# Effects of Organic Acid Coagulants on the Textural and Physical-Chemical Properties of Tofu  
[PERSON]  
1 Instituto de Investigacion, Universidad Agparaia del Ecuador, Guayaquil 090104, Ecuador; [EMAIL_ADDRESS]  
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2 Facultad de Ciencias Agrarias, Universidad Agparaia del Ecuador, Guayaquil 090104, Ecuador; [EMAIL_ADDRESS] (M.G.-T.); [EMAIL_ADDRESS] (J.P.-P.); [EMAIL_ADDRESS] (G.M.-G.)  
[PERSON]  
2 Facultad de Ciencias Agrarias, Universidad Agparaia del Ecuador, Guayaquil 090104, Ecuador; [EMAIL_ADDRESS] (M.G.-T.); [EMAIL_ADDRESS] (J.P.-P.); [EMAIL_ADDRESS] (G.M.-G.)  
[PERSON]  
2 Facultad de Ciencias Agrarias, Universidad Agparaia del Ecuador, Guayaquil 090104, Ecuador; [EMAIL_ADDRESS] (M.G.-T.); [EMAIL_ADDRESS] (J.P.-P.); [EMAIL_ADDRESS] (G.M.-G.)  
[PERSON]  
3 Grupo de Investigacion de Inocuidad y Valorizacion de Recursos Para la Agronidustria (INVAGRO), Facultad de Ingenieria, Universidad del Chimborazo, Km 11% Via Guano, Ribomba 060107, Ecuador; [EMAIL_ADDRESS]  
[PERSON]  
3 Grupo de Investigacion de Inocuidad y Valorizacion de Recursos Para la Agronidustria (INVAGRO), Facultad de Ingenieria, Universidad del Chimborazo, Km 11% Via Guano, Ribomba 060107, Ecuador; [EMAIL_ADDRESS] Departamento de Ingenieria Rural y Agroalimentaria, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain 33 Grupo  
value [5], comprised of 23.8% total solids, 15.4% protein, 9% fat, 62 mg calcium, and 580 mg phosphorus present per 100 g [2]. The tofu manufacturing process spans a broad history and involves a variety of technologies and treatments [5]. In turn, the protein content of the soybean used directly impacts the yield and quality of the tofu [1]. For instance, coagulation is achieved using salt, enzymes, and acid to create firm, silk, and soft tofu. Calcium sulfate and magnesium chloride are commonly used as salt coagulants; however, residual undissolved calcium sulfate in tofu or the rapid release of magnesium chloride often leads to a coarse texture, which is a sign of poor quality [6]. Microbial transglutaminase is commonly used to enzymatically crosslink soy proteins to create tofu with a low gel hardness, though this method is time-consuming. Additionally, glucono-d-lactone (GDL) as an acidifying agent has been extensively researched to produce tofu with a uniform network. It is important to note that proteins gel at a pH range from 5.6 to 5.8, depending on the soy variety used, irrespective of the GDL concentration [7]. Therefore, selecting coagulants and treatments is crucial, as it affects the nutritional and textural properties [8]. In contrast, various factors during processing, such as soaking, milling, pretreatment, the types of coagulants used, the operating conditions, pressing, packaging, and storage, affect the final quality [9]. Therefore, various techniques have been developed using alternative coagulants, such as Epson salt, which provides beneficial effects on the functional properties and decreases the susceptibility to spoilage [10]; in turn, coagulants obtained from crab shell waste were shown to increase the calcium levels and improve the overall firmness and texture of tofu [11]. Due to the influence of pH and ionic strength on the gelation process, tofu produced from organic acids exhibits remarkable physical characteristics, such as high stiffness, hardness, and a low non-freezable water content [12]. Also, using acid to cause protein precipitation improves the hydrophobicity, emulsification, and gel strength of the protein, as well as its rheological and sensory properties [13; 14]. Different types and concentrations of organic acids as coagulants can give rise to tofu with differences in texture, microstructural and rheological properties, pH levels, and chemical interactions in a gel. In turn, its acidification process can be accelerated, reducing the time available for the orderly aggregation of soy proteins, thus reducing the quality of the tofu [7].