Influence of the addition of KCl and CaCl 2 blends on the physicochemical parameters of salted meat products throughout the processing steps

The objective of this study was to evaluate the effects of different chloride salts (NaCl, KCl, and CaCl2) on the characteristics of salted meat products through the determination of moisture, pH, aw, chloride, ash levels, cooking loss, and instrumental color during the processing steps. Four salted meat treatments were elaborate using the following salts in the wet and dry salting stepsI: FC1I: 100% NaCl; F1I: 50% NaCl + 50% KCl; F2I: 50% NaCl + 25% CaCl2; F3I: 50% NaCl + 25% KCl + 25% CaCl2. The addition of CaCl2 led to the lowest pH and changes in aw, moisture, ash levels, and instrumental color when compared to the other treatments, which was different from the control (100% NaCl) and F1 (50% NaCl + 50% KCl), thus evidencing the great effect of CaCl2 on the characteristics of salted meat products during the whole processing. The partial replacement of NaCl by KCl and/or CaCl2 greatly increased the cooking loss of salted meat products. The replacement of NaCl by KCl promoted similar quality parameters.


Introduction
Salted meat products are consumed and appreciated worldwide due to their unique sensory characteristics and long shelf-life (Liu et al., 2014). The manufacture of salted meat products is based on the hurdle technology (Leistner, 1987), and several steps such as salting (wet or dry), drying and ripening can be used during processing (Mora et al., 2015), besides the addition of sodium chloride (NaCl) and additives, and vacuum packaging (Shimokomaki et al., 1998). The combination of these steps provides the sensory characteristics and microbiological stability for the processed product (Oshihara et al., 2013).
Changes in lifestyle associated with the modernization of society and the development of new products have led to a drastic change in eating habits, with increased consumption of processed products. Some of these products can be a major source of fat, sodium, and sugars, which can cause various health problems when consumed in excess, such as obesity, diabetes, and cardiovascular disorders (Roberfroid, 2002). Therefore, there is a growing consumer's demand for healthy eating perceptions and healthy lifestyle, with a preference for meat products rich in proteins and low in lipids, cholesterol and sodium (Lorenzo & Carballo, 2015).
Sodium chloride is an ingredient extensively used and very important to the development of numerous desirable sensory and technological characteristics in meat products (Onguglia et al., 2017). Ot plays an important role in salted meat products, once when combined with other techniques, it can preserve the product for months without refrigeration for later consumption (Torres et al., 1989). However, NaCl is the main source of sodium in the human diet (Desmond, 2006), and the excessive sodium intake causes several deleterious health effects such as high blood pressure, cardiovascular and renal diseases (Cook et al., 2016;Denton et al., 1995;Frieden, 2016;Strazzullo et al., 2009). The World Health Drganization (WHD) recommends a daily intake of 2 g of sodium, equivalent to 5 g NaCl. On this context, an effective reduction of NaCl during the manufacture of salted meat product, which presents a high sodium content after processing, is extremely necessary to make the product healthier.
There are many ways to reduce sodium content in meat products. Dne of the most used strategies for reducing or replacing NaCl is the use of other chloride salts as KCl (potassium chloride), CaCl 2 (calcium chloride) and MgCl 2 (magnesium chloride) (Aliño et al., 2010;Ripollés et al., 2011). Among the chloride salts, KCl is widely used due to the development of similar characteristics to NaCl in meat products; however, the addition of KCl promotes bitter and metallic taste, thus impairing the use in excess (Doyle & Glass, 2010;Grummer et al., 2013). Although CaCl 2 is also used as a substitute for NaCl, in some cases it can negatively affect the texture and flavor characteristics (Vidal et al., 2019).
Taking into account the deleterious health effects caused by the excessive consumption of sodium in salted meat products, the objective of this study is to evaluate the effects of blends containing NaCl, KCl, and CaCl 2 on the characteristics of salted meat treatments.

