The pH values of deep-fried and microwave-puffed shrimp
chips were 6.48 and 6.46, respectively. The addition of 0.5%
calcium lactate, calcium citrate, or calcium acetate to the
shrimp chip formulation significantly decreased pH in puffed
shrimp chips produced by deep-frying and microwave puffing.
However, the addition of calcium carbonate did not affect the
pH of shrimp chips, probably because the amino group reacted
with a carbonyl source in cassava starch during Maillard reaction,
resulting in elimination of water. Hydrogen ions were
released by Amadori rearrangement, which decreased the pH
of shrimp chips. Clawson and Taylor [24] reported that the pH
of two ground wheat samples, cooked in sealed glass ampoules
for 70 minutes at 121C, decreased from the initial
values of 6.12 and 7.81 to 5.88 and 6.32, respectively. Hamlet
and Sadd [25] found that pH dropped from 5.91 to 4.73 in a
pressure-cooking apparatus where basic flour, water, and salt
dough chips were cooked at 180C for 20 minutes.