Insights into maize starch degradation by sulfuric acid from molecular structure changes

Short-chain glucan self-assembly for green synthesis of functional biomaterials: Mechanism, synthesis, and microstructural control

Short-chain glucan (SCG) is a linear homopolymer containing 10 to 50 glucose units linked with α(1,4) glycosidic bonds. With its abundant, low-cost, nontoxic, biodegradable/biocompatible nature, self-assembled SCG particles (SSC) have emerged as functional biomaterials, which have recently attracted tremendous attentions in various fields. SCG self-assembly occurs through the spontaneous association of molecules under equilibrium conditions into stable and structurally well-defined nanoscale or micrometer-scale aggregates, which is governed by various intermolecular non-covalent interactions, including hydrogen-bonding, electrostatic, hydrophobic, and van der Waals. With precise and effective control of the self-assembly process of SSC, its structural modulation and function integration can be expected. Thus, we convinced that SCG self-assembly could provide an effective means of developing starch-based functional biomaterials with beneficial health properties and wide application in food industries. In this review, we provide an overview of recent advances in the green approach for the self-assembly of SSC, as well as the influence of thermodynamic and kinetic factors on its morphology and physicochemical properties. We highlight recent contributions to developing strategies for the construction of SSC with increasing complexity and functionality that are suitable for a variety of food applications. Finally, we briefly outline our perspectives and discuss the challenges in the field.

Preparation and Drug-Loading Properties of Amphoteric Cassava Starch Nanoparticles

Based on the characteristics of charge reversal around the isoelectric point (pI) of amphoteric starch-containing anionic and cationic groups, amphoteric cassava starch nanoparticles (CA-CANPs) are prepared by a W/O microemulsion crosslinking method using (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride as a cationic reagent and POCl₃ as an anionic reagent, and the effects of preparation conditions on the particle size of the CA-CANPs are studied in detail in the present study. CA-CANPs with a smooth surface and an average diameter of 252 nm are successfully prepared at the following optimised conditions: a crosslinking agent amount of 15 wt%, an aqueous starch concentration of 6.0 wt%, an oil–water ratio of 10:1, a total surfactant amount of 0.20 g·mL⁻¹, and a CHPTAC amount of 4.05 wt%. The pH-responsive value of the CA-CANPs can be regulated by adjusting the nitrogen–phosphorus molar ratio in the CA-CANPs. By using CA-CANPs with a pI of 6.89 as drug carriers and the paclitaxel (PTX) as a model drug, the maximum loading rate of 36.14 mg·g⁻¹ is achieved, and the loading process is consistent with the Langmuir isotherm adsorption, with the calculated thermodynamic parameters of ΔH° = −37.91 kJ·mol⁻¹, ΔS° = −10.96 J·mol⁻¹·K⁻¹ and ΔG° < 0. By testing the release rate in vitro, it is noted that the release rates of PTX in a neutral environment (37.6% after 96 h) and a slightly acidic environment (58.65% after 96 h) are quite different, suggesting that the CA-CANPs have the possibility of being a targeted controlled-release carrier with pH responsiveness for antitumor drugs.

Effects of Processing on Starch Structure, Textural, and Digestive Property of "Horisenbada", a Traditional Mongolian Food

Horisenbada, prepared by the soaking, steaming, and baking of millets, is a traditional Mongolian food and is characterized by its long shelf life, convenience, and nutrition. In this study, the effect of processing on the starch structure, textural, and digestive property of millets was investigated. Compared to the soaking treatment, steaming and baking significantly reduced the molecular size and crystallinity of the millet starch, while baking increased the proportion of long amylose chains, partially destroyed starch granules, and formed a closely packed granular structure. Soaking and steaming significantly reduced the hardness of the millets, while the hardness of baked millets is comparable to that of raw millet grains. By fitting digestive curves with a first-order model and logarithm of the slope (LOS) plot, it showed that the baking treatment significantly reduced the digestibility of millets, the steaming treatment increased the digestibility of millets, while the soaked millets displayed a similar digestive property with raw millets, in terms of both digestion rate and digestion degree. This study could improve the understanding of the effects of processing on the palatability and health benefits of Horisenbada.

Molecular structure of different prepared pyrodextrins and the inhibitory effects on starch retrogradation

Pyrodextrins with different molecular size were prepared by dry heating native corn starch with and without hydrochloric acid (HCl) at 180 °C for 0.5, 3, and 5 h. Those with HCl treatment displayed much smaller molecular size, narrower size distribution, and higher proportion of the chains with the degree of polymerization (DP) ~24-400 than the counterparts without HCl treatment. Pasting and rheological tests showed that the addition of pyrodextrins with HCl treatment displayed lower overall and setback viscosity, and reduced gel development and gel strength in comparison of those without HCl treatment. Differential scanning calorimetry (DSC) and wide-range X-ray (WXRD) data suggested that the pyrodextrin sample prepared by heating native starch with HCl at 180 °C for 5 h (A₅) displayed the most effective inhibition on starch long-term retrogradation. This study could supply a pathway by applying pyrodextrins to both increase nutrition value and retard starch retrogradation for bakery and beverage industry.

Acid hydrolysis of amylose granules and effect of molecular weight on properties of ethanol precipitated amylose nanoparticles

Amylose granules hydrolyzed with 2 M hydrochloric acid for various periods of time were used to prepare amylose nanoparticles through ethanol precipitation. Value of dextrose equivalent, viscosity average molecular weight and molecular chain length distribution of the acid hydrolyzed amylose granules were determined. The precipitated amylose nanoparticles were characterized by using dynamic light scattering and X-ray diffraction. Results showed that, after 48 h acid hydrolysis, viscosity average molecular weight of amylose decreased from 3.35 × 10⁵ to 0.336 × 10⁵ and the amylose macromolecular chains with DP > 1000 were cut into short ones. The short chain sugar molecules derived from the acid hydrolysis were not involved in the ethanol precipitation or incorporated into the precipitated amylose nanoparticles. The length and quantity of the residual amylose macromolecular chains after the acid hydrolysis were the main factors to influence size and crystallinity of the precipitated amylose nanoparticles.