Abstract:

This study aimed to optimize the extraction conditions of collagens from fresh back pigshin by ultrasonicassisted
and enzymatic hydrolysis at a low temperature. The collagen was characterized by analyzing its purity, isoelectric
point, molecular weight distribution, thermal denaturation temperature and amino acid composition. FTIR and UV spectral
properties were analyzed as well. The results showed that ultrasonic-assisted extraction was favorable to defatting of
pigskin without any negative impact on the natural structure of collagen. The optimal extraction conditions were obtained
as follows: material/liquid ratio 1:10 (m/V), pepsin dosage 1:50 (m/m), pH 2.5, extraction time 24 hours and extraction
temperature 4 ℃. The maximum absorption wavelength of the extract was 225 nm, consistent with the characteristics
of collagen. The purity and isoelectric point was 95.7% and 4.91, respectively. The thermal denaturing temperature was
around 38 ℃. The number-average molecular weight was 4.81 × 103 g/mol while the weight-average molecular weight
was 2.57 × 105 g/mol, indicating a concentrated and continuous distribution. Its amino acid composition complied with
the primary structure of collagen.

Key words: pigskin, collagen, extraction, characterization