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Web End = J Food Sci Technol (March 2017) 54(3):650658 DOI 10.1007/s13197-017-2497-8
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Effects of locust bean gum on the structural and rheological properties of resistant corn starch
Raza Hussain1 Ajaypal Singh1 Hamed Vatankhah1 Hosahalli S. Ramaswamy1
Revised: 5 November 2016 / Accepted: 13 January 2017 / Published online: 9 February 2017 Association of Food Scientists & Technologists (India) 2017
Abstract In this study, interactions between resistant corn starch (RS) (5% w/w) and locust bean gum (LBG) (0, 0.125,0.25, 0.50 and 1.0% w/v) on the viscoelastic, pasting and morphological characteristics of aqueous dispersions were evaluated. Results showed that the storage modulus (G0), loss modulus (G00), and apparent viscosity values of starch/gum (RS/LBG) mixtures were enhanced with the addition of LBG, and the rheograms demonstrated a biphasic behavior. RS/LBG samples were predominantly either solid like (G0 [ G00) or viscous (G00 [ G0), depending on the added concentration level of LBG. Gum addition also caused higher peak viscosity, breakdown and total set back of RS/ LBG mixtures. A strong correlation between rheological and structural properties was found. Confocal laser scanning microscopy (CLSM) images conrmed the transition of starch particles from a scattered angular shape to clustered structures cross-linked by dense aggregate junction zones justifying the observed changes in rheological properties.
Keywords Corn starch Rheology Locust bean gum
Pasting properties Confocal laser scanning microscopy
Introduction
Starch/hydrocolloid mixtures are often used in food industry to improve the quality and stability of developed formulations. Although, the reason for using their combinations depends on the type of product; the main reason appears to be
the fact that native starches, when used alone, do not generally exhibit ideal functional properties for the preparation of food products (Blibech et al. 2015). Moreover, native starches are often chemically modied to improve their resistance to various physical changes during processing (heat, shear, and acidic medium), retrogradation and breakdown, to impart better textures of pastes and gels, and to enhance cold storage and freezethaw stability (BeMiller 2011). Some limitations of native starch can be overcome by addition of a suitable hydrocolloid, without chemical modication, and thus improve product texture and rheology (Singh et al. 2016, Qiu et al. 2015), moisture retention and syneresis (Yamazaki et al. 2013) and...