Microstructural and Physico-Functional Characterization of Starches from Selected Cowpea (Vigna unguiculata L. Walp.) Varieties Developed for Pest and Disease Resistance

摘要

The microstructure, physico-chemical and functional properties of legume starches affect their cooking quality as well as the texture and rheological behaviour of foods processed from them. Thus, this study sought to establish the microstructural, physico-chemical and functional properties of the native starches of four cowpea varieties - Bengpla, Asetenapa, Asontem and CR-06-07, that have been developed against disease and pest infestation. The starches were extracted from the cowpeas and their gelation capacity, pasting characteristics, solubility, swelling volume and swelling power were studied using standard analytical methods. Microstructures of the starches were examined using light microscopy. Isolated starch granules from the microstructural examination showed irregular shapes with predominance of spheroid and oval forms in varying sizes. Starch granule sizes ranged from 1.9 mm in Asetenapa to 2.9 mm in Asontem. Swelling power, solubility and swelling volume at 95°C was highest in Bengpla with Asetenapa recording the lowest. However Asontem had the highest value in terms of solubility. With the exception of gelation capacity, significant differences (P ? 0.05) were observed in all the studied parameters amongst the different cowpea varieties. Thus, the cowpea starches showed wide variations in microstructure, physico-chemical and functional properties among the studied varieties and these could be used in the selection of the varieties for specific food processing applications.