• Voragen, A. G. J.
• Poutanen, Kaisa
• Lille, Martina
• Schols, H. A.
• Hilz, H.

Abstract

High-pressure processing (HPP) is one of the prosperous techniques infood processing. Under HPP the activities and specificities of different cellwall affecting enzymes change [1]. In juice production cell wall degradingenzymes are used to soften the tissue and destroy a highly viscous pectin gel,which is formed after mechanical mashing of the berries. Thus, cell wallpolysaccharides are key compounds for producing juice in higher yields andreduction of press cake quantities.The structure of cell wall polysaccharides is hardly affected by HPP directly,but the treatment might lead to improved enzyme control, giving a benefit foryield and colour of the juice. This is exemplified by Krebbers et al. [1] fortwo endogenous pectic enzymes affecting the viscosity of the mashed berries.They found a six fold higher activity of pectin methyl esterase after HPP oftomatoes, while the activity of polygalacturonase decreased by 70 %.The first step to show the influence of HPP on enzymatic activity was toanalyse cell wall polysaccharides. Mechanically mashed bilberries and blackcurrants were mechanically mashed and treated with 400 MPa at 32 – 43 °C for15 min. Part of this mash was processed to juice. Cell wall polysaccharideswere isolated from the mash, the juice, and the remaining press cake andanalysed. The effect of HPP is shown by comparing the obtained data with thedata from fresh berries and from juice and press cake of conventionalprocessing [2].This presentation shows how HPP affects the structure of cell wallpolysaccharides. Consequences of the use of enzymatic activity and specificity(endogenous and exogenous) before and after HPP will be discussed.REFERENCES: 1. Krebbers, B., Matser, A.M., Hoogerwerf, S.W., Moezelaar, R.,Tomassen, M.M.M., and Van den Berg, R.W., IFSET, 4(4), 377-385 (2003). 2.Hilz, H., Bakx, E.J., Schols, H.A., and Voragen, A.G.J., Carbohydr. Polym.,submitted (2004).

Topics

• impedance spectroscopy
• compound
• viscosity