scholarly journals Effect of Intermittent Microwave Volumetric Heating on Dehydration, Energy Consumption, Antioxidant Substances, and Sensory Qualities of Litchi Fruit during Vacuum Drying

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4291 ◽  
Author(s):  
Xiaohuang Cao ◽  
Jianping Chen ◽  
Md. Nahidul Islam ◽  
Wanxiu Xu ◽  
Saiyi Zhong
Keyword(s):  
Energy Consumption ◽  
Sensory Evaluation ◽  
Vacuum Drying ◽  
Volumetric Heating ◽  
Microwave Vacuum Drying ◽  
Sensory Qualities ◽  
Drying System ◽  
Litchi Fruit ◽  
Heating Profiles

To examine the processing characteristics and high quality of an improved microwave vacuum drying system, litchi fruits were dried using intermittent microwave volumetric heating while microwave vacuum drying at 2 W/g was carried out for comparison; the intermittent microwave heating profiles were set as (1) 5 min drying-on, 5 min drying-off; (2) 5 min drying-on, 10 min drying-off; and (3) 5 min drying-on, 15 min drying-off. Energy consumption during drying was determined, and physicochemical properties such as moisture content, vitamin C, total phenolics, color, and sensory evaluation of dried products were assessed. In microwave vacuum drying, intermittent microwave volumetric heating was found to be energy-efficient (about 32 KJ/g to 45 KJ/g) and saved at least 31% of energy consumption compared with microwave vacuum drying as well as decreasing product browning. In addition, microwave volumetric heating had no substantial effects on sugar and protein contents, while antioxidants were affected significantly (p ≤ 0.05). Moreover, sensory evaluation showed that intermittent microwave-assisted vacuum drying (IMVD) increased the acceptance of the dried product compared with microwave vacuum drying (MVD).

The Effect of Microwave Vacuum Drying on the Quality of Tiegun yam

2012 ◽  
Author(s):  
Zhihuai Mao ◽  
Dong Li ◽  
Guangyue Ren ◽  
Xiaoyan Du ◽  
Wenxue Zhu
Keyword(s):  
Vacuum Drying ◽  
Microwave Vacuum Drying

scholarly journals EFFECTS OF GROUNDNUT (ARACHIS HYPOGEA L) VARIETIES ON THE FLAVOUR PROFILE AND CONSUMER ACCEPTABILITY OF DAKUWA (A CEREAL-GROUNDNUT BASED SNACK)

2020 ◽  
Vol 4 (3) ◽  
pp. 86-92
Author(s):  
Adekanmi Kamar Oladele ◽  
Kazeem A. Sogunle
Keyword(s):  
Sensory Evaluation ◽  
Aromatic Compounds ◽  
Raw Materials ◽  
Consumer Acceptability ◽  
Arachis Hypogea ◽  
Browning Reaction ◽  
Sensory Qualities ◽  
Flavour Profile ◽  
Gas Chromatography Mass Spectroscopy

The quality of Dakuwa can be affected by raw materials and processing methods. This work studied the effects of groundnut (Arachis hypogea L.) varieties (Campala, white and Sere) on the colour, flavour profile and sensory properties of Dakuwa. The flavour profile of the Dakuwa samples was analysed with gas chromatography – mass spectroscopy (GC – MS), colour by chroma meter and proximate composition using standard methods while sensory evaluation was done by 25 untrained panelists. The results were analysed using one way analysis of variance. Dakuwa sample with Campala groundnut (DKWC) had the highest concentration of alcohols (20 μg /100 g), aldehydes (86 μg /100 g), ketones (1.9 μg /100 g),  heterocyclic aromatic compounds (11.2 μg /100 g), and total flavour compounds (151 μg /100 g) suggesting higher lipid oxidation and Maillard reaction compared to Dakuwa with Sere and White groundnuts.  DKWC had significantly lower L* (lightness) value and significantly higher browning index (84.75) suggesting a higher browning reaction compared to other samples. Sensory evaluation results indicated no significant (p > 0.05) difference in the samples. It can be concluded that any of the three groundnut varieties can be used to produce Dakuwa without altering its sensory qualities.

