Wheat
flour was used as material to be extruded and made for koji of white soy sauce.
The glucoamylase activity of koji is regarded as the index. The effect of
different extrusion parameters on the glacoamylase activity of koji were
studied. By single factor experiment, the effect of the moisture content of
flour, screw speed, feeding spend and barrel temperature on the glucoamylase
activity were investigated. Then the extrusion parameters were optimized by
Response Surface Methodology (RSM). The results showed that the optimal glucoamylase
activity was 1293.49 U/gunder the following extrusion conditions,
including moisture content of 40%, screw speed of 100 r/min, feeding speed of
10kg/h, and barrel temperature of 80 °C. The koji of higher glucoamylase
activity was utilized to ferment and the brewing experiment of white soy sauce
was conducted by low-salt solid-state fermentation. After the end of
fermentation, the contents of amino acid nitrogen and reducing sugar were 0.65 g/100mL
and 243.25 mg/mL respectively in the white soy sauce. The white soy sauce
tasted sweet and showed good flavor.
SUN Yan et al
. Effect of extrusion on the glucoamylase activity of koji for white soy sauce[J]. Food and Fermentation Industries, 2017
, 43(12)
: 93
-98
.
DOI: 10.13995/j.cnki.11-1802/ts.014673