3.1. Proximate analyses of bigeye snapper skin and bone
and their collagen
The proximate analyses of bigeye snapper skin, bone
and their collagen are shown in Table 1. Skin and bone
contained a high moisture content (62.3–64.1%). The
ash and fat contents of bone were greater than those of
skin. Conversely, a lower protein content was observed
in bone than in skin. Skin had a higher content of hydroxyproline
than bone. Sadowska et al. (2003) reported
that hydroxyproline content of cod skin was 14.6 mg/g
sample, which was lower than that of bigeye snapper
skin (19.5 mg/g sample). Different hydroxyproline contents
between two species might depend upon the species,
environment and body temperature of fish (Rigby,
1968; Sikorski, Kolakowska, & Pan, 1989). When collagen
was extracted from the skin and bone, it was noted