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[Display omitted] • High hydrostatic pressure modulated the anthocyanin-binding rate of native starches. • Starch's spatial structural change was key to the pressure regulation. • The outside-in binding shift after pressure increased the binding of potato starch. • Decreased ζ potential and specific surface area of pea/corn starch reduced binding. Native starches usually have poor polyphenol-binding efficiency despite remarkable architectural structures. In this study, the interaction between cyandin-3-O-glucose (C3G) and three starches under high hydrostatic pressure was investigated. Pressure (200–550 MPa) was found to promote the binding rate of potato starch from 31.6% to 47.0% but reduced that of corn and pea starch to below 10% at 550 MPa. Microscopy results showed that pressurized corn and pea starch-C3G complexes partially or completely lost spatial structures, whereas potato starch-C3G complexes retained structural integrity. The former had decreased zeta potentials and increased particle sizes at 550 MPa, suggesting surface charges and specific surface area losses caused poor binding. Potato starch-C3G complexes, however, exhibited unchanged zeta potential and particle size but the strongest fluorescence at 200 MPa, indicating a positive binding shift from surface to interior. Overall, high hydrostatic pressure can regulate the interactions of native starches with anthocyanins via spatial structural changes. [ABSTRACT FROM AUTHOR]

The effects of high pressure homogenization (HPH) at different pressures (50, 100, 150 and 200 MPa) and temperatures (4, 20, 40, 60 and 80 °C) on the interaction between corn starch (CS) and cyanidin-3-O-glucoside (C3G) were investigated. Based on analyses of zeta potential, attenuated total reflection-flourier transformed infrared spectroscopy and binding rate after adding shielding agents, the main interaction force changed from electrostatic interaction to hydrogen bonds. In comparison, the interaction between CS and C3G exhibited greater strength at low temperatures and pressures. Especially, 4 °C/50 MPa HPH caused the most significant enhancement in binding rate and binding amount, from 9.56 % to 25.16 % and 0.96 μg/mg CS to 2.52 μg/mg CS, respectively. At this condition, the specific surface area of CS-C3G increased from 433.57 ± 0.91 m2/kg to 440.93 ± 1.01 m2/kg. Surface fluorescence reduction was observed by confocal laser scanning microscopy, further X-ray diffraction patterns indicated the retention of partial spatial structure. Therefore, HPH opened the entry channels, increased contact area and preserved steric hindrance, which increased hydrogen bonding sites. At high temperatures and high pressures (> 40 °C, > 100 MPa), the increasing free starch chains provided new hydrogen bonding sites. Overall, HPH was an effective method to enhance the interaction by affecting starch structure. • The highest binding of cyanidin-3-O-glucose to corn starch occurred at 4 °C/50 MPa. • Specific surface area, spatial structure and free starch chain were main factors. • After processing, electrostatic interactions change to hydrogen bonds. • Thermally stable complexes were formed by high pressure homogenization. [ABSTRACT FROM AUTHOR]

The effects of high pressure homogenization (HPH) at different pressures (50, 100, 150 and 200 MPa) and temperatures (4, 20, 40, 60 and 80 °C) on the interaction between corn starch (CS) and cyanidin-3-O-glucoside (C3G) were investigated. Based on analyses of zeta potential, attenuated total reflection-flourier transformed infrared spectroscopy and binding rate after adding shielding agents, the main interaction force changed from electrostatic interaction to hydrogen bonds. In comparison, the interaction between CS and C3G exhibited greater strength at low temperatures and pressures. Especially, 4 °C/50 MPa HPH caused the most significant enhancement in binding rate and binding amount, from 9.56 % to 25.16 % and 0.96 μg/mg CS to 2.52 μg/mg CS, respectively. At this condition, the specific surface area of CS-C3G increased from 433.57 ± 0.91 m2/kg to 440.93 ± 1.01 m2/kg. Surface fluorescence reduction was observed by confocal laser scanning microscopy, further X-ray diffraction patterns indicated the retention of partial spatial structure. Therefore, HPH opened the entry channels, increased contact area and preserved steric hindrance, which increased hydrogen bonding sites. At high temperatures and high pressures (> 40 °C, > 100 MPa), the increasing free starch chains provided new hydrogen bonding sites. Overall, HPH was an effective method to enhance the interaction by affecting starch structure. • The highest binding of cyanidin-3-O-glucose to corn starch occurred at 4 °C/50 MPa. • Specific surface area, spatial structure and free starch chain were main factors. • After processing, electrostatic interactions change to hydrogen bonds. • Thermally stable complexes were formed by high pressure homogenization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Potato starch exhibited the largest anthocyanin-binding capacity. • Potato starch had high negative charges and form strong electrostatic interactions. • Corn starch had advantageous particle sizes to adsorb anthocyanins. • Negative surface charges and specific surface area were crucial for binding. In this study, the cyanidin-3-O-glucoside (C3G)-binding capacities of three native starches were investigated. While potato starch had the largest binding capacity of 0.34 mg/100 mg, corn and pea starch had binding capacities of 0.17 and 0.06 mg/100 mg. Confocal microscopy confirmed the binding results and revealed close associations between the surface properties and binding capacities. These findings were further substantiated with wettability and gelatinization results. The morphological observations showed that corn starch had advantageous particle sizes and more surface gullies, providing more opportunities to bind C3G. The zeta potential results, however, indicated that potato starch had the highest negative surface charges (−24 mV). These favorable electronic characteristics were believed to be responsible for the strongest electrostatic interactions. Hydrogen bonds, however, had a negligible effect on the formation of complexes. Overall, the negative surface charges and specific surface areas of the native starches were the most important factors determining C3G-binding capacities. [ABSTRACT FROM AUTHOR]

The influence of the system pH (3, 5, and 7) and hydrothermal processing of starch (65 °C/10 min and 95 °C/20 min) on the interaction between cyanidin-3-O-glucoside (C3G) and starch (corn starch, potato starch, and pea starch) were investigated from the molecular interaction force level, molecular structure level, and microscopic level to the macroscopic level. The binding rates and binding amounts are found to increase with increasing pH of the system, and the use of a moderate extent of hydrothermal processing of starch (65 °C/10 min) can elevate the binding rates and binding amounts at pH 5 and 7, that is 65 °C/10 min treated would have the best binding effect compared with 95 °C/20 min treated and untreated starch at pH 5 and 7.With increasing pH, more hydrogen bonds are formed between C3G and starch molecular chains due to the structural changes of C3G at high pH. As the degree of hydrothermal processing of the starch is enhanced, the starch structure is gradually broken, and more starch molecular chains are released, for which the chance to contact C3G improves, enhancing the binding rates and binding amounts, that is the binding rates and binding amounts of 65 °C/10 min and 95 °C/20 min treated are higher than untreated starch. In particular, compared with 95 °C/20 min treated starch, 65 °C/10 min treated starch maintains the spatial three-dimensional structure better and forms more binding cavities and sites. Furthermore, increasing the system pH and the use of a moderate extent of hydrothermal processing simultaneously show a synergistic effect. [Display omitted] • The highest binding rate is achieved at pH 7 and 65 °C/10 min of processing. • With increasing pH, electrostatic interactions change to hydrogen bond formation. • The 65 °C/10 min treated starch has a spatial effect. • pH and hydrothermal processing show a synergistic effect. [ABSTRACT FROM AUTHOR]