The effect of multifrequency ultrasound treatments on structure, rheological, and digestive properties of starch in frozen wheat dough

Abstract

This study explores the impact of multifrequency ultrasonic treatments on the properties of wheat frozen dough starch at different treatment times (15, 25, and 35 min). Fundamental properties analyzed included particle size, solubility, swelling power, differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), morphological traits, digestibility, and rheological characteristics. Results indicate that ultrasonication (US) enhances the amylose content, solubility, and swelling power of the frozen wheat dough starch. Treatment led to a significant increase (p < 0.05) in rapidly digestible starch (RDS) and resistant starch (RS) with a longer exposure time. Specifically, RDS content rose 30 % with multifrequency ultrasound (T2 20/40/60/25 min), while RS and slowly digested starch (SDS) decreased at 35 min. FTIR analysis revealed notable peaks between 3290 and 3299 cm⁻¹, corresponding to the O-H stretching of hydroxyl groups. Rheological characteristics increased in storage modulus (G’) and loss modulus (G’’) after 25 min (20/40/60) of US, then decreased at 35 min. Ultrasound treatment caused surface depressions and pores on wheat starch granules in the frozen dough. This research highlights the efficacy of multifrequency US in augmenting the functional, rheological, and ultra-structural properties of wheat frozen dough. By counteracting the deleterious effects of freezing, this innovative approach shows considerable promise in enhancing the processing quality of frozen dough starch.