Food & Nutrition

Arab Journal of Food & Nutrition
13. Preservation of Semolina with Gamma Irradiation and Studying Its Effect on
Pasta Quality (2008)
Firas S. Al-Azzeh\ University of Jordan
Supervisor: Dr. Ayed S. Amr
This study was conducted to extend semolina shelf life using minimum gamma
irradiation dose. The effect of varying gamma irradiation doses (0, 0.25, 1, 2.5, 5 and
10 KGy) before and after milling of wheat grains on the physiochemical and
rheological properties of semolina and its products during 6 months of storage was
investigated.
Minimum irradiation dose used to inhibit insect proliferation during storage
period was o.25 KGy in semolina and 1 KGy in wheat kernels. Ash, protein and water
content were not influenced with gamma irradiation, while Falling Number decreased
with increasing irradiation dose. Irradiation adversely affected wet gluten, dry gluten
and gluten index at 5 KGy dose.
Total titratable acidity values of 5 and 10 KGy irradiated semolina were not
changed with storage, while other irradiated and unirradiated treatments showed a
significant (p 0.05) increase in acidity values during storage period. Irradiation
treatments showed inconsistence significant changes in fat acidity values, while
storage period increased it significantly (p 0.05) for the control and all irradiated
treatments. The 0.25 KGy irradiated semolina after and before milling of wheat grains
decreased carotene concentration 14.1% and 10.3%, respectively. Fungi count
decreased 81.8% after applying 0.25 KGy dose for semolina.
Farinograph results showed that water absorption of semolina was increased with
increasing irradiation dose and storage period. Dough stability was deteriorated with
increasing irradiation dose, whereas it improved with storage for irradiated and
unirradiated samples.
Up to 10 KGy dose, tyrosine was the highest increasing amino acid whereas
phenylalanine was the highest decreasing one. Lysine content decreased 14% after
applying 10 KGy irradiation dose, while methionine content increased in this sample
with increasing irradiation dose. Number o bands for globulin protein and the bands
density decreased substantially at 5 KGy irradiation dose.
Cooking loss and cooking gain of lasagna increased with increasing irradiation dose.
After storage, cooking loss increased and cooking gain decreased. Sensory evaluation showed
that lasagna produced from 0.25 KGy irradiated solina and 1 KGy irradiated wheat grains did
not show any significant differences as compared with the control sample.
328
Volume 327 11, No. 25, 2011