Investigating the effect of emulsifying salts on reduced fat kaymak texture and sensory properties

Obesity is one of the most important health problems of our era, and there have been many initiatives to reduce the fat content of dairy products. Kaymak is a traditional Turkish dairy product with high fat (≥ 60%) content. The purpose of this study was to investigate the effect of various emulsifying salts (ES) on reduced fat Kaymak texture and sensory properties. Obesity and overweight are one of the most important health problems of our age, and there have been many initiatives by the World Health Organization and food manufacturers to combat obesity in recent years. Fat reduction in ready-to-eat consumer products is a part of the initiatives made by food manufacturers, and many dairy products are produced as semi- and low-fat. In the past, there are many studies in which proteins were used as a fat replacer. Caseins have emulsifying properties due to the presence of hydrophilic and hydrophobic regions separated from each other by their structure, and these properties of caseins are used in many dairy products, especially in the production of process cheese varieties. Cream is a traditional product unique to our country and differs from similar products produced with milk fat in the world in terms of composition and texture. According to the Turkish Food Codex Cream and Cream Communiqué, cream must contain at least 60% milk fat. On the other hand, cream produced with 60% milk fat has unique structural defects and problems such as water release during shelf life. For these reasons, a significant part of our country's producers have to produce 7% above the minimum amount of fat specified in the communiqué, in other words, containing 67% milk fat in the production of cream in order to prevent structural problems in cream. Since milk fat is the most valuable product of milk, milk oil used at a higher rate increases the costs of producers and causes consumers to access the product at higher prices. Contrary to their name, emulsified salts are substances that do not have emulsifying properties, but they modify milk proteins to show emulsifying properties. In the past, most of the research on emulsified salts has been carried out on the effects of emulsified salts on the functional properties of process cheeses, as would be expected. Cream Production; The production of reduced-fat cream was carried out in 3 independent trials. Direct reduction of oil content resulted in weak, semi-solid gels. Therefore, to compensate for the large loss in total dry matter, reduced-fat cream samples were fortified with rennet casein. In rennet casein production, skimmed milk was pasteurized (72○C for 2 min) and cooled to 8○C, then pre-acidified to pH 5.5 using 20% citric acid. Chymosin (BioRen® Premium 95LH300, 290 international milk coagulation units (IMCU)/mL, Biokim & Wenda Kimya San. ve Tic. A.Ş., İzmir, Turkey) and CaCl2 (30%) 5 g and 3 g, respectively. L added for milk. The temperature of the milk was increased to 30○C and it was waited (~2 hours) to obtain the curd. The curd was then cut, filtered and transferred into cheesecloth and pressed for 12 hours. In the production of reduced fat cream, fresh milk cream (40% milk fat) and the obtained rennet casein were mixed with TSC, DSP, TSPP at 5 and 10 mM levels, and then mixed for 10 minutes using a Thermomix® blender. A reduced-fat cream sample was produced in the same procedure without using ET as a negative control (without emulsified salt). The homogenized reduced-fat creams were then transferred to containers (80 g) and stored at 4○C. Normal fat cream (control) is prepared using 60% milk cream. After the milk cream was heat treated at 90°C for 2 minutes, it was transferred to containers and stored at 4°C. The cream samples used in this study are given in Table 3.1. Analyzes were performed on days 1, 14 and 30. Experimental Design and Statistical Analysis; Three repetitive trials of cream production were carried out in 3 months. In each experiment, 2 levels (5 and 10 mM) of 3 emulsifying salts (TSS, DSF, TSPF) were used to produce low-fat Cream samples. One low-fat cream, ET-free (without emulsified salt) as a negative control, and normal-fat cream (62% fat) as a control was produced. Statistical analysis was performed with JMP (version 13.0; SAS Institute Inc., Cary, NC, USA). Data were analyzed by analysis of variance (ANOVA) and statistical difference was determined at P<0.05 with the help of Tukey-HSD multiple comparison test. Pearson correlation coefficients were calculated among the various responses. Chemical analysis; In milk and cream samples, protein (total percent N × 6.38; Kjeldahl method; method 991.20; AOAC, 2007), total dry matter (method 990.19; AOAC, 2007), fat (method 2000.18; AOAC, 2007), ash (method 945.46; AOAC, 2007), pH (Inlab® solid pro; Mettler Toledo, Columbus, OH) titration acidity (method 947.05; AOAC, 2007) and salt (method 975.20, AOAC, 2007) were analyzed. Texture Analysis; The textural properties of the cream samples were monitored with a texture analyzer (TA.XTPlus; Texture Technologies Corp., Scarsdale, NY, USA). The cream samples were transferred to the containers and 75% of the containers were filled. Uniaxial compression was applied to the cream samples at 4○C. During the test, a 35 mm cylindrical probe was used with a penetration depth of 5 mm and a velocity of 1 mm/s. Analyzes were made in three replications. Sensory Analysis; Cream flavor and textural properties were analyzed by 10 trained panelists. For the cream samples, a hedonic scale of 0-9 points (0 I did not like it at all, 9 I liked it very much) was used to evaluate the consistency, flavor, smoothness, spreadability and overall score. Samples were randomly assigned a 3-digit number and evaluated at 4°C after 30 days of storage. Conclusion; Reducing the fat content of cream from 62% to 30% adversely affected the textural and sensory quality of cream during storage. Increasing the protein content by approximately 2 times was not sufficient to compensate for the textural properties. The use of 10 mM TSC in reduced-fat cream improved the textural and sensory properties of the cream. In conclusion, the use of TSC in reduced-fat cream with higher protein content (>4%) seems promising for the production of reduced-fat cream of acceptable quality. The effect of trisodium citrate (TSC), disodium phosphate (DSP) and tetrasodium pyrophosphate (TSPP) were investigated on reduced fat Kaymak (30% fat) at two different concentrations (5 and 10 mM). Regular fat Kaymak (control) and reduced fat Kaymak without ES (ES-free) were used as controls. Control sample exhibited highest hardness and consistency during storage. Reduced fat Kaymak with 10 mM TSC exhibited higher hardness compared to ES-free Kaymak. Disodium phosphate did not affect the textural properties of reduced fat Kaymak at any level. Samples manufactured with TSC exhibited highest sensory quality compared to all reduced fat Kaymak samples, while reduced fat Kaymaks manufactured with TSPP received lowest sensory scores. This study is the first study to investigate the effect of emulsifying salts on Kaymak (or any high fat and moisture containing dairy product).