Combined effect of fermentation, sun-drying and genotype on breadmaking ability of sour cassava starch.

The influence of genotype and post-harvest treatments on expansion ability of sour cassava starch was investigated using 13 cassava genotypes from Colombia. Starches from cassava grown at 1000 m and 1700 m.a.s.l (3 lowland and 10 highland clones respectively) were modified by fermentation (0 or 30 days) and drying (oven or sun) treatments. RVA average peak viscosity decreased regularly from 952 cP in native starch to 699 cP in fermented and sun-dried starch. Granule size analysis revealed that fermentation hydrolysed lowland and highland granules by exocorrosion and endocorrosion respectively. This result was corroborated by significantly higher RVA breakdown and lower intrinsic viscosity in highland clones, reflecting different sensitivity to fermentation. For the first time, amylose contents ranging from 15.7 to 21.7% were correlated with expansion ability (3.0-8.6 mL/g) of sour cassava starch. Therefore the combination of cassava genotypes (mainly amylose content) and post-harvest treatments is key for expansion ability. Supra-molecular granule structure influenced sensitivity to fermentation.