African Journal of
Food Science

  • Abbreviation: Afr. J. Food Sci.
  • Language: English
  • ISSN: 1996-0794
  • DOI: 10.5897/AJFS
  • Start Year: 2007
  • Published Articles: 846

Full Length Research Paper

Effects of processing techniques on the nutritional composition and anti-nutrient content of mucuna bean (Mucuna pruriens L.)

J. B. Mugendi1*, E. N. M. Njagi2, E. N. Kuria3, M. A. Mwasaru4, J. G. Mureithi5and Z. Apostolides6
  1Department of Foods and Nutrition, Kenyatta University, P. O. Box 43844-00100, Nairobi, Kenya. 2Department of Biochemistry and Biotechnology, Kenyatta University P. O. Box 43844-00100, Nairobi, Kenya. 3Department of Foods and Nutrition, Kenyatta University, P. O. Box 43844-00100, Nairobi, Kenya. 4Department of Foods Science and Post Harvest Technology, JKUAT, P. O. Box 62000-00200, Nairobi, Kenya. 5Kenya Agricultural Research Institute (HQ), P. O. Box 57811-00100, Nairobi, Kenya. 6Department of Biochemistry, University of Pretoria, Pretoria 0002, South Africa.
Email: [email protected]

  •  Accepted: 08 March 2010
  •  Published: 30 April 2010

Abstract

 

Mucuna bean (Mucuna pruriens) is an indigenous legume promoted in Kenya as a green manure cover crop. It contains high protein but it is under - utilized due to the presence of 3, 4-dihydroxy-L-phenylalanine (L-Dopa) and other anti nutritional compounds. To improve its nutritional potential as a protein source, mucuna bean was processed and evaluated for nutritional composition. Effects of processing at different pH, temperature and particle size, autoclaving, germination and fermentation on the contents of anti-nutritional compounds and crude protein were investigated. Raw beans contained high crude protein (27.9 g/100-1). Contents of ether extract; crude fibre and ash were 3.7, 7.9 and 3.5 g/100-1, respectively. Mineral content was comparable to that of common pulses. Raw whole mucuna bean contained high L-Dopa (7.0 g/100-1) content. Other anti-nutritional compounds included total phenols 7.1 g/100-1, trypsin inhibitor activity (TIA) 5.1 TIU and phytates 0.9 g/100-1. All processing techniques, except roasting, reduced levels of L-dopa by > 95% while less than 15% of protein was lost. Soaking dehulled bean in acidic medium (pH 3.2) at 60°C for 48 h reduced L-Dopa content to the recommended safe level of 0.1%. Processing mucuna bean increased its nutritional value and potential to improve food security.

 

Key words: Mucuna bean, anti-nutritional compounds, L-Dopa, processing methods.