scholarly journals Current Applications of Ultrasound in Fruit and Vegetables Osmotic Dehydration Processes

2021 ◽  
Vol 11 (3) ◽  
pp. 1269 ◽  
Author(s):  
Małgorzata Nowacka ◽  
Magdalena Dadan ◽  
Urszula Tylewicz
Keyword(s):  
Food Processing ◽  
Fruits And Vegetables ◽  
Osmotic Dehydration ◽  
Reduced Pressure ◽  
Transfer Processes ◽  
Long Duration ◽  
Mass And Heat Transfer ◽  
Ultrasound Assisted ◽  
Dehydration Processes

Ultrasound (US) is a promising technology, which can be used to improve the efficacy of the processes in food technology and the quality of final product. US technique is used, e.g., to support mass and heat transfer processes, such as osmotic dehydration, drying and freezing, as well as extraction, crystallization, emulsification, filtration, etc. Osmotic dehydration (OD) is a well-known process applied in food processing; however, improvements are required due to the long duration of the process. Therefore, many recent studies focus on the development of OD combined with sonication as a pretreatment method and support during the OD process. The article describes the mechanism of the OD process as well as those of US and changes in microstructure caused by sonication. Furthermore, it focuses on current applications of US in fruits and vegetables OD processes, comparison of ultrasound-assisted osmotic dehydration to sonication treatment and synergic effect of US and other innovative technics/treatments in OD (such as innovative osmotic solutions, blanching, pulsed electric field, reduced pressure and edible coatings). Additionally, the physical and functional properties of tissue subjected to ultrasound pretreatment before OD as well as ultrasound-assisted osmotic dehydration are described.

Fundamentals and Application of Osmotic Dehydration

2016 ◽  
Vol 7 ◽  
pp. 14-29
Author(s):  
M. Vázquez da Silva ◽  
J.M.P.Q. Delgado
Keyword(s):  
Fruits And Vegetables ◽  
Osmotic Dehydration ◽  
Structural Characteristics ◽  
Process Equipment ◽  
Hypertonic Solution ◽  
Water Removal ◽  
Mass Fluxes ◽  
Pre Treatment ◽  
Predicted Values

Osmotic dehydration is a water removal process that consists of placing foods, such as pieces of fruits and vegetables, in a hypertonic solution. Both mass fluxes lead to a decrease of the water activity in the product, increasing its shelf life. It can be used as a single dehydration process or as a pre-treatment of other processes such as drying, pasteurization or freezing. Heat and mass transfer gradients associated to the process produce changes in the chemical, physical and structural characteristics of the vegetable tissue. The knowledge and prediction of these changes are very important because they affect the quality of the final product, process modelling and design of process equipment. This work presents some new experimental data during osmotic dehydration of fruits. Some models were used so as to obtain predicted values during osmotic dehydration.

scholarly journals Influence of osmotic dehydration on bioactive compounds, antioxidant capacity, color and texture of fruits and vegetables: a review

2016 ◽  
Vol 46 (10) ◽  
pp. 1714-1722 ◽  
Author(s):  
Ana Paula Miguel Landim ◽  
Maria Ivone Martins Jacintho Barbosa ◽  
José Lucena Barbosa Júnior
Keyword(s):  
Antioxidant Capacity ◽  
Fruits And Vegetables ◽  
Osmotic Dehydration ◽  
Vegetable Crops ◽  
Analysis Method ◽  
Solid Gain ◽  
Current Scenario ◽  
Osmotic Agent ◽  
Process Factors

ABSTRACT: Osmotic dehydration (OD) is a conservation technique applied to foodstuffs, which promotes partial reduction of water, extends their shelf life and reduces both post-harvest losses and changes in product characteristics. Currently, it has been given emphasis on trying to understand how the process affects the quality of processed vegetables, because process variables can interfere in their antioxidant capacity, color and texture. Moreover, the antioxidant capacity can be affected by chemical changes, leaching losses, reduced moisture and solid gain as well as the present bioactive in the profile of the performed analysis method. In color, the overall changes are caused by temperature increase, which can cause enzymatic and/or non-enzymatic browning, decomposition or entrainment of pigments present in the tissue. Conversely, the osmotic agent has a greater impact on texture, which causes changes in the sensory attributes such as gumminess, even crispness and flavor of the product. Although there is a large number of studies on the OD, the current scenario in terms of effect on the quality of osmodehydrated products are still incipient, especially in relation to antioxidant capacity. Despite the fact that there is a large number of studies on the OD, current efforts are focused on understanding the process effect on the product quality, notably in relation to antioxidant capacity. Thus, further studies on the internal changes in osmodehydrated foods are needed, since there is a variation of process factors, which may have an impact on the different tissues of the fruit and vegetable crops submitted to OD.

scholarly journals Impact of ultrasound-assisted osmotic dehydration as a pre-treatment on the quality of heat pump dried tilapia fillets

2017 ◽  
Vol 123 ◽  
pp. 243-255 ◽  
Author(s):  
Min Li ◽  
Biao Ye ◽  
Zhiqiang Guan ◽  
Yunting Ge ◽  
Jun Li ◽  
...  
Keyword(s):  
Heat Pump ◽  
Osmotic Dehydration ◽  
Ultrasound Assisted ◽  
Tilapia Fillets ◽  
Pre Treatment

Principles for construction of bioluminescent enzyme biotests for analysis of complex media

2019 ◽  
Vol 485 (2) ◽  
pp. 229-233
Author(s):  
V. P. Kalyabina ◽  
E. N. Esimbekova ◽  
I. G. Torgashina ◽  
K. V. Kopylova ◽  
V. A. Kratasyuk
Keyword(s):  
Fruits And Vegetables ◽  
Rapid Assessment ◽  
Test System ◽  
Maximum Sensitivity ◽  
Toxic Chemicals ◽  
Complex Media ◽  
Luminescent Bacterium ◽  
Chemical Safety ◽  
Minimal Impact

We formulated the principles of designing bioluminescent enzyme tests for assessing the quality of complex media which consist in providing the maximum sensitivity to potentially toxic chemicals at a minimal impact of uncontaminated complex media. The developed principles served as a basis for designing a new bioluminescent method for an integrated rapid assessment of chemical safety of fruits and vegetables which is based on using the luminescent bacterium enzymes (NAD(P)H:FMN oxidoreductase and luciferase) as a test system.

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

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