Effects Of Drying Conditions On Aroma Components And Quality Of Chinese Jujube

In order to explore the effects of drying conditions on aroma quality, main nutrition quality and physical properties of Chinese jujube, and search method to evaluate the quality of dried Chinese jujube and provide technical and theoretical support for Chinese jujube industry, SPME/GC-MS(Solid phase micro-extraction coupled with gas chromatography mass spectrometry) technique and other analytical methods were applied to analyze aroma compounds, main nutrition and physical properties of five treated treatments (50,60,70℃hot-air drying, natural drying and Tangxin jujube). The results are as follows:1 , SPME/GC-MS techniques were applied in isolation and identification aroma compounds of five treated Chinese jujube samples. Respectively, 55,53,51,50 and 52 kinds of volatile compounds were identified from Chinese jujube at 50,60,70℃hot-air drying, natural drying and Tangxin jujube, and each kind of results took up 96.20%, 97.84%, 96.02%, 97.40% and 95.93% of total peak area respectively. Acids, aldehydes, ketones, esters, alcohols, alkanes and a few other compounds existed in the volatile compounds. Principal component analysis (PCA) was adopted to investigate the main aroma compounds form Chinese jujube. The results showed that aroma quality was strongly affected by esters, aldehydes, acids and phenol. Hot-air drying method could improve aroma quality effectively, aroma quality of hot-air drying at 60℃was better than that at 50,70℃hot-air drying, natural drying and CK. Evaluation of aroma quality and distinction of drying conditions were achieved with PCA method.2,The main nutrition was significantly influenced by drying conditions. Hot-air drying (50,60 and 70℃) were significantly influence on VC, reducing sugar, acid, phenolic and flavonoids compounds (P<0.05). Hot-air drying and natural drying have very significantly influence on the content of main nutrition, including VC, acids, reducing sugars and flavonoids (P<0.01). The main nutrition quality between dried Chinese jujube and CK was very significantly difference (P<0.01).3,The physical properties was significantly influenced by drying conditions. Hot-air drying were significantly influence on Hardness, Adhesiveness, Springiness, Chewiness and L value (P<0.05). Hot-air drying and natural drying have very significantly influence on Adhesiveness, Chewiness and L value (P<0.01), significantly influence on Springiness and L value (P<0.05) and no significantly influence on Cohesiveness. The physical properties between dried Chinese jujube and CK were very significantly difference (P<0.01).The present study shows that drying conditions exhibited strongly influence on aroma components, nutritional quality and physical properties of Chinese jujube. Evaluation of aroma quality and distinction of drying conditions were achieved with PCA method, providing ideas to establish a system of the evaluation. Effects of drying conditions on the nutrition and physical properties, as well as the quality evaluation of Chinese jujube need to be further studied.