Rehana Akhter

Physico-chemical, functional and structural properties of RS3/RS4 from kidney bean (Phaseolus vulgaris) cultivars

Starch isolated from four kidney bean cultivars (Yellow bean, Red bean, Black bean and White bean) were physically and chemically modified in order to prepare resistant starch (RS3/RS4). Following the Heat-moisture treatment (HMT) and Citric acid modification (CT) of the native starch, the amylose content got decreased whereas bulk and tapped density (g/ml) increased. Both HMT and CT reduced the swelling power and the solubility of native starch. Pasting temperature increased and peak, breakdown, final, and set-back viscosity decreased after both the modifications. Fourier Transform Infrared Spectroscopy (FTIR) analysis displayed peaks at 1020cm(-1) in HMT and 1724cm(-1) in CT starches. Differential Scanning Calorimetry (DSC) analysis revealed that samples were more stable after modification. X-ray diffraction (XRD) analysis revealed reordering of chain segments to more crystalline structure. These results suggested modifications resulted in starch with improved properties and could be a possible method for the RS preparation with better thermal stability.

Application of guar–xanthan gum mixture as a partial fat replacer in meat emulsions

Abstract The physicochemical, oxidative, texture and microstructure properties were evaluated for low fat meat emulsions containing varying levels of guar/xanthan gum mixture (1:1 ratio) as a fat substitute. Partial replacement of fat with guar/xanthan gum resulted in higher emulsion stability and cooking yield but lower penetration force. Proximate composition revealed that high fat control had significantly higher fat and lower moisture content due to the difference in basic formulation. Colour evaluation revealed that low fat formulations containing gum mixture had significantly lower lightness and higher yellowness values than high fat control formulation. However non-significant difference was observed in redness values between low fat formulations and the high fat control. The pH values of the low fat formulations containing gum mixture were lower than the control formulations (T0 and TC). The MetMb% of the high fat emulsion formulation was higher than low fat formulations. The significant increase of TBARS value, protein carbonyl groups and loss of protein sulphydryl groups in high fat formulation reflect the more oxidative degradation of lipids and muscle proteins during the preparation of meat emulsion than low fat formulations. The SEM showed a porous matrix in the treatments containing gum mixture. Thus, the guar/xanthan gum mixture improved the physicochemical and oxidative quality of low fat meat emulsions than the control formulations.