Unveiling the Transformative Power of Ultrasound on Starch

The application of ultrasound in starch treatment has emerged as a fascinating realm, unleashing areas of intense local heating and high-shear stresses. This process, briefly elucidated by BeMiller and Huber in 2015, has piqued significant interest, especially in the context of low-frequency (16-100 kHz; high-intensity) ultrasound’s potential role in food processing, as highlighted by Ashokkumar in 2015.

Navigating the Ultrasound Landscape

The treatment of starches with ultrasound unfolds in aqueous systems, with a myriad of variables influencing outcomes. From the nature of the medium, concentrations of dissolved gases, and treatment time to starch concentration, power, frequency, and amplitude of ultrasound, each parameter contributes to the nuanced effects observed during ultrasound treatment.

Diverse Outcomes: A Symphony of Changes

Under varying treatment conditions, the same starch or different starches subjected to identical conditions yield diverse results. The degree of change intensifies with treatment duration. These changes encompass granule surface damage, including erosion, pitting, and cracking. Simultaneously, alterations manifest in swelling power, solubility, gel clarity, hardness, adhesiveness, as well as reductions in paste and gel viscosities and the consistency coefficient (k) of pastes, as documented by studies such as those by Majzoobi et al., Hu et al., Amini et al., BeMiller and Huber, and Carmona-Garcia.

Granule Structures Under the Ultrasonic Lens

While ultrasonic energy typically falls short of disrupting granule crystallites, it induces changes in both amorphous and crystalline regions. A general weakening of granule structures is observed, with potential depolymerization of starch polysaccharide molecules. B-type starches might be more susceptible, but conclusive evidence is yet to be established. Studies by Carmona-Garcia et al. hint that larger granules may be more vulnerable to ultrasonication.

Depolymerization Unveiled

While ultrasonic treatment of starch pastes may not conform to traditional definitions of physically modified starch, it sheds light on intriguing changes, particularly depolymerization. OH radicals and mechanical effects are proposed culprits behind chain cleavages during ultrasonic treatment, leading to substantial decreases in paste viscosity, as discussed by BeMiller and Huber in 2015. The reduction in paste viscosities is attributed not only to the generation of OH radicals but also to disrupted swollen granules and the disintegration of supermolecular aggregates.

Beyond Modification: Facilitating Hydrolysis and Porosity

Ultrasound, extending its utility beyond physical modification, weakens granule structures, rendering it a tool for facilitating both acid- and enzyme-catalyzed hydrolysis of starch. This has practical applications, especially in producing porous starch granules using amylases. Recent interest also revolves around ultrasound’s role in the production of starch nanocrystals/nanoparticles, adding a layer of innovation to its diverse applications.

In the intricate interplay of ultrasound and starch, the outcomes are as diverse as the variables influencing the process. This exploration not only unravels the transformative effects of ultrasound but also provides a nuanced understanding of the intricate changes occurring within starch granules under the influence of this powerful technology.

Leave a Reply

Your email address will not be published. Required fields are marked *