Effects of extrusion on the stability and digestibility of instant coix seed porridge

Background and ObjectivesCoix seed is rich in nutrients but its tough husk and resilient structure require substantial energy and cooking time, limiting their utilization and consumption. This study aims to develop a convenient, high‐quality instant coix seed porridge to expand the consumption and utility of coix seed.FindingsExtrusion treatment significantly (p < .05) improved the stability and decreased viscosity of instant coix seed porridge compared to the cooking process, particularly when the extrusion moisture reached 22%. Furthermore, extrusion at the moisture of 18%–22% not only had no significant impact on the water‐soluble protein (WSP) content of instant coix seed porridge but also decreased the starch‐digested ratio when compared with the cooking process, thereby enriching its nutritional value. The increased stability of instant coix seed porridge was due to the exposed hydrophilic groups by disrupted the long‐ and short‐range ordered structure of coix seed starch as evidenced by X‐ray diffraction and Fourier transform infrared analyses. Furthermore, the decreased digestibility was attributed to the formation of starch–lipid complexes.ConclusionsExtrusion can be used to produce instant coix seed porridge with low viscosity, high stability, and delayed starch digestion. In addition, the instant porridge produced by this method can have the same WSP as cooking treatment.Significance and NoveltyThis study provides valuable insights into producing instant coix seed porridge.