Faculty of Natural and Agricultural Sciences
School of Agricultural and Food Sciences
Department of Food Science
Selected Highlights from Research Findings
Long cooking times is one of the most important factors limiting the utilisation of Hard-to-Cook (HTC cowpeas). Tempering HTC cowpeas in a solution containing monovalent (Na+) cations alone significantly reduced the cooking time of HTC cowpeas by about 44%. Micronization, an infra--red heat treatment, after tempering in water had a similar effect. However, tempering HTC cowpeas in a solution containing monovalent (Na+) cations followed by micronization reduced the cooking time of HTC cowpeas by at least 78%. Improved solubilization of pectins is responsible in part for these reductions in cooking times. During the tempering process, insoluble pectinates were converted to soluble pectins in the middle lamella probably due to an exchange of pectin divalent cations (I.e. Ca2+ and Mg2+ by monovalent cations (I.e. Na+ present in the tempering solution. Micronisation on the other hand induced breakage of pectin molecules into lower and more soluble molecular fractions in the middle lamella probably via the b-elimination reaction. These findings suggest that the improvement of pectin solubility played a major role in improving the degree of splitting, reducing the cooked texture and consequently the cooking time of HTC cowpeas
Contact person: Prof A Minnaar.
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