scholarly journals Effects of osmotic dehydration vacuum-microwave drying on the properties of tilapia fillets

2018 ◽  
Vol 36 (No. 2) ◽  
pp. 169-174 ◽  
Author(s):  
Liu Bing ◽  
Cao Jun ◽  
Feng Ai-Guo ◽  
Liu Yan ◽  
Yu Qun ◽  
...  
Keyword(s):  
Power Density ◽  
Osmotic Dehydration ◽  
Colour Change ◽  
Microwave Drying ◽  
Optimum Process ◽  
Drying Time ◽  
Vacuum Degree ◽  
Vacuum Microwave ◽  
Tilapia Fillets ◽  
Microwave Time

A novel drying method based on vacuum-microwave dehydration was developed to investigate the effects of different microwave gap ratios (MGR), microwave times, power densities and degrees of vacuum after osmotic pre-treatment on tilapia fillets. The results showed that the moisture value of fillets was decreased with the increased drying time, power density and vacuum degree. The shrinkage ratio, rehydration ratio and total colour change increased with elevated microwave time and power density. A high degree of vacuum was beneficial to the qualities of fillets. In conclusion, tilapia fillets retained their original quality properties after osmotically dehydrated vacuum-microwave drying (OD-VMD); optimum process parameters were MGR = 2, microwave time = 10 min, power density = 20 W/g, and vacuum degree = 0.08 MPa.

Study on the Effect of Vacuum Microwave Drying on Quality of Okra

2013 ◽  
Vol 791-793 ◽  
pp. 132-136 ◽  
Author(s):  
Jing Yi Li ◽  
Zhen Hua Duan
Keyword(s):  
Microwave Power ◽  
Fracture Resistance ◽  
Colour Change ◽  
Microwave Drying ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Vacuum Degree ◽  
Vacuum Microwave ◽  
The Impact

The purpose of this paper is to investigate the impact of vacuum microwave drying on the quality of okra. The curves of colour, fracture resistance, rehydration ratio and the content of vitaminC were obtained at various drying times, vacuum degrees and microwave powers. Results showed that an increase in drying time and microwave power resulted in serious colour change when compare the dry product to fresh okra. However, the higher the vacuum, the slighter the colour changed. The fracture resistance decreased and the brittleness was good when drying time was increased to high level of 14min and 16min. Increasing vacuum degree also made fracture resistance decreased; rehydration ratio increased with the time and microwave power increased, but decreased if the time exceeds 14min. The rehydration ratio of okra is also affected by the vacuum degree, increasing which led the rehydration ratio increased significantly at the beginning of drying and then slowly; the greater the drying time and microwave power, the more lost of vitaminC, however, higher vacuum degree was found to be beneficial to save the vitaminC.

scholarly journals Influence of vacuum microwave drying parameters on the physicochemical properties of red beetroots

2021 ◽  
Vol 23 (96) ◽  
pp. 8-14
Author(s):  
Yan Liu ◽  
Sergey Sabadash ◽  
Dan Gao ◽  
Feifei Shang ◽  
Zhenhua Duan
Keyword(s):  
Physicochemical Properties ◽  
Microwave Power ◽  
High Vacuum ◽  
Microwave Drying ◽  
Water Evaporation ◽  
Total Phenolic ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Vacuum Degree ◽  
Vacuum Microwave

In recent years, the consumption of red beetroots has increased significantly due to its good taste, high nutritional value and abundant active compounds. Red beetroot is prone to spoilage due to its high moisture content, making it perishable. Vacuum microwave drying is a gentle drying method by inducing fast water evaporation from food products at low temperature, which can improves the product quality. The objective of this study was to investigate the effects of vacuum microwave drying parameters, including microwave power (500, 1000, and 1500 W) and vacuum degree (50, 70, and 90 KPa), on the physicochemical properties (drying time, rehydration ratio, color change, and contents of betalain and total phenolic) of red beetroots. The results showed that microwave power and vacuum degree had significant effects on the physicochemical properties of red beetroots. All the red beetroots after vacuum microwave drying had higher lightness (L*), lower redness (a*) and yellowness (b*) than that of fresh red beetroots. The drying time, rehydration ratio, betacyanin content and betaxanthin content of red beetroots decreased significantly with the increase of microwave power (P < 0.05), while the rehydration ratio, color parameters (a*, b*, and chroma values), betacyanin content and betaxanthin content of red beetroots significantly increased with the increase of vacuum degree (P < 0.05). Compared with other microwave powers, the red beetroots dried at 500 W showed longer drying time, higher rehydration ratio, more yellowish hue, and higher contents of betacyanin and betaxanthin. The lowest values of total color difference (∆E) and hue angle (H°) of dried red beetroots were obtained at microwave power of 1500 W. The dried red beetroots obtained at 90 KPa had the shortest drying time, the highest rehydration ratio, the best color, and the highest contents of betacyanin and betaxanthin. Meanwhile, the red beetroots dried at 50 KPa had the highest total phenolic content (12.47 ± 0.09 mg GAE/g). Based on the physicochemical properties of red beetroots, vacuum microwave drying at low microwave powers and high vacuum degree appears to be a suitable method for drying red beetroots.

