# Evaluation of Different Drying Methods on the Quality Parameters of _Acanthopanax semicosus_ Fruits
## 3 Results
### Correlation Analysis of Physicochemical Properties, Bioactive Compounds, and Antioxidant Activity
#### 3.9.1 Color Parameters  
As shown in Figure 5, L* was strongly positively correlated with b and a*/b* (r = 0.98, \(p<0.001\)), suggesting that brighter samples retained more yellow pigments, possibly due to lower carotenoid degradation. A similar trend has been validated in other studies. For example, [PERSON] et al. (2019) investigated the drying process of Japanese quince and found that freeze-drying effectively reduced carotenoid degradation, maintaining a higher level of yellow pigments [44]. Conversely, L* was negatively correlated with a* (r = \(-0.99\), \(p<0.001\)), indicating that increased brightness was associated with reduced redness, likely due to anthocyanin degradation or lower Maillard reaction intensity. This result is consistent with the finding on the blueberry drying process, which demonstrated that  
Figure 5: Correlation heatmap illustrating Pearson correlation coefficients among quality parameters, bioactive constituents, and antioxidant activities in AS fruit samples subjected to different drying methods.  
freeze-dried samples exhibited a higher anthocyanin retention rate and a lower reduction in redness compared to hot-air-dried samples [61].  
a* was negatively correlated with b and a*/b* (r = \(-\)0.97, \(p\) < 0.01), meaning redder samples exhibited reduced yellowness, likely due to polyphenol oxidation. A similar trend was also observed in a study by [PERSON] et al. (2020), which reported that different drying methods had a significant impact on the color parameters of cherry laurel fruit. Specifically, freeze-drying was found to better preserve the red hue, whereas hot-air drying was more prone to anthocyanin degradation [62]. Furthermore, a was strongly and positively correlated with \(\Delta\)E (r = 0.99, \(p\) < 0.01) and protocatechuric acid (r = 0.90, \(p\) < 0.05), indicating that samples undergoing greater color changes exhibit increased red intensity and higher levels of protocatechuric acid. This finding suggests that drying-induced oxidation or polymerization of phenolic compounds plays a critical role in color development.  
b* was negatively correlated with \(\Delta\)E (r = \(-\)0.98, \(p\) < 0.05) and protocatechuric acid (r = \(-\)0.96, \(p\) < 0.05), indicating that greater color shifts corresponded to lower yellow intensity, possibly due to carotenoid degradation. The lack of significant correlation between b and antioxidant capacity (DPPH, ABTS) suggests that yellow pigments contribute minimally to antioxidant activity. [PERSON] et al. (2021) investigated the drying process of pomegranate seeds and found that freeze-drying effectively minimized carotenoid degradation while maintaining superior color stability. In contrast, hot-air drying and microwave drying resulted in more pronounced losses of yellow pigments [63]. The a/b ratio, positively correlated with L* and negatively correlated with b*, reflects a shift from yellow to red while increasing overall brightness.** This metric may serve as an indicator of pigment composition changes, particularly the balance between polyphenol oxidation and Maillard reaction byproducts.