(a) Pineapple peel (PP) |
---|

Coefficient | Ferulic acid | NFPC |
---|

Yield | Recovery | Yield | Recovery |
---|

Coefficient^{a} | *p*-value^{b} | Coefficient^{a} | *p*-value^{b} | Coefficient^{a} | *p*-value^{b} | Coefficient^{a} | *p*-value^{b} |
---|

Linear |

β_{1} | + 184.17 | 0.01 | + 0.72 | 0.27 | + 0.86 | < 0.00 | − 7.99 | < 0.00 |

β_{2} | − 115.91 | 0.06 | + 0.37 | 0.55 | + 0.13 | 0.13 | + 1.65 | 0.02 |

Quadratic |

β_{11} | − 64.00 | 0.01 | − 0.35 | 0.13 | − 0.32 | < 0.00 | + 1.16 | 0.09 |

β_{22} | − 79.11 | < 0.00 | − 0.73 | 0.01 | + 0.17 | 0.06 | + 1.39 | 0.05 |

Cubic |

β_{111} | − 12.69 | 0.69 | − 0.64 | 0.14 | – | – | – | – |

β_{222} | + 126.47 | 0.01 | + 0.38 | 0.34 | – | – | – | – |

Interaction |

β_{12} | − 127.35 | < 0.00 | − 1.42 | < 0.00 | − 0.21 | 0.08 | − 2.50 | 0.01 |

(b) Pineapple crown leaves (PCL) |
---|

Coefficient | Ferulic acid | NFPC |
---|

Yield | Recovery | Yield | Recovery |
---|

Coefficient^{a} | *p*-value^{b} | Coefficient^{a} | *p*-value^{b} | Coefficient^{a} | *p*-value^{b} | Coefficient^{a} | *p*-value^{b} |
---|

Linear | |

β_{1} | + 65.28 | < 0.00 | − 0.70 | 0.07 | + 0.98 | < 0.00 | − 6.23 | < 0.00 |

β_{2} | + 62.39 | < 0.00 | + 1.92 | < 0.00 | + 0.02 | 0.76 | + 0.59 | 0.49 |

Quadratic | |

β_{11} | − 5.84 | 0.13 | − 0.44 | 0.01 | − 0.28 | < 0.00 | − 1.46 | 0.14 |

β_{22} | + 5.51 | 0.14 | + 0.19 | 0.13 | − 0.07 | 0.23 | − 1.44 | 0.14 |

Cubic | |

β_{111} | + 20.78 | 0.02 | + 0.82 | 0.01 | – | – | – | – |

β_{222} | − 37.55 | < 0.00 | − 1.07 | < 0.00 | – | – | – | – |

Interaction | |

β_{12} | − 31.82 | < 0.00 | − 0.93 | < 0.00 | − 0.04 | 0.57 | − 1.35 | 0.28 |

- Note:
^{a}Coefficient indicates the regression constant of the linear, quadratic, cubic and interaction terms in the polynomial equation that explain the relationship between substrate concentration (X_{1}) and treatment time (X_{2}) with the yield and recovery of ferulic acid (Y_{1}, Y_{2}) and NFPC (Y_{3}, Y_{4}) ^{b}*p*-value lower than 0.05 indicate that the effect of the term on the yield and recovery of ferulic acid and NFPC are significant at 95% confidence interval. *p*-value lower than 0.01 indicate that the effect of the term on the yield and recovery of ferulic acid and NFPC are significant at 99% confidence interval