Titratable acidity and pH
Aliquots (10 mL) of potato juice were diluted with
40 mL of distilled water and titrated with 0.1 N
NaOH, beyond pH = 8.2. This potentiometric titration
was performed with a pH meter Crison, Model Micro
pH 2002 (Crison Instrument, S.A., Barcelona, Spain).
The results were calculated as a percentage of malic
acid [(ml NaOH*0.1 N/mL sample titrated)*100].The pH was measured in the juice of the crushed
potato before pH determination, using a pH meter
Crison, Model Micro pH 2002 (Crison Instrument)
which had been previously standardized to pH 4 and
pH 7, and a xerolyt electrod Ingold Lot 406-MG-DXK-
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