Muhammad Abdul Haq

Mango kernel starch-gum composite films: Physical, mechanical and barrier properties

Composite films were developed by the casting method using mango kernel starch (MKS) and guar and xanthan gums. The concentration of both gums ranged from 0% to 30% (w/w of starch; db). Mechanical properties, oxygen permeability (OP), water vapor permeability (WVP), solubility in water and color parameters of composite films were evaluated. The crystallinity and homogeneity between the starch and gums were also evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The scanning electron micrographs showed homogeneous matrix, with no signs of phase separation between the components. XRD analysis demonstrated diminished crystalline peak. Regardless of gum type the tensile strength (TS) of composite films increased with increasing gum concentration while reverse trend was noted for elongation at break (EAB) which found to be decreased with increasing gum concentration. The addition of both guar and xanthan gums increased solubility and WVP of the composite films. However, the OP was found to be lower than that of the control with both gums. Furthermore, addition of both gums led to changes in transparency and opacity of MKS films. Films containing 10% (w/w) xanthan gum showed lower values for solubility, WVP and OP, while film containing 20% guar gum showed good mechanical properties.

Effect of guar and xanthan gums on functional properties of mango (Mangifera indica) kernel starch

The effects of different concentrations of guar and xanthan gums on functional properties of mango kernel starch (MKS) were studied. Both guar and xanthan gum enhanced the water absorption of MKS. The addition of xanthan gum appeared to reduce the SP (swelling power) and solubility at higher temperatures while guar gum significantly enhanced the SP as well as solubility of MKS. The addition of both gums produced a reinforcing effect on peak viscosity of MKS as compared to control. Pasting temperature of MKS was higher than that of starch modified by gums indicating ease of gelatinization. Guar gum played an accelerative effect on setback but xanthan gum delayed the setback phenomenon during the cooling of the starch paste. Both gums were found to be effective in reducing the syneresis while gel firmness was markedly improved.

Osmotic Dehydration of Mango Cubes: Effect of Novel Gluten-Based Coating

Edible coating before osmotic dehydration (OD) reduces solute uptake, which can deteriorate product quality. Polysaccharide-based coatings have been reported for this purpose with limited success. Gluten, due to its inherent film formation property, has the potential to be used for this purpose. In this study, mango cubes of different maturity were osmotically dehydrated with and without gluten-based coating. An edible coating was prepared through fractionation of gluten. Osmotic dehydration was performed at 50°C for 2 h with osmotic solutions (OSs) at various concentrations (45, 55, 65 °Brix). Coating improved the dehydration efficiency index (DEI) due to a substantial decrease in solute gain (SG) and slight increase in water loss (WL). The coating modified the physicochemical properties and this effect was significantly observed at 55 °Brix. Coated mango cubes were harder and shrank more than uncoated mango. The physicochemical properties after OD were also found to be influenced by the maturity of raw mangoes.

Effect of Osmotic Pre-Treatment on Drying Characteristics of Pomegranate (Punica granatum L.)

This study was conducted to determine the effect of osmotic dehydration on air drying characteristics of pomegranate arils. Osmotic dehydration was performed at different time and temperatures combinations. Mass transfer parameters were studied using response surface methodology. After osmotic dehydration, the arils were air dried till moisture content became 8.0%. Page model of drying was fitted on experimental data. Osmotic pretreatment decreased the exponential coefficient of the model. Osmotic dehydration conditions and air drying constant were combined in a single mathematical model with optimization at lowest time for overall dehydration. This goal was achieved when the arils were pretreated for 93 minutes at 39°C. This research might help to choose drying conditions for pomegranate arils on an industrial scale.