Chemical Compositions and Antioxidant Properties of Pla-ra, Thai Indigenous Fermented Fish Product

Abstract

The objective of this study was to investigate the chemical compositions, protein degradation and antioxidant properties of two types of Pla-ra from three manufactures (I, II, III) of Ubon Ratchathani. The results showed that protein fat and ash contents of the two types of Pla-ra (type A and B) were 17.17-22.59% 3.5-12.68% and 59.29-69.11% dry basis, respectively. The pH values of type A samples were 6.64-7.14 while those values of type B samples were 5.28-5.43. These results corresponded to their total acidity. DPPH radical scavenging activity of type A sample from manufacture I was higher than other samples (P<0.05). This result was highly related to the degree of protein degradation which was represented by the trichloroacetic acid-soluble oligopeptide content, total volatile base nitrogen and a-amino acid. Higher values of ABTS radical scavenging activity and reducing power were found in type B samples. Metal chelating activity of type A samples from various manufactures was higher than 96% while that of type B samples was between 16.90-23.38%.