Physicochemical Properties of Flours that Relate to Sorghum Couscous Quality

Abstract

ABSTRACT Flours from eight sorghum cultivars were evaluated for their couscous‐making ability with the objective of finding predictive relationships between flour physicochemical properties and couscous quality. Chemical composition, physical characteristics, and pasting and gelatinization properties of the flours were determined. A laboratory procedure was used to prepare couscous. Couscous properties were evaluated and compared to a laboratory‐prepared and a commercial durum wheat couscous. Hard grain produced flours containing a high proportion of coarse particles with low ash and high damaged starch content and yielded a higher proportion of desirable sorghum couscous granules. A variety of colors ranging from brown to yellow were obtained when flours were processed into couscous. Cooked sorghum couscous stickiness was positively correlated ( r = 0.89, P < 0.01) with the amount of damaged starch in flour. Cooked couscous hardness correlated positively ( r = 0.79, P < 0.05) with apparent amylose content of flour and correlated negatively ( r = ‐0.75, P < 0.05) with flour peak viscosity. Durum wheat couscous was lighter and had more yellow color than sorghum couscous. Sorghum couscous was stickier and harder than durum wheat couscous. Addition of 2% oil to the cooking water considerably improved the texture of some sorghum couscous to a level comparable to that of durum wheat couscous.