Differences in degradation kinetics for sonolysis, microfluidization and shearing treatments of chitosan

Abstract

Solution concentration, temperature, reaction time and use or non‐use of concurrent ultrafiltration treatment for fragment removal are factors that affect the degradation rate constant in sonolysis, microfluidization and shearing treatments. The cause of these operation conditions and their effect on chitosan degradation rate constant were compared. Different operation conditions for each treatment resulted in various solution viscosities, ease of dissipation of cavitation, entanglement and stretching, in turn resulting in different rates of effectiveness of degradation by different degradation mechanisms. A rationale for applying these physical methods in practical chitosan production is proposed. Copyright © 2011 Society of Chemical Industry

Long-term stability of food-grade nanoemulsions from high methoxyl pectin containing essential oils

“…In previous studies, microfluidization-induced degradation of polymers, which was attributed to mechanical degradation due to powerful shear, turbulence, high-velocity impaction, highfrequency vibration, instantaneous pressure drop, and cavitation forces generated simultaneously during the treatment (Chen, Huang, Tsai, Tseng, & Hsi, 2011;Liu et al, 2009). In this line, the same behavior has been reported by Salvia-Trujillo et al (2013), where they attributed the decrease in viscosity values of nanoemulsions to molecular changes in the structure of sodium alginate present in the aqueous phase.…”

Mechanically modified xanthan gum: Rheology and polydispersity aspects

“…Mechanical modification of biopolymers is similar and has the same objectives as mechanical degradation of synthetic polymers in the sense that the only input is mechanical force at macroscopic level (Yu, Zakin, & Patterson, 1979). Since the polymer molecules respond to the stress applied during the process, by disentanglement, chain orientation and bond rupture (Nguyen & Kausch, 1992), it turns out that if the process is conducted in a controlled and specific manner it can be recognized as energy saving, environment friendly and an effective alternative to enzymatic or chemical modification of biopolymers (Chen, Huang, Tsai, Tseng, & Hsu, 2011;Gulrez, Al-Assaf, Fang, Phillips, & Gunning, 2012;Harte & Venegas, 2010;Villay et al, 2012).…”

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