Optimisation of Fermentation Conditions for Ogiri Production from Castor Seed in Ebonyi State

Ogiri, a fermented castor seed condiment widely consumed in South East Nigeria, is an important source of protein and flavour in traditional cuisine. Despite its cultural significance, the fermentation process is largely artisanal and inconsistently controlled. This study optimises key fermentation parameters including temperature, duration, and initial moisture content for the production of Ogiri from castor seed (Ricinus communis) obtained from farms in Afikpo, Ebonyi State. A central composite design with three factors at three levels was employed, and response surface methodology was applied to model the effects of temperature (30 to 40 degrees Celsius), duration (48 to 96 hours), and moisture content (50 to 70 percent) on protein content, pH, titratable acidity, and sensory acceptability as response variables. The fermented samples were analysed using AOAC standard methods, and sensory assessment was conducted by 25 experienced consumers of traditional condiments. The optimised conditions identified by the response surface model were 35 degrees Celsius, 72 hours, and 60 percent moisture content, yielding a product with 24.3 percent crude protein, desirable pH, and the highest sensory acceptability scores. The study contributes to the documentation and standardisation of indigenous fermented food processes in Nigeria and draws on recent fermentation engineering literature. Findings are relevant to cottage food enterprises, extension service officers, and food product developers in the South East zone. Keywords: fermentation, castor seed, Ogiri, response surface methodology, Ebonyi State