# Evaluation of Different Drying Methods on the Quality Parameters of _Acanthopanax semicosus_ Fruits
## 3 Results  
### Color Properties  
Color is a key quality indicator influencing consumer acceptability of food products [24]. Different drying methods result in variations in color, typically assessed using L*, a*, and \(\Delta\)E. The results indicate significant differences in these parameters across drying methods, as shown in Table 1.  
VFD-treated samples exhibited the highest L* value (33.56 \(\pm\) 0.23) and the lowest \(\Delta\)E (1.88 \(\pm\) 0.33), indicating superior color preservation. The sublimation process under low temperature and pressure minimizes enzymatic oxidation and pigment degradation, effectively preventing browning. The low a (0.52 \(\pm\) 0.02) and b (-3.33 \(\pm\) 0.21) values further confirm VFD's effectiveness in preventing color deterioration. Studies have demonstrated that freeze-drying retains bioactive compounds and reduces color changes more effectively than other drying methods [25; 26]. HD-treated samples had the lowest L* value (22.66 \(\pm\) 0.56) and the highest \(\Delta\)E (11.11 \(\pm\) 0.50), indicating significant darkening and color  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Sample Code** & **HD** & **VD** & **ND** & **MD** & **VFD** & **Fresh Fruit** \\ \hline L* & 22.66 \(\pm\) 0.56  & 30.36 \(\pm\) 0.26  & 26.92 \(\pm\) 0.18  & 27.41 \(\pm\) 0.22  & 33.56 \(\pm\) 0.23  & 32.01 \(\pm\) 0.16  \\ a* & 4.91 \(\pm\) 0.10  & 1.25 \(\pm\) 0.10  & 3.17 \(\pm\) 0.15  & 2.18 \(\pm\) 0.14  & 0.52 \(\pm\) 0.02  & -1.12 \(\pm\) 0.04  \\ b* & \(-\)7.11 \(\pm\) 0.03  & -4.37 \(\pm\) 0.19  & -6.42 \(\pm\) 0.08  & -6.38 \(\pm\) 0.05  & -3.33 \(\pm\) 0.21  & -2.45 \(\pm\) 0.11  \\ a*/b* & \(-\)0.69 \(\pm\) 0.01  & -0.29 \(\pm\) 0.03  & -0.49 \(\pm\) 0.02  & -0.34 \(\pm\) 0.02  & -0.16 \(\pm\) 0.01  & 0.46 \(\pm\) 0.02  \\ \(\Delta\)E & 11.11 \(\pm\) 0.50 [FOOTdegradation. [PERSON] et al. (2020) reported that hot-air drying caused a substantial decrease in L* and an increase in \(\Delta\)E, confirming severe color deterioration [PERSON] et al. (2020). ND-treated samples maintained a relatively high a value (3.17 \(\pm\) 0.15), suggesting that low-temperature air drying preserved anthocyanins to some extent. However, an \(\Delta\)E value of 6.77 \(\pm\) 0.26 indicates moderate color changes due to prolonged drying exposure. VD-treated samples exhibited a relatively high L* (30.36 \(\pm\) 0.26) and a low \(\Delta\)E (2.53 \(\pm\) 0.20), reflecting the protective effects of vacuum conditions in reducing oxidative degradation. MD-treated samples showed moderate L* (27.41 \(\pm\) 0.22) and an intermediate \(\Delta\)E (6.14 \(\pm\) 0.24), indicating that rapid internal heating limited excessive color loss but still caused some pigment degradation. MD-treated samples exhibited moderate L* (27.41 \(\pm\) 0.22) and an intermediate \(\Delta\)E (6.14 \(\pm\) 0.24), indicating that rapid internal heating prevents excessive color loss but still induces some pigment degradation. The moderate a value (2.18 \(\pm\) 0.14)* and b value (\(-\)6.38 \(\pm\) 0.05)* suggest that some anthocyanin loss and browning reactions occurred during microwave processing. Drying methods not only affect fruit moisture content but also play a crucial role in the retention of bioactive compounds and antioxidant activity. ND-treated samples retained the highest moisture content (14.97 \(\pm\) 0.12%), consistent with previous findings [PERSON] et al. (2020). While ND reduces thermal degradation, prolonged exposure to air and oxygen leads to polyphenol and vitamin C degradation [PERSON] et al. (2020). HD (9.48 \(\pm\) 0.02%) and VD (8.54 \(\pm\) 0.12%) showed moderate water removal efficiency, but their effects on bioactive compound retention varied significantly. High temperatures accelerate moisture evaporation but also degrade antioxidants [PERSON] et al. (2020). Vacuum drying enables lower-temperature dehydration, reducing thermal degradation, although its water removal efficiency is lower than MD and VFD.