Food & Nutrition

Arab Journal of Food & Nutrition
12. Effect of Baking Intensity (Browning) on the Protein Quality of Two Locally
Produced Types of Ka’ak (1994)
Baderah Musa Abu-Dweih\ University of Jordan
Supervisor: Dr. Salma K. Tukan
Co-Supervisor: Dr. Hamed R. Takruri
The effect of baking intensity on the protein quality of the two locally produced
bakery products, qurshallah and kersina, was studied. Kersina is leavened by yeast,
whereas qurshallah by ammonium bicarbonate and twice baked.
Three browning levels of each Ka’ak type (light, medium and dark) were
prepared by baking at the same temperature, but for different baking times. Proximate
analysis was done and crude protein, crude fat, crude fiber, ash and moisture contents
were determined. The browning levels of the two types were also biologically
evaluated for their protein quality by NPU.
Moisture content was significantly different among the various browning levels
in the two Ka’ak types, it decreased significantly with increasing baking time. Fat and
ash contents in kersina (19.4 and 1.8% dry matter respectively) were higher than those
in qurshallah (12.5 and 0.7% dry matter respectively) while the average protein
content was similar 9.6%, 9.5% dry matter basis respectively.
Food consumption and gain in body weight decreased with increasing browning
level. Dark browned qurshallah diet, medium and dark browned kersina diets (contain
7.5% protein as it is) caused a reduction in body weight of animals. Therefore, it is
recommended not to consume the dark browned qurshallah or kersina.
In spite of different ingredients and their proportions used for the production of
each type of ka’ak, the protein quality of qurshallah and kersina was similar. The
NPU op , NPU st and NDpE% values for light browned qurshallah were the highest (63.9,
64.7 and 4.2 respectively), and were significantly different from medium browned
qurshallah (56.4, 56.3 and 3.7 respectively), but not from dark browned qurshallah
(62.1, 62.9 and 4.2 respectively).
The NPUop, NPUst and NDpE% values for the three browning levels of kersina
were not significantly different from each other. The values for the light browning
were (60.2, 60.6 and 4 respectively), for the medium browning were (64.1, 64.8 and
4.2 respectively) and for the dark browning were (61.1, 61.6 and 4 respectively).
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Volume 155 11, No. 25, 2011