Optimization of liquid food continuous heat treatment: approach of microbiological safety and quality by rheological and kinetics of change at high temperature

• Grant number: 07/04137-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2008
• End date: December 31, 2010
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Engineering
• Principal Investigator: Alfredo de Almeida Vitali
• Grantee: Alfredo de Almeida Vitali
• Host Institution: Instituto de Tecnologia de Alimentos (ITAL). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil

Abstract

The importance of using food thermal treatment at high temperatures and short times is that this guarantees the microbiological security of the product and leads to a higher preservation of the quality characteristics, due to kinetic parameters that allow quality factors to have a lower destruction velocity than microrganisms. Modifications in the product can occur at high temperatures causing unexpected change of viscosity when extrapolating equations obtained up to temperatures around 90°C (rheological measurements in no pressurized equipment due to boiling of water). The increase or reduction of viscosity may lead to a modification of the fluid flow regime and also to cause a sub or over-processing, depending on the case. For these reasons, it is important to know the rheological properties of the product, thermal treatment target microrganisms, pH, quality aspects degradation kinetics at the process temperatures in order to determine the optimum thermal treatments for specific products. The objective of this project is to carry out rheological measurements of products (model and food solutions) at high temperatures and to attain kinetics data of quality alteration as browning, constructing an equipment for this purpose (pressurized capillary rheometer and heat exchanger). From the experimental data, the equipment will be validated with the data obtained in rotational rheometer. Then, it will be verified the extrapolation of viscosity values at high temperatures and a browning kinetics curve will be constructed for specific products, as well as theoretical calculations of loss of nutrients. Finally, the products thermal process will be optimized. (AU)

Filed patent(s) as a result of this research project