2.4. Effect of time after apple pressing
Cloudy apple juice was prepared from three apple cultivars:
‘Jonagold’, ‘Golden Delicious’ and ‘Rhode Island Greening’. Apples
were washed and passed through a comminuting machine (The
W.J. Fitzpatrick Company, Chicago, USA), and immediately pressed
in a hydraulic rack-and-frame press for juice extraction. The
resulting juice was treated at 14 mJ cm2 fixed UV dose after
0e120 min of apple pressing (10e20 min intervals). The flow rate
and color of the juice were measured at each sampling time. The
juice color was determined using the L0
, a0 and b0 Hunter color
parameters, and the total color difference (DE) was calculated at
each sampling time using the equation: DE ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
DL02 Da02 þ Db02 p .
After 120 min of apple pressing, juices were inoculated with E. coli
ATCC 25922 and treated at 14 mJ cm2
. Treatments were performed
in triplicate.