Malabar sole (Cynoglossus macrostomus) skin as promising source of type I acid and pepsin solubilized collagens with potential bioactivity.

t Fish skin is one of the major non-edible by�products formed during fish processing. This investigation
focused on the sustainable valorization of Malabar sole
(MS) skin for collagen, which can be utilized as potential
alternative of mammalian collagen. Acid and pepsin solu�bilized collagen (ASC and PSC) were successfully isolated
from MS skin with a yield (%, dry weight basis) of
49.5 ± 0.6 and 67.6 ± 0.5, respectively. The isolated
collagens were characterized by SDS-PAGE, UV-absorp�tion, DSC, SEM, FTIR spectroscopy, etc., analysis. Both
collagens were characterized as type I by SDS-PAGE and
the well preserved triple helical structure by FTIR and UV
absorption analysis. Denaturation temperature (�C) of the
MS skin collagens confirmed by DSC analysis was 33.67
(ASC) and 33.38 (PSC). Both collagens showed high sol�ubility in acidic pH and low NaCl level, and also exhibited
a comparatively high degree of fibril-forming capacity.
Antioxidant potential of the isolated collagens was
confirmed by DPPH (31.4–34.6% at 1.5 mg) and peroxyl
(64.6–68.3% at 0.3 mg) radical scavenging assays and
observed a dose dependent manner activity. Overall, the
results suggested the possibility of using the MS skin as a
potential substitute source of realistic type I collagen and
also help to reduce issues of fish processing discards.