*4.1. The Use of Different Types of Mineral Salts as Substitutes for Sodium Chloride in Bakery Products*

Today, all kinds of combinations of different ingredients are proposed as salt substitutes that do not give an unpleasant taste to the finished product. A natural combination of different salts is the Dead Sea salt (contains NaCl, KCl, MgCl2) which can be successfully used as a substitute for sodium chloride [75]. Natural salt extracted from the Dead Sea has a much lower sodium content compared to normal salt used in food (maximum 7% sodium in the form of sodium chloride) and even more it contains a number of minerals useful to the human body such as magnesium and potassium [98]. Research on the use of low-sodium salt from the Dead Sea in bakery products have been less conducted. This substitution is considered interesting, has potential and may be useful especially when it is used with other strategies, but more studies are needed, given that some changes in bread quality parameters have been reported [75,76]. The most used strategy to reduce the sodium chloride content is its partial replacement with potassium chloride in a proportion level of 20–30% and not higher because it would give the products a bitter and metallic

taste. Thus, a combination of NaCl and KCl may be a viable alternative for reducing the sodium content in the food industry [74]. Other studies have shown that a series of mixtures of various salts represented by chlorides of K+, Mg2+, NH4 <sup>+</sup> and carbonates can provide a taste similar to that of sodium chloride. Charlton et al. [68] also replaced 32% NaCl with a mixture of potassium chloride, magnesium sulfate and magnesium chloride in dark bread, the finished product obtained having a texture and flavor similar to a bread with only NaCl addition. [12].

However, currently the most widely used method of replacing sodium chloride is with other types of salt. This is due to the fact that sodium chloride also influences bakery products quality from the technological point of view. The lack of salt influenced in a negatively way the dough rheological properties, especially on the final leavening phase, when the dough gas retention capacity decreases. As a result, the crumb elasticity is reduced, and the porosity of salt-free products is not uniform and insufficiently developed. The bread is obtained with a pale and light crust. Technologically, a reduction of the salt up to 0.6–0.3% would be possible without a significant deterioration of the rheological properties or the performance of the yeasts during the bread making process. However, its effect on the sensory properties of bread is still a critical factor in consumer acceptance [12].

Replacing sodium chloride with other types of salt can technologically improve the quality of bakery products. Several types of salt have been used successfully as substitutes for sodium chloride. The basic principle is to replace sodium cations with others or replace chloride anions with anions such as glutamate and phosphate, as a way to give a salty taste. Currently, the easiest option for bread making is to replace NaCl with mineral salts or with other cations such as calcium, magnesium and potassium. The effect of different cations on the rheological properties of the dough is related to their position in the lyotropic series, also known as the Hofmeister series, which classifies ions based on their ability to cause aggregation or dissociation of proteins. Within the series, both anions and cations are classified in the order of the most stabilizing to destabilizing. Stabilizing ions lead to less hydration, more structure and a decrease in protein solubility, while destabilizing ions lead to more hydration and increased protein solubility, thus affecting both hydrophobic interactions and hydrogen binding.

The ranking, starting from the least stabilizing cations is: NH4<sup>+</sup> > Cs+ > Rb+ > K+ = Na<sup>+</sup> > H+ > Ca2 <sup>+</sup> > Mg2 <sup>+</sup> > Al3 +. Therefore, with the use of a stabilizing cation, it would be expected that the protein-protein interaction to increase and to promote the formation of a stronger gluten network and therefore of a non-sticky dough. Studies have shown that K<sup>+</sup> is the best option for maintaining the rheological properties similar to dough with sodium chloride, because K <sup>+</sup> is equivalent to Na <sup>+</sup> in the lyotropic series. However, this replacement leads to significant challenge of a metallic/bitter taste [99].

4.1.1. The Use of Calcium Chloride as a Substitute for Sodium Chloride in Bakery Products and the Benefits of Its Use on the Human Body

Calcium chloride is used in the bakery industry as an anti-caking agent but also as a substitute for sodium chloride. It is a solid inorganic compound at room temperature, soluble in water and its anhydrous salt is hygroscopic. Moreover, calcium chloride can also be a source of calcium for the human body. Given that billions of people suffer from osteopenia and osteoporosis, the addition of calcium chloride as a substitute for sodium chloride in bakery products can be considered appropriate. In the last decade, interest in the effects of calcium on the human body has increased and studies have expanded to include the entire life cycle. A whole range of foods and supplements in which calcium is added are widely used today. Calcium is distributed throughout the body in small amounts and is involved in the processes of vascular contraction, vasodilation, transmission of nerve signals, transmission of intracellular signals and hormonal secretion.

There are three major categories of people at risk for dietary calcium deficiency. These include women (amenorrhea, post-menopause), people with milk allergy or lactose intolerance, and risk groups for poor food intake (adolescents and the elderly) [100].

Calcium is an important element for the health of the human body and has vital functions inside cells by transmitting signals between the plasma membrane and intracellular mechanisms. Extracellular calcium is an essential cofactor in the proper formation of bones. Decreased calcium content in the bones can cause conditions such as osteoporosis, high blood pressure, arteriosclerosis, neurodegenerative diseases, malignancy, degenerative joint diseases. Increased calcium is recommended in colorectal cancer prevention treatments to lower blood pressure and blood cholesterol levels [101]. The uses of calcium chloride in the food industry are multiple as: anti-caking agent, antimicrobial agent, hardening agent, flavor enhancer, moisturizer, nutritional supplement, pH control agent, stabilizer and thickening agent, to improve textural properties, and so on.

Various studies in the bakery products on the total substitution of NaCl with calcium chloride (CaCl2) have shown that this has led to a significant increase in water absorption capacity and a higher degree of dough softening due to the fact that a certain amount of water remains unabsorbed from the dough system. However, it was found that at lower levels (~25%) of NaCl substitution, the water absorption capacity decreased slightly, which a positive fact is because more protein-protein interactions occurred, leading to a stronger gluten network and stronger dough through cohesive forces [69,102].
