Sm. Arbaisah et al., SOURSOP PECTINESTERASES - THERMOSTABILITY AND EFFECT ON CLOUD STABILITY OF SOURSOP JUICE, Carbohydrate polymers, 34(3), 1997, pp. 177-182
The thermostability of two forms of purified pectinesterase from sours
op fruit were studied. The heat stability data showed, that PE I is mo
re heat stable than PE II at pH 7.5. The D and Z values were evaluated
in the range 45-75 degrees C. The D values at 65 degrees C were appro
ximately 5.8 min and 3.3 min for PE I and PE II respectively. The chan
ges in temperature required to increase the inactivation rate tenfold
(Z value) were calculated at 8.5 and 8.6 degrees C for PE I and PE II
respectively. Both enzymes also tested positive for their ability to d
estabilise soursop juice cloud at 5 and 30 degrees C. Cloud destabilis
ation by PE I occurred the fastest (large decrease in A 660 nm) in the
natural juice at 30 degrees C. Copyright (C) 1997 Published by Elsevi
er Science Ltd. All lights reserved.