J. Agr. Sci. Tech. (2014) Vol. 16: 1313-1324 Modification in the Functional Properties of Sodium Caseinate-based Imitation Cheese through Use of Whey Protein and Stabilizer M. Hosseini 1*, M. B. Habibi Najafi 1, and M. Mohebbi 1 ABSTRACT Guar gum and whey proteins concentrate (WPC-35) were used as functional additives to improve the functional characteristics (hardness and meltability) of the Na-caseinate- based imitation cheese. Also, the alterations in the composition, sensory acceptance, color, and texture caused by these ingredients were evaluated. Imitation cheeses were formulated with three levels each of WPC (0, 1.5, and 3%) and guar gum (0, 0.3 and 0.6%) w/w in cheese formulation. Cheeses with higher guar and lower WPC were softer and melted to a greater degree. Use of the two food additives at increasing levels reduced the amount of protein significantly (P< 0.05). Unlike guar, WPC increased pH values. Color of the cheese was affected positively by guar and negatively by WPC (P< 0.05). The overall acceptability of the cheese was not affected by the levels of WPC, but it did improve with increasing level of guar used in the formulation. Taking into consideration the adverse impact of WPC on color and meltability and slight adverse effect of guar on the hardness of imitation cheese, use of WPC at 1.5% and guar at 0.3% level in the formulation of imitation cheese is recommended. Keywords: Guar gum, Physico-chemical properties, Sensory characteristics, Whey protein concentrate. INTRODUCTION and is used in both unmelted and melted states. In the unmelted state, cheese is Imitation cheeses or cheese analogues are exposed to operations involving a defined as products made by blending food combination of shear and compressive ingredients, involving sources of fat and stresses (e.g. cutting) that results in large deformation and fracture into smaller pieces. Downloaded from jast.modares.ac.ir at 18:58 IRST on Tuesday September 28th 2021 protein along with water, acid, emulsifying salts (ES), and cheese flavoring, and As an ingredient, analogue cheese is also employing thermal and mechanical energy used extensively in cooking applications, to produce a homogeneous product, e.g. on pizzas and cheeseburgers. A key simulating a specific cheese variety aspect of cooking performance of cheese is (Noronha et al ., 2008). The protein in cheese its heat-induced functionality, including analogue stabilize oil-in-water emulsion melting or flowability (O’Riordan et al ., through reducing the interfacial tension and 2011). Thus, the functional attributes of increasing the viscosity of the aqueous importance for imitation cheese include the phase, thereby decreasing the frequency of hardness and exhibiting the desired degrees collisions between oil droplets (Ennis and of meltability. Mulvihill, 1999). Imitation cheese is mostly The main protein source in dairy-based used as an ingredient of ready-to-eat foods imitation cheese products is rennet casein or _____________________________________________________________________________ 1 Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Islamic Republic of Iran. * Corresponding author; e-mail: [email protected] 1313 ______________________________________________________________________ Hosseini et al. sodium (Na) and/or calcium (Ca)-caseinates. interactions between casein and whey Rennet casein, due to its functional proteins (Solowiej 2007). Mleko and properties and desirable flavor, is preferred Foegeding (2000) reported that whey over alternative protein sources. For rennet proteins interact with casein network as casein which has a high calcium-to-casein filler. The most probably disulphide bonds ratio (~36 mg g -1 casein), the degree of between κ-casein and β-lactoglobulin was calcium sequestration and para -casein formed, but also α-lactalbumin could aggregation is easily controlled by using the participate in the interaction with casein. It correct blend of ES to give the desired was recommended to replace casein by degree of fat emulsification in imitation whey protein up to 2% only. cheese. This, in turn, gives the desired WPC has been implicated in reducing the degree of flow and firmness on cooking the meltability of imitation cheese (Mleko and imitation cheese (Guinee et al ., 2004). With Foegeding, 2000; Guinee et al ., 2004; Na-caseinate, the phenomenon of over- Solowiej, 2007). According to Cavalier- creaming is reported that when the oil-phase Salou and Cheftel (1991), the melting ability in analogue cheeses was over-emulsified, correlated with pH, texture, degree of casein the cheese product had poor meltability and dissociation, and degree of fat firmness characteristics. Thus, cheese emulsification. Since the viscosity of fully analogues