Quadratic orthogonal rotation combination design for Monascus pigments by solid fermentation of Monascus purpureus
Based on the primary studies on the solid fermentation by Monascus purpureus with rice,the fermentation techniques of Monascus pigments were optimized by quadratic regression orthogonal rotary tests.The quadratic orthogonal regression model is of Monascus pigments color value(Y) to five factors of temperature(X1),moisture content(X2),inoculation(X3),concentration of alcohol(X4) and time(X5) established as:Y=1542.3472-134.5833X1-94.4167X3-148.66667X5-83.2708X12+137.8542X22+89.9792 X42-171.6458X52-140.6250X3X5,It was concluded from the the optimal extraction that when temperature,moisture content,inoculation,concentration of alcohol and time are 31 ℃,42%,12%,0.7% and 8 d,respectively,the Monascus pigments color value(Y) is the maximal 1598 U/g and consistent with the confirmatory experiment result.