RESUMEN
This study aimed to investigate the multiscale structure, physicochemical properties, and in vitro digestibility of black rice starch (BRS) and gallic acid (GA) complexes prepared using varying ultrasound powers. The findings revealed that ultrasonic treatment disrupted BRS granules while enhancing the composite degree with GA. The starch granules enlarged and aggregated into complexes with uneven surfaces. Moreover, the crystallinity of the BRS-GA complexes increased to 22.73 % and formed V6-I-type complexes through non-covalent bonds. The increased short-range ordering of the complexes and nuclear magnetic resonance hydrogen (1H NMR) further indicated that the BRS and GA molecules interacted mainly through non-covalent bonds such as hydrogen bonds. Additionally, ultrasound reduced the viscoelasticity of the complexes while minimizing the mass loss of the complexes at the same temperature. In vitro digestion results demonstrated an increase in resistant starch content up to 37.60 % for the BRS-GA complexes. Therefore, ultrasound contributes to the formation of V-typed complexes of BRS and GA, which proves the feasibility of using ultrasound alone for the preparation of starch and polyphenol complexes while providing a basis for the multiscale structure and digestibility of polyphenol and starch complexes.
Asunto(s)
Oryza , Oryza/química , Ácido Gálico/química , Digestión , Almidón/química , PolifenolesRESUMEN
In this study, type III resistant starch (RS3) was prepared from high amylose maize starch (HAMS) using hydrothermal (RS-H), hydrothermal combined ultrasonication (RS-HU), hydrothermal-alkali (RS-HA), and hydrothermal-alkali combined ultrasonication (RS-HAU). The role of the preparation methods and the mechanism of RS3 formation were analyzed by studying the multiscale structure and digestibility of the starch. The SEM, NMR, and GPC results showed that hydrothermal-alkali combined with ultrasonication could destroy the granule structure and α-1,6 glycosidic bond of HAMS and reduce the molecular weight of HAMS from 195.306 kDa to 157.115 kDa. The other methods had a weaker degree of effect on the structure of HAMS, especially hydrothermal and hydrothermal combined ultrasonication. The multiscale structural results showed that the relative crystallinity, short-range orderliness, and thermal stability of RS-HAU were significantly higher compared with native HAMS. In terms of digestion, RS-HAU had the highest RS content of 69.40 %. In summary, HAMS can generate many short-chain amylose due to structural damage, which rearrange to form digestion-resistant crystals. With correlation analysis, we revealed the relationship between the multiscale structure and the RS content, which can be used to guide the preparation of RS3.
Asunto(s)
Amilosa , Almidón Resistente , Amilosa/química , Zea mays/química , Ultrasonido , Digestión , Almidón/químicaRESUMEN
In this study, high amylose maize starch(HAMS)was treated by Hydrothermal-alkali. SEM, SAXS, XRD, FTIR, LC-Raman, 13C CP/MAS NMR, GPC and TGA were used to study the changes in the granules and structure of HAMS. The results show that the granule morphology, lamellar structure, and birefringence of HAMS remained intact at 30 °C and 45 °C. With increasing temperature, the starch granules are fragmented, and the crystallinity, DD, FWHM values, molecular weight, and thermal stability of HAMS decrease. The double helical structure dissociated, and the content of amorphous regions increased, indicating the from order to the disorder of the HAMS structure. A similar annealing behavior occurred in HAMS at 45 °C, with the rearrangement of amylose and amylopectin occurring. At 75 °C and 90 °C, the short-chain starch produced by chain breakage regroups to form an ordered double helix structure. In general, the granule structure level of HAMS was damaged to different degrees at varying temperatures. HAMS showed gelatinization behavior in alkaline solutions when the temperature is 60 °C. This study expects to provide a model for the gelatinization theory of HAMS systems.
Asunto(s)
Amilosa , Zea mays , Amilosa/química , Temperatura , Zea mays/química , Dispersión del Ángulo Pequeño , Difracción de Rayos X , Almidón/químicaRESUMEN
In this work, Corn Starch (CS)-Lauric acid (LA) complexes prepared by different ultrasound times were explored for multi-scale structure and digestibility. The results showed that the average molecular weight of the CS decreased from 380.478 to 323.989 kDa and the transparency increased to 38.55 % after 30 min of ultrasound treatment. The scanning electron microscope (SEM) results revealed a rough surface and agglomeration of the prepared complexes. The complexing index of the CS-LA complexes increased by 14.03 % compared to the non-ultrasound group. The prepared CS-LA complexes formed a more ordered helical structure and a more dense V-shaped crystal structure through hydrophobic interactions and hydrogen bonding. In addition, fourier transforms infrared spectroscopy and the molecular docking revealed that the hydrogen bonds formed by CS and LA promoted the formation of an ordered structure of the polymer, retarding the diffusion of the enzyme and thus reducing the digestibility of the starch. With correlation analysis, we provided insight into the multi-scale structure-digestibility relationship in the CS-LA complexes, which provided a basis for the relationship between structure and digestibility of lipid-containing starchy foods.
Asunto(s)
Almidón , Almidón/química , Simulación del Acoplamiento Molecular , Espectroscopía Infrarroja por Transformada de Fourier , Enlace de Hidrógeno , Peso MolecularRESUMEN
High amylose corn starch (HACS)-oat ß-glucan (OBG) complex was prepared by ball milling treatment. The morphology and structure of the samples were characterized, and the digestibility of the samples was studied. SEM analysis showed that the grain structure of oat ß-glucan-starch after ball milling showed an irregular aggregate shape. The rheological results indicated that the apparent viscosity of the solution of HACS-OBG complex prepared by ball milling, with the values of both G' and Gâ³ decreasing on the increase of OBG addition. Multi-scale structure analysis showed that the disorder of the crystal structure and short-range structure of the HACS-OBG complex would lead to the decrease of the double helix structure content. In terms of digestibility, the RDS of the complex decreased from 75.88 % to 66.26 %, which suppressed the digestibility of starch. Molecular docking and quantum chemistry techniques further demonstrated the strong hydrogen bond interaction between HACS and OBG and the inhibition rate of OBG on the enzyme, which was conducive to the slow digestion of HACS-OBG complex. Therefore, ball milling treatment can promote the binding of OBG to starch, which may be an effective method for postprandial blood glucose control.