Free radical production by manothermosonication

• Published in: Ultrasonics 1998-02, Vol.36 (1), p.615-618
• Main Authors: Vercet, Antonio, Lopez, Pascual, Burgos, Justino
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; Hydroxyl radicals; Manothermosonication; Terephtalate dosimeter
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/S0041-624X(97)00115-7

The use of manothermosonication (MTS), a combined treatment of heat and ultrasound (20 kHz frequency) under moderate pressure, has been recently proposed as an alternative to conventional heat treatment of liquid foods. The efficiency of MTS has been proved on several enzymes of interest in food industry. One of the MTS enzyme inactivation mechanisms proposed is the interaction of free radicals produced by water sonolysis with some amino acid residues. In this paper we examine the rate of free radical production of the MTS system under different conditions of temperature, pressure and ultrasound amplitude using the terephtalate dosimeter. The ultrasound amplitude was varied between 20 and 145 μm at two different temperatures and pressures ( 70 ° C 200 kPa and 130 ° C 500 kPa ). In both cases, free radical production rate increases linearly with increasing ultrasound amplitude. The pressure effects on free radical production was studied under two different conditions at 117 μm: 70 °C and 130 °C. At 70 °C an increase of hydrostatic pressure results in an increase in free radical production rate, whereas increasing hydrostatic pressure at 130 °C had a negligible effect on free radical production rate. Temperature effects were studied between 30 and 140 °C at 117 μm ultrasound amplitude. Results show that increasing temperature results in a decrease in hydroxyl radical rate production.