Abstract: Rheological properties of Gum Habeil collected during three seasons had been studied. Intrinsic viscosity of aqueous solution of Gum Habeil was calculated by Fedor's equation. At a low concentration of aqueous deacetylated gum solution, the G' (viscoelastic) was appeared higher than G'' (viscosity) at frequency ranged from 1 to 10 Hz, but with increases concentration of deacetylated gum solutions G'' line was trend to appear higher than G' line at low frequency region. However, a crossover of G' and G'' lines was observed as the frequencies increased to 1.26, 3.97, and 9.99 Hz for 1.5, 3, and 5% w/w of gum solutions respectively. The concentrated crude gum dispersions 12.5 and 15% w/w were exhibited viscoelastic behavior, in contrast the 10% w/w of crud gum solution in distilled water appeared G'' higher than G' with the crosslink points at the middle of frequency range. The critical concentration C* of deacetylated gum solutions in deionized water, in sodium hydroxide alone, and in alkali with addition salt were determined to be 2.34, 2.37, and 2.41 g/dl respectively. The effect of temperature on rheological behavior was also studied. arabic 8 English 57
Aborawi M. Elgornazi, M. H. Awad, Nouri M. A. Soleiman(2-2020)

A total of 25 randomly purchased bread samples were analyzed in this study from 25 different bakeries in Tajoura city. Bread in Libya is highly consumed among all socioeconomic groups; it is mainly consumed in breakfast, dinner and school meals. Potassium bromate is the most popular additive used in bakery industry worldwide. Bakeries in the US used Potassium bromate as bread improver since 1914 to increase bread volume and texture and improve bread production. The main aim of this study is to assess the safety of bread by the measurement of residual potassium bromate using a rapid and reliable method and to investigate the level of compliance to the ban fourteen years later. This method is based on the reaction between bromate and iodide in acidic medium to produce iodine (I2). The absorbance of I2 was measured spectrophotometrically at 488nm. The calibration curve was linear (R2=0.9996) over the range 1.0 – 5.0mg/L of potassium bromate. Despite the ban of potassium bromate in Libya since 2005 due to its classification as a potential carcinogen it is still detected in local bread loaves. All samples showed high levels of potassium bromate to be 300 to 1333 more than the permissible level set by the American Food and Drug Administration (FDA) which is highly toxic for consumers and could threaten their health over prolonged regular consumption. A continuous pursuance and implementation of the ban on use of potassium bromate in baking industry in Libya is recommended. arabic 11 English 67
RAGIAB ALI MOKHTAR ISSA(1-2020)

مدينة مزدة هي أحد اكبر المدن الليبية في الجبل الغربي من حيث الكثافة السكانية , تقع مدينة مزدة في منتصف الشمال الغربي من ليبيا بين خطي عرض 13.4 شمالا و 28.17 جنوبا وخطي طول 14.10 شرقا و11.40 غربا وتقع جنوب مدينة طرابلس( بحوالي 200 كم) . تعتبر المياه الجوفية هي المصدر الرئيسي للمياه في هذه المنطقة والتي يعتمد عليها السكان في تلبية جميع احتياجاتهم من شرب ، زراعة ، صناعة , بالإضافة إلى الاستخدامات الأخرى. ويوجد بها العديد من الآبار والتي يتراوح عمقها من 500 متر إلى 750 متر. في هذه الدراسة تم اختيار عدد 4 آبار منتشرة بالمنطقة لغرض تصنيف نوعية المياه وتقييم استخدامها للأغراض المختلفة. تم قياس درجة الحموضة لعينات المياه في آبار قيد الدراسة ، بالإضافة إلى تقدير العناصرالثقيلة الرئيسية في المختبر كما تم تقدير العسرة الكلية للمياه والأملاح الذائبة الكلية.كما تم اجراء الفحص الميكروبي للكشف عن إمكانية وجود البكتريا من عدمه. بينت نتائج الاختبارات المعملية للمياه الجوفية للمنطقة بأن مياهها تعتبر متدنية النوعية وغير صالحة للشرب وذلك استنادا إلى مواصفات مياه الشرب في ليبيا لسنة (2008)الصادرةعن المركز الوطني للمواصفات والمعايير القياسية , معاييرمنظمة الصحة العالمية ((WHO لسنة (2011)، منظمة والأغذية الزراعة ( FAO), وأيضا وكالة حماية البيئة الأمريكية EPA) ). arabic 112 English 0
عزالدين محمد ابراهيم(8-2020)