Yield of ASC and PSC from the skin

Yield of ASC and PSC from the skin of striped catfish
ASC and PSC were isolated from the skin of striped catfish with yields of 5.1% and 7.7% (based on the wet weight of skin), respectively. The skin was not completely solubilised by 0.5 Macetic acid, as shown by the low yield of ASC. This result was in agreement with Jongjareonrak, Benjakul, Visessanguan, and Tanaka (2005) who reported the incomplete solubilisation of bigeye snapper skin in 0.5 M acetic acid. The present result was explained by the fact that collagen molecules in striped catfish skin were most likely cross-linked by covalent bonds through the condensation of aldehyde
groups at the telopeptide region as well as the inter-molecular cross-linking, leading to a decrease in the solubility of collagen (Foegeding, Lanier, & Hultin, 1996; Zhang et al., 2007). The yields of ASC and PSC from brownbanded bamboo shark (Chiloscyllium punctatum) were 9.38% and 8.86% (wet weight basis), respectively (Kittiphattanabawon et al., 2010) and those from bigeye snapper skin were 6.4% and 1.1% (wet weight basis), respectively (Jongjareonrak,
Benjakul, Visessanguan, Nagai, & Tanaka, 2005), whereas for brownstripe red snapper skin, the yields of ASC and PSC were 9% and 4.7% (wet weight basis), respectively (Jongjareonrak, Benjakul, Visessanguan, & Tanaka, 2005). With further limited pepsin digestion, the cross-linked molecules at the telopeptide region were cleaved, resulting in further extraction. Pepsin was able to cleave specifically at the telopeptide region of collagen from the skin of bigeye snapper (Nalinanon, Benjakul, Visessanguan, & Kishimura, 2007). The combined yield of ASC and PSC was 12.8%.
Thus pepsin could be used as an aid for increasing the extraction yield of collagen from the skin of striped catfish.