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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Plant, Soil and Nutrition Research » Research » Publications at this Location » Publication #358281
Title: Physico-chemical properties, phytochemicals and DPPH radical scavenging activity of supercritical fluid extruded lentils

Author
item YING, LV - Beijing University Of Agriculture
item Glahn, Raymond
item HEBB, RICHARD - Cornell University
item RIZVI, SYED - Cornell University

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2017
Publication Date: 11/2/2017
Citation: Ying, L., Glahn, R.P., Hebb, R., Rizvi, S. 2017. Physico-chemical properties, phytochemicals and DPPH radical scavenging activity of supercritical fluid extruded lentils. LWT - Food Science and Technology. 89:315-321. https://doi.org/10.1016/j.lwt.2017.10.063.
DOI: https://doi.org/10.1016/j.lwt.2017.10.063

Interpretive Summary: A process known as supercritical fluid extrusion (SCFX ) is often used to take flours from staple food crops and turn them into shapes and forms for cereals and snack foods. The objective of the present study was to determine optimal conditions for SCFX on a flour blend comprised of lentil flour and pre-gelatinized potato starch. The blend was extruded at temperature of 95-99.5 °C and screw speeds of 40, 80 and 120 rpm. The physical properties of the extruded products such as porosity, rehydration rate, expansion ratio, and crispness --improved as the screw speed increased. Furthermore, the density, water solubility index, brittleness, and hardness of the products decreased as the screw speed increased. SCFX increased the temperature at which starch gelatinization and protein degradation occur in lentil flour. Increased screw speed led to increased gelatinization in the starch. Unlike traditionally cooked lentils, the extruded red lentil products demonstrated no loss in quality when stored at room temperature for 60 days. In regards to nutritional benefits, Compared to raw lentil, SCFX increased the radical scavenging activity of lentils by 18%. In addition, SCFX and increased extruder screw speeds increased the protein digestibility of the lentil flour. The SCFX process rendered red lentil flour into a snack-type whole grain product with a more balanced nutritional and antioxidant composition.

Technical Abstract: A powder blend comprised of lentil flour and pre-gelatinized potato starch was processed using supercritical fluid (carbon dioxide) extrusion (SCFX). The blend was extruded at temperature of 95-99.5 degrees C and screw speeds of 40, 80 and 120 rpm. The physical properties of the extruded products such as porosity, rehydration rate, expansion ratio, and crispness --improved as the screw speed increased. Furthermore, the density, water solubility index, brittleness, and hardness of the products decreased as the screw speed increased. SCFX increased the transition temperature of starch and protein in lentil flour. Increased screw speed led to increased gelatinization in the starch. Unlike traditionally cooked lentils, no retrogradation of starch was observed for the extruded red lentil products stored at room temperature for 60 days. Compared to raw lentil, SCFX increased the total phenolic and DPPH radical scavenging activity of lentils by 30% and 18%, respectively. In addition, SCFX decreased the trypsin inhibitor content in the lentil flour. Higher screw speeds led to a greater reduction in the trypsin inhibitor content. The SCFX process rendered red lentil flour into a snack-type whole grain product with a more balanced nutritional and antioxidant composition.