Morphological structure and crystallinity of ‘Rainha’ sweet potato starch by heat–moisture treatment

Abstract

Heat-moisture treatment is type of physical modification that which cause changes in the technological characteristics of the starch. One of the sources of starch that presents potential of use of this treatment is sweet potato of the variety 'Rainha' (Ipomoea batatas). Therefore, the objective of this work was extract the sweet potato starch, apply the heat-moisture treatment in different relative humidity conditions (15, 20, and 25%), and characterize the starches as to water absorption capacity, morphology and crystallinity. Starch extracted from sweet potato resulted in a product of high purity. All modified starches showed a higher water absorption capacity when compared to native starch. The morphology of the starch granules remained unchanged after the modification and the same was observed with respect to the crystallinity. However, modified 15% moisture starch showed significant changes in the amylose content, water absorption, and crystallinity, these characteristics extend the use of this starch, for use in foods.

Nb/Starch-Doped ZnO Nanostructures for Polluted Water Treatment and Antimicrobial Applications: Molecular Docking Analysis

“…Because smaller sizes of ZnO QDs are generated at the inner side of the starch matrix, surface passivation quenches near-band-edge and oxygen vacancy-related emission characteristics, resulting in increased blue emission. 45 We can see that when Nb is doped into st-ZnO composites, the relative intensity of visible emission fluctuates. When compared to other samples, the intensity of the sample containing Nb (2%) increases drastically.…”

“…We noticed an intriguing broader blue emission spectrum ranging from violet to green at 392–440 nm in st-ZnO QDs, which we ascribed to recombination electrons trapped in random surface vacancies. Because smaller sizes of ZnO QDs are generated at the inner side of the starch matrix, surface passivation quenches near-band-edge and oxygen vacancy-related emission characteristics, resulting in increased blue emission . We can see that when Nb is doped into st-ZnO composites, the relative intensity of visible emission fluctuates.…”

“… 44 XRD spectra of native starch revealed clear diffraction peaks at 2θ° of 10, 12, 18, and 22°, indicating a characteristic pattern of starch. 45 , 46 Due to the chemical composition of starch, no major changes were found in st-ZnO, but there was a slight variation in peak intensity 47 and no peaks that corresponded to Nb were found in (2 and 4%) Nb/st-ZnO, implying that ZnO is formed in the pure wurtzite phase. 48 The intensity of ZnO peaks decreased with increasing Nb doping, implying that a higher ratio of Nb in samples makes ZnO least crystalline.…”