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. KeywordsContinuous microwave processing, Pasteurization, Sterilization , Specific energy consumption.