Background and Objectives: Intermediate wheatgrass (Thinopyrum intermedium, IWG) is a perennial grain crop being explored for mainstream food applications. The impact of extrusion on the nutritional and physicochemical characteristics of IWG was investigated for the first time. Extrudates were produced using a corotating twin-screw extruder. Findings: Extrusion resulted in slight decreases in dietary fiber, fat, starch, and amylose contents of IWG, whereas protein and ash contents did not change. Significant increase in starch damage after extrusion led to significant increases in starch digestibility and hydration properties of IWG. Correspondingly, slowly digestible starches and resistant starches were significantly reduced after extrusion. Pasting profile studies showed significant decreases in all pasting parameters measured except for breakdown viscosity after extrusion. Higher antioxidant activity and phenolic acid levels, mainly due to ferulic acid, were observed even after extrusion. However, carotenoids content decreased significantly (up to 65.8% reduction in lutein and 50.4% reduction in zeaxanthin). Conclusions: These findings show that extrusion cooking can improve the antioxidant activity and maintain high protein and dietary fiber levels in IWG, but it may not be suitable for preserving carotenoids in IWG. Significance and Novelty: Extrusion cooking could potentially be used to produce extruded snacks from IWG with high protein and dietary fiber.
Bibliographical noteFunding Information:
The authors are thankful to CW Brabender Instruments Inc. NJ, USA for allowing us to use their in‐house extruder for the extrusion experiments. The authors are grateful to Dr. Ryan J. Kowalski for providing technical assistance with the extrusion experiments. The authors also thank Leslie Loehr and Radhika Bharathi for their technical assistance in the laboratory. This study was funded by the Forever Green Initiative, University of Minnesota, Twin‐Cities, Minnesota, USA.
© 2022 The Authors. Cereal Chemistry published by Wiley Periodicals LLC on behalf of Cereals & Grains Association.
- antioxidant activity
- extrusion cooking
- intermediate wheatgrass
- nutritional property
- phenolic acid