Ultrasound technologies are increasingly used for modification of physicochemical properties of food systems. Effects of ultrasound (20 kHz, 750 W) up to 20 h on physicochemical properties of two varieties of sweetpotato flour were studied and compared with those of commercial wheat flour. Ultrasound induced structural modifications on starch granules mainly in the morphological changes of granules and reduction of the crystallinity. Longer treatment significantly decreased enthalpy change of gelatinization, pasting viscosities, gelling capacity, while increasing in vitro starch digestibility of raw flour. Besides, prolonged treatment reduced total phenolic contents and in vitro antioxidant activities of sweetpotato flours, mainly due to pyrolysis and release of hydroxyl radicals caused by cavitation. The extents of these changes were seen to depend on the treatment time and indicated degradation and modifications of the chemical components (e.g., starch and polyphenol) of flours. This study suggests that ultrasound processing as a non-thermal and energy-saving technique has potential to modify flour functionalities.

中文翻译：

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超声波对甘薯和小麦粉结构和理化特性的影响。

超声波技术越来越多地用于改变食品系统的理化特性。研究了长达20 h的超声（20 kHz，750 W）对两种甘薯粉的理化特性的影响，并与市售小麦粉进行了比较。超声对淀粉颗粒的结构修饰主要是颗粒的形态变化和结晶度降低。更长的处理时间显着降低了糊化的焓变，糊化粘度，胶凝能力，同时增加了生粉的体外淀粉消化率。此外，长时间的处理降低了甘薯粉的总酚含量和体外抗氧化活性，这主要是由于空化作用引起的热解和羟基自由基的释放。可以看出这些变化的程度取决于处理时间，并且表明面粉的化学成分（例如淀粉和多酚）的降解和修饰。这项研究表明，作为非热节能技术的超声处理具有改变面粉功能的潜力。