The aim of the present work was to search for a novel plant proteinase
enzyme from Jack fruit (Artocarpus integrifolis) as a source of photolytic enzymes to
acceleration of Ras cheese slurry. Plant proteinase would be natural products, which
can be easily extracted at relatively low cost and no legal barriers. This enzyme was
subjected to a purification scheme composed of ammonium sulfate fractionation
followed by gel filtration on G-100 Sephadex column. The enzyme was purified 2.70-
fold witt. a total yield of 23.77% of the original activity. There were relationships
between temperature and incubation time, the enzyme activity increase was observed
up to 55°C for 60 min reaction time and still constant thereafter. Proteinase was active
over a broad temperature rang retained about 37.4 and 24.9% of temperature
activity at 35 and 80°C for 5 and 60 min, An energy of activation of 9.98 KJ/mole for
the enzyme activity was derived from the Arrhenius plot of initial velocity (Vo) across a
temperature ranging from 40 to 550C. The optimum pH was pH 7.5. The rate of
thermal inactivation proceeded more rapidly at pH 7.0 and S.O. When heating atSOOC
for 60 min, the enzyme activity lost about 95% and 92% respectively. Michaelis-
constant of (Km) values of 2.0 mal;",): ;:;o:tj a maximum initial velocity (Vmax) of 0.75 ~
moles/mg when casein used as 0 suostrare. Molecular weight (MW) determination of
-22 k Da was estimated by gel flttration methods using a Sephadex G-100. Cu2., K?'
, FeZ' and Zn?' strongly inhibited the enzyme. However, Ca" slightly stimulated,
EDT A, sodium azide, Sodium citrate and urea among the chemical reagents inhibited
the proteinase activity,
Crud extracted proteinase was used to accelerate Ras cheese slurry ripening
with concentration of 1 and 2 ml/100 g curd. Slurries were incubated at 37°C for 7
days. The results indicated that the ripening indices of slurries (SNfTN, tyrosine and
tryptophane) gradually increased as rate of enzyme increased and as ripening period
progressed. Also, flavour of all slurries gradually improved during incubation period. At
the end of incubation period slurry with 2 mU100g curd had a high flavour scoring