title: Design, development and evaluation of an automatic fruit-juice pasteurization system using microwave - ultrasonic waves.
abstract: Conventional pasteurization treatments often lead to substantial decrease in fruits juice quality. Due to these issues, the objective of this research was to compare the combined effect of a novel thermal (microwave) and non-thermal (ultrasonic) treatments with conventional thermal pasteurization on some qualitative characteristics of sour cherry juice (vitamins, phenolics, anthocyanins, etc.). For this purpose, an automatic control system comprising of ultrasonic generator, ultrasonic transducer, horn, pump, circulator, microwave oven, container, pipe interface, temperature sensor, float, data acquisition card, microwave power control circuit, and reactor was designed and developed. Moreover, in order to optimize the effect of ultrasonic waves on the existing micro-organisms in the sour cherry juice, some preliminary experiments were carried out to optimize the ultrasonic probe and reactor design. The results of evaluations showed that using the combined automatic system, the qualitative properties of sour cherry (vitamin C content 14 %, total phenolics content 1 %, total anthocyanins content 6 %) can be better maintained compared with the conventional thermal method. Based on the results obtained in this study, the following processing conditions: microwave power of 541.7 W, temperature of 41 °C, ultrasonic power of 799.57 W and ultrasonic exposure time of 6 min were recommended for optimum processing of sour cherry juice.
authors.affiliation: Department of Biosystems Engineering, Tarbiat Modares University, P.O. Box 14115-336, Tehran, Iran ; Department of Biosystems Engineering, Shahrekord University, P.O. Box 115, Shahrekord, Iran.
authors.forename: Bahram
authors.initials: B
authors.lastname: Hosseinzadeh Samani
authors.affiliation: Department of Biosystems Engineering, Tarbiat Modares University, P.O. Box 14115-336, Tehran, Iran.
authors.forename: Mohammad Hadi
authors.initials: MH
authors.lastname: Khoshtaghaza
authors.affiliation: Department of Biosystems Engineering, Tarbiat Modares University, P.O. Box 14115-336, Tehran, Iran.
authors.forename: Saeid
authors.initials: S
authors.lastname: Minaei
authors.affiliation: Department of Agricultural Mechanization Engineering, Guilan University, P.O. Box 41635-1314, Rasht, Iran.
authors.forename: Hemad
authors.initials: H
authors.lastname: Zareifourosh
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Mahidol University, Mahidol, Thailand.
authors.forename: Mohammad Naghi
authors.initials: MN
authors.lastname: Eshtiaghi
authors.affiliation: Department of Biosystems Engineering, Shahrekord University, P.O. Box 115, Shahrekord, Iran.
authors.forename: Sajad
authors.initials: S
authors.lastname: Rostami
keywords: Microwave; Pasteurization; Sour cherry juice; Ultrasonic