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High pressure homogenisation of fruit- and vegetable-based products

Identification

Key words high pressure homogenisation, structure, rheology, bioaccessibility, fruit, vegetable, soup, purée, sauce
Latest version 2012/06/29
Completed by KU Leuven LFT

How does it work?

Primary objective
  • to disintegrate plant cell structures and wall material
  • to create new structural entities
  • to include oil into low-fat type of systems
  • to produce emulsions with higher or improved stability
Working principle In high pressure homogenisation, the non-homogenised fruit or vegetable based product enters the valve of the homogeniser at relatively low velocity. The pressure is then generated by a pump and the restriction to flow caused by the passage of the product through a very small gap (see Figure 1). The product flows between the valve and the seat at high velocity. As the velocity increases, the pressure decreases producing an instantaneous pressure drop. The fluid is finally discharged as the homogenised product (7). Phenomena of cavitation, shear and turbulence occur during the homogenisation process (8), leading to the disintegration of cell structures and wall material and the incorporation of oil into fruit- and vegetable-based products.
Images
Additional effects The rheological characteristics of the product (1,2) as well as the bioaccessibility of micronutrients can be affected by high pressure homogenisation (3-6).

The use of very high pressures (up to 350 MPa) leads to a serious increase in product temperature, which in turn results in the inactivation of micro-organisms in the product. (Ultra) high pressure homogenisation can hence also be used as a tool for food preservation (9).

Important process parameters operating parameters (e.g. flow rate, pressure, number of cycles, temperature) and device parameters (e.g. nozzle geometry and impingement design) (1).
Important product parameters composition (fat, water, protein, pectin...), viscosity (although of less importance compared to rotor-stators-systems), particle size of solids in the suspension.

What can it be used for?

Products All kinds of fruit- and vegetable-based dispersions which are sufficiently liquid and thus pumpable: soups, juices, sauces, purées.
Operations
  • Mechanical processing of fruit and vegetable based food products
  • Creation of stable emulsions (e.g. oil/vegetable emulsions)
  • Structure engineering through high pressure homogenisation can be used as a tool to influence carotenoid bioaccessibility in fruit- and vegetable-based food products
Solutions for short comings High pressure homogenisation can be used as a complementary technique to simple blending for the creation of fruit- or vegetable-based dispersions in order to obtain a desired rheological behaviour and/or optimal bioaccessibility of micronutrients.

What can it NOT be used for?

Products This technology can not be used for solid food products or products of which the viscosity is very high.
Operations Sterilisation
Other limitations The effect of high pressure homogenization on the structural characteristics of fruit-and vegetable-based products is largely dependent on the matrix type that is considered. For example, a decrease in viscosity with increasing pressure levels has been observed for carrots (6), whereas an increase in viscosity with increasing pressure levels has been observed for tomatoes (2,3,10). This explains why individual studies on different fruit and vegetable matrices are required in order to intelligently apply the technique of high pressure homogenization for the production of fruit- and vegetable-based food products.
Risks or hazards Heating of heat-sensitive products can occur at high pressures, without adequate temperature control.

Implementation

Maturity High pressure homogenisation has already been widely used in the dairy industry (although at lower pressures of 20-60 MPa). Interest towards this technique at pressures up to 350 MPa in the field of fruit- and vegetable processing is currently increasing.
Modularity /Implementation This technology can be inserted in an existing production line, where it complements simple blending. The pressures applied (up to 350 MPa) are higher than for standard homogenization (20-60 MPa).
Consumer aspects The consumer acceptancy of high pressure homogenised products is likely to be high as products with improved rheological characteristics and a high bioaccessibility of micronutrients can be obtained.
Legal aspects No issues expected
Environmental aspects Relatively low efficiency of energy use: in UHPH, 41-63% of the energy is lost as heat (13).

Further Information

Institutes KU Leuven LFT, Unilever
Companies GEA Niro Soavi, OMVE Netherlands, Tetra Pak
References 1. Lopez-Sanchez, P., Nijsse, J., Blonk, H.C.G., Bialek, L., Schumm, S., Langton, M. (2011). Effect of mechanical and thermal treatments on the microstructure and rheological properties of carrot, broccoli and tomato dispersions. Journal of the Science of Food and Agriculture, 91: 207-217.

2. Augusto, P.E.D., Ibarz, A., Cristianini, M. (2012). Effect of high pressure homogenization (HPH) on the rheological properties of tomato juice: Time-dependent and steady-state shear. Journal of Food Engineering 111, 570-579.

3. Colle, I., Van Buggenhout, S., Van Loey, A., Hendrickx, M. (2010). High pressure homogenization followed by thermal processing of tomato pulp: Influence on microstructure and lycopene in vitro bioaccessibility. Food Research International, 43: 2193-2200.

4. Christiaens, S., Van Buggenhout, S., Chaula, D., Moelants, K., David, C.C., Hofkens, J., Van Loey, A.M., Hendrickx, M.E. (2012). In situ pectin engineering as a tool to tailor the consistency and syneresis of carrot purée. Food Chemistry, 133: 146-155.

5. Knockaert, G., Lemmens, L., Van Buggenhout, S., Hendrickx, M., Van Loey, A. (2012). Changes in β-carotene bioaccessibility and concentration during processing of carrot puree. Food Chemistry, 133, 60-67.
6. Martinez-Tomas, R., Perez-Llamas, F., Sanchez-Campillo, M. et al. (2012). Daily intake of fruit and vegetable soups processed in different ways increases human serum beta-carotene and lycopene concentrations and reduces levels of several oxidative stress markers in healthy subjects. Food Chemistry 134, 127-133 .

7. Floury, J., Desrumaux, A., Axelos, M.A.V., Legrand, J. (2003). Effect of high pressure homogenisation on methylcellulose as food emulsifier. Journal of Food Engineering, 58: 227-238.

8. Floury, J., Bellettre, J., Legrand, J., Desrumaux, A. (2004). Analysis of a new type of high pressure homogeniser. A study of the flow pattern. Chemical Engineering Science, 59: 843-853.

9. Pereda, J., Ferragut, V., Quevedo, J.M., Guamis, B., Trujillo, A.J. (2007). Effects of ultra high pressure homogenization on microbial and physicochemical shelf life of milk. Journal of Dairy Sciences, 90: 1081-1093.

10. Svelander, C.A., Lopez-Sanchez, P., Pudney, P.D.A., Schumm, S., Alminger, M.A.G. (2011). High pressure homogenization increases the in vitro bioaccessibility of alfa- and beta-carotene in carrot emulsions but not of lycopene in tomato emulsions. Journal of Food Science, 76: H215-H225.

11. Betoret E., Sentandreu E.,Betoret N., Fito, P. (2012). Homogenization pressures applied to citrus juice manufacturing. Functional properties and application. Journal of Food Engineering 111, 28-33.

12. Stang M., Schuchmann, H., Schubert, H. (2001). Emulsification in High-Pressure Homogenizers. Engineering in Life Sciences 1(4), 151-157.

13. Cortés-Muñoz, M., Chevalier-Lucia,D., Dumay, E. (2009). Characteristics of submicron emulsions prepared by ultra-high pressure homogenisation: Effect of chilled or frozen storage. Food Hydrocolloids 23, 640–654.



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Created by LiesbethV on 29 June 2012, at 08:59