Functional properties and retrogradation behaviour of native and chemically modified starch of mucuna bean (Mucuna pruriens)

Abstract The structural and functional properties of slowly digestible starch (SDS) modified using pullulanase and prepared from chestnut starch were studied. The modified chestnut starches had 41.9 % SDS, which was higher than native chestnut starches (6.51 %) and cooked chestnut starches (18.6 %). The hydrolysis rate of the modified starches was 74.1 %. Scanning electron microscopy showed that the modified starch granules had a large surface area with signs of cracks and dents, and the cross-sections showed hollow internal structures. X-ray diffraction indicated that the crystallisation of the starch changed from the Cb-type to the V-type, although it retained a few C-type characteristics. Compared with native chestnut starch, the modified starches have a higher gelatinisation temperature using differential scanning calorimetry; and the texture profile analysis hardness, chewiness, cohesiveness, and gumminess of modified starch gels decreased significantly, while adhesiveness increased. When debranched using pullulanase there was a decreased solubility, swelling power, and freeze-thaw stability of the modified starches. These findings suggest that pullulanase modification changed the in vitro digestibility and crystalline structure of the modified starches.

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Influence of three alkalizing agents on some functional properties of cassava starch modified using epichlorohydrin

Bangladesh Journal of Scientific and Industrial Research ◽

10.3329/bjsir.v49i2.21997 ◽

2015 ◽

Vol 49 (2) ◽

pp. 63-68

Author(s):

B Daramola ◽

EA Bamidele

Keyword(s):

Functional Properties ◽

Functional Property ◽

Apparent Viscosity ◽

Potassium Hydroxide ◽

Room Temperature ◽

Ammonium Hydroxide ◽

Cassava Starch ◽

Pasting Properties ◽

Modified Starch ◽

Cross Linkage

Influence of three alkalizing agents namely, potassium hydroxide (KOH) , ammonium hydroxide (NH4OH), and dimethyl sulphoxide (DMSO) during modification as modification facilitator on some functional properties of cassava starch modified using epichlorohydrin (EPI) at room temperature was studied. Assessment of the principal functional property; pasting properties and associated pasting indices of technological importance, notably peak viscosity and set back viscosity. The low peak viscosity (RVU) of the cassava EPI-modified starch ranged from 119.67-178.17; 128.50-161.17 for samples alkalized using KOH and DMSO respectively in comparison to the high peak viscosity (RVU) of the native starch. NH4OH was less effective alkalizing agent under the conditions used in this study. Cassava- EPI modified starch showed improved paste stability expressed in breakdown viscosity (RVU) values of 22.08-48.75 and 37.92-55.58 for KOH and DMSO alkalized samples respectively. Evaluation of other functional properties such as swelling power, apparent viscosity and paste clarity of the cassava-EPI modified starch showed alkaline-type dependent cross linkage activity of EPI. Assessment of all the functional properties of starch accomplished under the conditions employed in this study revealed that irrespective of concentration of EPI added, activity of alkalizing reagents is in the order: KOH>DMSO>NH4OH. DOI: http://dx.doi.org/10.3329/bjsir.v49i2.21997 Bangladesh J. Sci. Ind. Res. 49(2), 63-68, 2014

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