基于电子鼻检测‘霞晖5号’桃果实的冷害

Detection of Chilling Injury in “Xiahui No.5” Peach by Electronic Nose

为了建立桃果实冷害的无损检测方法，将桃果实于0、5℃条件下冷藏，通过对感官评分、理化指标的综合分析建立果实冷害等级的评价标准；采用PEN3电子鼻获取桃果实挥发性物质的传感器响应值，并利用气-质联用技术测定桃果实的气味变化。研究建议了桃果实冷害的4级分类标准：感官评分达90分以上为0级；感官评分在80-90分之间，出库后硬度正常降低的果实为1级；感官评分在70-80分之间，出库后硬度未正常降低的果实为2级；感官评分低于70分的果实为3级。利用Fisher判别建立的数学模型判别准确率为91．7％，果实发生冷害时青香型物质的相对含量增大，果香型物质的相对含量降低；仅在发生冷害的果实中检出的物质为十四烷、十六烷、十九烷，其相对含量随冷藏时问延长而增大，可作为监测桃果实冷害发生情况的特征气体。研究结果可为实现桃果实冷害的无损、快速检测提供参考。

A new method to detect chilling injury in peaches by electronic nose （E-nose） was developed. Changes in sensory evaluation score, browning index, total soluble solids, titratable acid, extractable juice rate and hardness of peach during cold storage were measured. The volatile compounds emanating from peaches were assessed by using an E-nose （PEN3） and gas chromatography-mass spectrometry （GC-MS）. The suggested chilling injury classification was as follows： grade 0, scores above 90; grade 1, scores between 80 and 90 and normal softening after warehouse storage; grade 2, scores between 70 and 80 and fruits not normally softened after warehouse storage; and grade 3, scores below 70. The accuracy of the Fisher mathematical model was 91.7%. The relative content of grass-type flavor compounds increased along with increasing severity of chilling injury, whereas the relative content of fruit-type flavor compounds decreased. Tetradecane, hexadecane and nonadecane were found only in peaches with chilling injury, and their relative contents increased with storage time, indicating that they may be characteristic odor compounds of peach with chilling injury. The results obtained from this study could provide references for rapid and nondestructive determination of chilling injury in peach.