Effect of Processing Conditions on Drying Kinetics and Particle Microstructure of Carrot

Reyes, Antonio; Vega, Rolando E.; Bustos, Rubén; Araneda, Carmen

doi:10.1080/07373930802307282

Cited by 50 publications

(30 citation statements)

References 40 publications

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“…10. It is clear that the IR-HA dryer setting produced a dried product that had the least change in colour and that the hot air convective drying had the highest changes (Mongpraneet et al 2002 andReyes et al 2008). The higher value of (ΔE) for the HA dryer setting could be attributed to the longer period of drying and hence the case hardening of product.…”

Section: Colour Measurementmentioning

confidence: 91%

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer

EL-Mesery

Mwithiga

2014

J Food Sci Technol

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A conveyor-belt dryer was developed using a combined infrared and hot air heating system that can be used in the drying of fruits and vegetables. The drying system having two chambers was fitted with infrared radiation heaters and through-flow hot air was provided from a convective heating system. The system was designed to operate under either infrared radiation and cold air (IR-CA) settings of 2000 W/ m 2 with forced ambient air at 30°C and air flow of 0.6 m/s or combined infrared and hot air convection (IR-HA) dryer setting with infrared intensity set at 2000 W/m 2 and hot at 60°C being blown through the dryer at a velocity of 0.6 m/s or hot air convection (HA) at an air temperature of 60°C and air flow velocity 0.6 m/s but without infrared heating. Apple slices dried under the different dryer settings were evaluated for quality and energy requirements. It was found that drying of apple (Golden Delicious) slices took place in the falling rate drying period and no constant rate period of drying was observed under any of the test conditions. The IR-HA setting was 57.5 and 39.1 % faster than IR-CA and HA setting, respectively. Specific energy consumption was lower and thermal efficiency was higher for the IR-HA setting when compared to both IR-CA and HA settings. The rehydration ratio, shrinkage and colour properties of apples dried under IR-HA conditions were better than for either IR-CA or HA.

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Section: Colour Measurementmentioning

confidence: 91%

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer

EL-Mesery

Mwithiga

2014

J Food Sci Technol

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“…Rapid heating and vapor diffusion within the material during IR or combined mode drying has resulted in a porous structure in the product. Reyes et al (2008) had reported that in terms of microstructure of hence process economics, the effect of these two parameters were studied. Figure 6 gives the moisture curve for potato dried at two different air velocities, namely, 0.8 and 1.4 m/s, while maintaining the other processing conditions the same.…”

Section: Rehydration Ratiomentioning

confidence: 99%

“…Combined mode drying like convective-microwave (Andres et al, 2004;Araszkiewicz et al, 2007;Kowalski and Rybicki, 2004) and microwavevacuum (Giri and Prasad, 2007) have been successfully employed in order to improve the effectiveness of drying. In the recent past, a few studies on the application of IR for combined mode drying of food materials have been reported (Afzal et al, 1999;Mongpraneet et al, 2002;Hebbar et al, 2004;Jain and Pathare, 2004;Praveenkumar et al, 2005;Pathare and Sharma, 2006;Swasdisevi et al, 2007;Reyes et al, 2008;Mihoubi et al, 2009;Kowalski and Rajewska, 2009). During combined IR and hot air drying, the rapid heating of food materials by IR radiation (due to high heat density and depth of penetration) increases the rate of moisture migration towards the surface, while the convective air-1) Mass transfer is by diffusional mechanism 2) Moisture is initially (t=0) distributed uniformly throughout the mass of a sample 3) Mass transfer is symmetric with respect to the centre 4) Resistance to mass transfer at the surface is negligible compared with internal resistance of the sample…”

Section: Introductionmentioning

confidence: 99%

Hot Air Assisted Infrared Drying of Vegetables and Its Quality

Vishwanathan

Hebbar

Raghavarao

2010

FSTR

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Hot air assisted infrared (IR) drying of potato and carrot is carried out and product quality is compared with hot air dried samples. The synergistic effect of hot air and IR during combined mode (hot air assisted IR) drying reduced the processing time by nearly 48% as compared to hot air drying alone, besides improving the quality of products. Higher rehydration ratio and lower browning index values are observed for combined mode dried products. Photomicrographs of dehydrated carrot and potato showed superiority of product structure for combined mode dried products. The IR dried carrot had higher (by 17%) retention of carotenoid than hot air dried sample. The processing conditions such as velocity and temperature of air affected the drying characteristics during combined mode drying. Higher values of effective diffusivity of water are observed with combined mode drying.

