FellowshipS Seminar 2016

Poster ABSTRACTS
The incorporation of colourant into cheese
curd by high pressure processing
Catherine M. Wall 1,2* , Annalisa Segat 1,2 , Alan L. Kelly 3 Jeremiah J. Sheehan 1
1 Teagasc Food Research Centre Moorepark, Fermoy, Co. Cork
2 Dairy Processing Technology Centre, University of Limerick
3 Department of Food and Nutritional Sciences, University College Cork
During manufacture of coloured cheddar cheese, approximately 20 % of the colourant added (typically natural
compounds such as Annatto) is lost in the whey stream, and thus may be incorporated into subsequent whey products.
This creates a challenge in terms of the growing market demand for coloured cheese and the parallel growing and
lucrative global market for high quality whey protein ingredients which do not contain colourants. Although permitted
in the United States, the removal of colour from the whey stream by bleaching is prohibited in Europe and in Asia,
and thus there is a need to develop processes to facilitate the manufacture of coloured cheese without compromising
the whey stream value. In this study, the first objective was to investigate if high pressure (HP) processing could
enhance penetration of colour into the cheese curd after removing the main body of whey. The second objective was to
characterise whether a combination of HP treatments (250 or 400 MPa) and colourants (Annatto; β-Carotene) affected
gross composition, texture and microstructure of cheese, or influenced colour penetration into the curd, as assessed by
using 3D computer analysis, over a 30 day ripening period. The results indicated no significant differences (P>0.05) in
composition resulting from the various treatments; similar microstructures were also observed for both pressure-treated
and control curd samples. Over the 30-day ripening period, hardness decreased in the control and pressured-treated
curd samples, and proteolysis (pH4.6-soluble Nitrogen, Urea-PAGE) increased over ripening, but was not affected by
the various treatments. Furthermore, computer generated images revealed that the colour remained localised at the
curd’s surface/rind directly after the pressure treatments and after the 30 day ripening period.
47