Table 3.
Polynomial equation calculated for chemical composition of air-classified fractions of wheat bran.

Response1)		The second order polynomial2)	R2
Fine fraction	Crude protein (%)	Y1=14.93+0.007X3+0.000001X12-0.000009X32	0.577
	Crude Ash (%)	Y2=4.20+0.000822X1-0.001X2+0.00087X3-0.0000001X12-0.000002X32	0.810
	Crude fat (%)	Y3=2.68+0.000522X1+0.001365X2+0.00183X3-0.000001X12-0.000001X22-0.000003X32	0.818
	Total starch (%)	Y4=-19.3+0.0299X2-0.0141X3-0.000003X1X2+0.000008X2X3	0.863
Coarse fraction	Crude protein (%)	Y5=11.22-0.00144X1+0.00157X2-0.000001X1X3	0.832
	Crude ash (%)	Y6=6.76-0.001931X1+0.00089X2+0.00039X3+0.000001X12	0.800
	Crude fat (%)	Y7=-1.83+0.001710X1	0.487
	Total starch (%)	Y8=-17.1+0.00745X2-0.0031X3-0.000001X12+0.000001X1X2	0.800

Y₁:Crude protein of fine fraction (%), Y₂:Crude ash of fine fraction (%), Y₃:Crude fat of fine fraction (%), Y₄:Total starch of fine fraction (%), Y₅:Crude protein of coarse fraction (%), Y₆:Crude ash of coarse fraction (%), Y₇:Crude fat of coarse fraction (%), Y₈:Total starch of coarse fraction (%).
X₁: Mill speed (rpm), X₂: Separator reverse wheel speed (rpm), X₃: Air classifier reverse wheel speed (rpm).