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.

Effects of drying methods on color retention and chlorophyll of celery (ApiumgraveolensL.), spinach (Spinacia oleraceaL.), Malabar spinach (Basella albaL.)

2020 ◽  
pp. 53-61
Author(s):  
Dat Q Tran
Keyword(s):  
Microwave Drying ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Color Retention ◽  
Hot Air ◽  
Drying Techniques ◽  
Dried Vegetables

Dried vegetables are considered convenient for storage, transportation and preservation. The different drying techniques could influence the quality of resulting products. This study aimed to evaluate the effects of three distinguish drying methods as hot-air drying, foam-mat drying and microwave drying on the color retention and chlorophyll of green vegetables powder. Fresh spinach(Spinacia oleraceaL.), celery (Apium graveolensL.), Malabar spinach (Basella albaL.) were dried by different methods: hot air at 60oC, foam-mat at 60oC and microwave at 270 W until the samples reached approximately 9% of moisture content (wb). The drying time of the dried samples by microwave, foam-mat and hot-air method were 60, 210 and 240 min, respectively. Foam-mat dried vegetables were found to have the best quality in terms of color and the residual chlorophyll content. The findings suggest that foam-mat drying is promising in dried vegetable processing

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.

scholarly journals Modelling the kinetics of microwave drying of shallot (Allium cepa) slices

2021 ◽  
Vol 1195 (1) ◽  
pp. 012033
Author(s):  
C L Hii ◽  
C Govind ◽  
C L Chiang ◽  
D Mohammad
Keyword(s):  
Thin Layer ◽  
Allium Cepa ◽  
Microwave Power ◽  
Drying Kinetics ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Drying Rates

Abstract Convective drying is typically used to dry shallot (Allium cepa) commercially. However, a long drying time with a relatively low efficiency has led to the pursuit of new and improved drying methods. Microwave drying was chosen to be used due to its numerous advantages such as improved drying time, high drying efficiency and better product quality. In this research, three microwave power (180 W, 300 W, 450 W) and convective drying at 100°C were used. Results showed that drying kinetics (moisture content and drying rates) decreased the fastest at higher microwave power and the slowest using convective drying. In order to determine the best model to describe the thin-layer drying kinetics, four semi-empirical models were used namely Newton, Page, Logarithmic and Two-term models. Page model was found to be the best in describing the thin-layer microwave drying kinetics. Effective diffusivity values increased with higher microwave power and were found to be in the range of 6.62 × 10−6 m2/s to 3.69 × 10−5 m2/s with convective drying being the lowest (6.62 × 10−6 m2/s) and 450W being the highest (3.69 × 10−5 m2/s). Microwave drying is therefore able to improve drying kinetics compared to convective drying.

scholarly journals Comparative Study of Hot Air Drying and Microwave Drying for Dewatered Sludge

2021 ◽  
Author(s):  
Wittawat Wulyapash ◽  
Awassada Phongphiphat ◽  
Sirintornthep Towprayoon
Keyword(s):  
Microwave Power ◽  
Specific Energy Consumption ◽  
Microwave Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Dewatered Sludge ◽  
Dried Sludge ◽  
Seafood Processing

Abstract Large amounts of sludge are generated from wastewater treatment in seafood processing industries. Most of the dewatered sludge in Thailand is not utilized and disposed by landfilling. The dried sludge utilization as refuse-derived fuel (RDF) is an alternative solution due to the gross calorific value (GCV), which is greater than 21.9 MJ/kg. However, the key obstacle is its high moisture content of 87.4% (wet basis). Therefore, drying methods using hot air and microwave techniques were investigated for preparing dried sludge. The effects of hot air temperatures (100-150 °C) and microwave power levels (100-800 W) were compared on drying kinetics, specific energy consumption (SEC), and characteristics of the dried products. The results showed that drying times were decreased by increasing the hot air temperatures. In the same way, the increase in microwave power levels decreased the drying time. The application of microwaves contributed to reducing the drying time by more than 46% compared to the hot air. The reduction of drying times resulted in the saving SEC. The GCV of the dried sludge decreased with the decrease in the volatile matter (VM) due to the high component of VM as 79.5-80.3% (dry ash-free basis). The sludge dried by the microwaves showed a lower GCV than the hot air products. However, dried sludges still had high GCV (≥ 20.8 MJ/kg). Furthermore, the minimal variation of the product characteristics demonstrated that the microwave technique could be applied as an alternative drying method with a rapid process compared to the conventional hot air technique.

