Natural Polysaccharides From Aloe vera L. Gel (Aloe barbadensis Miller): Processing Techniques and Analytical Methods

Abstract

Aloe vera L. (Aloe barbadensis Miller) from Asphodelaceae (Liliaceae) family, is a medicinal plant frequently used in medicines, cosmetics, and food products. Seventy-five potentially active compounds have already been identified from A. vera extract, among them: enzymes, minerals, lignin, saponins, salicylic acids, amino acids, sugars, and vitamins. In this chapter, the authors highlight the mucopolysaccharide acemannan (an acetylated glucomannan), extracted from the mucilaginous gel leaves. Acemannan has a backbone of β(1–4)-linked mannose units, partially acetylated, interspersed by glucose units, and some galactose side-chains. However, several of its structural characteristics, such as degree of acetylation, presence of glucose monomers, and its molecular weight, are always quantified because they present inconsistencies and disparities. Growing conditions of the plant and harvesting period, different processes for obtaining the gel, and its derivatives, besides the many different analytical methods applied, contribute to the lack of standardization of A. vera gel and its derivatives. Therefore, this chapter aimed to present the different techniques used for processing mucilaginous gel along with the various analytic methods applied in recent years.