Abstract:
This study aimed to examine the effectiveness of co
mbined microwave-ultrasonic
pasteurization system on
Escherichia coli
and vitamin C content in sour cherry juice
(SCJ). Based on the findings, microwave output powe
r, ultrasound power, and ultrasonic
exposure time as well as the microwave-induced temp
erature were the most effective
factors in reducing
E. coli
and vitamin C content. In addition, the microwave-i
nduced
temperature and ultrasonic exposure time, as indepe
ndent variables, were both effective
on
E. coli
removal. At higher temperatures, the effectiveness
of ultrasonic waves as well as
cavitation intensity declined. However, their combi
ned effect (ultrasound and
temperature) was more significant than their indivi
dual effect. It was also found that any
increase in ultrasound power, ultrasonic exposure t
ime, and microwave output power led
to a significant reduction in vitamin C content, wh
ile the ultrasound power was the most
effective. On the basis of
RSM
modeling, the optimum processing condition was: 35
2.21W
microwave output power, 49.94 ̊C temperature, 475.13
W ultrasound power and 6 minutes
of exposure time. On the basis of response
surface methodology
(RSM) modelling, the
maximum vitamin C content was 142.5 mg per 100 mL w
ith no remaining
E. coli
.
Keywords:
Cavitation, Microwave output power, Pasteurization,
Ultrasound power.