scholarly journals Research of physicochemical properties and antioxidant activity of beetroots as affected by vacuum microwave drying conditions

2021 ◽  
Vol 5 (3(61)) ◽  
pp. 40-45
Author(s):  
Yan Liu ◽  
Sergei Sabadash ◽  
Zhenhua Duan
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Physicochemical Properties ◽  
Microwave Power ◽  
Sample Thickness ◽  
Microwave Drying ◽  
Antioxidant Power ◽  
Vacuum Degree ◽  
Vacuum Microwave ◽  
Ferric Reducing Antioxidant Power

The object of research is the beetroots, dried by vacuum microwave drying at different conditions. Physicochemical properties and antioxidant activity of beetroots were studied using vacuum microwave drying at different microwave power (500, 1000, and 1500 W), vacuum degree (–0.05, –0.07, and –0.09 MPa) and sample thickness (2, 4, and 6 mm). A colorimeter was used to evaluate the color quality of beetroots. Colorimetric methods were used to determinate contents of betalain, ascorbic acid and total flavonoid, and antioxidant activity (ferric reducing antioxidant power assay) of beetroots. Results showed that the drying time decreased with increasing microwave power and vacuum degree, while increased significantly with the increase of sample thickness. The lightness (L*) of dried beetroots was higher than that of fresh beetroots. The values of redness (a*) increased with the increase of vacuum degree. The values of yellowness (b*) increased with the growth of vacuum degree and microwave power, while reduced as the sample thickness added. The total color difference (∆E) of dried beetroots reduced with increasing vacuum degree, and displayed the lowest value (5.95) at a vacuum degree of –0.09 MPa as compared to fresh beetroots. The content of betacyanin, betaxanthin and ascorbic acid displayed a declining tendency with the growth of microwave power, while increased with the increase of vacuum degree. And the total flavonoid content of beetroots illustrated a decreasing tendency with the increase of vacuum degree, microwave power and sample thickness. The ferric reducing antioxidant power (FRAP) of dried beetroots decreased significantly with the increase of microwave power, and showed the highest value (14.70 mg trolox equivalents/g) at a microwave power of 500 W. The most favorable conditions for vacuum microwave drying of beetroots were microwave power of 500 W, vacuum degree of –0.09 MPa and sample thickness of 2 mm. It leads to better physicochemical properties of bioactive compounds and higher antioxidant activity of dried beetroots. The dried beetroots can be used as functional foods and value-added food products.

Microwave drying of amaranth and quinoa seeds: effects of the power density on the drying time, germination rate and seedling vigour

2018 ◽  
Vol 52 (4) ◽  
pp. 299-311 ◽  
Author(s):  
Rafael Hernández Maqueda ◽  
Isabel Ballesteros Redondo ◽  
Santiago Jiménez Jácome ◽  
Ángel H. Moreno
Keyword(s):  
Power Density ◽  
Germination Rate ◽  
Microwave Drying ◽  
Seedling Vigour ◽  
Drying Time

scholarly journals Drying of Phyla nodiflora Leaves: Antioxidant Activity, Volatile and Phytosterol Content, Energy Consumption, and Quality Studies

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 210 ◽  
Author(s):  
Lisa Yen Wen Chua ◽  
Bee Lin Chua ◽  
Adam Figiel ◽  
Chien Hwa Chong ◽  
Aneta Wojdyło ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Energy Consumption ◽  
Drying Kinetics ◽  
Microwave Drying ◽  
Convective Drying ◽  
Total Phenolic ◽  
Drying Methods ◽  
Drying Time ◽  
Antioxidant Power ◽  
Vacuum Microwave

Drying is an important process in the preservation of antioxidants in medicinal plants. In this study, leaves of Phyla nodiflora, or commonly known as frog fruit, were dried using convective drying (CD) at 40, 50, and 60 °C; vacuum-microwave drying (VMD) at 6, 9, and 12 W/g; and convective pre-drying followed by vacuum-microwave finish drying (CPD–VMFD) at 50 °C and 9 W/g. Drying kinetics of P. nodiflora leaves was modelled, and the influences of drying methods on the antioxidant activity, total phenolic content, volatile and phytosterol contents, energy consumption, water activity, and color properties were determined. Results showed that drying kinetics was best described by modified Page model. VMD achieved highest drying rate, whereas VMFD considerably reduced the drying time of CD from 240 min to 105 min. CPD–VMFD was the best option to dry P. nodiflora in terms of retaining volatiles and phytosterols, with lower energy consumption than CD. Meanwhile, VMD at 6 W/g produced samples with the highest antioxidant activity with 2,2′-Azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) value of 11.00 and 15.99 µM Trolox/100 g dw, respectively.

