Food & Nutrition

Arab Journal of Food & Nutrition
6. Investigations on Imparting Stretchability and Meltability to White Brined
Nabulsi Cheese (2004)
Jihad “Mohammad Rafeq” Quasem\ University of Jordan
Supervisor: Dr. Mohammad Ali Humeid
Boiled white brined (Nabulsi cheese) is the mostly consumed in Jordan, this
cheese should show meltability and high stretchability in order to fit in the production
of high quality Kunafa and other popular local sweets and pastries. However, these
characteristics are rarely available when usual processing and preservation methods
are used. The most outstanding characteristic of Nabulsi cheese is the long keeping
ability (more than one year) without refrigeration, since it is preserved in concentrated
brine (up to 25%). This work was based on the hypothesis that it would be possible to
imply meltability and stretchability to the cheese by adjusting pH or by adding low
concentrations of emulsifier salts or proteolytic enzymes to the original brine that may
specifically act on cross-linking bonds of casein.
A new apparatus for measuring the actual stretchability was designed and
constructed; measurements on different cheeses proved its validity and reliability to
measure stretchability up to 80cm. Detailed treatments revealed the success of the
proposed assumptions in inducing meltability and stretchability to cheese processed
and preserved according to the traditional methods.
The following results were obtained:1. It is possible to imply a low but acceptable level
of stretchability and meltability through adjustment of the pH in the range of 5.4-5.8 by
adding calculated amounts of citric acid considering the buffering capacity of the cheese and
storing it for few weeks to reach equilibrium. 2. It was found that adding puromelt C1
composed of (sodium citrate, sodium 2. phosphate and sodium polyphosphate) or
monosodium phosphate of 0.2% (w/w) calculated on total sample, including its
original brine, is capable of inducing high levels of stretchability and meltability after
the 3rd week of storage at room temperature. 3. It was found that adding papain
(extracted from papaya) or rennilase (pro duced from Mucor sp.) at 0.005% (w/w)
calculated on total sample, including its original brine, and adjusting pH to 5.8 is
capable to induce high levels of stretchability and meltability after the 2nd week of
storage at room temperature. Papain treatment was superior to the other enzyme
treatments in the absence of proteins desolation over long treatment period as well as
development of highly fibrous structure upon stretching and consistency of
stretchability for more than four weeks of storage.
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Conformational experiments proved the applicability of the new method on
commercial Nabulsi cheese samples. Sensory evaluation revealed the superiority of
puromelt C1 treatment with significant differences over papain treatment as well as
commercial Mashmouleh cheese that has high meltability and stretchability when used
in Kunafa making.
Volume 317 11, No. 25, 2011