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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Sustainable Biofuels and Co-products Research » Research » Publications at this Location » Publication #335328

Research Project: Enable New Marketable, Value-added Coproducts to Improve Biorefining Profitability

Location: Sustainable Biofuels and Co-products Research

Title: Physicochemical characterisation of the galactomannan from delonix regia seed

Author
item Nwokocha, Louis - Glyndwr University
item Williams, Peter - Glyndwr University
item Yadav, Madhav

Submitted to: Food Hydrocolloids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2017
Publication Date: 1/1/2018
Publication URL: http://handle.nal.usda.gov/10113/5651316
Citation: Nwokocha, L.M., Williams, P.A., Yadav, M.P. 2018. Physicochemical characterisation of the galactomannan from delonix regia seed. Food Hydrocolloids. 78:132-139.

Interpretive Summary: A new carbohydrate polymer with food gum properties has been prepared from the seeds of the legume plant, Delonix regia. It has been fully purified, and characterized. The molecular size, flow behavior of its solution and its thickening properties have been studied to evaluate its potential use in food products. It forms a very thick (viscous) solution in water at low concentration but shows the properties of a weak gel at higher concentrations. Such properties make it very useful for mixing in many food products for altering their texture and thickness, giving a better mouth feel. The properties of this new polysaccharide were found to be similar to commercial locust bean gum and therefore it has potential as a thickener in the food and related industries. These findings will be useful for the growers of such legume plant, who are trying to get additional revenue from its seeds. Commercialization of this material could potentially provide new uses for these seeds, which are low-valued products and could provide more revenue for their growers and processors.

Technical Abstract: This paper reports on the physicochemical characteristics of the polysaccharide extracted from the seeds of the legume Delonix regia which grows abundantly in Nigeria. The polysaccharide was found to consist of mannose and galactose with an M:G ratio 5:1 and average molar mass of 7.23 x 105 g/mol. The average value of intrinsic viscosity obtained using Fedors, Huggins and Kraemer equations was 9.9 dL/g. The double logarithmic plot of zero shear specific viscosity versus volume concentration gave a critical overlap concentration of 0.404 g/dL with a slope of 1.2 below and 6.8 above the critical overlap concentration. Under oscillatory shear, at polysaccharide concentrations less than 1% solutions exhibited purely viscous properties while at higher concentrations they exhibited the properties of a weak gel. The physicochemical characteristics of the polysaccharide were found to be similar to locust bean gum and therefore it has potential as a thickener in the food and related industries.