## 3 Results and Discussion
### Comparison of Antioxidant Activity  
The antioxidant activities of various camellia oils were evaluated using DPPH, ABTS, and FRAP assays, as depicted in Figure 7a-c. In the DPPH assay, C-C.O exhibited the highest antioxidant activity, with a value of 250.30 \(\upmu\)mol Trolox/mL (Figure 7a). Conversely, C. oleifera (C.O) demonstrated the highest activity in the ABTS and FRAP assays, with values of 249.99 \(\upmu\)mol Trolox/mL and 157.41 \(\upmu\)mol Trolox/mL, respectively (Figure 7b,c). These results underscore the significant influence of camellia oil varieties on their antioxidant capabilities [57], with C.O standing out as a notable source of bioactive compounds with high antioxidant potential. The presence of diacylglycerol (DAG) in DAG-enriched camellia oils (40% and 80%) derived from C-C.O resulted in notably lower antioxidant activities compared to other samples across all three assays (\(p<0.05\)). This implies that the formation of DAG, occurring during the enzyme-catalyzed reaction and molecular distillation process, may diminish the overall antioxidant efficacy of the oils.  
Camellia oil contains bioactive components, such astocopherol, squalene, and polyphenols, known for their antioxidant effects [10; 18; 24; 25; 26]. The correlations between these components and antioxidant activity in various camellia oils were explored in this study (Figure 7d). As anticipated, strong positive correlations were observed, particularly betweentocopherol and antioxidant activity, with coefficients of 0.90 (tocopherol and FRAP), \(>0.86\) (tocopherol and ABTS), and \(>0.83\) (tocopherol and DPPH) at \(p<0.01\). Furthermore, squalene exhibited a highly significant positive correlation with ABTS (\(r=0.80\); \(p<0.01\)), potentially explaining the high ABTS radical scavenging ability of C.G (Figure 7b), as its squalene content was significantly higher than that of other types of camellia oils (p \(<0.05\)) (Figure 4a). These results aligned with prior research highlighting the strong associations among vitamin E, squalene, and the antioxidant capacity of Camellia _spp._[16; 57]. For instance, [PERSON] et al. [16] reported a significant positive correlation of \(\alpha\)-tocopherol with DPPH (polar extract: \(r=0.977\); non-polar extract: \(r=0.754\); and whole oil: \(r=0.907\)), FRAP (\(r=0.972\)), and ABTS (\(r=0.821\)) at the 0.01 significance level. Interestingly, there were no significant correlations between total polyphenols and DPPH, ABTS, and FRAP (\(p>0.05\)). The above findings suggested that the antioxidant activities of camellia oils are heavily influenced by their bioactive components, especially topberol and squalene, highlighting the potential health benefits associated with these oils [16; 57]. Therefore, in the biosynthesis of DAG-enriched camellia oil, it is recommended to optimize process conditions, particularly the temperature, to maximize the retention of heat-sensitive tocopherols and polyphenols. This is crucial for enhancing the antioxidant activity of DAG-enriched oils and extending its shelf life.  
Figure 7: Antioxidant activity abilities of different types of camellia oils and correlated with their bioactive components. (**a**) DPPH radical scavenging abilities, (**b**) ABTS radical scavenging abilities, (**c**) FRAP abilities, and (**d**) correlations of between antioxidant activity abilities and bioactive components in different types of camellia oils. Mean values with different letters are significantly different from each other at \(p<0.05\). C.O, _C. oleifera_; C.S, _C. semiserrata_; C.G, _C. gauchowensis_; C-C.O, commercial _C. oleifera_; C-C-O-DAG (40%); commercial _C. oleifera_ diacylglycerol oil (40%); and C-C-O-DAG (80%), commercial _C. oleifera_ diacylglycerol oil (80%).