Effects of Microwave Vacuum Drying on Macroscopic Properties and Microstructure of Lotus (Nelumbo nucifera Gaertn.) Seeds

2018 ◽  
Vol 14 (3) ◽  
Author(s):  
Yingting Zhao ◽  
Yajun Jiang ◽  
Yimei Zheng ◽  
Zhiyu Li ◽  
Yaling Zhang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Structural Characteristics ◽  
Nelumbo Nucifera ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Microstructural Changes ◽  
Shrinkage Ratio ◽  
Microwave Vacuum Drying ◽  
Box Counting Method

AbstractThe structural characteristics of lotus (Nelumbo nuciferaGaertn.) seeds preserved by microwave vacuum drying (MVD) were investigated under various drying parameters, including microwave power density and vacuum degree. Dried lotus seeds were examined for microstructure by field emission scanning electron microscopy. Fractal dimension of the microscopic images was calculated by the box counting method. The apparent physical changes of the seeds, namely shrinkage ratio, rehydration rate, and hardness index, were determined to correlate well with their microstructural changes computed by the normalized changes of the fractal dimension (ΔFD/FD0). The samples at −90 kPa, 15 W/g exhibited a lower shrinkage ratio (46.2 %), higher rehydration rate (187.5 %) and lower hardness (3692.4 N). Although the physical and microstructural changes of the samples prepared by different drying methods (MVD, microwave drying, and hot air drying) varied, the changes of the ΔFD/FD0of the dried samples exhibited the same trends.

scholarly journals Effect of Drying Methods on Physicochemical Parameters of Different Red Beetroots (Beta vulgaris L.) Species

2019 ◽  
Author(s):  
Dóra Székely ◽  
Klaudia Vidák ◽  
Diána Furulyás ◽  
Ákos Ribárszki ◽  
Mónika Stéger-Máté
Keyword(s):  
Physicochemical Parameters ◽  
Color Change ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Total Polyphenol ◽  
Microwave Vacuum Drying ◽  
Hot Air ◽  
Vacuum Method ◽  
Drying Technology

The aim of this work was to study the influence of atmospheric, vacuum and microwave vacuum drying methods on the quality of dried beetroots. Three different red beetroot species ('Alto F1', 'Cylindra', 'Detroit') were chosen in this study. The microwave vacuum method reduced the total time of drying and decreased the shrinkage compared to the other drying methods. The quality of the dehydrated material was described by its color change, antioxidant capacity, total polyphenol, betacyanin, betaxanthin and each phenolic acids content. The attempts were made to suggest the microwave vacuum method for red beetroot samples as a gentle drying technology to reach a special texture that is favoured by costumers. During the experiments relevant differences could be observed between the investigated beetroot species on the effect of different drying methods. According to the examined parameters the 'Cylindra' species proved the most appropriate beetroot variety for microwave vacuum drying. Based on the results, the combined methods with hot-air at 60 °C followed by microwave vacuum finish drying was the most suitable assay to preserve the investigated parameters in the highest amount.

scholarly journals Physicochemical properties of bean pod (Phaseolus vulgaris) flour and its potential as a raw material for the food industry

2020 ◽  
Vol 73 (2) ◽  
pp. 9179-9187
Author(s):  
Marcela Martínez-Castaño ◽  
Diana Paola Mejía Díaz ◽  
José Contreras-Calderón ◽  
Cecilia Gallardo Cabrera
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Fiber ◽  
Food Industry ◽  
Structural Characteristics ◽  
High Water ◽  
Raw Material ◽  
Vacuum Drying ◽  
Drying Methods ◽  
The Sustainable Development ◽  
Functional Studies