produced only on the base of Na- hydrated solution of guar gum decreased caseinate is undesirable as a pizza topping with increasing temperature, it can improve and some other applications (O’Riordan et heat-induced flowability of cheese (Jackson al ., 2011). On the other hand, the high cost et al ., 2001). The properties of gels brought of rennet casein have forced processors to about by guar gum largely varies depending search for readily available low-cost upon the amount of gum used; it creates substitutes to partially or totally replace this rubbery mass which exhibits flow type of milk protein in analogue cheeses. In properties, coalesce readily after being the present study, Na-caseinate was subjected to shear, and shows no syneresis. employed due to its availability and Moreover, guar is capable of forming reasonable cost in Iran. On the basis of hydrogen bonds. Therefore, even when used literature review, it was presumed that in small quantities, it can bring about intense optimal levels of guar gum and WPC in competition in absorption of water with combination may confer the desired various hydrocolloids and water-soluble firmness and meltability to the Na-caseinate proteins (Chudzikowski, 1971). In general, based imitation cheese. stabilizers (such as guar) are one such Downloaded from jast.modares.ac.ir at 18:58 IRST on Tuesday September 28th 2021 When WPC is heated over the ingredient, which, in spite of their low denaturation temperature, the tertiary consumption level in the formulation, impart structure of the protein molecule (especially specific and important functions to the α-lactalbumin and β-lactoglobulin) is finished product (Bahram Parvar et al ., unfolded. This phenomenon allows both the 2013). Various gums i.e. guar, locust bean, exhibition of hydrophobic sites and the xanthan, arabic gum, and their admixtures sulfhydryl/disulfide interchange reactions have been used to create a heat reversible that induce the formation of aggregates gel for use in preparation of Soybean (Meza et al ., 2010). Thus, substitution of mozzarella cheese analogue (MCA). In casein with WPC produces cheese with the order to obtain MCA having superior highest firmness values. Firmness of flowability; guar is required in very little processed cheese analogues obtained from amounts than other gums. Guar gum led to acid casein and partially replaced by whey MCAs having greater hardness when products was much higher than standard compared to use of other gums (Yang, analogues with an increase in pH (5.0-7.0). 1983). Such phenomena have been ascribed to the 1314 Modification of the Properties of Imitation Cheese ________________________________ The upper and lower limits of the levels Trading Company (Shiraz, Iran). of WPC and guar gum to be used in the product that could give a cheese-like Manufacture of Imitation Cheese structure were determined in the preliminary studies. For example, when there was only guar, the structure was fluid and in level A basic formula and manufacturing above 0.6%, the structure was too fluid. method similar to Noronha et al . (2008) WPC at the levels between 1-3% was were used with some modifications for the required to harden the structure. preparation of imitation cheese samples. The objective of this study was to Imitation cheese, with an average moisture investigate the influence of different levels content of 52% (w/w), was manufactured in of WPC and guar gum on the composition, an experimental twin-screw cooker sensory acceptance, colour, and especially (dimensions: 10×25×15 cm, capacity: 1,800 3 functionality (texture and melting cm , mixer speed: 50 rpm, setting properties) of the Na-caseinate based temperature by circulating, electromotor imitation cheese. power: 180 watt) that had been prepared for this purpose (Tamesh Company, Mashhad, Iran). The ingredients for preparing MATERIALS AND METHODS imitation cheese were 24.5% Na-caseinate, 52% water, 14% hydrogenated soybean oil, Materials 7% rapeseed oil, 0.5% trisodium citrate, 1.3% NaCl, 0.2% potassium sorbate, and 1% Sodium caseinate (90% protein) was citric acid. It should be noted that sodium purchased from Iran Caseinate Company caseinate was replaced with WPC and guar (Tehran, Iran). Hydrogenated soybean oil gum. Indeed, 0, 0.3 and 0.6% guar and 0, (Ghoncheh Vegetable Oil Company, Tehran, 1.5, and 3% WPC were used instead of the Iran) and rapeseed oil (Aliagolestan Food same contents of Na-caseinate (Table 1). Company, Tehran, Iran) were used for Imitation cheese (800 g per batch) was preparation of imitation cheese. Trisodium manufactured by blending the vegetable oil citrate, citric acid, potassium sorbate, and with water at 50°C for 2 minutes. Then, this guar gum were all obtained from Merck mixture was