3.3. Optimizing the extraction conditions of capsaicinoids or red
colorants by orthogonal array design
For further optimizing the conditions of stage extraction of
capsaicinoids and red pigments, respectively, a group of orthogonal
experiment with four different parameters and three levels
for each variations including the concentration of ethanol, the
ratio of solvent to material, the extraction temperature and
extraction time, were designed on the basis of single-factor experiments
as shown in Table 1. And the experimental results were
displayed in Fig. 5.
From Fig. 5(A), the relative contents of capsaicinoids in the
extracted solution showed significant variation for nine experiments.
The yield of capsaicinoids in group 3 was higher than those
of other groups, which showed an about 3.4-fold difference when
compared to the lowest group (i.e., group 1).