(4):1550-5. doi: 10.1021/jf802933p.

DOI:10.1021/jf802933p

PMID:19178274

Abstract

The mechanism of lactate-induced beef color darkening is unclear. Our objective was to evaluate the ability of mitochondria isolated from bovine cardiac muscle to utilize lactate as a fuel for respiration. Addition of lactate (4, 8, and 16 mM) to isolated bovine cardiac mitochondria resulted in state IV oxygen consumption at pH 7.2 and 25 degrees C measured using a Clark oxygen electrode. Combining mitochondria with lactate, LDH, and NAD increased state IV oxygen consumption compared with that of lactate alone (p < 0.05). Moreover, oxygen consumption resulting from the addition of lactate-LDH-NAD (0.2 mM each) was comparable to oxygen consumption resulting from the direct addition of NADH (0.2 mM) to mitochondria at pH 7.2. Rotenone reduced (p < 0.05) lactate-mediated darkening in bovine cardiac muscle homogenates. Lactate-induced beef color darkening may be due to increased oxygen consumption by mitochondria, which out-competes myoglobin for oxygen and results in dark colored muscle.

摘要

乳酸导致牛肉颜色变深的机制尚不清楚。我们的目标是评估从牛心肌中分离出的线粒体利用乳酸作为呼吸燃料的能力。使用克拉克氧电极在pH 7.2和25摄氏度条件下，向分离出的牛心脏线粒体中添加乳酸（4、8和16 mM），可导致状态IV耗氧量。与单独添加乳酸相比，将线粒体与乳酸、乳酸脱氢酶（LDH）和烟酰胺腺嘌呤二核苷酸（NAD）结合可增加状态IV耗氧量（p < 0.05）。此外，添加乳酸-LDH-NAD（各0.2 mM）所导致的耗氧量与在pH 7.2条件下直接向线粒体中添加烟酰胺腺嘌呤二核苷酸（NADH，0.2 mM）所导致的耗氧量相当。鱼藤酮可降低（p < 0.05）牛心肌匀浆中乳酸介导的颜色变深。乳酸导致牛肉颜色变深可能是由于线粒体耗氧量增加，其与肌红蛋白竞争氧气，导致肌肉颜色变深。