Dietary safety evaluation of water hyacinth leaf protein concentrate

It has been shown that water hyacinth leaf protein concentrate (WHLPC) is nutritionally and economically available for applications in food and feed, such as biscuits or seasonings industries, but, its dietary safety has never been studied. The dietary safety of WHLPC was therefore evaluated by analyzing the contents of total alkaloids, phenolic compounds, and heavy metals, followed by laboratory animal feeding test. The total alkaloid and phenolic contents of WHLPC were 18.7 mg/kg and 5.2 mg/kg, respectively. WHLPC contained non-detectable Cd, 0.04 mg/kg Cr, 0.001 mg/kg Pb, 0.002 mg/kg Pt, 0.001 mg/kg Pd, 0.003 mg/kg Sn, 0.002 mg/kg Hg, 0.01 mg/kg Ba, 0.001 mg/kg Ag, 0.006 mg/kg Sd, and 0.03 mg/kg Al. The LD(50) of WHLPC in mice was more than 20.5 g/kg body weight (bw). After feeding mice for 7, 30, 60 or 90 days, either on diet containing WHLPC or a control diet of equivalent protein content, there were no significant differences in absolute body weight or weight gain of WHLPC-treated mice. The results of haematological analysis, histopathological evaluation, general dissection, and investigations of internal organs did not show any adverse effects from diet containing WHLPC. It was concluded that WHLPC is not acutely toxic and does not show sub-chronic in mice.