Influence of Different Drying Methods on Drying Characteristics, Carotenoids, Chemical and Physical Properties of Gac Fruit Pulp (Momordica cochinchinensis L.)

2016 ◽  
Vol 12 (4) ◽  
pp. 395-409 ◽  
Author(s):  
Wittawat Trirattanapikul ◽  
Singhanat Phoungchandang
Keyword(s):  
Antioxidant Activity ◽  
Heat Pump ◽  
Total Phenolics ◽  
Microwave Drying ◽  
Drying Methods ◽  
Fruit Pulp ◽  
Model Quality ◽  
Drying Time ◽  
Drying Characteristics ◽  
Momordica Cochinchinensis

Abstract Gac fruit (Momordica cochinchinensis L.) pulp is high in carotenoids and fiber; however, it is discarded during process. Both maturity stages of matured gac fruit could be used in the drying experiments. Gac fruit pulp was dried by different drying methods including tray drying (40–60 °C), heat pump-assisted dehumidified drying (40–60 °C), microwave drying (450–900 W), mixed-mode solar drying and freeze drying. The Modified Henderson model presented the best fit of desorption isotherms. New model proposed was the best drying model. Quality evaluation by β-carotene, lycopene, lutein, total phenolics and antioxidant activity revealed that heat pump-assisted dehumidified drying at 60 °C provided the highest lutein, total phenolics and antioxidant activity and could reduce drying time by 25 % and increased lutein, total phenolics and antioxidant activity by 12.6 %, 32.0 % and 0.3 %, respectively and is more promising drying method for gac fruit pulp.

scholarly journals Drying methods of the printing inks

2021 ◽  
Vol 12 (2) ◽  
pp. 29-37
Author(s):  
Ashraf Abd El-Rahman Elsayed Saad ◽  
◽  
Cem Aydemir ◽  
Samed Ayhan Özsoy ◽  
Semiha Yenidoğan ◽  
...  
Keyword(s):  
Environmentally Friendly ◽  
Microwave Drying ◽  
Health Impacts ◽  
Release Time ◽  
Drying Methods ◽  
Printing Industry ◽  
Drying Time ◽  
Printing Inks ◽  
Chemical Content ◽  
Time And Energy

Accelerating the transition to post-print processes needed in the printing industry and shortening the time the product's release time is closely related to the drying time of the ink film. The drying of fluid ink on the surface of the print substrate, transforming from liquid to solid occurs physically and chemically in several ways. Drying systems can be functional alone on the surface of the printing substrate for an ink film or depending on the chemical content of the ink and the properties of the printing substrate, drying can be achieved at the same time with more than one system.Recently, in order to reduce climate, environmental and health impacts and with the development of technology, significant changes are also being experienced in the printing industry and preferences are changing. In this study, more environmentally friendly LED UV and microwave drying systems that save time and energy together with existing basic drying systems such as absorption, evaporation, oxidation-polymerization and conventional UV used in the printing industry are examined. The advantages of different drying systems to the printing industry, preferred drying systems and new studies on this issue have been evaluated.

scholarly journals Effects of Different Drying Methods on Drying Kinetics, Microstructure, Color, and the Rehydration Ratio of Minced Meat

Foods ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 216 ◽  
Author(s):  
Aslı Aksoy ◽  
Salih Karasu ◽  
Alican Akcicek ◽  
Selma Kayacan
Keyword(s):  
Quality Parameters ◽  
Drying Kinetics ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Freeze Dried ◽  
Meat Samples ◽  
Drying Conditions ◽  
Minced Meat

