Effect of Accelerated Retting Process on Physiochemical and Pasting Properties of Cassava (Manihot esculenta Crantz) Flours

Aims: To compare the physicochemical (water, total titratable acid, amylose and amylopectin contents), functional (swelling and solubility powers) and pasting characteristics of cassava flour retted in two different ways.

Study Design: Flours were produced from two cassava cultivars subjected to natural and accelerated fermentations using a multi-strain mixed starter.

Place and Duration of Study: Department of Microbiology of the University of Yaounde 1 and Department of Food Science and Nutrition at the University of Ngaoundere, both in Cameroon, between November 2019 and February 2020.

Methodology: The cassava roots of each cultivars were divided into two groups and fermented by submerging peeled roots in tap water. One group of each cassava cultivar was inoculated with 1% (w/w) of the starter, while the other was subjected to a spontaneous fermentation. Retting stopped after the softening of the roots; that is after twenty-six hours for the inoculated groups, and after seventy-two hour for the control groups. The fermented roots were then squeezed, dried and grounded in a blender. Flours obtained were subjected to physicochemical, functional and pasting analysis.

Results: Flours produced in accelerated fermentation (AF) were characterized by their low amylopectin contents (46.59% and 43.57%), swelling power (6.71% and 7.56%), solubility (6.03% and 7.96%), and peak viscosity (6182 cP and 5676 cP) for Six-mois and Mintol-meko flours respectively. Whereas setback viscosity (1032 cP and 1068 cP), stability (0.27 and 0.24) and final viscosity (3565 cP and 3566 cP) of flours from natural fermentation (NF) were lower than those from AF.

Conclusion: The accelerated fermentation reduces the tendency of paste to downgrade, that is responsible for staling in baked products and could therefore produce flours that are less fluid.