Impact of Ultrasound on the Physical Properties and Interaction of Chitosan–Sodium Alginate

Rheological properties of carboxymethyl cellulose (CMC) solution: Impact of high intensity ultrasound

Today sonication process is used as a new green tool with unique impacts on foods preservation and processing. Ultrasonic modification is an appropriate strategy to obtain good gums with useful physicochemical characteristics and molecular structure. This research aimed to analyze the impacts of sonication at different intensities (0, 75, and 150 W) and time (0, 5, 10, 15, and 20 min) on the viscosity and rheological characteristics of carboxymethyl cellulose (CMC) solution. The results confirmed that the apparent viscosity of CMC solution reduced from 0.030 to 0.021 Pa.s with increasing shear-rate from 12.2 s-1 to 134.5 s-1 (75 W for 10 min). Also, the apparent viscosity of CMC solution reduced from 0.028 to 0.019 Pa.s with enhancing the sonication time from 0 to 20 min (shear-rate = 61 s-1, 150 W). Various rheological equations were employed to fit the empirical values, and the results confirmed that the Power law model was the best fit to explain the flow behaviour of CMC solution. The consistency coefficient of CMC solution significantly reduced from 0.065 Pa.sn to 0.032 Pa.sn (p < 0.05) with enhancing sonication time from 0 to 20 min (75 W). Furthermore, the consistency coefficient of CMC solution decreased significantly (p < 0.05) while the ultrasonic power enhanced. Flow behaviour index of CMC solution enhanced significantly (p < 0.05) while the intensity and time of sonication enhanced.

Ultrasound-assisted fabrication of biopolymer materials: A review

There is an urgent need to develop technologies that can physically manipulate the structure of biocompatible and green polymer materials in order to tune their performance in an efficient, repeatable, easy-to-operate, chemical-free, non-contact, and highly controllable manner. Ultrasound technology produces a cavitation effect that promotes the generation of free radicals, the fracture of chemical chain segments and a rapid change of morphology. The cavitation effects are accompanied by thermal, chemical, and biological effects that interact with the material being studied. With its high efficiency, cleanliness, and reusability applications, ultrasound has a vast range of opportunity within the field of natural polymer-based materials. This work expounds the basic principle of ultrasonic cavitation and analyzes the influence that ultrasonic strength, temperature, frequency and induced liquid surface tension on the physical and chemical properties of biopolymer materials. The mechanism and the influence that ultrasonic modification has on materials is discussed, with highlighted details on the agglomeration, degradation, morphology, structure, and the mechanical properties of these novel materials from naturally derived polymers.

High intensity ultrasound modified ovalbumin: Structure, interface and gelation properties

Influence of high intensity ultrasound (HIUS) on the structure and properties of ovalbumin (OVA) were investigated. It was found that the subunits and secondary structure of OVA did not change significantly with HIUS treatment from the electrophoretic patterns and circular dichroism (CD) spectrum. The amount of free sulfhydryl groups increased and intrinsic fluorescence spectra analysis indicated changes in the tertiary structure and partial unfold of OVA after sonication increased. Compared with the untreated OVA, HIUS treatment increased the emulsifying activity and foaming ability, and decreased interface tension (oil-water and air-water interface), which due to the increased surface hydrophobicity and decreased the surface net charge in OVA, while the emulsifying and foaming stability had no remarkable differences. The increased particle size may be attributed to formation of protein aggregates. Moreover, the gelation temperatures of HIUS-treated samples were higher than the untreated OVA according to the temperature sweep model rheology, and this effect was consistent with the increased in surface hydrophobicity for ultrasound treated OVA. These changes in functional properties of OVA would promote its application in food industry.