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Research r...FinishersTrial report 875

Trial report 875: Difference in heat stability of phytase and xylanase products

All tested phytase and xylanase products had a high heat stability with the exception of Porzyme 9302.


The heat stability of two phytase and four xylanase products was investigated, and the results demonstrated that enzyme activity dropped under the highest conditioning temperatures.

For the phytase products, Ronozyme NP and Phyzyme XP TPT, and for the xylanase products, Ronoxyme WX, Econase XT 25 and Danisco Xylanase 8000 G, more than 80% of the enzyme activity was preserved up to 95°C. All these products were comparable in terms of heat stability. Porzyme 9302 stood out by being less heat stable; at 90°C xylanase activity was reduced to half of the original level.

Conditioning and pelleting processes at a feed mill normally do not exceed 95°C and should therefore not cause problems to the activity of the studied enzymes except for Porzyme 9302.

Enzyme activity in this study demonstrates only heat stability and not the effect in the pig. To ensure that the feed contains the declared levels of enzymes, it is possible to analyse this for phytase, whereas for xylanase it is a matter of trust.

The effect of Ronozyme WX and Porzyme 9302 is currently being investigated in different dosages in finisher feed.

The heat stability of the products in this study was studied in a trial facility at the Technological Institute in Kolding where it was possible to control temperature and duration of conditioning and pelleting. The study included two commercial phytase and four xylanase products conditioned for 30 seconds in the temperature interval 80-100°C prior to pelleting. 

Financial support

The study was financially supported by the Pig Levy Fund and the EU and the Rural Development Programme under the Danish Ministry of Food, Agriculture and Fisheries and has project ID DSP09/10/58 and file no. 3663-D-07-00234.


Updated: 27.01.2011


Dorthe K. Rasmussen

Project Manager, Ph.D.

Phone: (+45) 3339 4442