Freeze- or spray-dried gluten hydrolysates. 1. Biochemical and emulsifying properties as a function of drying process Original Research Article

The biochemical and emulsifying properties of two gluten hydrolysates with an equal degree of hydrolysis (1.4%) produced with the same protease but differing in the drying process were studied. The drying processes were freeze-drying for LS2 and spray-drying for PS2. The drying process induced no modification of molecular size distribution, hydrophobicity and solubility of gluten hydrolysates. Nevertheless, the emulsifying properties of LS2 dispersions were greater than those of PS2 dispersions. Analysis of flocculation–creaming properties and resistance to coalescence of emulsions formed with soluble fractions from these dispersions showed that the difference between the emulsifying properties of LS2 and PS2 could be attributed to the differing behaviour of the insoluble fraction as a function of the drying process. Analysis of adsorbed peptides at the oil/water interface confirmed that the interfacial properties of soluble peptides from freeze- and spray-dried samples were equivalent.