Insight into elevated quality of whole millet (Pennisetum glaucum) cake through the process of extrusion

Abstract

The practice of extrusion treatment has gained widespread adoption in the food industry. This treatment notably improved the quality of whole millet cake and the underlying mechanism was investigated. The results showed that millet extruded at 14% moisture could enhance the quality of whole millet cake by reducing hardness and increasing springiness, specific volume, and height-to-diameter ratio. Moreover, the improvement effect became more pronounced as the extrusion temperature reached 170 °C. However, it was worth noting that excessive moisture (18%) and high temperature (170 °C) during extrusion led to the highest gelatinization degree, resulting in a sticky cake batter that fails to form a soft cake during baking. In contrast, extrusion at low moisture (14%) and high temperature (170 °C) promoted starch degradation and formation of more starch complexes. These effects reduced stickiness while increasing the elasticity of the cake batter. This, in turn, contributes to the superior quality of the cake prepared using extruded millet flour at 14% moisture and 170 °C. The formation of starch complexes played a crucial role in enhancing the elasticity of the cake batter and overall cake quality, as they acted as supports within the cake batter matrix.