Structural, thermal, and rheological properties of starches isolated from four different varieties of Indian barnyard millet ( Echinochloafrumentacea )

Abstract

The present study explored the properties of starches isolated from four different Indian varieties of barnyard millet. The amylose content ranged from 21.27 to 23.30% (db) and was highest for BMV2 (23.30%). The swelling power of millet starch varied from 2.10 to 18.80, while solubility ranged from 1.30 to 14.20. The peak viscosity (2492 RVU), the final viscosity (3832 RVU), and the setback viscosity (2077 RVU) were the highest for BMV3 as compared to that of other starches. The starches exhibited small spherical, large angular, and large spherical granules with A-type crystallinity and an average size of around 10 μm. The degree of crystallinity ranged from 25.7% (for BMV4) to 31.6% (for BMV1). The strong absorption bands from 3255 to 3260 cm−1 were attributed to –OH stretching of the polysaccharide skeleton. A higher yield and purity value suggests that barnyard millet starch can be exploited for commercial starch utilization. Practical applications Starch is the major component of barnyard millet grain. It can be isolated, modified, and used as a relatively cheap and novel source. The potential of native and modified starch in food, as well as non-food industry, can be further exploited. Since the amylose content of barnyard millet starch is high, it can be employed in preparing biodegradable films in combination with a suitable plasticizer.