## 4 Discussion
The higher observed solubility of the soybean-maize proteins can be employed to develop beverages, sauces, dairy analogs, and products in general because it will facilitate its incorporation and homogeneous distribution in food formulations. On the other hand, soybean isolate and hydrolysate did not present significant differences in the WAI (\(p>0.05\)). The soybean-maize samples had significantly lower (\(p<0.05\)) water absorption indexes than the soybean counterparts. This result is attributable to the low availability of polar amino acid residues, the higher degree of hydrolysis, and the size of the peptides that reduced the entrapment of water. In the specific case of soybean-maize hydrolysate, this was more evident. However, the WAI of the soybean-maize proteins is consistent with [PERSON] et al. 's values, [37], for a soybean isolate (5.7 mL/g protein). Other legumes such as peas, lentils, chickpeas, and navy beans, WAI values of 3.7, 3.7, 2.9, and 3.8 g water (H\({}_{2}\)O)/g protein were reported, respectively [9]. Proteins with low water absorption are ideal for developing products with high lipid interactions such as dressings. Regarding the properties associated with hydrophobicity, the isolate and hydrolysate of soybean and soybean-maize proteins had the same FAI (\(p>0.05\)); therefore, fat absorption was independent of protein content and degree of hydrolysis. [PERSON] et al. [37] previously reported an FAI of 1.9 mL/g for a soybean protein isolate, whereas values obtained herein were higher, likely due to the sample's nature. [PERSON] and [PERSON] [9] reported an FAI for peas, lentils, chickpeas, and navy beans of 1.9, 2.1, 2.0, and 1.6 g oil/g protein, respectively. Given the adequate capacity of soybean-maize proteins to trap fat, these could be used as ingredients for vinaigrettes, sauces, sausages, ice creams, and bakery products. Furthermore, these proteins can improve yields, texture, mouthfeel, and flavor retention of foods. The SMI and SMH proteins had the highest emulsifying activity and were not significantly different (\(p>0.05\)). The SI showed the lowest EAI, possibly due to its lower solubility and higher content of reducing sugars that interfered with establishing interactions at the water-protein-oil interface. This result is consistent with [PERSON] and [PERSON] [41], who observed that the high carbohydrate content of maize germ protein favored the EAI. About the ES, the SH was more stable at 24 h of storage followed by the soybean-maize hydrolysate, soybean-maize isolate, and finally, soybean isolates with 43.4% of stability. However, at 48 h of storage, all soybean and soybean-maize samples showed a slight stability increase, and statistical analysis indicated no significant differences among proteins (\(p>0.05\)). According to different authors, it is due to the high hydration and unfolding of globular proteins that improved surface tension by making a more rigid water-protein-oil interface [42; 43]. Given the EAI of soybean-maize proteins, these are exciting alternatives to replace active tension agents used in the food industry for beverages, sauces, dressings, meat analogs, and others. The FA of both the soybean isolate and hydrolysate were higher than the soybean-maize. However, the less soluble soybean proteins had a higher foaming capacity, possibly due to the structure, flexibility, charge density, and electrostatic repulsions [13]. [PERSON] and [PERSON] [44] reported that the foaming activity of black gram (Phaseolus mungo) proteins depended on the globulin nature. The highest foam stability was observed in the SI \(>\) SMH \(>\) SMI \(>\) SH. [PERSON] and [PERSON] [9] observed that, similar to soybean-maize proteins, the proteins of lentils, peas, and chickpeas with good solubility did not have high foaming activity but showed adequate FS due to the flexibility of proteins and electrostatic repulsions. The foams of soybean-maize proteins, in addition to excellent stability, presented higher density than soybeans, i.e., involving a smaller amount of gas per amount of protein.