دراسة المحتوي الكيمياءي والفاعلية ضد الميكروب لبعض النباتات الطبية في ليبيا arabic 13 English 92
Asma Omar jebril (1-2008)

Modern improvements in Fourier transform infrared spectroscopy instrumentation spread out the application of this technique to the field of food research. This study is focused to evaluate the efficiency of FT-IR spectroscopy in order to assess the Libyan virgin olive oil adulteration with cheaper vegetable oils: sunflower oil and corn oil. Taking a closer inspection to different regions of recorded IR spectra of both pure oil sample (virgin olive oil, sun flower oil, corn oil) and their mixture: It is noticed that an absorbance shift was identified at about 3000 cm-1 due to the C-H stretching vibration of the cis-double bond proved to be reliable index for assessing of virgin olive oil adulteration by vegetable oil addition. Also, the absorbance at about 3008 cm-1, characteristic to the oils with a high saturated fatty acids content and short carbohydrate chain, recorded appreciable changes by increasing of vegetable oil percent added in virgin olive oil. Based on the calibration curve (absorbance versus percent of vegetable oil added in virgin olive oil), it is possible to determine the degree of virgin olive oil adulteration. A significant positive correlation for both adulterant oils (R2 > 0.97) at wavenumber 3008.3 cm-1 was observed in our study. Our data demonstrated that FT-IR spectroscopy proved to be a valuable tool to identify the differences recorded in oil samples spectra and finally, to appreciate the degree of virgin olive oil adulteration
Ragiab Ali Mokhtar Issa(1-2018)

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)