The sustainable development of agro-industry requires the efficient use of all raw matters, which implies physicochemical and functional studies of by-products for finding their potential usage in industrial processes. The objective of the present study was to assess some physicochemical and functional properties of fIour obtained from the bean pod. Two types of drying methods were tested: convection and vacuum. The fIours tended to yellow color according to b* parameter values (convection drying: 17.54; vacuum drying: 18.35), with a slight red hue. They also showed high water-holding (convection drying: 8.30 g g-1; vacuum drying: 7.56 g g-1) and oil holding capacity (convection drying: 2.53 g g-1; vacuum drying: 2.56 g g-1), polyphenols content (convection drying: 26.62 mg GAE g-1 DW; vacuum drying: 3.77 mg GAE g-1 DW) and antioxidant capacity (convection drying: 33.42 µmol Trolox g-1; vacuum drying: 5.27 µmol Trolox g-1). The results were similar for the two types of drying methods, except for the antioxidant capacity. Since convection drying is more economical and available than vacuum drying, only the fIour obtained by convection method was analyzed on compositional and structural characteristics. This fIour showed to be a good source of dietary fiber (66.93%), being the insoluble fiber the predominant fraction (59.97%). Moreover, a high content of ash (6.65%) and low lipid content (0.58%) were also found. The IR spectrum showed signs corroborating the presence of dietary fiber, which also was evidenced morphologically. Overall, the results obtained indicated that the bean pod fIour obtained by convection drying has potential use as a raw material for the food industry.

Effects of Drying Methods on Antioxidant Properties and Phenolic Content in White Button Mushroom

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Hongfang Ji ◽  
Ailin Du ◽  
Lingwen Zhang ◽  
Shuang Li ◽  
Mingduo Yang ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Total Phenolic ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Button Mushroom ◽  
Microwave Vacuum Drying ◽  
White Button Mushroom

Abstract In order to explore the potential drying process, the effects of different drying methods (sun drying, hot-air drying, microwave-vacuum drying, and freeze drying) on the antioxidant properties and phenolic contents in white button mushroom fruit bodies were investigated. The Folin-Ciocalteu method was used to determine total phenolic content, while 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power, iron-chelating ability, and hydroxyl radical scavenging activity assays were used to elucidate antioxidant activities. Results indicated that antioxidant properties in dried white button mushroom were affected by the drying methods to different extents, and phenolic contents showed significant differences (p<0.05) among different drying methods. Microwave-vacuum drying possessed the highest antioxidant activity in DPPH radical scavenging, reducing power and iron-chelating ability, respectively; and the content of phenolic compounds was 4.945 mg gallic acid equivalents (GAE) /g dry weight (DW). Sun drying was the worst in antioxidant activity and content of phenolic compounds was 1.964 mg GAE/g DW. Additionally, significantly positive correlation was found between the total phenolic content and antioxidant activity (p<0.01). As far as antioxidant activities are concerned, microwave-vacuum drying is proposed as an appropriate drying technique for white button mushroom.

Optimization of microwave vacuum drying of lotus (Nelumbo nucifera Gaertn.) seeds by response surface methodology

2012 ◽  
Vol 18 (5) ◽  
pp. 477-488 ◽  
Author(s):  
Yuting Tian ◽  
Yi Zhang ◽  
Shaoxiao Zeng ◽  
Yafeng Zheng ◽  
Feng Chen ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Nelumbo Nucifera ◽  
Vacuum Drying ◽  
Microwave Vacuum Drying

Comparison of different drying methods on Chinese yam: changes in physicochemical properties, bioactive components, antioxidant properties and microstructure

2020 ◽  
Vol 16 (9) ◽  
Author(s):  
Qing-ming Li ◽  
Lei Xia ◽  
Feng Wang ◽  
Shi-yin Guo ◽  
Jin-hao Zou ◽  
...  
Keyword(s):  
Antioxidant Properties ◽  
Principal Component ◽  
Far Infrared ◽  
Pasting Properties ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Bioactive Components ◽  
Chinese Yam

