Combined Application of Ultrasound and Temperature for Eenergy-Saving and Mild Preservation of Liquid Foods

Abstract

throughout the solution of the dynamic heat transfer model. In this work, the model is solved applying the Orthogonal Collocation Method on Finite Elements, in the axial position and it is integrated with numerical Solver (DASSL). In this procedure, it is possible to choice the right number of finite elements and also the best number of placement root for each finite element. This way, the better configuration for the system can be defined, which is based on the actual operating condition of the equipment. It also permits to identify the best heat load for the freezer. 30 832 7663From a current literature survey regarding the application of ultrasound in combination with heat it is concluded that further research is needed to determine the feasibility and usefulness of ultrasound applications for fluid systems in continuous flow. This study evaluates the effects of an ultrasound treatment in continuous flow for the preservation of liquid food. Microbial inactivation, energy consumption, and product quality have been assessed. A comparison between conventional heating and combined ultrasound in continuous flow has been carried out. At identical degrees of microbial inactivation the combined ultrasound and heat treatment requires a lower maximum processing temperature. From energy balances it is derived that the total energy consumption is not reduced compared to the conventional heating. Detrimental effect of the combined process on quality parameters like colour and L-ascorbic acid are not detectable.2 42 Engineering, von-Behring-Str. 9, D-34260 KaufungenRetaining food grade quality is essential for a bottle to bottle PET recycling process. A PET recycling process comprising reactive extrusion of bottle flakes under vacuum followed by solid-state polycondensation to again increase the viscosity to the required value of bottle blowing has been investigated in detail applying a comprehensive reaction model. Quality parameters like viscosity and content of carboxyl end groups and vinyl end groups (potential acetaldehyde) have been calculated for different process conditions. The recycling process is assessed under consideration of the requirements of the food packaging industry. 353* Clarification of Wines by Micro/UltrafiltrationF e r n a n d o G o n c Ë a l v e s M a r i a N o r b e r t a d e P i n h o *The present work addresses the optimisation of wine clarification by microfiltration (MF) and ultrafiltration (UF) in terms of productivity and macromolecular removal minimisation. Two DSS PVDF membranes were tested: one of MF with 0.45 lm pore size, and another of UF with 100 MWCO. The wine permeation flux was practically the same for micro and ultrafiltration. The use of pressures higher than 1 bar revealed no improvement in permeation flux. Clarification was achieved with both membranes with a particle removal of ca. 70 %. Low polysaccharide removal was obtained: 12 % for MF and 21 % for UF. The clarification of wine by membrane (MF and UF) had no significant effect on polyphenolic content.The engineering design...

Nutritional improvement of plant foods by non-thermal processing

“…Combined heat and ultrasound treatments have been reported to lower maximum processing temperatures by 25-50 %. After treatment, changes in colour and vitamin C were minimal (Zenker et al 2001).…”

“…These combinations were found to be effective against micro-organisms and enzymes. The combined use of heat and ultrasound, or heat and ultrasound under pressure, markedly increases the lethality of heat treatments and consequent reductions in time and/or temperature of heat processes (Sala et al 1995;I Alvares, unpublished results;Zenker et al 2001). Combined heat and ultrasound treatments have been reported to lower maximum processing temperatures by 25-50 %.…”

The Use of Ultrasound and Combined Technologies in Food Preservation

“…(2,35,40) The combined use of heat and ultrasound markedly increases the lethality of heat treatments and consequent reductions in time and/or temperature of heat processes. (36,37) Combined heat and ultrasound treatments have been reported to lower maximum processing temperatures by 25-50%. After treatment, changes in color and vitamin C were minimal.…”

“…After treatment, changes in color and vitamin C were minimal. (36) Different authors have investigated combinations of heat and ultrasound to decrease the intensity of heat treatments. The heat resistance of B. cereus, Bacillus licheniformis, B. stearothermophilus, and thermoduric streptococci decreased following ultrasonication treatment at 20 kHz.…”

“…(7,38,39,40,41) The effect of the combined treatment of ultrasound and heat in a continuous process on microbial destruction was demonstrated by the comparison of the integrated time-temperature intensity (F value) of each treatment. (36) …”