Then, other single-factors including the ratio of the solvent to
material, the extraction temperature and the extraction time were
further investigated in order to optimize the extraction conditions
of capsaicinoids from FRPs, respectively. The results were shown in
Fig. 4(A). The extraction yields of capsaicinoids were firstly
increased with ascending ratio of solvent to material in the range of
2e4 mL/g and got to a high yield at 4 mL/g and then changed
smally. Similarly, they were firstly increased with an extended time
in the range of 0.5e2.0 h and got to a high yield at 2.0 h of extractive
time, and then changed smally. But, they increased all along with
the increase of the temperature of water bath and got to the best
yield at 90 C. Therefore, the optimal conditions for extraction of
capsaicinoids from FRPs by single-factor experiments were summarized
as follows: the ratio of solvent to material of 4 mL/g, the
temperature of water bath at 90 C and extractive time in 2.0 h.