Influence of different deastringented method on the quality of the millstone persimmon

Studies on de-astringent of Gansu zhouqu millstone persimmon were carried out by four treatment methods(with alcohol,lime water,CO2,and warm water).In addition,the quality of de-astringent Gansu zhouqu millstone persimmon was researched. After de-astringency,soluble tannin content,soluble solids content,fruit firmness,elasticity,cohesion,chewiness of Gansu zhouqu millstone persimmon fruits were assessed at 0,24,48,72,96,120,144,168 h. Results showed that the persimmons were effectively de-astringent by four treatment methods(with alcohol,lime water,CO2,and warm water) and using warm water to treat persimmon for 48 h,the persimmons were completely de-astringent,while using alcohol,CO2,lime water to treat persimmon for 96,96,120 h,soluble tannin content of Gansu zhouqu millstone persimmon fruits was lower than the taste threshold.Fruit firmness had a great difference by four treatment methods on de-astringent,which the fruit firmness using alcohol,lime water,CO2 were higher than using warm water. But the method of warm water caused the flesh browning of persimmon and lime water on the surface of persimmon was residual. Further work was required to explore the optimal de-astringent condition of millstone persimmon by CO2.