2.2.3. Acid hydrolysis
The first 25 ml of 0.5%e2.5% (v/v) diluted sulfuric acid was
added to the insoluble component from pretreatment steps. The
fruit peels were hydrolysed in the reactor between 70 and 110 C for
10e30 min as the experimental design required. After hydrolysis,
pH adjustment was carried out with 1 M NaOH until the pH reached
a pH of 7. Insoluble particles were separated from the hydrolysate
by filtration. The soluble component was then added with the
previously filtered solution from the pretreatment step for the next
procedure [18]