Properties of modified atmosphere heat pump dried foods

Hawlader, Mohammad Nurul Alam; Perera, Conrad O.; Tian, Min

doi:10.1016/j.jfoodeng.2005.03.028

Cited by 116 publications

(79 citation statements)

References 16 publications

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“…A larger value of hue angle indicates greater shift from red to yellow. Hawlader et al (2006) stated that a decrease in hue angels values is an indication of more browning colour and shifting away from yellowness, which is not the case in this study, where the values of hue angles increased with drying microwave powers, shifting towards yellow and red. Microwave drying causes a smaller increment of redness a, which means the final products are less brown than conventional air-dried ones (Vadivambal and Jaya, 2007 6.…”

Section: Resultscontrasting

confidence: 71%

Drying kinetics and colour change of lemon slices

Darvishi¹,

Khoshtaghaza²,

Minaei³

2014

International Agrophysics

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A b s t r a c t. The effect of microwave-convective heating on drying characteristics and colour change of lemon slices was investigated. The drying experiments were carried out at 180, 360, 540 and 720 W and at 22°C, with air velocity of 1 m s -1 . The values of effective moisture diffusivity were found to be in the range between 1.87 10 -8 and 3.95 10 -8 m 2 s -1 , and the activation energy was estimated to be 10.91 W g -1 . The drying data were fitted with six mathematical models available in the literature. The model describing drying kinetics of lemon slices in the best way was found. The colour change of the dried lemon slices was analysed and considered as a quality index affecting the drying quality of the product. The values of lightness/darkness, yellowness/blueness and hue angle increased, while the value of redness/greenness decreased with increasing microwave power.K e y w o r d s: drying kinetics, mathematical modelling, colour, lemon slice INTRODUCTIONThe fresh weight of lemon fruits contains a high percentage of water (about 87% w.b.). Accordingly, they exhibit relatively high metabolic activity compared with other plantderived foods such as seeds. This metabolic activity continues after harvesting, thus making most fruits highly perishable commodities (Atungulu et al., 2004;Pendre et al., 2012).Drying improves the product shelf life without addition of any chemical preservative and reduces both the size of package and the transport cost (Al-Harahsheh et al., 2009;Figiel, 2010;Singh et al., 2010). Drying also assists in reducing post harvest losses of fruits and vegetables especially, which can be as high as 70% (Tunde-Akintunde and Ogunlakin, 2013).High temperatures or long drying times in conventional air drying may cause serious damage to product flavour, colour and nutrients, reducing bulk density and rehydration capacity of the dried product (Contreras et al., 2008). The desire to avoid these problems to some extent, to prevent significant quality loss, and to achieve fast and effective thermal processing has resulted in the increasing use of microwaves for food drying. However, microwave processing has the disadvantage of non-homogeneous distribution in the microwave cavity, creating problems of non-uniform heating. To overcome some of the limitations of single microwave or hot air driers, one strategy is to combine microwaves with hot air. In the microwave-convective drying method, forced air is supplied to carry away the water vapour driven from the interior of the food to its surface.Colour has to be considered as a special parameter that seems to be one of the first attributes of quality that a consumer perceives, and that may influence the consumer judgment of other attributes such as flavour (Chen et al., 2005).Simulation models may be used to develop new drier systems that result in energy savings and optimum processing conditions (Arumuganathan et al., 2009;Hassan-Beygi et al., 2009). A knowledge of effective moisture diffusivity is necessary for designing and modeling mass-transfer...

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Section: Resultscontrasting

confidence: 71%

Drying kinetics and colour change of lemon slices

Darvishi¹,

Khoshtaghaza²,

Minaei³

2014

International Agrophysics

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“…It is reported that the HPD dryer has an advantage of 22 to 40% reduction in the power consumption. Hawlader et al (2006) dried apple, guava and potato pieces in a HPD dryer using nitrogen and carbon dioxide to replace air. The evacuation during drying seemed to benefi t the fi nal colour of the products, which showed lesser browning.…”

Section: Heat Pump Dryingmentioning

confidence: 99%

Recent advances in drying and dehydration of fruits and vegetables: a review

2010

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Fruits and vegetables are dried to enhance storage stability, minimize packaging requirement and reduce transport weight. Preservation of fruits and vegetables through drying based on sun and solar drying techniques which cause poor quality and product contamination. Energy consumption and quality of dried products are critical parameters in the selection of drying process. An optimum drying system for the preparation of quality dehydrated products is cost effective as it shortens the drying time and cause minimum damage to the product. To reduce the energy utilization and operational cost new dimensions came up in drying techniques. Among the technologies osmotic dehydration, vacuum drying, freeze drying, superheated steam drying, heat pump drying and spray drying have great scope for the production of quality dried products and powders.

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“…Latter, Hawlader et al (2006) evaluated the performance of solar-assisted heat-pump dryer and water heater again in the tropics, and a simulation programme was developed by them. After comparing between both results, they reported that the total drying time of the product decreases with the increase in drying potential.…”

Section: Type Of Heat Pump Assisted Dryingmentioning

confidence: 99%

“…Moreover, various types of product have been dried in experimental heat pump dehumidified dryers. Dried product included biomaterials (Alves-Filho and Strommen 1996a) sawn rubber, wood and banana (Prasertsan and Saen-saby 1998), banana , holy basil (Phoungchandang et al 2003), garlic (Boonnattakorn et al 2004) mangoes (Chottanom and Phoungchandang 2005), ginger (Hawlader et al 2006) composite food products (Rahman et al 2007), and red pepper (Alves-Filho et al 2007), protein (Alves-Filho et al Fig. 10 Schematic diagram of CHPD system using CaO/H2O/ Ca(OH)2 reaction operating in heat enhancement mode (Ogura et al 2004) 2008).…”

Section: Assessments Of Agricultural Producementioning

confidence: 99%

Heat pump assisted drying of agricultural produce—an overview

Patel

Kar

2011

J Food Sci Technol

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This review paper included the recent progress made in heat pump assisted drying, its principle, mechanism and efficiency, type and its application for drying of agricultural produce. Heat pump assisted drying provides a controllable drying environment (temperature and humidity) for better products quality at low energy consumption. It has remarkable future prospects and revolutionaries ability. The heat pump system consists of an expansion valve, two heat exchangers (evaporator and condenser), and a compressor, which are connected by using copper tubes. In this paper we also provided a review discussion on different type of heat pump assisted drying system ready for remarkable and commercial use in different type of food industries. Here we also have given some major advantage and disadvantage of heat pump assisted drying.

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Properties of modified atmosphere heat pump dried foods

Cited by 116 publications

References 16 publications

Drying kinetics and colour change of lemon slices

Drying kinetics and colour change of lemon slices

Recent advances in drying and dehydration of fruits and vegetables: a review

Heat pump assisted drying of agricultural produce—an overview

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