**2.5 Soy protein hydrolysates**

Soy protein hydrolysate is produced by restricted enzymatic hydrolysis of soy products that consequently improves their nutritional and practical characteristics [30]. The enzymes generally use for hydrolysis of soy protein are mainly endo and exopeptidases (*e.g.* leucine aminopeptidase) that derived from fermentation of selected strains of bacteria (*e.g. Bacillus licheniformis*) [30]. The most important characteristics of SPH are the maximized digestibility of protein, excellent protein solubility and minimized ANF that ultimately enhance its efficiency. Significant solubility of the SPH is mainly due to the formation of short chain hydrophilic polypeptides and the elimination of insoluble fractions through a sedimentation step by a centrifugation process [31]. In addition, SPH has numerous bioactive low molecular weights peptides with health improving properties such as antioxidative and immunostimulatory compounds [32–34].