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“…El modelo de Page entregó el mejor ajuste a los datos experimentales, con R 2 ≥99%. Este modelo ha sido aplicado con buenos resultados por varios investigadores en la descripción de la cinética de secado de vegetales (Vega y Lemus, 2006;Ah-Hen et al, 2011;Reyes et al, 2008). Teniendo en cuenta que el modelado de la cinética tiene como objetivo predecir la velocidad y el tiempo de secado, el modelo de Page se podría utilizar para simular cinéticas de secado de brócoli triturado.…”

Section: Ajuste De Las Curvas De Secado a Modelos Empíricosunclassified

“…Este tipo de modificación se conoce como secado en lecho fluidizado pulsante, el cual se logra con la ubicación de un disco perforado rotatorio debajo de la cama perforada que sostiene el lecho de partículas, provocando la fluidización intermitente del sólido en las zonas donde circula el aire (Reyes et al, 2008). El secador de lecho fluidizado pulsante facilita la fluidización de partículas que presentan una forma irregular, partículas frágiles o bien partículas con una distribución de tamaño heterogénea, y mejora la uniformidad de la fluidización reduciendo la formación de canales.…”

Section: Introductionunclassified

Efecto de las Condiciones de Secado en Lecho Fluidizado Pulsante sobre el Contenido de Sulforafano de Brócoli

2017

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ResumenSe investigó el efecto de las condiciones de secado de brócoli enriquecido en sulforafano, en un secador de lecho fluidizado pulsante, sobre el contenido de sulforafano y la cinética de secado, para identificar las condiciones de operación que minimizan las pérdidas de sulforafano en el producto. Se utilizó un diseño central compuesto, cuyos factores fueron temperatura del aire de secado y velocidad de giro de la placa rotatoria. Las curvas de secado se ajustaron a modelos empíricos, encontrándose el mejor ajuste con el modelo de Page (R 2 ≥99%). El tiempo de secado disminuyó al aumentar la temperatura del aire de secado y al aumentar la velocidad de giro de la placa giratoria. Las condiciones óptimas de secado predichas por el modelo de regresión fueron 29°C y 108 rpm, resultando en 1.5 µmol sulforafano /g (base seca), valor que representa una concentración de sulforafano 1.36 veces la del brócoli fresco. Este valor se confirmó experimentalmente. Palabras clave: secador de lecho fluidizado pulsante; brócoli; sulforafano; cinética de secado; optimización Effect of the Drying Conditions in a Pulsed Fluidized Bed Dryer on the Sulforaphane Content of Broccoli AbstractThe effect of the drying conditions of sulforaphane-rich broccoli in a pulsed fluidized bed dryer, on the sulforaphane content and drying kinetics was studied, with the aim of identifying the operating conditions that minimize the loss of sulforaphane in the dehydrated product. A central composite design was used, in which drying air temperature and plate rotational speed were the variables considered. The drying curves were fitted to empirical models and it was found that Page´s model showed the best fit (R 2 ≥99%). The drying time decreased with the increase of drying air temperature and the increase of the plate rotational speed. The regression model predicted that 29°C and 108 rpm were the optimal conditions, resulting in a sulforaphane content equal to 1.5 µmol/g in dry basis, giving a value that is 1.36-fold the sulforaphane content in fresh broccoli. This value was experimentally confirmed. Keywords INTRODUCCIÓNEl sulforafano es un isotiocianato que proviene de las plantas crucíferas, y es reconocido como el agente anticancerígeno de origen natural más poderoso que se conoce hasta ahora (Matusheski et al., 2004). Su precursor, la glucorafanina, se encuentra principalmente en brócoli, y por lo tanto esta verdura ofrece un gran potencial como fuente de sulforafano. Según datos de la FAO, la producción anual de brócoli en Sud América es de 72 mil toneladas, lo que corresponde al 1% de la producción mundial. Se ha investigado el procesamiento de brócoli para aumentar el contenido de sulforafano (Wang et al., 2012;Matusheski et al., 2004). Pérez et al. (2014) informaron las condiciones de escaldado que maximizan el contenido de este compuesto en brócoli. Recientemente, Mahn y Pérez (2016) reportaron un proceso de incubación de brócoli escaldado, que permite obtener un 94% de conversión de glucorafanina en sulforafano. Una vez maximizado el co...

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Effect of Processing Conditions on Drying Kinetics and Particle Microstructure of Carrot

Cited by 50 publications

References 40 publications

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer

Hot Air Assisted Infrared Drying of Vegetables and Its Quality

Efecto de las Condiciones de Secado en Lecho Fluidizado Pulsante sobre el Contenido de Sulforafano de Brócoli

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