Application of pork fat diacylglycerols in meat emulsions Rikke Miklos a , Xuebing Xu b , René Lametsch a, ⁎ a Department of Food Science, University of Copenhagen, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark b Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark abstract article info Article history: Received 3 May 2010 Received in revised form 21 September 2010 Accepted 11 October 2010 Keywords: Emulsions Diacylglycerols (DAGs) Fat binding Lard Meat products Texture Water binding The properties of fat are of major importance when meat products are produced. By enzymatic modification triacylglycerols (TAGs) can be converted to diacylglycerols (DAGs) resulting in changes of the physical and chemical properties of the fat. In this study the texture as well as the hydration and binding properties were investigated in meat emulsions prepared with lard substituted with different amounts of DAGs derived from the lard. In emulsions prepared with DAGs the percentage of total expressible fluid decreased from 28.2% in products prepared with lard to 11.8% in emulsions prepared with 100% DAGs. The fat separation decreased from 10.9% to 7.8% when 10% of DAGs were applied and no fat separation was observed for emulsions prepared with 50% and 100% DAGs. Emulsions containing DAGs were more elastic and solid reflected in a significant increase in Young's modulus and the maximum hardness. The results suggest future opportunities for the application of DAGs to improve the quality of meat products. © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved. 1. Introduction The quality of fat is an essential aspect in the production of meat products. The specific role of fat differs between types of products but affects the rheological and structural properties of the product besides contributing to succulence, flavour and texture. In the production of meat emulsions, the physical properties of the fat fraction are crucial in the formation of a stable emulsion as fat stabilises the solubilized pro- tein gel and helps to prevent shrinkage of the protein during cooking by acting as a filler (Feiner, 2009; Lurueña-Martinez, Vivar-Quintana, & Revilla, 2004). The technological quality of fat is determined by the fatty acid composition, the position of the fatty acids in the glycerol backbone, the melting point and the crystallisation behaviour (Davenel, Riaublanc, Marchal, & Gandemer, 1999). In pork fat these properties depend on breed, feed, age and slaughter weight of the individual pigs (Hernandez, Navarro, & Toldra, 1998; Hugo & Roodt, 2007; Wood et al., 2008). Hence, variation in the fat quality is a major issue, which manufacturers of meat products have to face (Davenel et al., 1999) and problems associated with poor fat quality are a serious challenge (Hugo & Roodt, 2007). By enzymatic modification the physical and chemical properties of fats and lipids can be manipulated in several ways, e.g. interesterifica- tion with other oils and fats and by formation of partial acylglycerols (Rønne, Yang, Mu, Jacobsen, & Xu, 2005; Vu et al., 2007; Weber & Mukherjee, 2004; Xu, 2000). Thereby enzymatic modification of pork fat opens new ways to affect the technological quality. In general, partial acylglycerols in the form of diacylglycerols (DAGs) have higher melting points compared with their corresponding triacylglycerols (TAGs), which serve as a new possibility to overcome problems with texture. Since DAGs have a hydrophilic polar group in the molecular structure and exhibit surface activity, DAGs have the ability to form emulsions and retain water (Nakajima, 2004). As the water holding capacity in meat products normally is increased by addition of salt and phosphates, a stronger water retention caused by partial acylglycerols can be speculated to reduce the need for salt and addition of phosphates can maybe be avoided in some meat products. In addition DAGs have been reported to result in a lower fat accumu- lation in the human body (Flickinger & Matsuo, 2003; Maki et al., 2002; Meng, Zou, Shi, Duan, & Mao, 2004; Murase, Aoki, Wakisaka, Hase, & Tokimitsu, 2002). Cooking oil based on DAGs is already on the markets in Japan and USA, where DAGs have been evaluated as “generally recognized as safe (GRAS)” by FDA (Morita & Soni, 2009). In this study the application of pork diacylglycerols (DAGs) pro- duced from lard by lipase-catalysed glycerolysis has been investigated in meat emulsions. The aim of this work was to investigate the effect of substitution of TAGs with DAGs in meat emulsions for evaluation of the future perspectives of use of DAGs in meat products. 2. Materials and methods 2.1. Preparation of meat Pork Semimembranosus muscles (pH 5.65–5.77) were purchased from a local meat market. All visible fat and connective tissue were removed before cutting into smaller pieces. The pieces were mixed Meat Science 87 (2011) 202–205 ⁎ Corresponding author. Tel.: + 45 35333483; fax: + 45 35333341. E-mail address: rla@life.ku.dk (R. Lametsch). 0309-1740/$ – see front matter © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2010.10.010 Contents lists available at ScienceDirect Meat Science journal homepage: www.elsevier.com/locate/meatsci