Optimization of extraction parameters of PTP1β (protein tyrosine phosphatase 1β), inhibitory polyphenols, and anthocyanins from Zea mays L. using response surface methodology (RSM)

Table 4 Polynomial equations calculated using the RSM program for extraction conditions of Zea mays L.

Response variables	Second order polynomial equations^a	R²	p-value
Total polyphenol content (mg GAE/g)	Y_TPC = 12.967917 + 0.236917X₁ + 0.119583X₂-0.184667X₃-1.221042X₄-0.001699X₁₂-0.000781X₁X₂ + 0.021901X₂²-0.013988X₁X₃ + 0.003563 X₂X₃ + 0.012854X₃² + 0.16953X₁X₄²-0.021797X₂X₄-0.007281X₃X₄+ 0.029538X₄²	0.935	0.0001
Total anthocyanin content (mg C3GE/100 g)	Y_TAC = 412.389167 + 0.248000X₁ + 4.349167X₂-14.648667X₃-23.737500X₄-0.027356X₁₂-0.058562X₁X₂ + 0.341094X₂²-0.079975X₁X₃-0.072875X₂X₃ + 0.288875X₃² + 0.279406X₁X₄²-0.230156X₂X₄ + 0.099687X₃X₄ + 0.388867X₄²	0.917	0.0001
Extraction yield (%)	Y_EY = 29.279167-0.538500X₁-0.842500X₂-0.823000X₃-0.010833X₄ + 0.006002X₁₂-0.007188X₁X₂ + 0.059427X₂² + 0.004625X₁X₃-0.003125X₂X₃ + 0.010508X₃² + 0.004219X₁X₄² + 0.014844X₂X₄ + 0.003437X₃X₄-0.0077997X₄²	0.887	0.0001

^aX₁, extraction temperature (°C); X_2, extraction time (hour); X_3, solid-liquid ratio (%); X₄, solvent volume (1:X)

ISSN: 2662-7671