Textural properties and microstructure of low-fat and sodium-reduced meat batters formulated with gellan gum and dicationic salts Alfonso Totosaus a, * , M. Lourdes Pe ´ rez-Chabela b a Food Science Lab, Tecnolo ´gico de Estudios Superiores de Ecatepec. Av. Tecnolo ´gico y Av. Central, Ecatepec 55210, Estado de Mexico, Mexico b Departamento de Biotecnologı ´a, Universidad Auto ´noma Metropolitana Iztapalapa, Av. San Rafael Atlixco 186, 09270 Mexico, D.F., Mexico article info Article history: Received 28 January 2008 Received in revised form 29 July 2008 Accepted 30 July 2008 Keywords: Low-fat Reduced-sodium Sausages Gellan gum Texture Microstructure abstract Instrumental texture characteristics of low-fat, reduced-sodium meat batters formulated with other salts (KCl and MgCl 2 or CaCl 2 ) with gellan gum were evaluated. Fat and sodium reduction through incorpo- ration of gellan gum and either of the dicationic salts produced less rigid, more ductile structures. Inclusion of magnesium chloride resulted in better performance, whereas addition of calcium chloride resulted in less desirable properties. The dicationic salts level used probably inhibited the gellan gum thermoreversible properties, affecting its water holding properties. Microstructural differences between the dicationic salt treatments were apparently due to the effect of dicationic salt concentration on myofibrillar protein extraction and solubilization, and gellan gum gelation properties. Use of magnesium chloride in tandem with gellan gum in the studied low-fat, reduced-sodium meat batters effectively compensated for the structural differences caused by fat and sodium reduction. Ó 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. 1. Introduction Fat content is essential to meat product characteristics such as flavor, juiciness and texture and therefore fat content cannot be reduced simply by using less fat or direct replacement with another type of fat (Jimene ´ z-Colmenero, 2000). An alternative is to use functional ingredients that mimic the properties of fat in emulsified cooked meat products. These fat replacements or substitutes contribute a minimum of calories to formulated meats and do not dramatically alter their flavor, juiciness, mouthfeel, viscosity or other organoleptic and processing properties. Carbohydrates such as starches or gums are currently added to improve cooking yields, increase moisture retention, reduce formulation costs, modify product texture and improve freeze–thaw stability. Use of these ingredients has increased with the development of low-fat meat products (Keeton, 1994). System functionality in emulsion-type sausage products is notably affected by reduction or elimination of fat and consequent addition of fat replacements, other additives and processing vari- ables. The main factors affected by reduction of fat in emulsion sausage products are skin toughness, internal product characteristics (i.e. hardness, cohesiveness, and gumminess), sensory attributes, chemical composition and purge (Rogers, 2001). However, the simultaneous reduction of fat and sodium chloride in emulsified comminuted meat products presents a technological challenge. If both salt and fat content are reduced, the water used to replace the fat decreases ionic strength to <0.4, affecting perceived saltiness, flavor characteristics, texture, water binding and the preservative effect (Ruussunen & Poulanne, 2005). Salt is necessary during meat processing to induce structural changes through electrostatic interactions between muscle proteins and the sodium and chloride ions; these cause swelling of myofibrils, depolymerization of myofilaments, and dissociation of the actomyosin complex (Xiong, 1997). Reduced salt concentrations also lead to decreases in extracted and solubilized myofibrillar proteins, affecting the functionality of the entire meat system. The addition of calcium, magnesium or potassium chloride salts to meat batters in the presence of NaCl enhances protein extraction and solubility, emulsion stability, and favors the orderly gelation of proteins (Barbut & Findlay, 1991; Nayak, Kenner, & Slider, 1996; Nayak, Kenney, Slider, Head, & Killefer, 1998a; Piggot, Kenney, Slider, & Head, 2000; Seman, Olson, & Mandigo, 1980). The use of other ionic species could prove advantageous since most fat replacers currently used in the food industry are anionic poly- saccharides, which depend heavily on ion type and concentration for gelling. Gellan gum is a linear anionic microbial heteropolysaccharide requiring both a heating cycle and cations for gelation (Kang & Pettitt, 1993; Morris, 1990). Divalent cations have a more pronounced effect on gellan gum rheological properties than monovalent cations due to differences between the gelation mechanisms of these cation types. Divalent cations directly cross- * Corresponding author. Tel.: þ52 55 5000 2227. E-mail address: alfonso.totosaus@gmail.com (A. Totosaus). Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt 0023-6438/$34.00 Ó 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.lwt.2008.07.016 LWT - Food Science and Technology 42 (2009) 563–569