2.4.2. pH, color andfirmness
The pH was determined with a pH-meter equipped with a penetration electrode (Crison PH 25, Spain). TheL*,a* andb* color
coordinates were recorded with a Minolta spectrophotometer (Minolta CM-2500d). The hue angle was calculated as
H ¼tan 1 b*/a*. Firmness was measured by recording the maximum rupture force (N) developed during a puncture test
performed with a Texture Analyzer (Texturometer TAXT2i, Stable Micro Systems Ltd.) on discs of 10 mm diameter