Purification and characterization of papain from carica papaya latex its application in the hydrolysis of tigernut protein homogenate

Thesis Abstract

In this study, the production of tiger nut suspension was carried out using a proteolytic enzyme (papain) isolated from the latex of C. papaya. The crude papain isolated was subjected to three steps purification system of 80% ammonium sulphate saturation using sephadex G50 and G200 filtrations at pH 7.2 and 37oC. The protein concentration of the crude enzyme obtained was 136 µg/ml, while its specific activity was 1.15U/mg. After 80% ammonium sulphate precipitation, the specific activity obtained was 1.31U/mg. Sephadex G50 and G200 filtrations gave specific activities of 1.48 and 1.28U/mg respectively. The optimal activity of papain was achieved at 90oC and pH 7.5 at 37oC and 1ml of 1% casein solution. The Vmax and Km were observed to be 1.133U/min/ml and 0.217µg/min/ml respectively. Pure papain obtained was used to hydrolyse tiger nut protein at 37oC and pH 7.5 compared with O-pthalaldehyde as a standard hydrolysing agent. The degree of hydrolysis was monitored with tiger nut protein concentrations ranging from 0.1-1.0g/ml and incubation times of 0, 10, 30, 60 and 120min at 340nm. The results obtained from this study suggest that the optimum incubation time for papain to hydrolyse tiger nut protein is 10min at pH 7.5 and 37oC and also, suggests that papain hydrolyses plant derive proteimn more than O-pthaldidehyde (OPA). All results obtained from this study suggest that it is highly promising to use papain extracted from unripe C. papaya as a proteloytic enzyme in the hydrolysis of tiger nut protein preparation to fortify and enrich the milk like beverage produced from tiger nut with amino acids at mild industrial conditions.