Drying methods affect organoleptic and physicochemical properties of rehydrated ginkgo seed slices

Fresh Ginkgo biloba L. seeds (GBS) contain toxic compounds that are deleterious when consumed frequently, but the drying process can reduce its content. In this study, fresh GBS was rehydrated using two steps: dried using different methods (freeze-drying, infrared drying, hot-air drying, and pulse-vacuum drying) followed by rehydration by submerging into water. The influence of drying methods on rehydration kinetics and quality attributes were evaluated. Results showed the Weibull model provided the best fitting for each rehydration curve (Coefficient of determination (R2) > 0.99, residual sum of squares (RSS), reduced chi-square (χ2), and root mean square error (RMSE) closer to zero). Toxic compounds (ginkgotoxin, ginkgolic acid, and cyanide) decreased significantly while total phenolic content (TPC) and total flavonoid content (TFC) increased in rehydrated products compared with fresh GBS. The sensory score was acceptable for all rehydrated products. Besides, rehydrated products showed retention of antioxidant activities and the formation of Maillard reaction products (MRP). Amongst rehydrated products, infrared drying coupled to rehydration stood out being superior with higher TPC, TFC, MRP, and antioxidant activities and lowest enzyme activities, which were again corroborated from the principal component analysis. The present findings will offer more information in selecting the best drying method for GBS's rehydration as a snack, breakfast, or others.