This study aimed to investigate the effect of different drying methods, namely ultrasound-assisted vacuum drying (USV), vacuum drying (VD), and freeze-drying (FD), on the drying kinetics and some quality parameters of dried minced meat. In this study, USV was for the first time applied to the drying of minced meat. The USV and VD methods were conducted at 25 °C, 35 °C, and 45 °C. The different drying methods and temperatures significantly affected the drying time (p < 0.05). The USV method showed lower drying times at all temperatures. The rehydration values of the freeze-dried minced meat samples were higher than those obtained by the USV and VD techniques. The samples prepared using USV showed higher rehydration values than the vacuum dried samples for all temperatures. The effects of the different drying techniques and drying conditions on the microstructural properties of the minced meat samples were investigated using scanning electron microscope (SEM). The USV method resulted in higher porosity and a more open structure than the VD method. Total color differences (ΔE) for VD, USV, and FD were 8.27–20.81, 9.58–16.42, and 9.38, respectively, and were significantly affected by the drying methods and temperatures (p < 0.05). Higher drying temperature increased the ΔE value. Peroxide values (PV) significantly increased after the drying process, and samples treated with USV showed lower PV values than the VD treated samples. This study suggests that USV could be used as an alternative drying method for minced meat drying due to lower drying times and higher quality parameters.

scholarly journals Novel Drying Methods for Sustainable Upcycling of Brewers’ Spent Grains as a Plant Protein Source

2020 ◽  
Vol 12 (9) ◽  
pp. 3660 ◽  
Author(s):  
Anubhav Pratap Singh ◽  
Ronit Mandal ◽  
Maryam Shojaei ◽  
Anika Singh ◽  
Przemysław Łukasz Kowalczewski ◽  
...  
Keyword(s):  
Panel Study ◽  
Microwave Drying ◽  
Drying Methods ◽  
Brewing Industry ◽  
Drying Time ◽  
Overall Acceptability ◽  
Process Waste ◽  
Spent Grains ◽  
Energy And Exergy Analysis ◽  
Drying Technology

Brewers’ spent grains (BSGs) are the most important by-product of the brewing industry and are rich in protein and fiber. However, abundant amounts of BSGs are discarded annually worldwide. This project aimed to employ and compare innovative drying techniques to introduce snacks with protein sources derived from leftover BSGs. This study explored the dehydration kinetics of BSGs and the effect of three different drying methods—oven drying (OD), freeze drying (FD), and vacuum microwave drying (VMD)—on their protein content and functionality. Then, an energy and exergy analysis for the drying methods was given. Accordingly, a snack product (baked chips) using the dehydrated BSGs was developed by a sensory panel study to assess consumer acceptability of the final products. It was found that the VMD process took less drying time (48 min) compared to OD (50 min), with higher effectiveness as a drying process. VMD-treated BSG also showed moderate protein functionality and the highest overall acceptability when used in baked chips. Thus, VMD might be used as a sustainable drying technology for thermal treatment and valorization of BSG. In addition to having implications for dietary health, findings can help improve the economy of the breweries and other industries that deal with the processing of grains by valorizing their process waste and contributing to sustainability.

scholarly journals Freeze-drying techniques for preserving aphids (Homoptera, Aphidodea)

1994 ◽  
Vol 5 (2) ◽  
pp. 105-113 ◽  
Author(s):  
Anders Albrecht
Keyword(s):  
Freeze Drying ◽  
Body Shape ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Freeze Dried ◽  
Drying Techniques ◽  
Wax Coating ◽  
And Storage

Techniques for collection, preparation and storage of freeze-dried aphid samples, including galls, are described. Freeze-drying can be done with the aid of a home freezer, a drying agent, and suitable containers alone, but drying time can be reduced considerably with cheap and simple vacuum drying equipment. Freeze-drying methods have several advantages compared with traditional mounting techniques. Body shape, colours, wax coating and microsculpture are excellently preserved. The labour required per sample, for preparation as well as for identification, is reduced to a minimum, and complete colony samples can be stored as entities. Aspects of practical handling and study of freeze-dried aphid samples are discussed.

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