Original Article Triacylglycerols, fatty acids and conjugated linoleic acids in Italian Mozzarella di Bufala Campana cheese § Raffaele Romano *, Anella Giordano *, Lina Chianese, Francesco Addeo, Salvatore Spagna Musso Universita ` degli Studi di Napoli Federico II, Dipartimento di Scienza degli Alimenti, Via Universita ` 100 – 80055 Portici, NA, Italy 1. Introduction Mozzarella di Bufala Campana is an italian protected designation of origin (PDO) cheese from the regions of Campania, Latium, Puglia and Molise (D.M., 2003). Mozzarella di Bufala Campana is a pasta filata cheese product that is made from whole buffalo milk and an acid whey starter. Mozzarella cheese is made into oval-shaped balls with weight varying from 16 to 800 g and shipped in an expedition sauce. Mozzarella di Bufala Campana cheese is allowed to have a maximum moisture content of 65% (w/w) and must contain at least 52% (w/w) milk fat (D.M., 2003). This cheese is unique in that it has a legal limit for humidity content. In addition, there is a legal limit for water buffalo protein of at least 4.2% (w/w) and fat content of 7.2% (w/w). More than 98% (w/w) of water buffalo milk fat is composed of triacylglycerols (TAGs) present in a large number of small fat globules (Alais, 2000). Milk fat droplets are enveloped by a biological trilayer membrane composed of phospholipids and proteins (Keenan and Dylewski, 1995). Water buffalo milk fat globules vary in diameter from 2.1 to 4.0 mm (average 2.80 mm). The large fat globules make natural creaming of the water buffalo milk easier. The fat globule size is positively correlated to the proportion of unsaturated fatty acids, suggesting that water buffalo milk butter would possess a better keeping quality than its bovine counterpart because of its higher proportion of solid fat (Menard et al., 2010). A higher proportion of solid fat would result in a slower rate of fat hydrolysis and lower rancidity development. Milk homogenization disrupts fat membranes, releasing free fat in emulsion. During homogenization, lipases associated with high somatic cell counts release fatty acids (FAs) from the TAG emulsion, causing an undesirable rancid flavor in milk. In the case of Gorgonzola and Provolone cheeses, a small amount of lipolysis contributes to the characteristic piquant flavor. At the same time, unsaturated phospholipids undergo oxidization to produce a characteristic flavor described as painty, fishy or metallic (Fox and McSweeney, 2006). Knowledge of the supramolecular structure of milk fat is of primary importance in understanding the nutritional properties of dairy products in relation to the content of essential polyunsaturated fatty acids (Parodi, 2004). Among the essential polyunsaturated fatty acids, conjugated linoleic acids (CLAs) are the most sensitive to oxidation. CLAs are a group of geometric and positional isomers of linoleic acid (C18:2 n-6), including cis–trans, cis–cis and trans–trans fatty acids (cis-9, trans-11; trans-9, trans-11; trans-10, cis-12; trans- 10, trans-12; cis-9, cis-11; and trans-9, cis-11) (Fritsche and Fritsche, 1998; Mulvihill, 2001). C18:3 n-3 and C18:2 n-6 are incompletely hydrogenated in the rumen. The portion of linoleic and linolenic acid not fully hydrogenated to stearic acid is isomerized in the rumen by Butyrivibrio fibrisolvens (Kepler and Tove, 1967), Lactobacillus, Propionibacterium, Bifidobacterium, and Enterococcus strains (Collomb et al., 2004). This catalysis results in higher concentrations Journal of Food Composition and Analysis 24 (2011) 244–249 ARTICLE INFO Article history: Received 15 April 2009 Received in revised form 28 September 2010 Accepted 1 October 2010 Available online 8 December 2010 Keywords: Fatty acids Triacylglycerol composition Water buffalo milk fat Mozzarella cheese CLA Food analysis Food composition ABSTRACT Water buffalo Mozzarella di Bufala Campana, a protected designation of origin (PDO) cheese that complies with European Union legislation, has shown potential nutritional value for its conjugated linoleic acid (CLA) content. In the current study, triacylglycerols (TAGs) and fatty acids (FAs) in commercial samples of Mozzarella di Bufala Campana were characterized over a 1-year period. The distribution of TAGs represented by CN, where N equals the number of carbon atoms, ranged between N = 24 and N = 56. The TAG and FA pattern in Mozzarella di Bufala Campana was similar to the pattern of the parent milk and the bovine counterparts. The data acquired over four seasons showed a significant difference between winter-spring and summer-autumn water buffalo milk fat composition. Using high- resolution gas chromatography, a cis9-trans11 C18:2 isomer was found to represent approximately 80% of the total CLA fraction. ß 2010 Elsevier Inc. All rights reserved. § Note: Part of this paper has been published in Italian in Progress in Nutrition 10; 2008; 22–29; see Romano et al. (2008). * Corresponding authors. E-mail addresses: rafroman@unina.it (R. Romano), anella-g@libero.it (A. Giordano). Contents lists available at ScienceDirect Journal of Food Composition and Analysis journal homepage: www.elsevier.com/locate/jfca 0889-1575/$ – see front matter ß 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jfca.2010.10.004