294 Chapter 11
(13.79 MPa), followed by transfer to the
packaging machine for hot packaging. The
hot process imparts a shelf life of at least two
months under refrigerated storage.Cheeses Produced by Direct Acid
Addition and Heat
In cheeses produced by direct acid addition
and heat, the curd is formed by direct acidi-
fi cation of hot milk with food - grade acids. In
general, the directly acidifi ed cheeses are
consumed in fresh or unripened form. These
cheeses derived from milk coagulation with
acid under sub - boiling temperatures are
known by various names in different parts of
the world. They are made from whole milk,
low - fat milk, skim milk, cream, or whey or
their mixtures. Milk of various species of
animals is used in production of these
cheeses. Depending upon its origin, curdling
of hot milk may be carried out with vinegar,
lactic acid, calcium lactate, lime/lemon juice,
acid whey, or yogurt/fermented milk. In
terms of commercial signifi cance, ricotta,
chhana, paneer, and queso blanco are dis-
cussed in this section.
Table 11.11 gives the proximate chemical
composition of acid and heat - coagulated
cheeses. The composition of cheddar cheese
is given for comparison.
Ricotta Cheese: Ricotta, like cottage
cheese, is a high - moisture cheese. Ricotta is
not a pressed curd type of cheese. Its compo-
sition varies depending on whether it is made
exclusively from whey or from a blend of
whey and milk. Originally, ricotta was made
from whey derived from mozzarella or pro-
volone cheese production. Ricotta is now
prepared from whole milk with or without
the addition of whey. When made from a
blend of 95% sweet whey and 5% milk,
ricotta contains 68% to 73% moisture, 16%
protein, 4% to 10% fat, and 4% lactose.
Ricotta has a bland to slightly cooked but
pleasing fl avor. Its texture is soft and creamy.
It is consumed as such as a spread and may(154 ° F to 158 ° F)/30 minutes or equivalent.
The mix is homogenized at 1,000 to 1,500 psi
(6.9 to 10.3 MPa) at 63 ° C (145 ° F) and cooled
to 32 ° C (90 ° F). Rennet is added at the rate
of 1 ml/1,000 kg cream and blended. Using a
starter consisting of Lactococcus lactis sub-
species lactis/cremoris and Leuconostoc
crem oris at the 5% to 6% level, the cream
cheese mix is cultured at 30 ° C to 32 ° C (86 ° F
to 90 ° F) for fi ve hours. The long - set process
employs 1% starter and incubation for 16
hours at 22 ° C (72 ° F). Addition of Leuconostoc
sp. imparts a buttery aroma. The fermenta-
tion is continued until a pH of 4.4 to 4.5 is
attained. Some processors use the thermo-
philic yogurt culture to acidify cream cheese
mix to pH 4.4 to 4.6 at 43 ° C (109 ° F).
However, the fl avor lacks the buttery notes
obtained with mesophilic culture. After the
required pH is reached, the curd is agitated
until it is lump free. Next, enough hot water
at 76 ° C (169 ° F) is added to bring the tem-
perature to 51 ° C (124 ° F). At this point, the
curd should be smooth and creamy.
In the traditional process, the cultured
cream is transferred to draining bags, which
are dipped in hot water and allowed to hang
and drain for two hours. However, most
modern plants are equipped with centrifuges
to separate whey. Cream cheese collects in
the bowl. The curd is collected and salted to
obtain 0.75% salt in the cheese. The yield of
cream cheese should be 2.7 to 3.1 kg/kg of
fat. The cheese is subsequently packaged by
cold - pack procedure without any additives or
heated and cooled to 2 ° C to 4 ° C (36 ° F to
39 ° F) for storage. The cold - pack cream
cheese has more aroma and fl avor, and no
pasty/sticky body. However, it lacks the long
shelf life obtained by the most commonly
used hot - pack procedure. This procedure
involves heat treatment of cream cheese in a
kettle or scraped surface heat exchanger.
Cream cheese is mechanically mixed with
a stabilizer (0.35% locust bean gum) and
1% salt and brought to 70 ° C (158 ° F). The
hot mixture is homogenized at 2,000 psi