Treatments, raw materials, and additives
The bovine raw meat (biceps femoris) was purchased from slaughterhouses with assured hygienic quality. The additives sodium nitrite and sodium erythorbate were donated by the company Kerry of Brazil. The salts NaCl, KCl, and CaCl 2 were purchased from Anidrol, Brazil.
Four salted meat treatments were made, as shown in Table 1. The concentration of KCl and CaCl 2 substitute salts was based on the calculation of ionic strength to make up the ionic strength of 50% and 25% of NaCl, obtaining the same final ionic strength in all treatments. Then, the blends were made in sufficient quantity for the salting steps, depending on the weight of the raw meat, using 2 kg salt per kg of meat. Similar amounts of the additives sodium nitrite (150 ppm) and sodium erythorbate (500 ppm) were added in the wet salting step, and the salt was the variable of the wet and dry salting steps.

Processing
The manufacturing process was carried out according to Vidal et al. (2019) and the salts added were described in Table 1. The bovine raw meat pieces have been cut standardized to be submitted to the salting steps (wet and dry). On the wet salting step, the treatment were submerged in a respective saturated solution with respective salts, sodium nitrite and sodium erythorbate for 1 hour. During the dry salting period, the treatments were in contact with respective salts for 144 hours (6 days) at 13 °C. The ripening step were carried out in a controlled climatic chamber (Onstala Frio, Curitiba, Brazil) with 55% humidity, 25 °C and 0.5 m/s forced air ventilation for 24 hours. After the process, the pieces were vacuum packed with polyethylene (Spel, São Paulo, Brazil) and stored at 25 °C.
All the manufacture process was performed in three replicates on different days with the same methodology, formulation and technology. All the processing steps were carried out in the Meat Laboratory of the Department of Food Technology (DTA) at University of Campinas (UNOCAMP).

Physicochemical characterization
The chloride content was determined according Doughty (1924) using silver nitrate for reaction and potassium chromate as indicator. The moisture and ash content was determined according to Horwitz & Latimer (2005). The pH was determined by homogenizing 10 g sample and distilled water (1I:10), utilizing combined electrode (22 DM, Digimed, São Paulo, Brazil).
The instrumental color was measured using the Hunter Lab colorimeter (Colourquest OO, Hunter Associates Laboratory Onc., Virginia, USA) with D65 illuminant, 20 mm aperture and standard 10° observer. COELAB L*, a*, and b* parameters were determined as an indicator of luminosity, red intensity, and yellow intensity, respectively. The whiteness index (W) was calculated by the following equationI: ( ) . The samples were kept at room temperature (25 °C) during analysis.
All analyses were performed in triplicate for each replicate of the experiment.

Cooking loss
The samples of the different treatments were cut into portions of 6x6 cm and desalted using a ratio of 1I:6 (sampleI:water), with continuous water exchange every 2 hours for 30 hours, and then vacuum packed for cooking. Cooking was carried out in a water bath (RSA-1708, RSA, Campinas, Brazil) at 80°C, and the temperature of the samples was monitored by a thermocouple. From the moment the center of the sample reached 72 ° C, remaining at this temperature for 60 minutes.
After cooking procedure, the cooked samples were weighed after 30 minutes at room temperature. The cooking loss was calculated as a percent of weight difference between raw meat and cooked sample using the following equationI: ( ) cooking loss raw sample cooked sample / raw sample x 100 = − .

Statistical analysis
For each process, at least three samples were taken for each analysis. The results were expressed as the averages from all data. Data were analyzed using a General Linear Model (GLM) considering the treatments as a fixed effect and the replicates as a random effect. Significant differences were analyzed by the Tukey's test at the 5% level of significance utilizing the commercial software Statistica v. 8 (Statsoft Onc., Tulsa, Dklahoma, USA).

