The use of acetic acid in reducing mercury content in demersal fishes at buyat bay and its value added improvement as cookies product

Abstract

It has been long indicated that the community live along the coastal of Buyat Bay consume fishery products which contaminated by the attendance of heavy metal mercury which are being one element of wastes resulted from the mining industry namely PT NEWMONT MINAHASA RAYA located near to Buyat Bay. It is known that mercury is a harsh chemical compound which can affect on the function of brain system, skin irritation, and kidney disfunction. The negative impact comes from the mercury pollution in marine water, is the increase of unsafe feeling among the people to consume fishery products; and this is definitely against the national programs in improving the healthy and quality of people by increasing the fish consumption. Therefore, it is necessary to find out how to provide fish products located at contaminated waters which can be safely consumed. The result of this research showed that the fresh flesh of Banded Grunter fish (Ephinephelus sp) and the flesh of Long-jawed mackerel fish (Nemiptervs sp) caught from Buyat Bay on December 2004, naturally possessed lower mercury contents such as 0.017 ppm and 0.034 ppm than that of allowed by WHO as 0.5 ppm. The soaking of fish fleshes in 5% acetic acid for 30 minutes was able to reduce the mercury content as 61.76-64.70%; further the soaking of fish livers in 5% acetic acid for 30 minutes was able to reduce the mercury content as 77.27¬88.21%. Fish cookies was made by the equal concentration of Banded Grunter and Long-jawed mackerel fleshes and added into the formulation of cookies with three level concentrations such as 5, 10, dan 15%. Thirty panelists could accept the cookies products containing all different concentrations without any significant differences. The chemical properties of cookies containing 15% fish fleshes are followed: water 3.19%, ash 2.67%, crude protein 16.75%, crude fat 23.48%, and carbohydrate 53.89%; which is 80% higher than that of control cookies. The use of 15% fish in the formulation could increase the amount of essential amino acids as 130-380 %, mainly for lysine. Protein digestibility of cookies was about 79.32-82.96%, whereas the increase of fish concentration would also improve the protein digestibility of protein in cookies products.