Effects of heat pretreatment on the yield and bioactivity of powdered egg whites hydrolysates by three different proteases. Efeito do pré-tratamento térmico sobre o rendimento e a bioatividade de hidrolisados de clara de ovo em pó por três diferentes proteases. ABSTRACT Egg white proteins have already shown great potential to generate bioactive peptides after enzymatic hydrolysis. The present study aimed to verify the influence of heat treatment on the efficiency of the hydrolysis of powdered

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... g white proteins by different proteases. The results were evaluated based on the hydrolysis yield, the antioxidant capacity against ABTS radical and the SDS-PAGE behavior of the hydrolysates. Heat treatment was indispensable for Alcalase to hydrolyse egg white proteins; increased the yield by pepsin hydrolysis and promoted the formation of peptides of lower molecular mass when papain was applied. Regarding the bioactivities tested, heat treatment was favorable for the hydrolysis by Alcalase, indifferent for the hydrolysis by papain and unfavorable for the hydrolysis by pepsin. The highest hydrolysis yield was obtained with pepsin (85.3%); the highest antioxidant capacity was obtained by Alcalase (5,254 μM Trolox /g sample).