Some characteristics of commercial Som-fug produced in Thailand

Seven commercial brands of Som-fug were analysed for chemical composition, biogenic amines and acceptance. Commercial Som-fug contained 11.4–16.2% protein, 1.13–1.56% lipid, 69.66–77.08% moisture, 2.45–3.60% ash and 3.37–4.90% salt. The pH values ranged from 4.56 to 4.60 and total acidity varied from 1.42% to 2.35%. Lactic acid was the major organic acid in all samples, but citric acid, succinic acid and pyruvic acid were found only in some brands. Differences in the trichloroacetic acid soluble peptides and lipid oxidation, among all samples, were observed. The proteolysis of myosin heavy chain was observed on SDS–PAGE analysis. Additionally, the formation of biogenic amines, including tryptamine, putrescine, cadaverine, histamine and tyramine, was observed in commercial Som-fug, but β-phenylethylamine was not detectable in any samples. Different Som-fug samples showed different acceptabilities, especially for taste and appearance. Therefore, raw materials, ingredients and process should be factors for determining the characteristics of Som-fug products.