Abstract:

In order to investigate the effect of shellac coating treatment on volatile components in fruits stored at room temperature, the volatile components was harvested by dynamic head-space absorption trapping method from the intact fruits of Citrus reticulata Blanco (Ponkan) with shellac coating during the storage period of 10－40 days, and analyzed by thermal cryo-trappinggas chromatography/mass spectrometry (TCT-GC/MS). Results indicated that terpenes and their derivatives were the predominantly typical compounds among all volatile samples. Limonene, as the major component, was determined at low content of (10 ± 3)% in the control samples, which was probably due to a pre-experimental releasing peak during the storage period; however, the fruits with treatment of 6% and 12% bleached shellac coating exhibited a decrease in limonene content from 34.67% to 14.64% at the 10th day or from 40.83% to 11.69% at the 40th day. Therefore, shellac coating treatment was beneficial to the maintenance of characteristic aroma in citrus fruits. The slow-releasing effect of aroma components could be strengthened by increasing concentration of coating agent, and the membrane uniform could also be improved by adding auxiliaries such as nano-SiOx. On the other hand, there was a late peak of for the release of limonene, which demonstrated that the content of limonene was increased from 12.41% to 19.29% at the 10th day and from 10.30% to 35.16% at the 40th day.

Key words: Citrus reticulata Blanco (Ponkan), lac, coating preservation, volatile, thermal cryo-trapping—gas chromatography / mass spectrum (TCT-GC/MS)