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In this study, the feasibility of mango kernel starch (MKS) as a new film-forming material was studied. A filmogenic solution of MKS (2% w/v) was prepared with different plasticizers (glycerol, sorbitol, PEG-400, and a 1:1 mixture of glycerol and sorbitol) at different concentrations (40,50, 60, and 70% w/w of starch weight). The films were prepared by a casting technique and the effects of plasticizers on the physical, barrier, sorption, and mechanical properties were investigated. It was noted that glycerol, sorbitol, and their 1:1 combination produced homogeneous, transparent, and smooth films, whereas PEG-400 did not form film with appropriate characteristics. The scanning electron micrographs showed that MKS films had a uniform surface with no holes or fracture. The glycerol-plasticized films exhibited higher solubility, water vapor permeability (WVP) and elongation at break (EAB), but lower tensile strength (TS) than those obtained with sorbitol and combined plasticizers. Glycerol-plasticized films also presented high equilibrium moisture contents at all humidity levels. The TS decreased and the solubility, WVP, and EAB increased with increasing concentration of plasticizers. Low oxygen permeability (OP) was evident in sorbitol plasticized films at 40% plasticizer concentration while lower WVP values were found in combined plasticizers films.

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.

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