Physico-chemical Characterization of Grain Tef [Eragrostis tef (Zucc.) Trotter] StarchStarch isolated from five grain tef (Eragrostis tef) varieties was characterized and compared with commercial maize starch. Grain tef starch is formed of compound granules, comprising many polygonal shape (2-6 µm in diameter) simple granules. The crude composition is similar to that of normal native cereal starches. The amylose content ranges from 24.9 -31.7%. Gelatinisation temperature range was 68.0-74.0-80.0 °C, typical of tropical cereal starches, and resembling the temperature range of rice starch. The mean intrinsic peak viscosity (269 RVU), breakdown viscosity (79 RVU), cold paste viscosity (292 RVU) and setback viscosity (101 RVU) determined were considerably lower than that of maize starch. Tef starch has higher water absorption index (WAI) (mean 108%) and lower water solubility index (WSI) (mean 0.34%) than maize starch.

The cassava flours and starches have elicited great use in the food and non-food industry. The diversity in cassava genotypes accounts for differences in end-product properties, and would require characterization of cassava varieties for suitability of culinary and processing. This review showed that screening criteria of cassava cultivars end-user properties include proximate contents, amylose content, structural, swelling, gelatinization and pasting characteristics, including freeze-thaw stability properties of cassava-derived flours and starches. Literature shows that the physiochemical properties vary with genetic factors (i.e. genotype). In this review, the amylose content was found to be the main genetic trait for discriminating the cassava varieties for gelatinization and pasting processes including resistant starches. Moreover, cassava derived raw materials (flours and starches) were found to have various application in baking, edible film, syrup, glucose, alcohol, and soups production.

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Properties of tef starch from five varieties were compared with commercial maize starch. In most tef varieties the paste clarity (measured as % T) was similar to that of maize starch, but the paste was visually less white in colour. Tef starch gel texture was short and in most varieties was slightly firmer than that of maize starch. Tef starch adhesiveness was less than maize starch. Retrogradation extent of tef starch evaluated, as % gel syneresis under storage at 4 °C and ‐18 °C at 3, 7, 10 and 21 storage test days, was lower than that of maize starch. Storage with three freeze‐thaw cycles (‐18 °C 24 h; 23 °C 6 h) gave a similar trend. In tef starch initial digestion by α‐amylase and hydrolysis by mild HCl treatment was slightly higher than in maize starch, probably in part because of the smaller granule size and higher amorphous portion of tef starch. Alpha‐amylase degradation of tef starch granules was by surface erosion, probably due to the absence of surface pores in the granules.