Comparative study of hot air drying and microwave drying for dewatered sludge

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

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Multi-stage continuous and intermittent microwave drying of quince fruit coupled with osmotic dehydration and low temperature hot air drying

Innovative Food Science & Emerging Technologies ◽

10.1016/j.ifset.2017.10.007 ◽

2018 ◽

Vol 45 ◽

pp. 132-151 ◽

Cited By ~ 26

Author(s):

Jalal Dehghannya ◽

Seyed-Hamed Hosseinlar ◽

Maryam Khakbaz Heshmati

Keyword(s):

Low Temperature ◽

Osmotic Dehydration ◽

Microwave Drying ◽

Hot Air Drying ◽

Air Drying ◽

Hot Air ◽

Multi Stage

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Impact of Different Drying Techniques on Quality Traits of Ginger (Zingiber officinale Rosc.) Rhizomes

International Journal of Environment and Climate Change ◽

10.9734/ijecc/2021/v11i1230553 ◽

2021 ◽

pp. 30-37

Author(s):

Annu Kumari ◽

Yeluru Mohan Babu ◽

Eggadi Ramesh ◽

Tshering Ongchu Lepcha ◽

Suman Tamang ◽

...

Keyword(s):

Essential Oil ◽

Fiber Content ◽

Microwave Drying ◽

Crude Fiber ◽

Drying Methods ◽

Hot Air Drying ◽

Air Drying ◽

Sun Drying ◽

Crude Fiber Content ◽

Hot Air

Under the present investigation, ginger was produced at the instruction cum research plots of the Department of Plantation Crops and Processing, Faculty of Horticulture, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal. The experiment was laid out in a factorial CRD. The study was undertaken with four ginger varieties namely Gorubathan, Suprabha, Suruchi and Suravi to evaluate the effect of different drying methods (sun drying, hot air drying at 50OC, 60oC and 70oC and microwave drying on time required for drying to a moisture content of 8 – 10% and to chemical composition (essential oil, oleoresin content and crude fiber content) of the end product. Results shown that Gorubathan variety has the highest essential oil (2.243%) and oleoresin content (14.840%) among the four varieties in this study, highest crude fiber content (5.253%) was observed in Suprabha and highest dry recovery (25.77%) was obtained from Suravi variety. In hot air drying, with increase in temperature essential oil, oleoresin and crude fiber content in dry ginger as well as dry recovery reduced. With high dry recovery (25.77%), essential oil (2.037%) and oleoresin content (13.510%) and moderately low crude fiber content (4.637%), it can be concluded that Suravi variety is best suitable for producing dry ginger. Apart from microwave drying, sun drying can be recommended as better practice, when hygienically conducted, based on essential oil and oleoresin content.

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Drying Behaviour and Change in Colour and Textural Properties of Mushroom During Drying

International Journal of Food Engineering ◽

10.1515/1556-3758.1696 ◽

2012 ◽

Vol 8 (1) ◽

Cited By ~ 1

Author(s):

Tarsem Chand Mittal ◽

Sajeev Rattan Sharma ◽

Jarnail Singh Muker ◽

Satish Kumar Gupta

Keyword(s):

Textural Properties ◽

Microwave Drying ◽

Drying Methods ◽

Button Mushroom ◽

Hot Air Drying ◽

Air Drying ◽

Hot Air ◽

Drying Behavior ◽

L Value ◽

Drying Behaviour

Button mushroom in the form of whole and slices were dried using convective hot air drying and microwave drying methods. Main objectives were to study the drying behavior and change in colour and textural properties. To get moisture content of 0.08 g/g, hot air drying at 600C took 463 minutes and 350 minutes for whole and sliced mushroom respectively whereas these times were just 9 minutes and 8.5 minutes when the microwave oven was run at 60% of its maximum power (1350 W). The convective hot air drying process can be put into two falling rate periods. The decrease in brightness (indicated by L-value) in dried samples was about 44% as compared to the fresh ones. The variation within the differently dried samples was not much. Hardness was lowest (<2>N) in fresh samples and was highest (>5.5 N) in microwave dried samples with hot air dried samples in between. For most of the samples, the springiness were between 0.4 and 0.6 except for hot air dried sliced samples where it was 0.9. Except in hot air dried samples, the change in cohesiveness was not much. Adhesiveness was found in fresh mushroom only..