Ultrasound-assisted osmotic process on quality of microwave vacuum drying sweet potato

2018 ◽  
Vol 36 (11) ◽  
pp. 1367-1379 ◽  
Author(s):  
Camel Lagnika ◽  
Jiapeng Huang ◽  
Ning Jiang ◽  
Dajing Li ◽  
Chunquan Liu ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Vacuum Drying ◽  
Microwave Vacuum Drying ◽  
Ultrasound Assisted

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 Optimization of Microwave Vacuum Drying and Pretreatment Methods for Polygonum cuspidatum

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Wanxiu Xu ◽  
Guanyu Zhu ◽  
Chunfang Song ◽  
Shaogang Hu ◽  
Zhenfeng Li
Keyword(s):  
Mathematical Models ◽  
Scale Up ◽  
Drying Kinetics ◽  
Vacuum Drying ◽  
Orthogonal Experimental Design ◽  
Polygonum Cuspidatum ◽  
Drying Time ◽  
Microwave Vacuum Drying ◽  
Thin Layer Drying ◽  
Drying System

This study was conducted to optimize the drying process of Polygonum cuspidatum slices using an orthogonal experimental design. The combined effects of pretreatment methods, vacuum pressure and temperature of inner material, drying kinetics, color value, and retention of the indicator compounds were investigated. Seven mathematical models on thin-layer drying were used to study and analyze the drying kinetics. Pretreatment method with blanching for 30 s at 100°C increased the intensity of the red color of P. cuspidatum slices compared with other pretreatment methods and fresh P. cuspidatum slices. P. cuspidatum slices dried at 60°C retained more indicator compounds. Furthermore, microwave pretreatment methods, followed by microwave vacuum for 200 mbar at 50°C, resulted in high concentration of indicator compounds, with short drying time and less energy. This optimized condition for microwave vacuum drying and pretreatment methods would be useful for processing P. cuspidatum. The Newton, Page, and Wang and Singh models slightly fitted the microwave vacuum drying system. The logarithmic, Henderson and Pabis, two-term, and Midilli et al. models can be used to scale up the microwave vacuum drying system to a commercial scale. The two-term and Midilli et al. models were the best fitting mathematical models for the no-pretreatment case at 600 mbar and 60°C.

Energy consumption, physical properties, protein structure and digestibility of edible insects dried using three methods

2021 ◽  
pp. 1-12
Author(s):  
T. Chaowattanakul ◽  
V.M. Khieu ◽  
C. Rojviriya ◽  
S. Siriwong ◽  
W. Jittanit ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Protein Structure ◽  
Physical Properties ◽  
Vacuum Drying ◽  
Edible Insects ◽  
Microwave Vacuum Drying ◽  
Silkworm Pupae ◽  
Drying Techniques ◽  
Tray Drying ◽  
Hardness Values

This study evaluated the effects of three drying techniques, tray drying, roasting and microwave vacuum drying, on the physical properties, secondary structures, in vitro protein digestibility and X-ray tomographic structure of crickets (Acheta domesticus) and mulberry silkworm pupae (Bombyx mori L.). The protein contents of dried crickets and silkworm pupae were 49-54% and 51-53% (dry basis), respectively. Roasting produced a significantly higher browning index than the other two methods for crickets and silkworm pupae. The microwave vacuum-dried crickets exhibited the lowest hardness, with hardness values of approximately half those of the tray-dried and roasted crickets. Tray-drying and microwave vacuum drying silkworm pupae produced similar hardness values, which were lower than that of roasted silkworm pupae. The energy consumption of the tray dryer was the lowest, followed by the roaster and microwave vacuum dryer. No significant changes in the secondary protein structure of dried silkworm pupae were observed. A significant decrease in α-helix and β-turn and increase in β-sheet was observed in roasted crickets. Cricket and silkworm pupae powders produced from all drying techniques could be easily digested (90-95% digestibility). This work presents valuable knowledge for understanding the effects of different drying techniques on the properties of dried edible insects, aiming to support the production of alternative and sustainable protein sources for the growing population to improve food security.

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