Papain from papaya (Carica papaya L.) fruit and latex: Preliminary characterization in alcoholic–acidic buffer for wine application

Papain from ripe fruit and from papaya latex was characterised, in comparison with stem bromelain, under wine-like conditions, with the aim to evaluate their applicability for white wine stabilization.Papains proteolytic activity was investigated, in McIlvaine buffer toward different synthetic peptide substrates and Bz-Phe-Val-Arg-pNA appeared the most suitable one for detecting proteolytic effect at wine average minimum pH (3.2). Kinetic parameters estimated in McIlvaine (as reference) and in tartaric buffer (mimicking wine medium), indicated a good hydrolytic activity toward selected substrate, at wine average minimum pH value (3.2) in spite of ethanol presence, in both mediums. Papain from latex showed a significantly higher and stable catalytic activity respect to fruit papain and stem bromelain, retaining after 7 days, about 50% of its initial activity.

► Papain showed a good hydrolytic activity toward Bz-Phe-Val-Arg-pNA substrate. ► Papain resulted active at wine average minimum pH value (3.2). ► Latex papain had significantly higher and stable activity respect to fruit papain.