Physico-chemical and sensory attributes of low-sodium restructured caiman steaks containing microbial transglutaminase and salt replacers

Highlights

• Quality attributes of low-sodium restructured caiman steaks were investigated.

• Microbial transglutaminase (MTG) improved instrumental and sensory texture.

• Salt replacers improved texture, succulence, and consumer acceptance.

• Combination of MTG and salt replacers is a suitable salt reduction strategy.

Abstract

Our objective was to examine the physico-chemical and sensory attributes of low-sodium restructured caiman steaks containing microbial transglutaminase (MTG) and salt replacers (KCl and MgCl₂). Trimmings from caiman carcasses were processed into restructured steaks with or without MTG and salt replacers; the five treatments were CON (1.5% NaCl), T-1 (1.5% NaCl + 1% MTG), T-2 (0.75% NaCl + 1% MTG + 0.75% KCl), T-3 (0.75% NaCl + 1% MTG + 0.75% MgCl₂), and T-4 (0.75% NaCl + 1% MTG + 0.375% KCl + 0.375% MgCl₂). T-4 demonstrated the greatest (P < 0.05) succulence and the lowest (P < 0.05) values for cooked hardness, springiness, and cohesiveness. The greatest (P < 0.05) purchase intention was for T-3. Furthermore, T-3 and T-4 were similar (P > 0.05) to controls in salty flavor. Our findings suggest that the combination of MTG, KCl, and MgCl₂ can be employed as a suitable salt reduction strategy in restructured caiman steaks without compromising sensory attributes and consumer acceptance.

Introduction

The increasing costs of meat production have prompted the industry to develop novel processing strategies to utilize the carcasses, and value-addition of low-value meat cuts generates additional revenue. Meat restructuring allows for efficient utilization of low-value cuts and carcass trimmings. Restructured meats exhibit consumer-desirable texture and appearance, and thus have an increased retail value (Marques, Marostica, & Pastore, 2010). Restructured meats are commonly manufactured using salt and mechanical processes to extract myofibrillar proteins, which form a protein matrix entrapping fat, water, and flavor compounds, resulting in a desirable texture and flavor (Pearson & Gillett, 1996).

The increase in consumer health consciousness has led to the development of healthy meat products through reformulation and using muscle foods with a high nutritive value (Trespalacios & Pla, 2007). Meat from caiman (Caiman crocodilus yacare) is low in fat and rich in polyunsaturated fatty acids (Paulino et al., 2011, Romanelli et al., 2002). Commercial caiman production (primarily for leather) is an emerging agricultural activity (Vicente Neto et al., 2007) in Brazil, where significant quantity of caiman meat is wasted due to the lack of suitable processing technology to utilize the carcass trimmings.

The role of sodium in hypertension and cardiovascular diseases (He & MacGregor, 2008) is a major concern in food industry because processed meats are a major source for sodium in human diet (Engstrom, Tobelmann, & Albertson, 1997). Therefore, sodium reduction is a priority in meat industry. Sodium reduction can lead to obstacles because salt (NaCl) is a reliable protein extractor, which enhances flavor and palatability traits. Potassium chloride (KCl) can be used as a salt replacer, but it imparts bitterness and decreases saltiness. Magnesium chloride (MgCl₂) has also been explored as a salt replacer (Hur et al., 2004, Ruusunen and Puolanne, 2005). In general, salt reduction strategies compromise sensory and textural attributes of meat products (Doyle and Glass, 2010, Ruusunen and Puolanne, 2005) and negatively influence consumer acceptance (Desmond, 2006). In this perspective, sodium reduction strategies in restructured meat products need further research (Cofrades et al., 2011, Lee and Chin, 2011).

Microbial transglutaminase (MTG) is an enzyme promoting protein aggregation in muscle foods through covalent cross-linking between glutamine and lysine residues (Lee and Lanier, 1995, Seguro et al., 1995). MTG is active at the pH range 5–8 and temperature range 2–60 °C. The efficiency of MTG is governed by the availability of the target amino acids, which depends on the species of meat (Ahhmed et al., 2007, Kawahara et al., 2007, Lennon et al., 2010). In meat products, MTG is utilized to improve water-holding capacity and texture (Chin, Gob, & Xiong, 2009). Furthermore, MTG has been proposed as an ingredient to achieve protein gelation and matrix formation in low-salt meats (Colmenero et al., 2005, Fulladosa et al., 2009).

Caiman carcass trimmings can be utilized for manufacturing heart-healthy, low-sodium processed meats through restructuring and salt reduction strategies. Nonetheless, investigations are yet to be undertaken to explore the use of MTG in combination with potassium chloride and magnesium chloride in low-sodium restructured caiman meat products. Therefore, the objective of the present study was to examine the sensory attributes, texture, and color of low-sodium restructured caiman meat steaks containing potassium chloride, magnesium chloride, and MTG.