油桃采后结合态香气变化规律及其与可溶性糖的关联性

以‘瑞光1号’油桃为研究对象，研究其采后常温（20 ℃）和低温（1 ℃）贮藏下游离态和结合态香气物质变化规律。采用酶解法释放结合态香气物质，利用顶空固相微萃取法结合气相色谱-质谱联用对油桃游离态和结合态香气物质分别进行定性和定量分析，并研究结合态香气物质与可溶性糖之间的相关性。结果表明，油桃果实常温和低温贮藏条件下游离态和结合态香气物质种类存在很大差异。常温贮藏下检测到油桃中游离态香气物质37 种，结合态香气物质30 种，其中8 种物质以游离态和结合态2 种形式存在。游离态香气物质第4天下降至最低值后第6天有所上升，第8天含量有所下降，结合态香气物质第6天降至最低值后第8天有所上升。低温贮藏下检测到游离态香气物质21 种，结合态香气物质32 种，其中7 种物质以游离态和结合态2 种形式存在。随着低温贮藏时间延长，游离态香气物质含量下降，结合态香气物质呈现先上升后下降的趋势。相关性分析表明结合态香气物质含量与果实中可溶性糖含量之间显著相关，与蔗糖的相关系数最高。

Changes of Bound Aroma Compounds and Their Relationship between Soluble Sugars in Nectarines during Postharvest Storage

Changes of free and glycosidically bound aroma compounds in‘Ruiguang 1’nectarines were investigated during postharvest storage at room temperature(20℃)or low temperature(1℃).Enzymatic hydrolysis was used to release the bound aroma compounds.Headspace solid-phase microextraction(HS-SPME)combined with gas chromatographymass spectrometry(GC-MS)was used for qualitative and quantitative analysis of the free and bound aroma compounds in nectarines.The correlation between bound aroma compounds and soluble sugars was studied.Results showed that the compositions of free and bound aroma compounds were significantly different in nectarines stored at 20℃and 1℃.In nectarines storage at 20℃,a total of 37 free aroma compounds and 30 bound ones were identified,of which,8 compounds were detected in both free and bound forms.The free aromas decreased until day 4 and then increased until day 6 but decreased again on day 8.The bound aromas decreased to the minimum on day 6 then increased on day 8.In nectarines stored at 1℃,a total of 21 free aroma compounds and 32 bound ones were identified,of which,7 compounds existed in both free and bound forms.The free aromas decreased with storage time,while the bound aromas increased at the beginning and then decreased.Correlation analysis showed a significant correlation between the bound aromas and the soluble sugars,especially sucrose,showing the highest correlation coefficient.