Effect of Extraction Methods on Chemical and Physical Properties of Aloe Vera (Aloe Barbadensis Miller) Polysaccharides Fraction: Liguid Gel and Powders

The aim of this study was to evaluate the influence of extraction methods on chemical and physical properties of Aloe vera polysaccharides. The study was conducted on two commercial products: Aloe vera powder and an extract liquid of whole leaf. The kinetics of hydrolysis is carried out on the Aloe vera products. Hot, cold extraction with water and boiled ethanol extraction were carried out to obtain polysaccharide fractions (A1, A2, A3, and A4). The molecular weights of each fraction were determined. Proteins, galacturonic acid and sugars were quantified. Results showed that approximately, 25% of sugars were present in Aloe vera powder. The best extraction method were cold extraction (pH 5.3, 25°C, 4h) which showed the higher extraction yields (69.4±0.1%) in polysaccharide (Poly) A, than other extraction methods. Interestly, results showed a decrease of molecular weights, molecular number, and protein contents from 150 to 30 kDa, from 97 to 29 kDa and from 4.9±0.1 to 0.00% respectively with polysaccharides fractionment methods. Moreover, the total sugar content increases in polysaccharide fraction: 29.2±0.1%, 76.6±0.1% and 93.4±0.4% for Poly A, A1 and A2 respectively. The highest sugar content were observed in Poly A3 ≈ 97.8±1.5% probably glucomannan, with 77.3±6.5% of mannose, 18.7±2.8% of glucose. The data suggest that the fractionment methods could lead to product the purified polysaccharide which could be use for nutritional, biological and medicinal properties.