Theory and Fundamentals of Ultrasound

Wu, Ta Yeong; Guo, Ningqun; Teh, Chee Yang; Hay, Jacqueline Xiao Wen

doi:10.1007/978-94-007-5533-8_2

Cited by 63 publications

(33 citation statements)

References 18 publications

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“…It is also evident from the literature that ultrasonic frequency is one of the significant factors affecting acoustic cavitation (Tiwari, ). Improved extraction efficiency at lower frequency may be linked to the generation of larger but relatively fewer cavitational bubbles which implode with higher energy level, thus resulting in a greater degree of cell disruption (Wu et al ., ).…”

Section: Resultsmentioning

confidence: 97%

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Kumari

Tiwari

Hossain

et al. 2017

Int J of Food Sci Tech

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Ultrasound-assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream-skinned Lady Claire (LC) and pink-skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE-untreated (control) and the UAE-treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid-liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography-tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R 2 > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.Ultrasonic extraction of potato-peel phenolics B. Kumari et al. * Significant difference (P < 0.05) within a column, relative to SLE treatment between the variety. ** Significant difference (P < 0.05) within a column, relative to LR variety between extraction conditions. abc Letters followed by different alphabet within a column are significantly different (P < 0.05), relative to LC variety among extraction conditions.

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Section: Resultsmentioning

confidence: 97%

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Kumari

Tiwari

Hossain

et al. 2017

Int J of Food Sci Tech

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“…A energia liberada durante esse processo é o princípio da sonoquímica; de acordo com a teoria mais aceita, no momento de implosão das bolhas, condições de milhares de kelvins e centenas de atmosferas são produzidas em pequenos pontos (teoria do hot spot). Estas condições duram tempos muito curtos, porém suficientes para promover a geração de radicais tais como hidroxila, hidrogênio ( • H) e hidroperoxila (HO2 • ) [86][87][88] .…”

Section: Sonoquímicaunclassified

“…Por outro lado, em frequências altas, as bolhas de cavitação são estáveis e seus colapsos são menos violentos. Nesse caso, os radicais ainda podem ser produzidos dentro das bolhas e a maior estabilidade permite o escape desses radicais para o seio da solução 87,88,90…”

Section: Efeito Da Frequência Ultrassônicaunclassified

“…9.4 é mostrado que o efeito de crescimento das micelas ocorre em uma escala muito menor quando o ultrassom de 1 MHz e 10 MHz são utilizados. A alta frequência ultrassônica promove a cavitação estável, na qual as bolhas oscilam por mais tempo, tendo maior tempo de vida e um colapso menos violento 87,88 . Nessas condições, parece que a radiação US atua sobre as bolhas de gases eletrogerados, promovendo oscilações por maiores períodos e inibindo o crescimento das micelas.…”

Section: Os Intermediários Observados Naunclassified

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Efeito interferente de compostos orgânicos no tratamento de efluentes sintéticos, contendo metil parabeno por processos eletroquímicos

Dionísio¹

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“…15.3). This mechanism takes place owing to the asymmetric collapse of the microbubbles, which can reach a speed on the order of 100 m/s (Wu et al, 2013). This causes the erosion of the food surfaces, increasing the superficial area and reducing the external resistance to mass transfer.…”

Section: Mechanisms That Reduce External Resistancementioning

confidence: 99%

Ultrasound assisted hydration of grains with sigmoidal behavior: kinetics of hydration, cooking, germination and nutrient incorporation

Pastor¹,

Claudio²

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Ultrasound assisted hydration of grains with sigmoidal behavior: kinetics of hydration, cooking, germination and nutrient incorporationThis Thesis had as objectives to study the hydration process of grains with sigmoidal behavior, evaluating ultrasound technology to improve it, the possible effects on germination, cooking and a possible incorporation of nutrients. The work was developed in three parts. The first part consisted of describing the hydration kinetics of many grains to have a data bank of hydration kinetics, allowing further selections. Furthermore, this part compared the differences among grains hydration kinetics, associating them with the intrinsic properties of the grains and questioning some inferences previously published in the literature. The second part was related to study the effect of ultrasound on the hydration kinetics of grains with sigmoidal behavior, being studied Andean lupin, mung beans and white kidney beans. Further, the effect of ultrasound in combination with soaking water at high temperatures was studied to demonstrate if they have additive, synergic or antagonist effect. The effect of ultrasound technology was evaluated in the water uptake, extraction of components, germination and cooking kinetics. The third part consisted of studying and describing the incorporation of a nutrient inside the grains, taking advantage of the hydration process. Further, ultrasound was used to improve this incorporation. The main results of this work corroborate that the hydration process is a complex phenomenon, and many intrinsic properties of the grains causes the kinetics differences. In addition, the fact that only legume grains have sigmoidal behavior of hydration was proved. Further, the ultrasound accelerated the hydration process of grains with sigmoidal behavior without affecting the grain starch, improving the extraction of undesirable components, enhancing or hindering the germination (depending on the grain), but without affecting the cooking process. Another result was that the higher the soaking water temperature is, the lower the ultrasound effect on hydration is. Finally, regarding nutrient incorporation, a hydrophilic nutrient (iron) was incorporated in a grain during hydration process demonstrating that it is possible. The iron incorporation had the same behavior as the water uptake, suggesting similar mechanisms and phenomena of mass flow. In addition, the incorporated iron was attached not only to the bean cotyledon, but also mostly in the seed coat. Furthermore, ultrasound technology enhanced this process. The cooking process of the studied grains was improved, and its germination was hindered by the incorporated iron. In conclusion, ultrasound technology can be used for improving the hydration process of grains with sigmoidal behavior, being also practical for nutrient incorporation into grains.

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Theory and Fundamentals of Ultrasound

Cited by 63 publications

References 18 publications

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Efeito interferente de compostos orgânicos no tratamento de efluentes sintéticos, contendo metil parabeno por processos eletroquímicos

Ultrasound assisted hydration of grains with sigmoidal behavior: kinetics of hydration, cooking, germination and nutrient incorporation

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