AbstractIn the present study, we aimed to assess the effects of hot air drying (HAD), microwave drying (MD), far-infrared radiation drying (FIRD), vacuum drying (VD) and microwave vacuum drying (MVD) on the quality, bioactive components, pasting properties, antioxidant properties, in vitro digestibility and microstructure of Chinese yam. Results showed that these drying processes greatly affected the quality of yam (p<0.05). MVD yam had a good color and its bioactive components were maintained. VD and MVD samples had the lowest setback value and breakdown value, indicating that they had a better cold paste stability and hot paste stability. In addition, MVD samples had a uniform honeycomb microscopic pore structure, and thus the rehydration rate of MVD samples was significantly higher compared with the other drying approaches. When five differently dried samples were compared by principal component analysis (PCA), the MVD samples were found to have the highest comprehensive principal component values. Therefore, based on our results, MVD was an ideal approach to dry high-quality yam.

Drying characteristics and bioactivity evolution of Platycodon grandiflorum as affected by different microwave combined drying methods

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuan-Yuan Liu ◽  
Wei-Qiao Lv ◽  
Ruo-Hui Lin ◽  
Dong Li ◽  
Li-Jun Wang
Keyword(s):  
Reaction Model ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Rehydration Ratio ◽  
Hot Air Drying ◽  
Drying Characteristics ◽  
Platycodon Grandiflorum ◽  
Microwave Vacuum Drying ◽  
Hot Air ◽  
Drying Technology

Abstract This study was to investigate the effect of different drying methods on the drying kinetics, physical properties, and bioactivity of Platycodon grandiflorum (PG). Four drying methods were employed to conduct the dehydrated process, namely, hot air drying (AD), vacuum drying (VD), microwave hot airflow rolling-bed drying (MHARD), and pulse-spouted microwave vacuum drying (PSMVD). PSMVD showed the highest drying rate among four drying methods based on the result of fitting first-order reaction model. And PSMVD-dried product showed higher rehydration ratio and better mechanical properties, suggesting a better rehydration characteristic. In addition, considering the content of Platycodin D, PSMVD is a promising drying technology for the dehydration of PG.

scholarly journals Effects of sonication and freezing on the color, mechanical and thermophysical properties of osmo-microwave-vacuum dried cranberries

2020 ◽  
Author(s):  
Izabela Anna Staniszewska ◽  
Szymon Staszyński ◽  
Magdalena Zielińska
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Moisture Diffusion ◽  
Moisture Diffusivity ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Volumetric Heat Capacity ◽  
Drying Time ◽  
Microwave Vacuum Drying

The aim of study was to determine the effects of sonication (S), convective freezing (F), convective freezing preceded by sonication (SF) as well as cryogenic freezing (N) on the osmo-microwave-vacuum drying kinetics, energy usage and properties of dried cranberries such as moisture content, moisture diffusion, water activity, density, porosity, thermal conductivity, thermal diffusivity, volumetric heat capacity, lightness, redness, yellowness, total differences in color, saturation and hue, hardness, cohesiveness, springiness, and chewiness. Osmo-microwave-vacuum drying of cranberries took from 13.5 to 16.0 min. All initial treatments increased the moisture diffusivity and thus reduced the drying time. The most energy effective method was osmo-microwave-vacuum drying preceded by sonication (S) of fruits. Osmo-microwave-drying of cranberries subjected to convective freezing preceded by sonication (SF) resulted in the highest lightness (32.5 ± 0.5), redness (33.9 ± 0.7), and yellowness (11.3 ± 0.5) of fruits, as well as the lowest cohesion (the lowest resistant to stress associated with manufacturing, packaging, storage, and delivery). The lowest hardness, i.e. 12.3 ± 0.4 N and the highest cohesiveness and springiness, i.e. 0.38 ± 0.02 and 0.74 ± 0.03 of dried fruits, were noted for berries subjected to initial cryogenic freezing (N). Cryogenic freezing (N) combined with osmo-microwave-vacuum drying resulted in the largest color changes of fruits and the highest thermal conductivity. Sonicated and convectively frozen (SF) fruits were characterized by the highest thermal diffusivity. Sonication (S), convective freezing (F) and their combination (SF) significantly reduced the volumetric heat capacity of cranberry fruits.

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