Effect of ultrahigh pressure on structural and physicochemical properties of rice and corn starch in complexes with apple polyphenols

Abstract BACKGROUND Ultrahigh‐pressure (UHP) treatment, a non‐thermal processing technology, exerts a bactericidal effect and affects food texture. How UHP treatments influence starch–polyphenol complexes has not yet been reported. Here, we studied the effects of UHP treatment on the structure of common rice starch (CRS)–apple polyphenol (AP) and common corn starch (CCS)–AP mixtures. RESULTS Overall, UHP treatment decreased the particle size of the CRS–AP and CCS–AP composites. Furthermore, the Δ H values of the CRS–AP and CCS–AP mixtures decreased, and the heating stability was improved after UHP treatment. X‐ray diffraction indicated that the relative crystallinity of the mixtures was unaffected by UHP treatment. Fourier‐transform infrared spectroscopy proved that no new absorption peaks were observed in the infrared spectra, and the order of starch – AP was decreased after UHP treatment. These results indicated that UHP treatment inhibited the retrogradation of the starch–AP mixture. Our analyses of the microstructures of CRS–AP and CCS–AP mixtures showed increased folding and more pronounced network structures under high‐pressure. CONCLUSIONS These results provide a theoretical basis for further exploring the properties of starch–AP mixtures following UHP treatment and provide insights regarding the use of UHP treatments for food production. © 2020 Society of Chemical Industry