Time and temperature of extraction are important parameters
to be optimised even in order to minimise energy cost of the process
(Spigno, Tramelli, & Faveri, 2007). In ASE 300 instrument, the
temperature is controllable between 40 and 200 C in increments
of one degree. Temperature was evaluated at three factor levels
(40, 65, and 90 C) while keeping other independent variables as
constant. The maximum responses were observed at 40 C (Fig
1b). Optimum temperature was selected at 40 C since an increment
in the temperature level resulted in the decrease of the
two responses. This could be attributable to the possible degradation
of pomegranate peel polyphenols at temperatures above 40 C.
In addition, extracts were cloudy and dark at above 40 C. The extent
of cloudiness and darkness increased with temperature. Similar
observations were reported from extraction of apple
polyphenols (Alonso-Salces et al., 2001).
3.3