METAL-BINDING PEPTIDES FROM RED TILAPIA (Oreochromis spp.) VISCERA HYDROLYSATES

The by-products of the fish industry represent around 60% of the animal's weight, of which generally only 30% is used, while the remaining 70% is wasted. In Colombia, aquaculture presents a growth trend of 12% per year on average; being red tilapia (Oreochromis sp.) one of the three most commercially cultivated species. One of the main fish by-products in tilapia is the viscera, which represent between 12-18% of the animal's weight and can contain up to 12% protein. Therefore, searching for profitable and environmentally friendly methods to use this type of by-products is necessary. The present study aimed to produce metal chelating peptides from red tilapia viscera proteins (RTVP) hydrolysis. RTVP were hydrolyzed using Alcalase 2.4L, and iron and calcium chelating activity of hydrolysates was evaluated based on DH. The hydrolysate with the highest activity was fractionated through different cut-off membranes to assess the activity in relation to the molecular weight. Finally, the ability of hydrolysate and the fraction with the highest iron chelating activity to improve the iron bioavailability in Caco-2 cells model was evaluated. The results showed a correlation between DH and metal chelating activity reached the highest activity with a DH of 42,6 and 25,3% for iron and calcium chelating activity, respectively. On the other hand, the fractionation by molecular weight only improved the iron chelating activity, reaching the highest activity with peptides less than 1 kDa. Besides, complete hydrolyzate and the fraction increased iron uptake in Caco-2 cells model compared with iron salt in its free form. Thus, enzymatic hydrolysis is a suitable strategy to obtain value-added products from RTV, and RTV hydrolysates are an alternative for food fortification that deserves further research.