Physicochemical Characterization ofAcaciatortilisvar. spirocarpaGum from (Sudan)

Abstract

Authenticated twenty four samples ofA. tortilisvar.spirocarpa gum were collected from different treesfrom Khartoum and Gazira states -Sudan. Physicochemical results show that , themean values obtained for moisture content were 11.7and10.9%, ash content were 2.9 and 2.5%, pH values were 5.8 and 4.6 , specific optical rotation were +80.0 and+76.6 . Nitrogen content were 2.2 and 1.4%, protein content 13.8 and 8.4%,calorific value was 4.03Kcal mol-1, absolute viscosity were 45cps and 23cps. Percentage average values for rhamnose, arabinose and galactose values were found to be in range(4.5-2.9),(43.4-40.3) and (17.1-13.9) respectively and glucouronic acid 8.17 and 8.43%, acid equivalent weight 2376.1 and 2301.5 .Cationic composition was studied using ICP technique showed that calcium has the highest value(8718-7727ppm) then potassium(3320-1087ppm), magnesium(1820-1330ppm) and sodium(98.9-42.3ppm).The rest of the elements Fe,Al,Mn,Co,Ni,Cr and the heavy metals Pb,Zn,Cu,As were found as traces. Molecular weight distribution was determined using Gel Permeation chromatography showed three main components arabino glactan protein(AGP), arabino galactan(AG), and glycoprotein(GP).Average molecular weight was estimated to be (4.62-4.59)x105and the radius of gyration was 35-21nm. Emulsification study showed that A. tortilis var.spirocarpapossessed high emulsifying power and stability as oil- in- water emulsion, the emulsion particles possessed smaller droplet size compared to those of other Acacia gums. The gum is classified as grade 1 emulsifier. Rheological study of A.tortilis var.spirocarpashowed that the gum is Newtonian fluid at high shear rate and high concentration and the result of oscillatory test of the gum solution revealed a solid-like behaviour . Results showed insignificant difference within samples collected from different location.On comparing between A. tortilisvarieties:spirocarpa ,raddiana and . tortilis, there are insignificant difference between them in the physicochemical and functionalityproperties, so they can be marketed as one species.