Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-28T05:14:28.668Z Has data issue: false hasContentIssue false
  • English
  • Français

Assessment of two instruments for continuous measurement of the curd-firming of renneted milk

Published online by Cambridge University Press:  01 June 2009

Richard J. Marshall ,
David S. Hatfield  and
Margaret L. Green
Richard J. Marshall
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading R02 9 AT, UK
David S. Hatfield
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading R02 9 AT, UK
Margaret L. Green
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading R02 9 AT, UK
Get access Rights & Permissions [Opens in a new window]

Summary

Continuous measurements of curd-firming using a commercial vibratingreed viscometer and a pressure transmission system (PTS) developed at this Institute were compared both in the laboratory and during Cheddar cheesemaking. The coefficient of variation about the mean of the curd-firmness measured in reconstituted skim-milk 40 min after renneting was 3·5% with the viscometer and 2·6% with the PTS. The effects of changes in conditions on the curd-firming rate of raw whole milk were determined. As the rennet concentration was raised the rates increased linearly as measured by the viscometer, but non-linearly as measured by the PTS. Addition of CaCl2 increased the rates measured by both instruments rapidly at first then more slowly at higher levels. Raising the temperature increased the rate exponentially in the case of the viscometer but more slowly with the PTS. With both instruments the curd-firming rates of milk at pH 5·8 were 6·5 times those at pH 6·7 but the rates fell slightly at pH 5·6. In experimental cheesemaking, the mean readings of both instruments at the subjectively determined cutting time of the curd had the same coefficient of variation.

The commercial viscometer is probably more suitable for laboratory investigations of the earlier stages of the coagulation of milk by rennet whilst the PTS may prove the more useful in indicating the optimum cutting time of the curd during cheesemaking.

Type
Original Articles
Information
Journal of Dairy Research , Volume 49 , Issue 1 , February 1982 , pp. 127 - 135
Copyright
Copyright © Proprietors of Journal of Dairy Research 1982

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bachman, S., Klimaczak, B. & Gasyna, Z. 1978 Non-destructive viscometric studies of enzymic milk coagulation. I An ultrasonic viscometric method for the measurement of milk clotting activity of proteolytic enzymes. Acta Alimentaria Polonica 4 55–62Google Scholar
Berrjdge, N. J. 1952 Some observations on the determination of the activity of rennet. Analyst 77 57–62CrossRefGoogle Scholar
Burgess, K. J. 1978 Measurements of the firmness of milk coagulum. Irish Journal of Food Science and Technology 2 129–134Google Scholar
Burnett, J. & Scott-Blair, G. W. 1963 A speed-compensated torsiometer for measuring the setting of milk by rennet. Dairy Industries 28 220–223Google Scholar
Chapman, H. R. & Burnett, J. 1972 Seasonal changes in the physical properties of milk for cheesemaking. Dairy Industries 37 207–211Google Scholar
Chapman, H. R. & Harrison, A. J. W. 1963 Control of acid development in Cheddar cheesemaking. Journal of the Society of Dairy Technology 16 139–144CrossRefGoogle Scholar
Green, M. L., Hobbs, D. G., Morant, S. V. & Hill, V. A. 1978 Intermicellar relationships in rennet-treated separated milk 2. Process of gel assembly. Journal of Dairy Research 45 413–422CrossRefGoogle Scholar
Hatfield, D. S. 1981 A new instrument to measure cheese curd rigidity, and preliminary trials in cheesemaking. Journal of the Society of Dairy Technology 34 139–142CrossRefGoogle Scholar
Kelley, L. A. 1951 The factors affecting rennet coagulation time and rennet curd tension. Thesis, University of Wisconsin, USA.Google Scholar
Kowalchyk, A. W. & Olson, N. F. 1977 Effects ofpH and temperature on the secondary phase of milk clotting by rennet. Journal of Dairy Science 60 1256–1259CrossRefGoogle Scholar
Roth, W. & Rich, S. R. 1953 A new method for continuous viscosity measurement. General theory of the Ultraviscoson. Journal of Applied Physics 24 940–950CrossRefGoogle Scholar
Scott-Blair, G. W. & Burnett, J. 1958 Physical changes in milk caused by the action of rennet. 1. Description of apparatus for measuring rigidity moduli and internal viscosities, tests of reliability and some observations on syneresis. Journal of Dairy Research 25 297–303CrossRefGoogle Scholar
Tarodo de la Fuente, B., Alais, C. & Frentz, R. 1969 Study of the coagulation of milk by rennet and of syneresis of the coagulum using a thromboelastograph. Lait 49 400–416CrossRefGoogle Scholar
Tarodo De La Fuente, B. & Frentz, R. 1966 Thromboelastic studies on milk coagulation by rennet: effect of temperature and Ca concentration. Lait 46 371–393CrossRefGoogle Scholar
Thomasow, J. & Voss, E. 1977 Methods for the determination of the firmness of milk coagulum. International Dairy Federation Annual Bulletin Document no. 99Google Scholar
Tuszyński, W., Burnett, J. & Scott-Blair, G. W. 1968 The effects of variations in pH of the removal of calcium and of the addition of sulphur-bond inhibitors on the setting of renneted milk. Journal of Dairy Research 35 71–83CrossRefGoogle Scholar
Vanderheiden, G. 1976 An apparatus for continuously monitoring the structural rigidity of a gel. CSIRO Food Research Quarterly 36 45–47Google Scholar