Enzymatic Preparation Of Collagen Oligopeptides From Flatfish (Paralichthys Olivaceus) Skin And Their Functions

Low-value fish and the castoff of marine processing are utilized to produce bioactive peptides, which not only can make best use of fishery resource, but also can produce products with added value.Flatfish (Paralichthys olivaceus) skin was enzymatically hydrolyzed to prepare collagen oligopeptides with multiple bioactivities. Flatfish skin was pretreated to well swelling with 0.2%citric acid at 4℃. The technical parameters were optimized by the single factor experiments and Response Surface Methodology, which were as follows: pH 10, substrate concentration of 70g/L, alkaline proteinase 2709 4%, temperature 55 ℃, and the maximum hydrolysis degree was achieved as 22.36%.Subsequently, Gel Filtration Chromatography and MALDI-TOF-MS were applied to determine the molecular weight distribution of the hydrolysates. The majority of molecular weight distributed between 0.6 and 1.8kD, which indicated that the hydrolysates were classified as oligopeptides.Further more, in this paper, functions of the oligopeptides were studied: moisture absorption and retention was determined by the method of weighing which is easy and doable; tyrosine used as substrate, catalyzed by tyrosinase, the activity of inhibiting tyrosinase was determined by the quantity of melanin; the external inhibiting activity of ACE was determined by uv-spectrophotometer; the collagen oligopeptides solutions was daubed on the skin of the mice to determined the capacity of collagen formation.The oligopeptides expressed better moisture absorption and retention, compared with common moisturizer such as: glycerin and chitosan. Meanwhile, the oligopeptides inhibited the activity of tyrosinase to prevent the formation of melanin. The oligopeptides showed its anti ACE activity with IC₅₀ is 1.65mg /ml. Animal experiment indicated that the collagen oligopeptide promoteed the collagen formation in the skin when the dose was 5%, P<0.01.