Physicochemical Properties of the Gum from Neem Tree ( Azadirachta Indica )

Abstract

Four samples 1, 2, 3 and 4 of

Neem gum were collected from four differe

nt

locations in Khartoum state. These samples were mixed are

presentative composite

samples were made from all collected

samples. Physicochemic

al

methods were

undertaken to characterize

the gum. The parameters such as moisture content, ash

content, pH

value, specific optical rotation, intrinsic viscosity, nitrogen content,

protein content, acid equivalent

weight, total

uronic acid, tannin content, average

molecular weight and sugar content. Results obtained for all parameters show

insignificant differe

nt. Mean values obtained for the properties studied were as

follows: moisture content 10.6%, ash content 3.

5

%, pH 6.78, specific optical

rotation (

-

)65.

4, intrinsic

viscosity10.7cm

3

/g

-

1

, nitrogen content 4.03%, protein

content 25.18%, acid equivalent weight

26

.8*10

3

total uroinc acid 0.71%, tannin

content 0.15%. Acid hydrolysis followed by HPLC measurement revealed that a

sugar composition of arabinose

15.7

%

and 20.04% galactose. Cationic

composition showed that magnesium (17.2ppm ) has the highest value amo

ng the

catatonics studied, followed by potassium (1.1069ppm), sodium(0.4025ppm),

calcium(0.3401ppm), zinc(0.15255ppm)

in the same order

but the lead, iron,

chrome and nickel were not found in the samples. The molecular weights of

samples were estimated fro

m light scattering measurement using GPC

-

MALLS

technique. The values of M

n

are found to be (

2.48*10

6

).