Physicochemical, rheological, morphological, and in vitro digestibility properties of cross-linked starch from pearl millet cultivars

Abstract

The effect of epichlorohydrin (0.5%) as a cross-linking agent on physicochemical, rheological, morphological, and in vitro digestion properties of pearl millet starches from different cultivars was studied. Degree of crosslinking (DC) ranged between 40.61% and 89.75%, lower values of DC were observed for cv.HC-10 and cv.HHB-67 whereas higher values were observed for cv.HHB-223 and cv.GHB-732. Cross-linked starch from cv.GHB-732 showed the lowest amylose content, swelling power, and solubility as compared to other cultivars. Rheological properties of starches during heating showed their elastic behaviour. G′ value was much higher than the G′′ value at all frequency values for starch pastes. Plots of shear stress (σ) versus shear rate (γ̇) data for cross-linked starch pastes were fitted to Herschel-Bulkley model and yield stress (σ o ), flow behaviour index (n), and consistency index (K) were evaluated. Scanning electron micrographs (SEM) investigations revealed that cross-linked starch granules had slightly rough surfaceand grooves with slight fragmentations. Readily digestible starch (RDS) of cross-linked starches varied from 46.1% to 50.6%, cv.GHB-732 had the lowest value. Slowly digestible starch (SDS) and resistant starch (RS) content of cross-linked starches ranged from 34.5% to 36.4% and 13.6% to 19.4%, respectively. cv.HC-10 had the highest value for SDS content while the highest RS content was observed for cv.GHB-732. In comparison to native starches, cross-linked modification decreased SDS and RDS content whereas RS content was increased. ARTICLE HISTORY

Investigation of changes in rheological properties during processing of fermented cereal beverages

“…The breakdown viscosity was calculated as the difference between the maximum and minimum viscosity and was determined at 54.5 mPaÁs. These results are in agreement with the study of Siroha and Sandhu (2018), who have reported, that breakdown viscosity (BV) of modified starches from millet in the range of 15 to 470 mPaÁs. The final viscosity of the investigated millet paste was 107 mPaÁs, which was determined at the end of the cooling phase.…”

“…In our study, the millet porridges reached the maximum viscosity of 608 mPaÁs at a temperature of 93 °C. This finding is in accordance with the results of Siroha and Sandhu (2018), who found peak viscosities of modified starch from pearl millet cultivars at 299-1164 mPaÁs at 87.4-90.7 °C. Smanalieva et al (2015) reported that the peak viscosity of Kyrgyz variety rice flour using rotational rheometry was determined at 107-372 mPaÁs between 91.4-95.2 °C.…”

Effect of heat treatment and γ-irradiation on pasting, rheological, and fungal load of whole and dehulled millets

“…We noticed gel like behavior of millet samples that changed between elastic to viscous. Similar observation in pearl millet starch was documented in a study by Siroha and Sandhu (2018).…”

Effect of Cross-Linking Modification on Structural and Film-Forming Characteristics of Pearl Millet (Pennisetum glaucum L.) Starch

“…CL starches showed rough surfaces and small cavities on the surface of granules. Cross-linking modification slightly affects the starch granule as compared to native starch [36,37]. Native pearl millet starches were polygonal in shape and had well defined edges, while a slightly rough surface and a black zone on the surface were observed for CL starches [37].…”

“…Cross-linking modification slightly affects the starch granule as compared to native starch [36,37]. Native pearl millet starches were polygonal in shape and had well defined edges, while a slightly rough surface and a black zone on the surface were observed for CL starches [37]. Mirmoghtadaie et al [38] reported that oat starch granules were not affected by cross-linking modification.…”