Relationships between Tomato Maturity and Dielectric Parameters
Guodong Wang · Xibei zhiwu xuebao · 2008
With 'Jinpeng No.1' tomato fruit ranked 5 maturities as research materials,the relationships between 8 electric parameters and maturity were studied with the parallel-plate electrode system in the range of 126 Hz~5 MHz.Thus ideal electric indexes were screened to reflect fruit maturity.As a result,best appropriate range of testing frequency was among 500 kHz~5 MHz.Among the best appropriate range of testing frequency,with increasing of tomato maturity,complex impedance Z declined gradually,but relative permittivity e rose constantly.Furthermore,at the color turning term(TU) of tomato,loss coefficient d was at maximum but impedance phase angle θ was at minimum.It could be concluded that under the appropriate testing frequency,complex impedance Z and relative permittivity e were the proper electric parameters to judge tomato maturity,and loss coefficient d and impedance phase angle θ could be indexes to judge tomato color turning term(TU).