The effects of thermal processing on properties of fundamental food polymers in commercial Asian and experimental sorghum noodles

Abstract

Processing variables of 100% sorghum noodles were evaluated. A dough was made, extruded to create noodles then dried. Structural, physical, and cooking characteristics of the experimental sorghum noodles, as well as thin spaghetti, commercial Asian rice, broad bean, tapioca, sweet potato and egg noodles were evaluated. In comparison to the commercial noodles, the experimental sorghum noodles had high dry matter loss, but similar water uptake and moisture. The dry matter loss of sorghum noodles was greatly affected by the heating stage before extrusion, with a lower dry matter loss resulting from a longer heating time. The internal structure of the noodles was evaluated with the ESEM. Starch noodles had a thick starchy continuous phase that was smooth and amorphous. The protein based noodles were held together by a gluten matrix, small endosperm pieces with intact starch granules were visible and suspended within the matrix. Noodles made from any grain or starch other than wheat must rely on starch gelatinization for their structure. The sorghum noodles produced in this experiment indicated that sorghum could be used to produce a non-wheat noodle. A sorghum noodle could be a new food product for those who are gluten-intolerant or an alternative food product for the semi-arid tropic regions where sorghum is a native grain.