Functional properties of cowpea (Vigna unguiculata) starch as modified by guar, pectin, and xanthan gums

Abstract

In the present study, the effect of different hydrocolloids (guar, xanthan, and pectin) were evaluated on some functional properties of cowpea starch. It was found that these hydrocolloids significantly enhanced the water absorption while reducing the swelling power and solubility. Only pectin was found to be an effective gum which reduces the syneresis of the cowpea starch gel during freeze–thaw process. The results indicated that guar gum caused a noticeable increase of peak viscosity as well as viscosity at 95°C examined by viscoamylograph whereas reducing trend was observed for both peak viscosity and viscosity at 95°C when pectin was added. It was also observed that guar gum caused a rapid rise in viscosity during the cooling period whereas the addition of the xanthan as well as pectin dropped the viscosity of cowpea starch. The heating stability of cowpea starch was found to be reduced by the addition of guar and xanthan gums while set back capability was successfully reduced by all selected hydrocolloids. The firmness of cowpea starch gel could be improved by the addition of all selected hydrocolloids during storage as compared to native starch.

Effect of hydrocolloids on functional properties of navy bean starch

“…Similar increases in the peak and final viscosities for guar gum have been observed for pea and many other starches . Higher guar gum concentration also led to higher viscosities for cowpea and pea starches, as did high guar gum molecular weight . For pectin, the ratio of the final and peak viscosities increased slightly with pectin concentration, from 0.83 to 0.90 and 0.84 to 0.88, respectively.…”

“…These results suggest that increased pectin concentration did not further inhibit starch gelatinization, and that its much lower solution viscosity (0.01–0.02 Pa s at 65°C) also did not lead to a large increase the overall viscosity. Nawab et al reported that pectin lowered the peak viscosity of cowpea starch, although higher pectin concentration led to lower peak viscosity. They suggested that pectin may have prevented amylose leaching from the starch granule.…”

“…These results differ from those for other pulse starches. Nawab et al found that xanthan gum slightly increased the peak viscosity of cowpea starch and reduced the final viscosity, whereas xanthan gum increased the peak viscosity and had very little effect on the final viscosity for pea starch . The xanthan gum solutions had higher viscosity at 65°C than the guar gum solutions (0.08–0.26 Pa s), yet the relative increase with xanthan gum concentration was smaller, suggesting that higher xanthan gum concentration both lowers the paste viscosity by preventing starch granule swelling, and increases the paste viscosity due to a high solvent viscosity.…”

“…The hardness of pea starch gels decreased with addition of the hydrocolloids, as did the tensile strength of pea starch vermicelli for most hydrocolloids. Addition of guar gum to cowpea starch increased the peak viscosity , while xanthan gum led to a much smaller increase and pectin decreased the peak viscosity. Each of the hydrocolloids increased the firmness of cowpea starch gels, but the effect decreased with hydrocolloid concentration.…”

Effect of Taro Starch-Hydrocolloids Mixture as a Functional Ingredient on the Quality of Milk Dessert

“…Hydrocolloids serve as emulsion stabilizer, suspending agents, *Address correspondence to this author at the Department of Food Science and Technology, University of Karachi, Karachi -75270, Pakistan; Tel: +92-333-2445517; Fax: +92-21-99243206; E-mail: ferozalam@uok.edu.pk gelling agents, thickeners, fiber sources, mouth feel improvers, fat replacers and processing aids. The functional and rheological properties of starch and hydrocolloid mixtures have been extensively reported in literatures [7][8][9][10][11][12][13]. It is well known fact that the addition of hydrocolloids increases the viscosity of starch dispersion and influences the retrogradation rate.…”