Improved antioxidant activity of Vitamin E through solubilization in ethanol: A model study with ground beef T.M. Wills a , C.A. Mireles DeWitt a, * , H. Sigfusson b a Department of Animal Science, Oklahoma State University, Rm 101, Stillwater, OK 74078, USA b Gorton’s Technology and Innovation Center, 303 Main Street, Gloucester, MA 01930-5097, USA Received 3 May 2006; received in revised form 13 November 2006; accepted 21 November 2006 Abstract Previous research has demonstrated that vitamin E (tocopherol) applied to muscle foods using an oil carrier targets the neutral lipid fraction (NLF: triacylglycerols) instead of the polar lipid fraction (PLF: phospholipids) and therefore does not act as an effective anti- oxidant. This paper demonstrates that d-tocopherol (TOH) applied using a polar carrier was effectively incorporated into the PLF of ground beef and reduced subsequent TBARs development. TOH was incorporated in the PLF at 2820 ± 231 lg TOH/g lipid and in the NLF at 167 ± 66.2 lg TOH/g lipid. Cooking ground beef (patties) did not result in loss of absolute amount of d-tocopherol (5020 ± 975 lg vs. 6220 ± 1510 lg TOH, respectively). In addition, the development of thiobarbituric reactive substances (TBARs) in cooked product was significantly ðp < 0:05Þ lowered by TOH incorporation on days 2, 9, 15, and 22. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Vitamin E; Tocopherol; Phospholipid; Triacylglycerol; Antioxidant 1. Introduction Processed meat items are commonly manufactured from muscle tissue high in total lipids to aid in their emulsion stability and improve their texture. Lipids of processed meat products are much more susceptible to oxidation than lipids of whole muscle. This low oxidative stability is lar- gely due to incorporation of oxygen and release of heme catalysts and/or degradative enzymes as a result of cellular disruption during the grinding, mixing, or mincing process (Dawson & Gartner, 1983). Furthermore, the polar mem- brane phospholipids are also more susceptible to oxidative changes than the neutral triacylglycerols (Dawson, Shel- don, Larick, & Ball, 1990). As a consequence, antioxidants are often added to processed meats in order to improve their lipid stability (Faustman, Liebler, & Burr, 1999). Oxidation is considered to be a surface phenomenon, occurring at a lipid-water interface (Boyd, Boyd, & Bar- clay, 1990). Determining the partitioning characteristics of antioxidants between different phases is an important parameter used to select antioxidants that favor distribu- tion toward the microenvironment that is most susceptible to oxidation (Huang, Frankel, Aeschback, & German, 1997). Thus, directing the added antioxidant to or near the origin of the oxidation initiation and/or propagation is of particular importance. The partitioning of antioxi- dants has primarily been studied in various model or sim- ple food systems (Cornell, DeVilbiss, & Pallansch, 1970; Frankel, Huang, Kanner, & German, 1994; Huang et al., 1997). Results from these studies indicate partitioning is influenced by both the lipid and antioxidant surface (Cho, McClements, & Decker, 2002; McClements & Decker, 2000; Porter, Black, & Drolet, 1989; Richards, Chaiyasit, McClements, & Decker, 2002). Direct addition of a-tocopherol using oil (typically from corn) as a carrier to processed meat products has previously been reported to have no significant antioxidant effect (Buckley, Morrissey, 0309-1740/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2006.11.012 * Corresponding author. Tel.: +1 405 744 6616; fax: +1 405 744 4716. E-mail address: christina.dewitt@okstate.edu (C.A. Mireles DeWitt). www.elsevier.com/locate/meatsci Meat Science 76 (2007) 308–315 MEAT SCIENCE