Characterisation of Hydrocolloids from Nigerian Edible Seeds for Food Thickening Applications

Hydrocolloids derived from locally available Nigerian seeds offer sustainable, low-cost alternatives to imported food thickening agents such as guar gum and xanthan gum. Despite the availability of several seed hydrocolloid sources in Nigeria, systematic comparative characterisation of their rheological, thermal, and functional properties for food applications has not been conducted. This study extracts and characterises hydrocolloids from four Nigerian edible seeds, namely Brachystegia eurycoma (ofor), Mucuna sloanei (ukpo), Detarium microcarpum, and Prosopis africana, collected from markets in Enugu (South East) and Niger State (North Central). Extraction was conducted by hot water extraction and spray drying. Characterisation included proximate composition, intrinsic viscosity, molecular weight estimation, rheological behaviour by rotational and oscillatory rheometry, thermal properties by differential scanning calorimetry, and emulsification properties. Application testing in tomato-based sauce and egusi soup was conducted to evaluate performance in relevant food matrices. Results showed that Brachystegia eurycoma hydrocolloid exhibited the highest intrinsic viscosity and predominantly elastic behaviour, making it potentially superior for food thickening applications. Detarium microcarpum hydrocolloid exhibited intermediate viscosity with notable emulsification capacity. The study fills a characterisation gap in the literature on African seed hydrocolloids and contributes to the understanding of structure-function relationships in non-conventional hydrocolloids. Findings are relevant for food ingredient manufacturers and product developers. Keywords: hydrocolloid, seed gum, rheology, food thickener, Nigeria