Chloride, ash, and moisture contents
The moisture contents are presented in Table 2, chlorides levels in Table 3 and ash in Table 4. There is a relationship among the chloride levels and the ash and moisture contents of the samples. The treatment F2 (50% NaCl + 50% CaCl 2 ) had the lowest ash (P < 0.05) and the highest moisture contents (P < 0.05) in the final product when compared to the other treatments. These results may be due to the difficulty of CaCl 2 to penetrate into the product, once it was used in excess (equivalent to 50% of ionic strength).CaCl 2 is used in several products as a dehydrating agent, once calcium ions increase the mass transfer leading to a higher dehydration rate (Lewicki & Michaluk, 2004). However, the high dehydration may have formed a dry barrier on the surface of the samples, impairing the water release from meat and the penetration of salt (Vidal et al., 2019).

pH and aw
The results of pH of salted meat treatments are shown in Table 5. On general, a decrease in the pH values was observed during the process. The addition of CaCl 2 decreased the pH values when compared to the treatments containing only    NaCl and KCl, once the treatments F2 (50% NaCl + 50% CaCl 2 ) and F3 (50% NaCl + 25% KCl + 25% CaCl 2 ) presented lower pH values when compared to FC1 (100% NaCl) and F1 (50% NaCl + 50% KCl). Dther authors have reported the effect of CaCl 2 on the pH reduction of meat products with reduced NaCl content (Gimeno et al., 2001;Lawrence et al., 2003;Gimeno et al., 1999;Vidal et al., 2019).
Aw is a very relevant parameter to ensure food safety, and especially in salted meat products, the low aw can confer stability during several months of storage (Toldrá, 2006). As expected, the addition of salts to the treatments significantly reduced the aw values during the process, as shown in Table 6. The treatment F2 (50% NaCl + 50% CaCl 2 ) presented the highest aw values (P <0.05) during the dry salting and in the final product. As previously discussed, the higher addition of CaCl 2 during the dry salting may have caused a rapid surface drying, impairing the water release in the treatments.

Instrumental color
The color characteristics of meat and meat products are fundamental for the consumers' acceptance of the product, and myoglobin is the only pigment present in sufficient amount capable of providing red color (Mancini & Hunt, 2005). As can be seen in Table 7, the color parameters L* (luminosity), a* (red-green dimension), b* (yellow-blue dimension) and W (whiteness index) of the treatments were affected by the addition of different salts. Values are means. a, b, c, d Means in the same column followed by different lowercase letters present statistically significant difference by the Tukey test (P < 0.05). A,B,C,D Means in the same line followed by different capital letters present statistically significant difference by the Tukey test (P < 0.05). AWSI: after wet salting; ADSI: after dry salting; FPI: final product. FC1I: 100% NaCl; F1I: 50% NaCl + 50% KCl; F2I: 50% NaCl + 50% CaCl 2 ; F3I: 50% NaCl + 25% KCl + 25% CaCl 2 . A lower intensity of red color was observed in the salted meat products (P <0.05) with the addition of KCl (F1I: 50% NaCl + 50% KCl), which was more pronounced (P <0.05) in the treatments with the addition of CaCl 2 (F2I: 50% NaCl + 50% CaCl 2 and F3I: 50% NaCl + 25% KCl + 25% CaCl 2 ) in relation to the control made with 100% NaCl (FC1). On addition, the parameter W (whiteness index) increased (P < 0.05) in all treatments during the manufacturing process of the salted meat products. Similar results were found by Vidal et al. (2019) who replaced NaCl by KCl and CaCl 2 in jerked beef.

Cooking loss
The heat treatment induces the water loss in meat and meat products, and the determination of this parameter during cooking is very important to predict yielding, the nutritional quality, and the sensory properties of the product, mainly regarding the juiciness perception . The cooking loss values are presented in Table 4.
As mentioned, the cooking loss is a very important parameter affecting several characteristics, and the differences in cooking loss around 9% between the control and the treatments with partial replacement of NaCl by salt substitutes can directly affect the quality of the final product.

Conclusion
The addition of CaCl 2 during the processing of salted meat products significantly affected all the parameters studied when compared to the treatments containing only NaCl (control) or NaCl + KCl, with a consequent impact on product's quality.
The replacement of NaCl by KCl and CaCl 2 significantly increased the cooking loss, which may affect the sensory characteristics of the salted meat product. On general, the treatment containing NaCl + KCl presented similar characteristics to the control treatment containing only NaCl; however, the use of KCl should be carried out with caution due to the risk of hyperkalemia in patients with kidney disease.