Table 5 Second order polynomial equation calculated by response surface methodology program on yield and total ginsenosides

Responses	Polynomial equation	R2	Significance	Lack of fit
Yield (%, Y1)	Y1 = 71.5013 - 19.5166X1 + 7.12453X2 + 1.96518X3 - 7.85676X12 + 5.20266X1X2	0.971	0.000	0.072
	-2.93469X22 + 1.53743X1X3 - 0.865563X2X3 + 3.62642X32
Total ginsenosides	Y2=9.6602-0.0236685X1 + 0.688243X2 + 0.84433X3 - 1.75861X12	0.846	0.018	0.664
(mg/g, Y2)	- 0.00852562X1X2 - 0.498489X22 + 0.889431X1X3 - 0.30844X2X3 - 0.30844X32