*3.2. Influence of the Extraction Parameters on TAC*

This study aimed to find the best parameters for extracting anthocyanins from red onion skins. The TAC ranged from 0.45 to 1.43 mg C3G/g DW, based on the experimental design (Table 2). Subsequently, from Table 3, it was noticed that for TAC, a Model F-value of 868.48 implied the model was significant, and *p*-values less than 0.05 implied that the model terms were significant. The ANOVA revealed that the significant model terms were B, D, AB, AD, A2, B2, C2, and D2. Only a 0.01 variation in TAC could not be explained by the existing model, according to the determinant coefficient of R<sup>2</sup> = 0.99. Moreover, the predicted R2 of 0.98 agreed with the adjusted R2 of 0.99.
