Effect of annealing on the chemical and physico-functional properties of fermented provitamin A cassava starch

Abstract

This study reports the effect of annealing on chemical and physico-functional properties of fermented pro-vitamin A cassava starch of cassava roots TME-IBA 070539 variety. The provitamin cassava starch flour was extracted to produce native starch flours (NCS). Fermentation was carried out on the tubers at 24 and 48 hours to produce provitamin A cassava fermented starches FCS24 and FCS48 respectively. The starch flour samples NCS, FCS24 and FCS48 were then annealed at 50°C to produce annealed native starches (ANCS), annealed 24 hours fermented cassava starch (AFCS24) and annealed 48 hours fermented cassava starch (AFCS48). The chemical and physico-functional properties were evaluated using standard methods. The result revealed negligible amount of crude protein and ash content. However, the carbohydrate content in all the samples ranged between 93.39 – 95.01% signifying high purity starches. These processes imparted positively the β- carotene content which ranged between 2.50 – 2.80 μg/100g in the cassava starches. Although, no significant (p>0.05) difference was observed in the β-carotene content when compared with the corresponding annealed starches except for a slight reduction at AFCS48. The amylose content decreased significantly (p>0.05) by 21.72 and 38% in the combined process of annealing and fermentation as observed for AFCS24 and AFCS48 respectively. Also, amylose leaching was more pronounced in the NCS than the fermented and annealed starches. No significantly (p<0.05) difference was observed in the corresponding samples; ANCS, AFCS24 and AFCS48 for total titratable acidity while pH decreased significantly in the annealed starches. The swelling and solubility increased with increase in temperature, generally annealing lowered the swelling capacity and increased the solubility of the starch samples and this could be harnessed in food preparations and in the industries.