Electron beam irradiation pretreatment enhances the formation of granular starch-phenolics complexes

Research on electron beam irradiation in the multiscale structure of starch and its related applications: A review

Electron beam irradiation (EBI), as a typical "green" emerging technology, can effectively alter the functional properties of starch by influencing its microstructure. This alteration enables starch to meet the current demands of consumers and the market for "health food." This paper reviews studies on modifying various starches using EBI and describes the changes in microstructure, physicochemical properties, and functional properties induced by this method. Additionally, the effects of EBI on starch-containing food products are discussed, along with issues to be addressed and research gaps in the synergistic treatment of modified starch. It is noted that the source, irradiation dose, and irradiation time all influence the effectiveness of starch modification. Given the characteristics of EBI technology, integrating physical, chemical, and biological modification methods can optimize the modification process and enhance efficiency. This technology can potentially diversify modified starch varieties and expand their applications. Furthermore, there remains significant research potential in producing modified starch using EBI technology and applying it to the food industry.

Synergistic modification of hot-melt extrusion and nobiletin on the multi-scale structures, interactions, thermal properties, and in vitro digestibility of rice starch

Background

Rice starch has high digestibility due to its large carbohydrate content. Synergistic modification of hot-melt extrusion (HME) and additives such as flavonoids, hydrocolloids, proteins, lipids, and other additives has the tendency to retard the rate of starch hydrolysis. Hence, the current investigation aimed to study the combined effect of the HME-assisted addition of nobiletin (NOB, 0, 2, 4, and 6%) on the multi-scale structures, interactions, thermal, and digestibility characteristics of rice starch.

Methods

The study employed density functional theory calculations and an infrared second derivative of an Fourier-transform infrared (FTIR) spectrometer to analyze the interactions between NOB and starch. The physicochemical properties of the starch extrudates were characterized by FTIR, 13C nuclear magnetic resonance, X-ray diffraction, and differential scanning calorimetry, while the digestibility was evaluated using an in vitro digestion model.

Results

HME was found to disrupt the crystalline structure, helix structure, short-ordered structure, and thermal properties of starch. The interaction between NOB and starch involved hydrophobic interactions and hydrogen bonds, effectively preventing the molecular chains of starch from interacting with each other and disrupting their double helix structure. The addition of NOB led to the formation of a highly single-helical V-type crystalline structure, along with the formation of ordered structural domains. Consequently, the combined treatment significantly enhanced the ordered structure and thermal stability of starch, thus effectively leading to an increase in resistant starch and slowly digestion starch.

Discussion

The study underscores that synergistic modification of HME and NOB holds promise for enhancing both the nutritional value and functional properties of rice starch. These findings offer valuable insights for developing high-quality rice starch products with broader applications.

Gallic acid forms V-amylose complex structure with starch through hydrophobic interaction

This study aimed to investigate the role of amylose and amylopectin in the formation of starch-polyphenol complex and elucidate the interaction mechanisms. Gallic acid (GA) was used to complex with maize starch with various amylose contents. Results showed GA formed V-type crystals with normal maize starch (NMS) and high amylose maize starch (HAMS), while higher relative crystallinity was exhibited in HAMS-GA complexes than NMS counterparts. Molecular structure analysis revealed more amylose in GA-starch complexes than in treated starch counterparts without GA, and this was more apparent in HAMS than NMS, implying amylose is preferred to complex with GA than amylopectin. FTIR detected higher R1047/1022 value in starch-GA complexes than their starch counterparts without GA, suggesting increased short-range ordered structrure of complexes. Typical signatures of hydrophobic interactions were further revealed by isothermal titration calorimetry, indicating the complexation of GA to starch is mainly through hydrophobic bonds. More binding sites were observed for HAMS (72.50) than NMS (11.33), which proves the preferences of amylose to bind with GA. Molecular dynamics simulated the complexation of GA to amylose, and confirmed hydrophobic bond is the main interaction force. These findings would provide guidance for precise design and utilization of starch-polyphenol complexes in functional foods.

Effects of ultrasound-induced V-type rice starch-tannic acid interactions on starch in vitro digestion and multiscale structural properties

V-type starch-polyphenol complexes, known for their improved physicochemical properties compared to native starch, are challenging to form efficiently. In this study, the effects of tannic acid (TA) interaction with native rice starch (NS) on digestion and physicochemical properties were investigated using non-thermal ultrasound treatment (UT). Results showed the highest complexing index for NSTA-UT3 (∼ 0.882) compared to NSTA-PM (∼0.618). NSTA-UT complexes reflected the V6I-type complex having six anhydrous glucose per unit per turn with peaks at 2θ = 7°, 13°, and 20°. The maxima of the absorption for iodine binding were suppressed by the formation of V-type complexes depending on the concentration of TA in the complex. Furthermore, rheology and particle size distributions were also affected by TA introduction under ultrasound, as revealed by SEM. XRD, FT-IR, and TGA analyses confirmed V-type complex formation for NSTA-UT samples, with improved thermal stability and increased short-range ordered structure. Ultrasound-induced addition of TA also decreased the hydrolysis rate and increased resistant starch (RS) concentration. Overall, ultrasound processing promoted the formation of V-type NSTA complexes, suggesting that tannic acid could be utilized for the production of anti-digestion starchy foods in the future.

Synergistic impact of heat-ultrasound treatment on the properties and digestibility of Sagittaria sagittifolia L. starch-phenolic acid complexes

The current research investigated the multi-scale structural interactions between arrowhead starch (AS) and phenolic acids, such as ferulic acid (FA) and gallic acid (GA) to identify the mechanism of anti-digestion effects of starch. AS suspensions containing 10 % (w/w) GA or FA were subjected to physical mixing (PM) followed by heat treatment at 70 °C for 20 min (HT) and a synergistic heat-ultrasound treatment (HUT) for 20 min using a dual-frequency 20/40 KHz system. The synergistic HUT significantly (p < 0.05) increased the dispersion of phenolic acids in the amylose cavity, with GA showing a higher complexation index than FA. XRD analysis showed a typical V-type pattern for GA, indicating the formation of an inclusion complex, while peak intensities decreased for FA following HT and HUT. FTIR revealed sharper peaks possibly of amide bands in the ASGA-HUT sample compared to that of ASFA-HUT. Additionally, the emergence of cracks, fissures, and ruptures was more pronounced in the HUT-treated GA and FA complexes. Raman spectroscopy provided further insight into the structural attributes and compositional changes within the sample matrix. The synergistic application of HUT led to increased particle size in the form of complex aggregates, ultimately improving the digestion resistance of the starch-phenolic acid complexes.