The classification of natural gums. Part IV. Identification and discrimination of Acacia, Combretum and Proposis gum exudates

Abstract

Principal component projection, discriminant component projection and, for classification, linear discriminant analysis (LDA) have been used to study the relationship between and distinguish closely related Acacia, Combretum and Proposis gum exudates, all arabinogalactan proteins. A set of eight gums from the Acacia and seven from Combretum series, selected randomly, could be all correctly classified using LDA. Combretum gums can readily be distinguished from Acacia gums ( Vulgares and Gummiferae series) using either analytical parameters associated with either the carbohydrate or protein moieties. The Proposis gums form a closely identifiable grouping, apart from P. Juliflora, which is indistinguishable from Acacia senegal. Gums of the Phyllodinaea series can readily be discriminated from other Acacia species used in the food industry. The method offers a basis for a quality control system to ensure the compliance of commercial gum products with national and international legislative requirements.