Protein-enriched “green” gari from optimized cassava root-leaf mixtures using Box-Behnken design

Abstract

ABSTRACT This study employed the Box-Behnken design of response surface methodology to optimize solid-state fermentation of cassava root-leaf mixtures for producing fortified gari, termed “green gari.” Three variables were examined: cassava root concentration (0–100%), sodium chloride concentration (2–10%), and fermentation time (10–30 days). Responses analyzed included total cyanide, crude protein, pH, and ash content. A quadratic model with R² values between 0.98 and 0.99 showed an excellent fit ( p < 0.0001). Optimal conditions were identified at 38.02% cassava root, 2% sodium chloride, and 10 days of fermentation. Under these conditions, values for total cyanide, crude protein, pH, and ash content were 55.5 µg/g DM , 16.2 g/100g DM , 4.6, and 12.3 g/100g DM , respectively. The resulting green gari had 6.81 µg/g DM total cyanide, 12.60 g/100g DM crude protein, 9.70 g/100g DM ash, and 8.86 g/100g DM crude fiber. The product met the WHO recommended safety limit for cyanide in cassava products and demonstrated improved nutritional quality, particularly in crude protein content, indicating its potential as a protein-enriched food product for human consumption.