Study On Impedance Spectroscopy, Near-infrared Spectral Characterization Of Cucumber Under Different Storage Methods

This research subject was aimed at study the relationship between impedance spectroscopy characteristic, respiration, conductivity, near-infrared spectroscopy, total soluble sugar, soluble protein, vitamin C and water loss under different conditions.The results showed that:the change variation of impedance spectrum characteristic with the loss of water was different under different storage conditions. At room temperature, the Rp began to increase from the second day with the degree of water loss gradually deepened; the Cp began to decrease from the third day. Under the condition of plastic wrap, the Rp of cucumber changed little at the first four days, but increased significantly at the fifth day, then became equilibrium state. Under the condition of refrigerated, the Rp increased during the first three days; but, from the fourth day it decreased with moisture loss. The change of characteristic frequency was also different. By comparison different varieties of cucumber’s impedance characteristic, found that, we could compare their water-retention and freezing capacity.The relative conductivity changed greatly by refrigerated from the third day. It changed little under the condition of refrigerated and plastic wrap. The breathing intensity changed greatly at room temperature from the fourth day. At this time, the quality of cucumber had changed, and even became decay. Under refrigeration the respiration intensity decreased from the sixth day.The near-infrared spectra of cucumber under different storage conditions changed differently. The absorption peak decreased with the extension of storage time. At room temperature, the absorption peak changed most than other two conditions. It drop at the beginning then lift by refrigerated.The three nutrients:soluble sugar, soluble protein and vitamin C’s trend were basically same, and linearly with the loss of water.It was proved that it was practicably to react the quality changes of cucumber through impedance spectroscopy parameters, the correlation coefficients were:-0.941*,-0.967*,-0.913*(*:at0.05level was significantly related)...