Preparation of Nano-hydroxyapatite Obtained from Lates Calcarifer Fish Bone by Alkaline Hydrolysis Method

Fish bone by-products are considered as abundant and cheap sources of Hydroxyapatite (HAp). The preparation of HAp powders from fish bones not only contributes to improving the added value of by-products but also reduces undesirable impacts on the environment. In this study, nano-HAp was successfully obtained from Lates calcarifer fish bone originated from a seafood export company in Khanh Hoa province. After pretreatment of fish bones for removing organic matters, the bones were under alkaline hydrolysis at 200°C within different time intervals of 30 mins, 1 and 1.5 hours. Results of XRD and SEM analysis showed that the calcium formed was HAP and it possessed an average size of 50-64 nm. The values of the Ca/P molar ratio from 1.896 to 1.921 prove that the nano-HAp powders are B-type biological hydroxyapatites which have been confirmed by FTIR spectrum. In addition, the contents of heavy metals such as As, Pb, Hg, Cd are measured by emission spectrophotometer and detected within safety limits of regulatory requirements of Vietnam regulation and US Pharmacopeia for food and dietary supplement standard. These properties show that nano-HAp from Lates calcarifer fish bone are applicable and to be used as an input material in food and medicine field.