Applications of Several Hybrid Drying Methods for a Bioproduct: Effects on Drying Kinetics and Product Colour

2007 ◽  
Vol 2 (5) ◽  
Author(s):  
Kian Jon Chua
Keyword(s):  
Colour Change ◽  
Drying Kinetics ◽  
Microwave Drying ◽  
Drying Methods ◽  
Thermal Processes ◽  
Adsorption System ◽  
Drying Time ◽  
Pressure Drops ◽  
Cyclic Pressure ◽  
Drying Techniques

In response to growing expectations for more effective drying of bioproducts with improved quality, this paper presents recent experimental results obtained from employing several hybrid drying techniques. The hybrid drying methods could be classified into thermal and non-thermal processes. The thermal processes included combined convective/infrared and convective-microwave drying while non-thermal process refers to dehydration under conditions of successive pressure drops incorporating an adsorption bed. Potato samples were taken to be the model bioproduct. A comparison of the drying kinetics with product colour degradation showed convective-microwave drying to be an effective method in shortening the drying time to achieve the desired moisture content whilst maintaining acceptable product quality. Bioproduct dehydration in a non-thermal cyclic pressure drop adsorption system resulted in substantial minimisation of the product colour change but at the expense of a longer drying time.

The impacts of vacuum microwave drying on osmosis dehydration of tilapia fillets

2018 ◽  
Vol 42 (1) ◽  
pp. e12956 ◽  
Author(s):  
Qi Wang ◽  
Bing Liu ◽  
Jun Cao ◽  
Chuan Li ◽  
Zhenhua Duan
Keyword(s):  
Microwave Drying ◽  
Vacuum Microwave ◽  
Tilapia Fillets

scholarly journals Ultrasound-assisted osmotic dehydration and convective drying of apples: Process kinetics and quality issues

2016 ◽  
Vol 37 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Dominik Mierzwa ◽  
Stefan J. Kowalski
Keyword(s):  
Osmotic Dehydration ◽  
Colour Change ◽  
Apple Fruit ◽  
Point Of View ◽  
Convective Drying ◽  
Drying Process ◽  
Drying Time ◽  
Ultrasound Enhancement ◽  
Kinetics Of

Abstract The aim of the present theme issue was to study the influence of ultrasound enhancement on the kinetics of osmotic dehydration and the effect of convective drying from the point of view of drying time and quality of dried products. Apple fruit was used as the experimental material. The kinetics of osmotic dehydration with (UAOD) and without (OD) ultrasound enhancement were examined for 40% fructose and sorbitol solutions. The effective dehydration time of osmotic process was determined. Preliminary dehydrated samples with OD and UAOD were next dried convectively with (CVUS) and without (CV) ultrasound assistance. The influence of OD and UAOD on the kinetics of CV and CVUS drying was analysed. The parameters of water activity and colour change were measured for the assessment of product quality after drying process.

scholarly journals Functional properties of dried tarragon affected by drying method

2018 ◽  
Author(s):  
Banu Koç ◽  
Nazan Çağlar ◽  
Gamze Atar
Keyword(s):  
Moisture Content ◽  
Color Change ◽  
Colour Change ◽  
Microwave Drying ◽  
Perennial Herb ◽  
Drying Method ◽  
Drying Time ◽  
Infrared Drying ◽  
Temperature Levels ◽  
Asteraceae Family

Tarragon is a small shrubby perennial herb in the Asteraceae family. It is cultivated for the use of its aromatic leaves in seasoning, salads, sauces, vinegars, mustard and spices. In this study, tarragon was dried in two different drying equipment (infrared (ID) and microwave dryers (MD)) to compare the drying and final product properties (moisture content, water activity and colour change). Three different output power levels of 125, 250 and 500 W were used for MD, whereas the ID treatment involved three drying temperature levels that were 60, 70 and 80°C. A comparison of the drying kinetics, MD was more effective in shortening drying time when compared with ID. Keywords: Tarragon, microwave drying, infrared drying, color change 

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