Influence of different drying methods on the quality of the slices of Zizyphus jujuba

To study the influence of different drying methods on quality of the slices of Zizyphus jujuba, the volume density, rehydration characteristics, the total content of ketones and phenols, the colour and the volatile components were analyzed respectively.The results showed that rehydration characteristics, the total content of ketones and phenols, and the total number of volatile components were maximum in slices by FD. Meanwhile, there was no significant difference between the brightness ( 61.92 ± 0.44) and chromatic aberration ( 0.67 ± 0.14) and that of control. However, the off-flavor component ( acetic acid) content was so high ( 41.55% ± 4.64%) . There were significant differences in total content of ketones and phenols between IMVD and CMVD ( p < 0.05) . The brightness increased by 2.39 and chromatic aberration fall by 2.68 of the slices by IMVD compare to CMVD due to the excessive thermal treatment. It could easily lead to oxidation and degradation by HAD, IR and IMD, so the total content of ketones and phenols and the number of volatile components fall beyond 55% with producing offflavor components such as furfuralcohol and furfural.The brightness of slices falled to 51.79.Nevertheless, the three drying methods could improve intensity of redness and control formation of acetic acid.So it can develop compound-drying technology to realize advantageous complementarities.It provided basic data for further study on drying methods of the slices of Zizyphus jujuba.