Yew Yuan Glenn Cheng

• Bsc (Honours) Food & Human Nutrition
• Snapshot Survey of Cyanogen levels in Cassava for Retail Sale in a South-east Asian Region Context. A Singapore Study

Cassava (Manihot esculenta), an edible starchy root, are purchasable from Singapore farmer markets. Fresh roots (n= 25) were purchased from two outlets in North-East of Singapore. A KCN standard curve (represented as HCN), helped determine the relationship between colourimetric absorbance with HCN quantity. Enzymeactivity on a partially purified, concentrated Linamarase provided by CIAT (Cali, Colombia) was tested with its substrate Linamarin (a glucoside), to ensure an enzymatic unit (EU) of ≥ 3 EU/ml (Cooke, 1979) for proper function of the cyanogenic potential (CNp) assay on cassava roots. CNp of the cassava roots were determined by colourimetric analysis after chopping and peeling and the average was 36.9mg/kg (as HCN) on a fresh weight basis. This complied with the CODEX Alimentarius standards for ‘Sweet cassava’. However, 9 roots had CNp ranged 50.8–75.9mg/kg. Hence, a re-evaluation is necessary as not all cassava roots sold in Singapore have CNp within safe limits.

Funding source: Newcastle University

Supervisor: Dr Gerard M O'Brien