DEVELOPMENT OF OPERATIONAL STRATEGIES FOR FREEZE DRYING PROCESS: LEMON JUICE APPLICATION

Special Symposium - Innovations in Food Technology (LMC Congress)

Flexible Production, PAT & Modelling (Food-3b)

Dr Edinara Adelaide Boss
State University of Campinas
Chemical Process Department
C. P.: 6066 – Zip Code 13081-970 Brazil.
Brazil

Prof Rubens Maciel Filho
State University of Campinas (UNICAMP)
Department of Chemical Processes, School of Chemical Engineering
Zeferino Vaz, University City
Barrão Geraldo - Campinas - São Paulo - Brazil

Laboratory of Optimization, Design and Advanced Control.
Department of Chemical Processes. School of Chemical Engineering.
State University of Campinas (UNICAMP)


PO BOX 6066
ZIP 13081-970
Brazil

Keywords: Lemon juice, Freeze-drying, Parametric Sensitivity Analysis, Factorial Design.

The economy had became competitive, with impact on the industries of fruits juices which must advance in the sense of minimizing production costs and, at the same time, generating products that obey more and more rigorous patterns of quality. Due to this fruit juice drying is becoming increasingly attractive in the food industry.
The stability, the storage and the distribution of fruit juice in the liquid or frozen form are difficult and relatively expensive to be made. A possible alternative solution for this problem is the stab and the transport in powder form. In the conventional dehydration high temperature leads to the product lost of flavor and several of its components due to volatility. Freeze-drying process can be seen as an excellent option for solution of these problems, since this process works at low temperatures.
Due to the relatively large number of variables to be analyzed it was necessary to submit the lemon juice freeze-drying process to an initial screening design. The methodology of Plackett-Burman is an adequate tool, since it makes possible to determine the influence of various factors with only a small number of trials, instead of using more extensive factorial design, which would furnish more complete information, but would also involve complexity and is more time consuming. The variables studied were: thickness of the layer, frozen form, fragmentation and three different addictives. The amount of removed water and product appearance (capacity to form powder) are the response to be analyzed. These variables were chosen taking into account the process behavior observed in the step of the experimental data collection.
The freeze drying process was submitted to a parametric sensitivity analysis by means of a complete factorial design in two levels, and this procedure was proposed as a tool to identify the effect of the process variables and the interaction among them. The parameters were disturbed and their main effects analysed, so that it was possible to propose operational strategies for high performance operation.

Presented Wednesday 19, 17:10 to 17:15, in session Flexible Production, PAT & Modelling (Food-3b).