Hot air dehydration of figs (<i>Ficus carica</i> L.): drying kinetics and quality loss

Piga, Antonio; Pinna, Ivo; Özer, K.B.; Agabbio, Mario Carlo Salvatore; Aksoy, Uygun

doi:10.1111/j.1365-2621.2004.00845.x

Cited by 84 publications

(85 citation statements)

References 11 publications

(9 reference statements)

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“…It is obvious that the constant rate period was absent, and drying of paddy took place in the falling rate period for the entire duration. Similar observations have been reported for the drying of soybean (Rafiee et al 2009), mushroom (Arumuganathan et al 2009), apricots (Doymaz 2004), figs (Piga et al 2004), peach (Kingsly et al 2007) and plums ). The drying in falling rate period shows that, internal mass transfer has occurred by diffusion.…”

Section: Resultssupporting

confidence: 80%

Drying characteristics of paddy in an integrated dryer

2014

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Drying characteristics of paddy (long grain variety PR-118 procured from PAU, Ludhiana) in an integrated dryer using single as well as combined heating source was studied at different air temperatures. The integrated dryer comprises three different air heating sources such as solar, biomass and electrical. Drying of paddy occurred in falling rate period. It was observed that duration of drying of paddy from 22 to 13 % moisture content (w.b.) was 5-9 h depending upon the source of energy used. In order to select a suitable drying curve, six thin layer-drying models (Newton, Page, Modified Page, Henderson and Pabis, Logarithmic and Wang and Singh) were fitted to the experimental moisture ratio data. Among the mathematical models investigated, Wang and Singh model best described the drying behaviour of paddy using solar, biomass and combined heating sources with highest coefficient of determination (r 2 ) values and least chi-square, χ 2 , mean bias error (MBE) and root mean square error (RMSE) values. However, Page model adequately described the drying behavior of paddy using electrical heating source.Keywords Paddy . Integrated paddy dryer . Drying models . Moisture ratio Paddy or rough rice (Oryza Sativa L.), the most widely grown food grain crop, is the staple food of over 3 billion people. World and Indian rough rice production in 2010 was 700 million tonnes and 143.9 million tonnes respectively (FAOSTAT 2010). Rice provides more calories per hectare than any other cereal crops. Its nutritional value is high among cereals and grains. Though the protein content of rice is less than that of wheat, the protein digestibility and biological value of rice protein are the highest among wheat and other cereals. After harvesting, paddy normally goes through two moisture treatments; one is drying that may be required for safe storage, and the other is water absorption in preparation for further processing. Quality deterioration takes place if fresh paddy is not immediately dried to safe moisture level. Drying reduces bulk quantity, thus, facilitates in transportation, handling and storage. Although sundrying is economical, mechanical drying speeds up the process, prevents losses, ensures use of safer drying temperatures and produces superior product compared to sun drying (Mudahar and Bains 1982). In view of high cost and non-renewable nature of the present conventional electrical energy source, different renewable energy sources such as solar and bio mass may be employed for paddy drying. The combining of conventional and non-conventional energy sources for paddy drying will be helpful for exploiting solar and bio mass sources as much as possible.The drying characteristics of food is a complex phenomenon and requires simple representations to predict

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Section: Resultssupporting

confidence: 80%

Drying characteristics of paddy in an integrated dryer

2014

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“…The first and the second lines were shown the first drying and the second falling periods, respectively. Similar results have been observed in drying some agricultural products such as: onion (Rapusas and Driscoll, 1995), lettuce and cauliflower leaves (López et al, 2000), apricots (Doymaz, 2004), figs (Piga et al, 2004), peaches , plums , berberis fruit (Aghbashlo et al, 2008), mushroom (Arumuganathan et al, 2009) and carrot slices (Aghbashlo et al, 2009). In other word, moisture content of all these products has been high, but drying behavior of some was similar to a straight line.…”

Section: Mathematical Modelssupporting

confidence: 69%

Modeling of moisture diffusivity, activation energy and specific energy consumption of high moisture corn in a fixed and fluidized bed convective dryer

Chayjan¹,

Parian²,

Esna-Ashari³

1970

Span. j. agric. res.

