Abstract
Leaf protein isolate from water hyacinth (Eichhornia crassipes ) was prepared and the chemical composition was studied. It contained 49.6% protein, 16.0% total lipids, 26.9% total carbohydrates, 1.7% fibre and 5.8% ash. Calcium, magnesium, copper, zinc, manganese and potassium were determined. Nutritional properties of the isolate are discussed in relation to its amino acid composition and to its in vitro digestibility by proteolytic enzymes. Comparison with the FAO/WHO reference pattern showed that all of the essential amino acids were present at high levels in the leaf protein isolate. The limiting amino acid in the isolate was methionine (i.e. methionine + cystine). In vitro digestibility was highest with digestion by pepsin followed by pancreatin and lowest with digestion by pepsin alone. Digestion with pancreatin alone gave intermediate values.