2.4. Chemical analysis
Direct pH measurement was taken using a standard pH meter (Mettler Teledo 320, Switzerland). The titratable acidity (TA) was measured by the method of AOAC (2000) and calculated as lactic acid and expressed as g/100 g Nham dry weight basis. Organic acids in Nham were extracted and analysed by high- performance liquid chromatography (HPLC) according to the method of Nassos, Schade, King, and Stafford (1984) with a slight modification by Visessanguan et al. (2004).