Carrageenans in Beaker Sausage as Affected by pH and Sodium Tripolyphosphate A. TRIUS, J.G. SEBRANEK, R.E. RUST, and J.M. CARR ABSTRACT We investigated effects of meat pH or sodium tripolyphosphate (STPP) on performanceof carageenans (kappa, iota or lambda) in low-fat beaker sausage model systems. Adding STPP or using high-pH meat affected performance of the meat batter in similar ways. High-pH meat batters or those containing STPP had lower force values when extruded, lower cooking losses, and were firmer when cooked. The addition of lambda- carrageenan produced the softest texture. Kappa- and iota-carrrageenan improved water retention of low-pH meat batters. After staining, light microscopy revealed different structural effects of the carrageenans. Key ‘Words: meat pH, sodium tripolyphosphate, antioxidants, carrageen- ans, beaker sausage INTRODUCTION SE~E~.ALANTEMORTEMANDPOSTMORTEMCONDITIONS canlead to pork with variable ultimate pH. Such conditions, known as DFD (dark, firm, dry) and PSE (pale, soft, exudative), respec- tively, have strong influences on the basic functional properties of the meat from the affected carcasses. PSE pork is a serious problem for the meat industry (lO-30% of all carcasses), and occurs when postmortem glycolysis is rapid while muscle tem- perature is still high (Miller, 1989). This combination greatly lessenswater binding, and is also the cause of meat softness, pale color, and loss of water-soluble nutrients during storage (purge). The high pH of DFD meat somtimes may be beneficial becauseof its higher capacity to retain water. However, it can also be undesirable in cured meat products for color develop- ment or when a specified degree of product dryness must be achieved such as in dried sausage. In the fresh meat market, the dark color of this meat may cause the consumer to reject it. In cooked meat products, the persistenceof residual pinkness is a problem for the meat canning industry (Schmidt and Trout, 1984). Phosphates are common ingredients added to meat products. Among them, sodium tripolyphosphate is most commonly used accounting for 80% of the phosphates incorporated either alone or in combination (Barbut et al., 1988). Phosphates are impor- tant functional additives affecting water-holding capacity, bind- ing, and cooking yields. They also improve color, texture, and flavor, and provide protection against oxidation and microbial growth (Dziezak, 1990). The mechanism by which phosphates increase meat hydration is not fully understood, and various hy- potheses have been proposed. Trout and Schmidt (1983) con- cluded that phosphates increased water-binding capacity of meat products through increasesin ionic strength and pH. Lewis et al. (1986) reported that the ability of phosphates to maintain a high pH seemed to be the most effective and pointed out that ionic strength would have little added effect when a total level of 2% salt was present. Barbut and Mittal (1991) listed several factors that could be responsible for the increase in water hold- Author Trius is with the Dept. of Food Science & Human Nutri- tion, iowa State Univ., Ames, IA 50011. Authors Sebranek and Rust are with the Depatiments of Animal Science and Food Sci- ence & Human Nutrition, Iowa State Univ., Ames, IA 50071. Au- thor Carr is with Sanofi Bio-Industries, Waukesha, WI 53187. Direct all inauiries to Dr. J.G. Sebranek. ing capacity: shifting the pH away from the isoelectric point of the meat proteins, increaseof protein solubility, and dissociation of actomyosin. Three major carrageenan types exist: kappa, iota, and lambda. Kappa- and iota-carrageenanform thermoreversible gels upon heating and cooling, and lambda-carrageenan, as a nongelling gum, typically is used as a thickener. Carrageenans also have been utilized by the meat industry to enhancewater retention in meat mixtures, particularly low-fat, high-moisture products, Several researchers have reported use of carrageenans in various meat products (Fox et al., 1983; Wallingford and Labuza, 1983; Foegeding and Ramsey, 1986; Egbert et al., 1991; Barbut and Mittal, 1992; Bater et al., 1992a, b; Huffman et al., 1993). Meat model systems, such as sausage-type emulsions pre- pared under laboratory conditions, frequently have been used by researchers to study effects of hydrocolloids on functionality of meat batters (Foegeding and Ramsey, 1986; Garcia-Cruz and Scamparini, 1992; Wallingford and Labuza, 1983; Zeuthen and Olsen, 1987). Model systems are less complex than commercial sausageemulsions and facilitate study of different parameters and their interactions by decreasing the number of variables. Our objective was to determine the effects of different car- rageenans in beaker sausage under various pH conditions. Both the effect of initial meat pH and the effect of sodium tripoly- phosphate were studied. MATERIALS & METHODS Initial meat pH effect Pork chops (rib, top loin, loin, center loin, and butterfly chops) were purchasedfrom a local grocery store (Ames, IA). Chops were selected using visual color, assuming a pale color indicated low pH and a dark red color high pH. The pH of each chop was measured(Accumet@ 925 pH/ion meter, Fisher Scientific Co., Pittsburgh, PA) after homogenizing IOg of meat with 90 mL distilled water. Chops were catego&ed into two grouns: chons with a DH <5.6 and those with DH >6.0 (15 choosl pH Eoup/replication). Then, chops were packaged&in plastic‘ bagsand frozen at -40°C for no longer than 2 wk. Once the study began, chops were thawed for 24 hr at 2”C, debonedand trimmed of excess fat. Chops of the two pH groups were separately ground twice through a 4.5mm plate (Jupiter model 863, Jupiter GmbH, Schomdorf, Germany) and the ground meat of each pH group was blended together to form a uniform block. The pH of the two meat blocks was measuredagain (duplicate), afterhomogenizing log of the ground meat with 90 mL distilled water, to assure that no changes occurred during frozen storage. A sample was removed for chemical analysis (AOAC, 1990). Thetwo pH meat blocks were divided into four equal portions (22Og), and different carrageenan treatments were applied. The study was de- signed as a factorial arrangement of two factors: pH and carrageenan type, with two levels for pH (c5.6, >6.0), and four for carrageenan (kappa, iota, lambda, and control). All carrageenans (kappa type from .&heuma cottonii, iota type fromEucheuma $nosum; and lambda type from Giaartina SD.) were movided bv Sanofi Bio-Industries. Inc. fWau- kesha, WI). Brink solutions were prepared 24 hr in advance by mixing distilled water (30% of meat (M) weight), sodium chloride (2% of weight of meat and water (M+W)), and the corresponding carrageenan (0.5% of the weight of M+W). The solutions were stored at 2°C. Each meat portion of each pH group (experimental units) was mixed with its brine solution for 3 min (Kitchen Aid model KSM90, Kitchen Aid Inc.. St. Joseph, MI, speed L 4). Meat batters were left 1 hr at 2°C to enable protein extraction. 946-JOURNAL OF FOOD SCIENCE-Volume 59, No. 5, 1994