Eur Food Res Technol (2011) 232:433–440 DOI 10.1007/s00217-010-1407-3 123 ORIGINAL PAPER EVects of phospholipid hydroperoxide glutathione peroxidase mRNA expression on meat quality of M. longissimus dorsi in pigs Wei Chen · Yongqing Zeng · Jingxiang Cui · Qimei Chen · Jinfang Du · Lun Yang · Yanxia Hu · Yiping Song · Yuan Qian Received: 24 August 2010 / Revised: 11 November 2010 / Accepted: 3 December 2010 / Published online: 25 December 2010  Springer-Verlag 2010 Abstract Antioxidant enzymes protect muscle tissues against oxidation from reactive oxygen species and increase the stability of the muscle. Phospholipid hydroper- oxide glutathione peroxidase (GPx4) is an important anti- oxidant enzyme in muscle tissue. So the aim of this study was to identify the eVects of mRNA expression level of GPx4 gene on meat quality properties in Longissimus dorsi of three pig breeds. Total 36 pigs (12 pigs for each breed) were used to measure the meat quality properties and to analyze the expression levels of GPx4 gene by quantitative real-time PCR. The results showed that meat quality, GPx4 activity, and GPx4 mRNA levels were aVected by pig breeds. There were the lowest expressible moisture, drip loss, and cooking loss in Laiwu Pig among the three breeds, and also there were the highest GPx4 activity and the expression levels of GPx4 gene in Laiwu Pig compared with the other two pig breeds. Analysis of meat samples divergent for water-holding capacity identiWed highly nega- tive associations between expressions levels of GPx4 gene and expressible moisture, drip loss and cooking loss. These results suggest that the higher mRNA expression level of GPx4 gene up-regulate the water-holding capacity and the activity of GPx4, and the expression of GPx4 gene plays an important role in physiological changes related to the meat quality properties and the mechanisms of the antioxidant ion of meat. Keywords Meat quality · GPx4 activity · Quantitative real-time PCR · GPx4 gene · mRNA expression · Pig Introduction The sensory attributes of pork, such as odor, Xavor, tender- ness and juiciness, or the main physical and biochemical parameters, are associated with these attributes: pH, color, and water-holding capacity (WHC) that are essential attri- butes of pig meat quality properties [1, 2]. Meat is sensitive to lipid oxidation, and pork muscle with higher phospho- lipid hydroperoxide glutathione peroxidase (PHGPx or GPx4, EC. 1.11.1.12) activities would be less susceptible to lipid oxidation [3]. However, GPx4 can inhibit the lipid oxidation, and GPx4 plays an essential role in protecting the muscle against the damage by the superoxide anion rad- ical [4]. GPx4 is a 20–22-kDa monomer that was Wrst puriWed in 1982 by Ursini et al. [5]. And it was described as a ‘peroxi- dation-inhibiting protein’ [6]. The fact that GPx4 is a monomer may allow it to bind with the wider range of sub- strates than the tetrameric GPXs [7, 8]. GPx4 is a unique antioxidant enzyme that can directly reduce lipid hydroper- oxides and is generally considered the main line of enzy- matic defense against oxidative biomembrane destruction in animals [9]. GPx4 is located in both the cytosol and the membrane fraction, so GPx4 can directly reduce the phospholipid hydroperoxides, fatty acid hydroperoxides, and cholesterol hydroperoxides that are produced in peroxi- dized membranes and oxidized lipoproteins [10]. Meat is an excellent source of total glutathione that is the major redox system within tissues. It is found in the reduced (GSH) and oxidized (GSSH) forms; therefore, glutathione is consid- ered the major thiol-disulWde redox buVer in animal tissues W. Chen · Y. Zeng (&) · J. Cui · Q. Chen · J. Du · L. Yang · Y. Hu · Y. Song · Y. Qian College of Animal Science, Shandong Agricultural University, 61 Daizong Street, Tai’an 271018, People’s Republic of China e-mail: yqzeng@sdau.edu.cn