Abstract:
Twenty gum samples from Acacia sengal var. senegal were collected from seven locations within the Sudan gum belt with different soil types and seasons. The locations are AL-Nihud, AL-Obied, AL-Deain and Nyala, which represented the sandy soil areas whereas Abojebaha, AL-Gadaref and Upper Nile, represent the clay soil areas of the belt.
The Physicochemical analysis carried out included moiture content, optical rotation, intrinsic viscosity, protein content, pH value, acid equivalent weight and ash content were done. The results shows a range of the physicochemical properties varied according to the soil types. Sand soil areas gave moisture contents ranging from 10.15% to 14.89%, specific optical rotation from -27.64 to -30.14, intrinsic viscosity from 16.64 ml/g-1 to 22.74 ml/g-1, protein content from 1.73% to 2.24%, pH value from 4.3 to 4.44, acid equivalent weight from 1133.8 to 1291.5 and ash content from 3.15% to 3.75%. While the clay soil areas gave moisture contents ranging from 9.70% to 12.20% , specific optical rotation from 28.38 to -30.61, intrinsic viscosity from 16.29 ml/g-1 to 19.77 ml/g-1, protein content from 1.68% to 2.05%, pH value from 4.22 to 4.36, acid equivalent weight from 1237.8 to 1328.5 and ash content from 3.04% to 3.97%.
The gum samples have been fractionated to determine the molecular weight and molecular mass distribution which reflects the functionality of the gum. The molecular weight of the samples from the sandy soil fall in the range from 5.40×105 to 1.44×106 with an AGP molecular weight from 2.68×106 to 6.15×106 and AGP% in range from 6.53% to 20.14%. In the same context molecular weight of the samples obtained from the clay soil ranged from 3.43×105 to 6.07×105 with an AGP molecular weight ranging from 1.91×106 to 2.69×106 and AGP% from 3.21% to 11.45%.
Emulsion properties of the gum samples were also evaluated by measuring the droplet size. 70% of the samples had good emulsion properties. However, in the present study it has been found that 78% of these good emulsifier samples were obtained from the locations characterized by sand soil , only one sample (5%) showed fair emulsion properties, whereas, 5 samples representing 25% showed poor emulsion properties.
