Kruger J., Minnis-Ndimba R., Mtshali C., Minnaar A.
Department of Food Science, Institute for Food, Nutrition and Well-being, University of Pretoria, Private Bag X20, Hatfield, South Africa; Materials Research Department, IThemba LABS, National Research Foundation (NRF), PO Box 722, Somerset West, South Africa
Kruger, J., Department of Food Science, Institute for Food, Nutrition and Well-being, University of Pretoria, Private Bag X20, Hatfield, South Africa; Minnis-Ndimba, R., Materials Research Department, IThemba LABS, National Research Foundation (NRF), PO Box 722, Somerset West, South Africa; Mtshali, C., Materials Research Department, IThemba LABS, National Research Foundation (NRF), PO Box 722, Somerset West, South Africa; Minnaar, A., Department of Food Science, Institute for Food, Nutrition and Well-being, University of Pretoria, Private Bag X20, Hatfield, South Africa
Cowpea is a nutritionally important drought-resistant legume in sub-Saharan Africa. It is, however, underutilised, in part due to the hard-to-cook (HTC) defect caused by adverse storage conditions resulting in seeds not softening during cooking. This study introduced a novel evaluation of the potential role that minerals play in the development of the HTC defect. The mineral distribution in the cotyledons of normal and HTC cowpeas were analysed by Proton Induced X-ray Emission (PIXE) spectrometry. The phytate, tannin and total phenolic contents were analysed together with in vitro mineral bioaccessibility. In HTC cowpeas, Ca and Mg were more concentrated in the cell wall-middle lamella area of the parenchyma cells. This, together with the reduction in phytate content, confirmed the 'phytase-phytate-mineral' hypothesis as a mechanism for development of the HTC defect. Despite the phytate reduction in stored cowpeas, the HTC defect decreased the bioaccessibility of Ca, Fe and Zn in cowpeas. © 2014 Elsevier Ltd. All rights reserved.
Calcium; Defects; Drought; Electromagnetic wave emission; Iron; Magnesium; Phosphorus; Protons; Spectrometry; X ray scattering; Zinc; Bioaccessibility; Cowpea; HTC; Phytate; PIXE; Proton induced x-ray emissions; Minerals; calcium ion; ferric ion; magnesium; mineral; phytate; tannin; zinc ion; mineral; phytic acid; Article; cell wall; cooking; cotyledon; cowpea; hypothesis; in vitro study; chemistry; cooking; Fabaceae; metabolism; plant seed; spectrometry; Cooking; Fabaceae; Minerals; Phytic Acid; Seeds; Spectrometry, X-Ray Emission