Effect of solar dehydration on amino acid pattern and available lysine content in four tropical leafy vegetables

The amino acid pattern in fresh and solar dried tropical leafy vegetables were evaluated. There were increases in aspartic acid, glutamic acid, valine, leucine and isoleucine content. Decreases were observed in lysine and histidine. These changes indicate that during solar dehydration of vegetables there are complex interactions involving the N‐bearing compounds, particularly the amino acids. Despite the variable extent of lysine destruction in the four vegetables, its content in dried Amaranthus leaves was in excess of that in the FAO/WHO reference protein. Dried Amaranthus leaves were also rich in all the other essential amino acids. Dried Amaranthus leaves can therefore, be used for supplementing cereal based diets that are limiting in lysine. Dried cowpea, cassava and sweet potato leaves were also rich in essential amino acids with the exception of the sulfur containing amino acids.

Key words:

• Solar drying
• leafy vegetables
• amino acids
• Amaranthus
• food processing
• cowpea
• cassava
• sweet potato
• protein quality