Table 2. Polynomial equations calculated by RSM program for reducing residual patulin content and maintaining polyphenolics in apple juice

Response variables	Second order polynomials1)	R2	Significance
Residual patulin content	Y1 = 728.088621 + 1.986810X1 − 827.846840X2 − 22.801698X3 − 0.018315X12 − 1.023421X1X2 + 347.422072X22 − 0.102468X1X3 − 1.458808X2X3 + 0.949145X32	0.9163	0.0126
Polyphenolics content	Y2 = 11.333125 + 0.077562X1 + 0.40125X2 − 0.098375X3 + 0.000875X12 − 0.04825X1X2 − 0.011X22 − 0.002325X1X3 + 0.0375X2X3 − 0.0003X32	0.9026	0.0191

X₁, storage temperature (°C); X₂, irradiation dose (kGy); X₃, storage period (day).