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Xinjiang is the main producing area of raisins and the largest green raisins production base in China. The browning of Thompson seedless grape raisin is extremely serious during the drying process, and has become the key issue in the development of Xinjiang raisin industry. Previous studies have shown that dehydration speed has a great impact on the browning of Thompson seedless grape, but few relevant mechanisms have been studied. Here, we demonstrate the effect of dehydration speed on lipid metabolism and its relation to the browning of the Thompson seedless grape during drying. Compared to slow dehydration treatment, rapid dehydration treatment of the Thompson seedless grape exhibited a lower degree of browning and activities of lipoxygenase (LOX), a higher index of unsaturated fatty acids and degree of unsaturated fatty acid. Moreover, the Thompson seedless grape treated with rapid dehydration resulted in a lower rate of superoxide anion production, hydrogen peroxide content, membrane permeability, and malondialdehyde content. These findings demonstrate that rapid dehydration inhibiting the browning of Thompson seedless grapes might be due to the inhibiting activities of LOX and the lower accumulation of reactive oxygen species. These activities can inhibit lipid peroxidation and slow the decomposition of unsaturated fatty acid in the membrane in Thompson seedless grapes, protecting the cellular membrane structural integrity, which may result in less contact of polyphenol oxidase with phenolic substrates and less enzymatic browning during drying. The results provide a theoretical basis for the application of rapid dehydration in drying Thompson seedless grapes. [ABSTRACT FROM AUTHOR]