A study of some aspects of the quality and yield of cheddar cheese made from milk concentrated by ultraflitration : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the Department of Food Technology at Massey University
Ultrafiltration (UF) is a concentration and separation process which operates at the molecular level. It has been successfully applied to certain soft cheese varieties with
the primary advantage of increased yields. When applied to Cheddar, which is a hard variety, problems are encountered. These are lack of flavour and texture development, lack of
economically viable yield increase and practical problems in handling of UF curd.
An investigation was undertaken to study the application of UF technology to the manufacture of Cheddar cheese.
The emphasis was on the biochemical and biophysical problems in UF Cheddar and the possible yield advantages in making the product.
Results suggest that UF per se does not contribute to problems in the quality of UF Cheddar. No major problems
were encountered in the cheese making process or in final cheese quality when cheese was made from 2:1 UF retentate using conventional method and equipment. There were, however, no yield advantages. When 3:1 and 5:1 retentates were used, some modification in the method of manufacture, particularly in the cutting time and cutting device, was necessary.
The quality of cheese obtained from 3 : 1 retentate was found to be inferior while that from 5:1 retentate was comparable with respect to the control
The biochemical and biophysical problems associated
with the quality of UF Cheddar could be overcome to a large
extent by adjusting the amount of starter and rennet added
on the basis of quantity of milk prior to UF. This yields
Cheddar of normal one-day pH but with residual rennet concentration
much higher than that in the conventional
product. The higher level is probably required to over come
the 'dilution' effect of the extra whey proteins present in
the UF product. This 'dilution 'effect may be partly due to
the difficulty of rennet diffusion in UF Cheddar and partly
a result of a decrease in concentration of flavour compounds
due to the presence of extra whey proteins. The results
show that subs tanti a l savings i n rennet are not possible in
cheesemaking from 5:1 UF retentate. The results also
suggest that it is possible to make UF Cheddar with a
required residual rennet concentration by regulating the
amount of rennet added to the retentate and draining the
whey at a predetermined pH.
The yield advantage in cheesemaking from 5:1 retentate
(if UF Cheddar is made to normal MNFS of 53.5%) was limited
to 4% largely because only one third of the whey proteins of
UF milk was retained in the cheese. Theoretical analysis of
mass balance data indicated that this yield advantage could
be improved to about 6% by reducing 'fines' losses and to
about 8% by decreasing fatlosses as compared with the
Given the current state of UF cheesemaking technology,
it is possible that reductions in losses in conventional
cheese-making plants may prove to be a more profitable
method of increasing yields of Cheddar cheese than the use
of UF cheesemaking methods.