Effects of drying methods on drying characteristics, quality and antioxidant content substances of Akebia Trifoliata

Providing a theoretical basis for the development of production processes for dried Akebia Trifoliata. Taking Akebia trifoliata as the research object to comparatively analyze the effects of three drying methods, heat pump drying（HPD), microwave vacuum drying（MVD), and heat pump-microwave vacuum combined drying（HPD-MVD）on the drying characteristics, drying quality, and antioxidant substance content of Akebia Trifoliata. The results show that the time for HPD, MVD, and HPD-MVD to reach the drying end point is 330, 24, 102 min respectively, among which HPD-MVD has the highest effective moisture diffusion coefficient（D_eff=1.09×10⁻⁶). The drying kinetics fitting results indicated that the Page model provided the best fit for the HPD and MVD groups（Adj.R²＞0.99), while the HPD-MVD group showed the highest degree of fit with the Wang and Singh model（Adj.R²=0.965). In terms of quality, the HPD-MVD group exhibited a bright color with the highest L* value and the lowest a* and b* values, superior rehydration properties compared to the MVD group, and the highest contents of total sugars, crude protein, total amino acids, and most mineral elements（Fe, Cu, Ca etc.). Regarding antioxidant substances, the total phenolic and total flavonoid contents of the HPD-MVD group were increased by 83.3% and 43.7% respectively, compared to the HPD group. In summary, HPD-MVD can significantly improve the drying efficiency of Akebia Trifoliata while bettering the quality of the dried product.