The measurement of pH of cocoa beans followed the protocol of
Senanayake et al. (1997). For pulp pH, 10 whole cocoa beans with attached
pulp were shaken in 100 ml of MiliQ water for 15 min. The
beans were separated by decanting and the pH of the supernatant was
measured using a digital pH meter. For nib pH, the shells of the whole
beans were peeled to obtain the nibs (cotyledons) which were then
ground in a BCG300 grinder (Breville, Sydney, Australia). Aliquots
(10 g) of the ground sample were stirred in 100 ml of MiliQ water for
15 min and the pH of the supernatant was measured as described
previously.