Structure characterization of C-type starch granule by acid hydrolysis

Physical Properties of Starches Modified by Phosphorylation and High-Voltage Electrical Discharge (HVED)

High-voltage electrical discharge (HVED) is considered as a novel, non-thermal process and is currently being researched regarding its effect on microorganisms (decontamination of food), waste water treatment, and modification of different compounds and food components. In this paper, four native starches (maize, wheat, potato, and tapioca) were treated with HVED, phosphorylated with Na₂HPO₄ and Na₅P₃O₁₀, and modified by a combination of HVED with each phosphorylation reaction both prior and after chemical modification. Pasting properties, swelling power, solubility, gel texture, and particle size were analyzed. Although HVED induced lower contents of P in modified starches, it had an effect on analyzed properties. The results revealed that HVED treatment alone had a limited effect on pasting properties of starches, but it had an effect on properties of phosphorylated starches, both when it was conducted prior and after the chemical modification, reducing the influence of Na₅P₃O₁₀ and Na₂HPO₄ on the decrease of pasting temperature. With minor exceptions, the gel strength of starches increased, and the rupture strength decreased by all modifications. HVED treatment resulted in a decrease of the particle size after the modification of maize and wheat starches, while potato and tapioca starches were not significantly influenced by the treatment.

In situ 13 C solid-state polarization transfer NMR to follow starch transformations in food

Convenience food products tend to alter their quality and texture while stored. Texture-giving food components are often starch-rich ingredients, such as pasta or rice. Starch transforms depending on time, temperature and water content, which alters the properties of products. Monitoring these transformations, which are associated with a change in mobility of the starch chain segments, could optimize the quality of food products containing multiple ingredients. In order to do so, we applied a simple and efficient in situ ¹³ C solid-state magic angle spinning (MAS) NMR approach, based on two different polarization transfer schemes, cross polarization (CP) and insensitive nuclei enhanced by polarization transfer (INEPT). The efficiency of the CP and INEPT transfer depends strongly on the mobility of chain segments-the time scale of reorientation of the CH-bond and the order parameter. Rigid crystalline or amorphous starch chains give rise to CP peaks, whereas mobile gelatinized starch chains appear as INEPT peaks. Comparing ¹³ C solid-state MAS NMR experiments based on CP and INEPT allows insight into the progress of gelatinization, and other starch transformations, by reporting on both rigid and mobile starch chains simultaneously with atomic resolution by the ¹³ C chemical shift. In conjunction with ¹ H solid-state MAS NMR, complementary information about other food components present at low concentration, such as lipids and protein, can be obtained. We demonstrate our approach on starch-based products and commercial pasta as a function of temperature and storage.

Synthesis and Characterization of Cassava Starch Nanocrystals by Hydrolysis Method

Cassava starch nanocrystals (CSN) has not been reported in open literature, although other starches such as rice, corn, potato and bean were widely used as the main material. Thus, the objective of this research was to investigate the possibility of synthesizing high yield of CSN at different concentration of sulphuric acid (H2SO4). The physical and chemical properties of synthesize CSN was also investigated. Synthesized CSN was prepared by hydrolysing native cassava starch (NCS) with several concentration of H2SO4 (2.8 M, 3.0 M, 3.2 M and 3.4 M). The acid hydrolysis process took five days with continuous stirring speed of 300 to 400 rpm, with constant temperature of 37 °C. The hydrolysed solution of CSN underwent centrifuging process with distilled water until neutral to make sure that no acid residues remain in the CSN solution. The CSN precipitate was dried in an oven over night at 60 °C. The highest yield (1.1 %) produced was from 3.4 M CSN. Morphology test by Transmission Electron Microscopy indicated that the samples have been destructed and degraded to be nanocrystals with a size range of 5 - 20 nm. X-ray Diffraction (XRD) and 13C Nuclear Magnetic Resonance (NMR) were used to indicate the type of crystallinity for both NCS and CSN.