Characterization of Collagen in the Muscle of Several Crustacean Species in Association with Raw Meat Texture

Abstract

Meat firmness of muscles of sixteen crustacean species was examined to clarify the contribution of the following three factors to the raw meat texture: 1) total collagen content in muscle, 2) distribution of intramuscular collagen fibers, and 3) properties of an α component, α2 (AR-I), which is one of the constituents of Type AR-I collagen. Total collagen content varied among species, ranging from 0.04 to 0.58% per wet tissue and from 0.4 to 3.5% per total tissue protein. The component α2 (AR-I) was distributed widely among custacean species, but it was not detected in some species of crabs. Moreover, a considerable difference in the relative staining intensity of the α2 (AR-I) component to the total collagen (α2 (AR-I)/total collagen) was revealed among species. The muscles of prawns and shrimps which showed relatively high collagen content and high relative staining intensity of α2 (AR-I)/total collagen tended to be firm in contrast to those of crabs, whose firmness and collagen contents were lower. In light microscopic observation, the muscles of prawns and shrimps exhibited a dense distribution of collagen fibers, while the muscles of crabs had a sparse distribution. These results indicated that the three factors described above had very important roles in determining the raw meat texture of crustaceans.