280 Chapter 11
browning of cheese on pizza is enhanced if
too much galactose accumulates or too
much lactose is retained or proteolysis is
abnormal. Judicious selection of culture
strains exhibiting non - browning character
of pizza cheese is needed to minimize this
defect.- Oiling - off is undesirable because it imparts
an oily surface to pizza. The fat freed by
heat during baking may even run off the
edges of pizza, giving an unsightly appear-
ance. The fat content of the cheese and
protein matrix strength are critical factors
in this regard. Pizza cheese is generally
made from part - skim milk to reduce exces-
sive fat, which might otherwise oil - off.
Aged cheese tends to oil - off more than
fresh cheese due to the proteolysis factor.
High acidifi cation and enhanced salting
generally reduce calcium content of pizza
cheese, resulting in effi cient emulsifi ca-
tion. Accordingly, oiling - off is thereby
reduced. - Blistering (size, number, and color) is
another functional attribute of mozzarella
cheese during the baking process. Large
blisters are undesirable. They are caused by
excessive ripening of the cheese. A young
cheese generally has a large number of
small blisters. - Shreddability is a function of fat and mois-
ture content. Generally, low - moisture, part -
skim mozzarella has satisfactory shredding
properties. Chemical analysis for moisture,
fat, salt, and pH should be performed on
representative samples of each batch to
ensure conformation to the product stan-
dards and specifi cations.
Finally, microbiological analyses should
be recorded to ensure consumer safety. The
coliform count should be less than 10 CFU/g.
Cheese should show negative counts for
E. coli , Staph. (Coagulase positive), Salmo-
nella, and Clostridium perfringes. The
mold and yeast count should be less than
100 CFU/g.
salt content, lactose/galactose content, and
proteolytic activity during storage (Chandan,
1997 ).
- Stretchability depends on the calcium -
phosphate level and proteolysis in cheese.
The calcium content is controlled by
acidity developed at the time of whey
draining and at the hot - water stretching
stage. The conversion of dicalcium paraca-
seinate to monocalcium paracaseinate is
engineered by controlling culture activity.
It is important to limit further lactic acid
production; otherwise, paracasein will be
produced from monocalcium paracasein-
ate. Paracasein cannot hold milk fat, result-
ing in low - fat, poor - quality cheese. On the
other hand, too much calcium (predomi-
nantly dicalcium paracaseinate) gives short
stretch with a tough and grainy texture. Too
much proteolysis in aged cheese also nega-
tively infl uences stretchability. - Meltability depends on the proteolytic
activity of the culture, fat content, and
moisture content of mozzarella cheese.
Higher meltability is observed with higher
fat and higher moisture content. Fresh
mozzarella is relatively tough and elastic,
but on ripening for about three weeks, it
develops the desired texture and melt-
ability character. Overmelting also is unde-
sirable because melted cheese runs off the
pizza. - Browning results from the Maillard reac-
tion between the free hydroxyl group of
a carbohydrate (lactose or galactose) and
a free amino group of an amino acid in
milk protein. Proteolytic activity of the
culture liberates more free amino groups.
The growth of Streptococcus thermophilus
involves hydrolysis of lactose to glucose
and galactose. Glucose is metabolized by
glycolysis to lactic acid. The process results
in a net accumulation of galactose with the
free hydroxyl group available for interac-
tion with the free NH 2 group of hydrolyzed
protein to yield brown pigment. Thus,