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Thin layer drying characteristics of high moisture corn under fixed, semi fluidized and fluidized bed conditions with high initial moisture content (66.82% wb) in a laboratory fluidized bed convective dryer was studied at air temperatures of 50, 65, 80 and 95°C. In order to find a suitable drying curve, seven thin layer-drying models were fitted to the experimental data of moisture ratio. Among the applied mathematical models, Midilli et al. model was the best for drying behavior prediction in corn thin layer drying. This model presented high values for correlation coefficient (R 2 ). Fick´s second law was used to compute moisture diffusivity with some simplifications. Computed values of moisture diffusivity varied at the boundary of 4.87 × 10 -11 -2.90 × 10 -10 m 2 s -1 and 1.02 × 10 -10 -1.29 × 10 -9 m 2 s -1 during the first and second drying falling-rate, respectively. Values of effective moisture diffusivity for corn were also increased as input air temperature was increased. Value of activation energy varied from a minimum of 18.57 to a maximum of 50.74 kJ mol -1 from 50 to 95°C with drying conditions of fixed to fluidized bed. Specific energy consumption (SEC) for thin-drying of high moisture corn was found to be in the range of 0.33 × 10 6 -1.52 × 10 6 kJ kg -1 from 50 to 95°C with drying condition of fluidized and fixed bed, respectively. Increase in air temperature in each air velocity caused decrease in SEC value. These corn properties would be necessary to design the best dryer system and to determine the best point of drying process.Additional key words: drying; maize; Midilli et al. model; semi fluidized. ResumenModelización de la difusividad de la humedad, la energía de activación y el consumo específico de energía para el grano de maíz húmedo en un secador convectivo de lecho fijo y fluidizado Se estudiaron las características del secado en capa delgada del grano de maíz húmedo en condiciones de lecho fijo, semi-fluidizado y fluidizado con alto contenido de humedad inicial (66,82%), en un secador de convección de lecho fluidizado de laboratorio a las temperaturas del aire de 50, 65, 80 y 95°C. Con el fin de encontrar una curva de secado apropiada, se ajustaron siete modelos matemáticos de secado en capa delgada a los datos experimentales de la ratio de humedad. Entre los modelos aplicados, el de Midilli et al., con un alto coeficiente de correlación (R 2 ), fue el mejor para predecir el secado del maíz en capa delgada. Se utilizó la segunda ley de Fick para calcular, con algunas simplificaciones, la difusividad de la humedad, que dio unos valores entre 4,87 × 10 -11 -2.90 y 1,02 × 10 -11 -1.29 m 2 s -1 durante la primera y segunda fase de secado de rapidez decreciente, respectivamente. Los valores de la difusividad efectiva de la humedad para el maíz también aumentaron al aumentar la temperatura de entrada del aire. El valor de la energía de activación varió desde un mínimo de 18,57 a un máximo de 50,74 kJ mol -1 entre 50 y 95°C, con condiciones de secado del lecho fijo a fluidizado. El c...

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“…The water activity of samples to which sucrose has been added was later dried for 240 min at 80°C, 0.633. This is similar to the values of 0.61-0.63 obtained by Piga et al (2004) for dried figs. The commercial dried fruits studied here: dried figs, pineapple and cranberry, had water activities of 0.69, 0.57 and 0.55, respectively.…”

Section: Drying Characteristicssupporting

confidence: 90%

“…The water activity of the pulp, 0.966, was comparable to values of other comparable fresh fruits such as olives, 0.96-0.97 (Fernández-Salguero et al, 1993) and figs, 0.96 (Piga et al, 2004).…”

Section: Properties Of V Infausta Pulpsupporting

confidence: 59%

Softening of dried Vangueria infausta (African medlar) using maltodextrin and sucrose

et al. 2013

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Softening of dried Vangueria infausta using maltodextrin and sucrose was investigated experimentally. The pulp of V. infausta was dried in a convective dryer, the influence of drying temperature as well as relationship between water content and water activity were examined. In this study, 48 samples of V. infausta pulp, with and without maltodextrin or sucrose, were dried at air temperatures of 60 and 80°C, at a constant air velocity of 3 m/s, for 0-240 min, and until constant weight. The water content, water activity, hardness and toughness were evaluated throughout the drying process. Samples dried at 80°C exhibited shorter drying times than samples dried at 60°C. The water activity of fruit dried for 240 min at 80°C varied from 0.633 to 0.759, and the fruit was thus safe regarding microbiological spoilage. The hardness and toughness of the dried fruit pulp increased with the reduction in water content, and it was observed that samples of pure pulp became unacceptably hard and tough, when dried to the level needed to obtain microbiological stability. The addition of sucrose as well as maltodextrin has shown to be able to reduce the hardness as well as the toughness of the dried fruit pulp; which can be considered as a strategy to obtain dried fruit pulp with suitable consistency.

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Hot air dehydration of figs (Ficus carica L.): drying kinetics and quality loss

Cited by 84 publications

References 11 publications

Drying characteristics of paddy in an integrated dryer

Drying characteristics of paddy in an integrated dryer

Modeling of moisture diffusivity, activation energy and specific energy consumption of high moisture corn in a fixed and fluidized bed convective dryer

Softening of dried Vangueria infausta (African medlar) using maltodextrin and sucrose

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