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In many food products, such as meringues, beer or chocolate mousses, protein foams play an important structural and textural role. Wheat gluten proteins, a co-product of the industrial wheat starch isolation process, have very low solubility in water. Controlled enzymatic hydrolysis increases its solubility in aqueous media but also enhances the foaming properties. The air-water interfacial properties of wheat gluten hydrolysates were evaluated and related to their foaming properties. The use of such, for protein hydrolysates not very commonly used, techniques can be helpful to determine their air-water interfacial behavior in more complex media. Foaming capacity and stability of structurally different peptic and tryptic wheat gluten hydrolysates with degrees of hydrolysis (DH, i.e. the percentage of cleaved peptide bonds) of 2 and 6, were related to the kinetics of their adsorption at an air-water interface as well as to the properties of a compressed protein film at this interface. Foam formation increased with increasing protein concentration, as did the rate of adsorption to the air-water interface of all samples. Foams from DH 2 hydrolysates were more stable than those from their DH 6 counterparts, and this at all protein concentrations tested. However, at protein concentrations from 0.010% to 0.050% (wprot/v), peptic DH 2 and 6 hydrolysates had better foaming stability than their tryptic counterparts of the same DH. The opposite was observed when protein concentrations ranged from 0.050% to 0.150% (wprot/v). The calculation of an average elasticity (up to 20 – 25 mN/m) from the variation in surface pressure for a variation in surface area in Langmuir isotherms showed that DH 2 samples had higher elasticity than DH 6 samples, which was in agreement with their foaming stabilities at various protein concentrations.