ZAL R. KOTHAVALLA AND H. C. VERMA 301
coagulated at 95° F. with rennet in the proportion of 6.7 ml. for 100 lb. of milk
based on the findings in the preceding experiment. The results are given
in Table II.
The results show that the richer the milk the higher was the yield of cheese
but the increase in the yield was not maintained proportionately after a certain
level of fat content in milk was reached. For instance, the difference between
the yield of cheese from 100 lb. each of 2 per cent and 6 per cent milks was
about 16 lb., whereas the difference between 6 per cent and 10 per cent milks
was only 5 lb. 6 oz., or one third of the former.
It was further observed that the higher the initial fat content of milk,
the higher was the loss of fat in whey. This loss was particularly high in the
case of milks containing 8 per cent and 10 per cent of fat. The study of the
physical characteristics of the finished cheese revealed that the cheese made
from milk containing 6 per cent fat excelled all others in the matter of body,
texture and flavour which are the main features on which the quality of a cheese
is judged. It could, therefore, be concluded that 6 per cent fat content in
milk is the most desirable one as it also gives good yield without excessive
loss of fat in whey.
(iii) Effect of varying the quantity of starter used.—This experiment was
conducted with the object of determining the quantity of starter which should
be used for developing the desired lactic flavour and aroma in the cheese in the
normal period of making the cheese and its ripening. Starter was used in the
proportion of 0.5, 1.0 and 1.5 oz., to 100 lb. of milk. The acidity of the
starter varied from 0.70 to 0.82 per cent lactic acid which is considered normal.
On the basis of the findings in the preceding experiments, the optimum
conditions with regard to fat per cent of milk, renneting temperature and
quantity of rennet, were adopted in this case. The cheeses were then kept
submerged in the collected whey for 8, 16, 24 and 32 hours for the purpose
of ripening (Plate XX, fig. 1). Each variation in the quantity of starter was
repeated six times and the results are presented in Table III.
It will be seen from Table III that, while there was no appreciable
rise in the acidities from the stage of basketing the curd till the completion
of draining or steeping the cheese, the rise in acidity became pronounced during
the ripening period in all cases. It was more rapid in the case where 1.0 oz.
and 1.5 oz. of starter were used than with 0.5 oz. The differences between the
acidities at the stage of steeping though not marked are still indicative of the
action of the varying quantities of starter used. It was noticed that the
addition of 0.5 oz. starter gave the least acidity both at steeping and at the
completion of the ripening stages. Although the difference between the
acidities at steeping resulting from the use of 1.0 and 1.5 oz. starter was only
0.01 per cent lactic acid, the latter developed more acidity and at a faster
rate for obvious reasons; The flavour of all the cheeses was flat at steeping,
with their body and texture more or less uniform.
During ripening the flavour and aroma became pronouncedly lactic much
earlier in the case of cheese containing 1.0 and 1.5 oz. of starter and this
tendency persisted right through the ripening period. It was also noticed
that the rise in acidity was closely associated with increased shrinkage and
firmness of body and compactness of texture.