Effect of Processing Methods on Pasting Properties of Gum Extracts from Selected Soup Thickeners in South-East, Nigeria

Abstract

The work was designed to determine the effect of processing methods on pasting properties of gum extracts of selected soup thickeners common in Imo state, South-East, Nigeria. The cotyledons, flours (full-fat and de-fatted) and gum extracts from de-coated Afzelia africana “akparata”, Mucuna sloanei “ukpo”, Brachystegia eurycoma “achi” and Detarium microcarpum “ofor” seeds were obtained after boiling at 100oC for 10, 20, 30 min; roasting at 130oC for 10, 20, 30 min and soaking at ambient temperature for 8, 16, 24 h. The flours from each of the raw seeds served as control. The flours were de-fatted using petroleum ether and gums extracted using propan -2- ol. The pasting properties of the seed gums extracted and conventional guar were determined using a Rapid Visco Analyzer (RVA) (Madel RVA 3D +, Newport Scientific Pty LTD., Sydney, Australia 1995) with the thermocline for windows software. Analysis of variance (ANOVA) was performed on the collected data at p<0.05. The results were statistically analyzed using Statistical Package for Social Sciences (SPSS) version 23. The mean peak time, pasting temperature, setback and final viscosity of the gums from the different legume seeds under different processing methods were all higher, while their mean peak and trough viscosities were lower than that of guar gum. Reduced setback viscosity (298 to 129) RVU and breakdown viscosity (3866 to 3182) RVU obtained from processed seeds are indications that gums from them will form more stable paste than guar gum and if added to starch-based foods will have the tendency of retarding the problem of retrogradation.