Anatomical proportions and chemical and amino acid composition of common shrimp species in Central Vietnam

This investigation was conducted to evaluate the shrimp flesh (SF) and shrimp by-product (SB) of the most abundant shrimp species (Metapenaeus affinis, Penaeus semisulcatus and Penaeus monodon) caught in Central Vietnam, with the emphasis on yield, gross and amino acid (AA) composition and effect of heat treatment. The results showed that the mean edible SF and SE (head and shells with tail) yields of the three shrimp species averaged 56.7 and 43.3%, respectively, of the total wet body weight, with the M. affinis generating the highest by-product yield (45.7%) and P. semisulcatus (40.6%) the lowest. Significant differences in dry matter (DM), crude protein (CP) and ash content were found between SF and SE. The DM content of SF (21.5%) was lower than of SE (24.9%) and the ash content (on a DM basis) of the SE in all shrimp species was more than three times that of the SF (p<0.05), whereas the CP content was almost twice as high in the SF as compared with the SE (p<0.05). The SE of the three species contained (on a DM basis) between 44.0 and 49.8% CP (p<0.05) and between 13.5 and 18.1% chitin (p<0.05). The Ca content of SE differed also between species (p<0.05). On average, the sum of AA in SE corresponded to 89.3% of the CP and essential AA accounted for about 50% of the total AA. The most abundant AA were arginine, aspartic and glutamic acids, which accounted for 33% of the total AA. Minor, but significant differences in some AA concentrations of SE between species were observed (p<0.05). With the exception of the DM and ether extract content, all other chemical constituents of entire shrimp, SF and SE were not significantly affected by heat treatment (p>0.05).