The purpose of this study was to characterize the chosen functional properties of native and acylated protein concentrates received from lentil seeds by acidic or flocculation-acidic coagulation and estimate of effect trypsin hydrolysis on studied proprieties. From the lentil seeds, proteins were extracted by weak solution of lye and chemically modified with acetic anhydride (acylation) at the same time. Then protein in extract were exuded applying two ways of aggregation of particles: coagulation by souring the extract 2M HCl to the point of the smallest solubility of proteins (pH = pI) or acidic coagulation joint from the flocculation of proteins using polyelectrolytes ‘Magnafloc LT22S’ (kationic) or ‘Magnafloc LT27’ (anionic). Unmodified protein concentrates were prepared analogically, except no acylating agent witch was added during extraction. Protein concentrates were hydrolyzed with tripsin and than desiccated by lyophilisation. Protein content, solubility, water and oil absorption, emulsifying activity, emulsion stability, foam capacity and foam stability were determined in concentrates and their hydrolysates. Both the modification and the way aggregation of proteins caused changes of individual functional proprieties. Native protein concentrates possessed good ability to water absorption, carrying out from 184 to 234% in dependence from the way precipitation of protein, and oil absorption in range 61–70%. Acylation essentially (α=0,05) increased water absorption of concentrates, in largest degree about 136% (in case aggregation of proteins by anionic flocculant) and significantly increased ability to oil absorption (in range 8-15%) in the case of concentrates received with utilization of flocculation. The emulsifying activity and emulsion stability did not change significantly after protein modification, achieving maximum value (42 and 39% respectively), for concentrates received with flocculant ‘Magnafloc LT 22S’. These concentrates were also characterizing by ten times better ability to foam creating. The foam capacity remaining preparations was small and achived 2ml in both cases. Acylation improved foam proprieties of lentil proteins, yet the growth of foam stability was observed only in the case proteins coagulated by the acid. The chemical modification caused of highest protein solubility in range above isoelectric point. However solubility of acylated proteins decreased in the strong acid medium. The hydrolysis of studied protein concentrates caused increased their solubility in range pH 3,5-6,5. Hydolysates in comparison with concentrates were characterizing higher water absorption and emulsion stability. The hydrolysis of proteins caused the significant improvement of their foam proprieties.