Physico-Functional Characterization of Flour and Protein Isolates from Nigeria Cultivated Solojo Cowpea [Vigna unguiculata (L.) WALP]
Olubamike Adetutu Adeyoju
Production, Analytical and Laboratory Management, Federal Institute of Industrial Research, Oshodi, F.I.I.R.O., Lagos-Nigeria.
Kayode Oyebode Adebowale
Department of Chemistry, Indistrial Unit, University of Ibadan, Ibadan-Nigeria.
Bamidele Iromidayo Olu-Owolabi
Department of Chemistry, Indistrial Unit, University of Ibadan, Ibadan-Nigeria.
Henry Okwudili Chibudike *
Department of Chemical, Fiber and Environmental Technology, Federal Institute of Industrial Research, Oshodi, Lagos-Nigeria.
Chinedum Eunice Chibudike
Planning, Technology Transfer and Information Management, Federal Institute of Industrial Research, Oshodi., F.I.I.R.O., Lagos-Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Cowpea, an important protein food, is used for its nutritional and functional properties. A study was carried out to determine the physico-functional characteristics of Flours and Protein Isolates from Two (2) Varieties of Nigerian Cultivated Solojo Cowpea (Vigna Unguiculata L. Walp), to assess their potential use in the food industry. Functional properties were analysed which include Moisture, crude protein, crude fat, crude fibre, ash, carbohydrate and dry matter which were in the range of 9.15-9.83, 26.53-29.00, 2.50-3.99, 2.95-3.22, 4.24-4.80, 50.95-53.98 and 90.17-90.85% respectively. Bulk density ranged between 0.69 and 0.80 g/dm3. Water and oil absorption capacities ranged between 1.89 and 2.15, and 1.95 and 2.31 ml/g, respectively. Swelling power had values varying from 265 to 268% while foam capacity varied from 10.00 to 21.00 ml. The effect of ionic strength on foaming capacity (FC) and stability (FS) of the protein isolates using standard methods was carried out. Amino acids and molecular weight of the protein isolates were determined by amino acid analyser and sodium-dodecyl-sulphate-polyacrylamide-gel-electrophoresis. Surface morphology, functional group and thermal properties were determined for protein isolates by scanning electron microscopy, Fourier Transform Infrared (FTIR) spectrometry and differential scanning calorimetry, respectively. The results indicate that the two varieties of cowpea have great potential as functional agents in the food industry.
Keywords: Solojo cowpea, under-utilised legumes, protein isolate, functional, nutritional, DAS, BS, Vigna unguiculata L. Walp