Infrared spectra of walnut seed under different storage conditions

Abstract: 【Objective】To study the effects of key factors on walnut(Juglans regia L.) seed storage life and the appropriate storage conditions,and to develop an efficient,fast,safe method to measure the chemical changes of walnut under different storage conditions.【Methods】Three kinds of walnuts with different physical and chemical quality were selected,and the storage condition included temperature(-20 ℃,4 ℃,15 ℃),seed moisture content(4%,8%,12%) and walnut type. L18(37) orthogonal design table was involved in experiment. Fourier transform infrared spectrometer was used to measure the walnut seeds under different storage conditions,and the infrared spectra similarity,the reduction of characteristic peak area of fat and carbohydrate were used as the index of oxidative rancidity. The optimum storage conditions were determined by extreme difference analysis.【Results】The results showed that temperature was the key factor affecting the storage longevity of seeds,and 4 ℃ was the optimal temperature with seed moisture content of 8%; there was a certain relationship between the storage life and walnut seed physicochemical quality.【Conclusion】The appropriate storage temperature and water content for walnut storage should be determined according to the physical and chemical quality of walnut.. Fourier transform infrared spectrometer could be used as a method for fast,efficient,direct determination of chemical composition and relative content of walnut seed. The results of this study could provide a certain theoretical basis for the preservation of walnut germplasm.