Optimization of an Extrusion Cooking Process to Increase Formation of Resistant Starch from Corn Starch with Addition of Citric Acid

• Published in: Die Stärke Vol. 72; no. 3-4
• Main Authors: Neder‐Suárez, David, Amaya‐Guerra, Carlos Abel, Pérez‐Carrillo, Esther, Quintero‐Ramos, Armando, Mendez‐Zamora, Gerardo, Sánchez‐Madrigal, Miguel Ángel, Barba‐Dávila, Bertha Alicia, Lardizábal‐Gutiérrez, Daniel
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.03.2020
• Subjects: ambient temperature; Citric acid; Cooking; cooking extrusion process; Corn; corn starch; dextrinization; Extrusion; Extrusions; gelatinization; hydrolysis; Infrared analysis; Moisture content; Optimization; resistant starch; Room temperature; Starch; Viscosity; Water absorption; Water content; water solubility; water uptake; X-radiation
• ISSN: 0038-9056; 1521-379X
• DOI: 10.1002/star.201900150

Effects of extrusion cooking process (ECP) with citric acid (CA) addition on the physicochemical changes and resistant starch (RS) formation in native corn starch (NCS) are evaluated. NCS at different feed moisture levels (18–32%) and CA concentrations (0–10.3%), are subject ECP under constant conditions of screw speed (233 rpm) and die temperature (127 °C). The obtained extrudates are stored at 4 °C for 120 h and then at room temperature. The water absorption index (WAI), water solubility index (WSI), RS content, peak temperature (Tp), ∆H, peak viscosity (PV), setback viscosity (SV), FT‐IR, X‐ray analysis and microstructural (SEM) properties are evaluated. RS content and WSI increased with decreasing moisture content (MC), WAI, PV and SV shows that increases in MC caused an increase, while ∆H and Tp decreases with decreasing MC. SEM shows that ECP with CA destroys the granular structure of NCS generated amorphous structures owing to gelatinization and dextrinization. FT‐IR analysis shows that extruded samples with CA cause starch hydrolysis, increasing the intensity of bands 994 and 1016 cm−1 in comparison to NCS. The highest RS yield (1.15 g/100 g) is obtained at 18% moisture content and 5.2% of CA: an increase of 71% with respect to NCS. The aims of this study are to evaluate and optimize the conditions of extrusion with addition of citric acid (CA) to determine their effects on physical, chemical, structural, rheological properties and resistant starch formation (RSF). It is found the highest RS yield reaches an increase of 71%. These results indicate that addition of CA during extrusion may be advantageous for RSF.