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The effect of osmosis pretreatment on hot-air drying and microwave drying characteristics of chili (Capsicum annuumL.) flesh

International Journal of Food Science & Technology ◽

10.1111/ijfs.12128 ◽

2013 ◽

Vol 48 (8) ◽

pp. 1589-1595 ◽

Cited By ~ 27

Author(s):

Dandan Zhao ◽

Cuiping Zhao ◽

Hongyan Tao ◽

Kejing An ◽

Shenghua Ding ◽

...

Keyword(s):

Microwave Drying ◽

Hot Air Drying ◽

Air Drying ◽

Drying Characteristics ◽

Hot Air

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Viscoelastic Characterization of Microwave Drying Nature Rubber

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.1344 ◽

2011 ◽

Vol 291-294 ◽

pp. 1344-1350

Author(s):

Fu Quan Zhang ◽

Yong Zhou Wang ◽

Mei Chen ◽

Mao Fang Huang

Keyword(s):

Rheological Behavior ◽

Viscoelastic Properties ◽

Microwave Drying ◽

Hot Air Drying ◽

Air Drying ◽

Hot Air ◽

Drying Technology

Nature rubber (NR) is neither completely viscous nor elastic in nature, but viscoelastic in their properties. In the experiment, we used two types of equipments named rubber process analyzer (RPA) 2000 and mooney viscometer to characterize the viscoelastic properties of NR dried by microwave and hot-air, respectively. In present research, RPA tests on uncured NR dried by different methods were carried out using frequency and strain sweeps, and Mooney viscometer was detected using the big rotor at 100°C. The results showed that microwave drying has not influenced the viscoelastic properties of NR greatly, without changing the profiles of its rheological behavior. Compared with hot-air drying, the properties of NR dried by microwave improved significantly. As a new application, microwave drying technology offered an alternative way to the drying of NR.

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ENERGY REQUIREMENT AND QUALITY ASPECTS OF CHINESE JUJUBE (ZIZYPHUS JUJUBA MILLER) IN HOT AIR DRYING FOLLOWED BY MICROWAVE DRYING

Journal of Food Process Engineering ◽

10.1111/j.1745-4530.2009.00372.x ◽

2011 ◽

Vol 34 (2) ◽

pp. 491-510 ◽

Cited By ~ 25

Author(s):

SHUZHENG FANG ◽

ZHENGFU WANG ◽

XIAOSONG HU ◽

FANG CHEN ◽

GUANGHUA ZHAO ◽

...

Keyword(s):

Energy Requirement ◽

Microwave Drying ◽

Chinese Jujube ◽

Hot Air Drying ◽

Air Drying ◽

Hot Air ◽

Quality Aspects ◽

Zizyphus Jujuba

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Effect of Microwave Drying on Cure Characteristics of Natural Rubber

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.421.27 ◽

2011 ◽

Vol 421 ◽

pp. 27-30

Author(s):

Yong Zhou Wang ◽

Fu Quan Zhang ◽

Mei Chen ◽

Hong Hai Huang ◽

Mao Fang Huang ◽

...

Keyword(s):

Natural Rubber ◽

Induction Period ◽

Arrhenius Equation ◽

Curing Temperature ◽

Microwave Drying ◽

Maximum Torque ◽

Hot Air Drying ◽

Air Drying ◽

Cure Characteristics ◽

Hot Air

In this work, the cure characteristics of nature rubber (NR) dried by microwave and hot-air were analyzed by using Vulcameter. The effect of curing temperature on induction period (tC10), optimum cure point (tC90), maximum Torque (MH) and minimum induced torque (ML) were studied. The results showed that the tC10, tC90 and ML of NR dried by hot-air were bigger than those of NR dried by microwave, however, the MH of former was bigger. And the tC10, tC90 of NR dried by microwave or hot-air can fitted Arrhenius equation well, the K1, K2 and K of Arrhenius equation coefficient for NR dried by microwave were all bigger than those of NR dried by hot-air. With the increasing of curing temperature, the MH of NR dried by microwave or hot-air decreased gradually and its trend was well satisfied with linear relationship, and the MHo of NR dried by microwave was bigger than hot-air drying.

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