Continuous Microwave Processing and Preservation of Acidic and Non Acidic Juice Blends

Continuous microwave processing system is one of the
pasteurization/sterilization techniques that offer good potential for high
quality, reduced process times and energy as compared with
conventional techniques. The overall goal of these studies was to
process and preserve the fruit and vegetable juices through continuous
flow of microwave heating system. Two categories of 10 blends were
prepared and processed through continuous – flow of microwave
heating system (2kW) at 250 ml/min, using specially designed
applicator in cubical cavity. The objectives of this work are to study
the effects of Microwave heating on juice properties viz., optical
properties, Chemical and biochemical and characteristics like sensory,
nutritional, protein and vitamins. The effect of microwave heating on
rate of pasteurization/sterilization, the effect of microwave power and
shelf life of juices. Storage of one year studies showed that all blends
were found to have insignificant variation and equivalent to fresh juice.
Continuous MW pasteurization (45 l/hr)/sterilization (30 l/hr) was
developed using experimental parameters .Specific Energy
consumption was 0.160 KW-hr/kg and energy cost for 1kg of blend
juice processing was 1.12 INR compare to the conventional cost
approx. 4.9 INR (1kWh=7.00INR).Energy saved during MW Heating
is approx. 337 % and processing time was reduced about 3 times
compared to conventional, indicating increase in the production of
processed juice. The above continuous MW processing have reduced
the cost, energy, manpower and space compared to conventional, high
pressure processing and plasma technique.