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Physicochemical properties of extruded germinated wheat and barley as modified by CO 2 injection and difference extrusion conditions
Author(s) -
Singkhornart Sasathorn,
Gu BonJae,
Ryu Gi Hyung
Publication year - 2013
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2012.03186.x
Subject(s) - extrusion , phytic acid , germination , chemistry , food science , water content , protease , glucan , expansion ratio , plastics extrusion , moisture , absorption of water , agronomy , materials science , biochemistry , enzyme , composite material , organic chemistry , biology , geotechnical engineering , engineering
Summary Germinated wheat and barley were extruded with a pilot‐scale corotating twin‐screw extruder under different barrel temperatures (100 and 120 °C), feed moisture content (30 and 35%) and CO 2 injection. The effect of germination, barrel temperature, feed moisture content and CO 2 injection on physical properties, proximate composition, γ‐aminobutyric acid, β‐glucan, phytic acid and protease activity was investigated. Results indicated that the barrel temperature, moisture content and CO 2 injection significantly affected water absorption index ( WAI ), water‐soluble solid index ( WSI ), specific length, expansion ratio, bulk density, mechanical properties and colour of all extruded products ( P < 0.05). Extrusion process significantly decreased γ‐aminobutyric acid and protease activity in extruded germinated wheat ( EGW ) and barley ( EGB ) products (with and without CO 2 injection). However, extrusion process (with and without CO 2 injection) increased β‐glucan in EGB and decreased phytic acid in EGW . The content of proximate composition, γ‐aminobutyric acid, β‐glucan, phytic acid and protease activity was slightly affected by CO 2 injection.