scholarly journals Drying characteristics and quality evaluation in convective drying of Cissus quadrangularis Linn.

2018 ◽  
Vol 192 ◽  
pp. 03041
Author(s):  
Setthawat Thanimkarn ◽  
Ekkapong Cheevitsopon ◽  
Jiraporn Sripinyowanich Jongyingcharoen

This study aimed to investigate the effect of drying temperature (40, 60, 80, and 100°C) on drying characteristics of Cissus quadrangularis Linn. (CQ) undergoing convective drying. Physical properties and phytochemicals of the dried CQ were also evaluated. CQ with the thickness of 5 mm was dried from about 10 to 0.1 g water/g dry matter. The results showed that increasing drying temperature increased drying rate (DR) and effective moisture diffusivity (Deff) and consequently decreased drying time. The drying time, maximum DR, and Deff were in the ranges of 85-1920 min, 0.0059-0.0248 g water/g dry matter·min, and 0.7302-9.1281×10-9 m2/s, respectively. Lower drying temperature could preserve quality of the dried CQ. Decreasing drying temperature resulted in greener and lower bulk density and shrinkage. The greatest total phenolic content (TPC) and quercetin content were obtained by drying the CQ at 60°C.

2018 ◽  
Vol 6 (2) ◽  
pp. 552-565 ◽  
Author(s):  
Eunice Akello Mewa ◽  
Michael Wandayi Okoth ◽  
Catherine Nkirote Kunyanga ◽  
Musa Njue Rugiri

The objective of the present study was to determine the drying kinetics, moisture diffusivity and sensory quality of convective air dried beef. The effect of temperature of drying (30-60°C) and thickness of samples (2.5-10 mm) on the convective thin-layer drying kinetics of beefdried in a cabinet dryer was evaluated. Five semi-theoretical models were fit to the drying experimentaldata with the aim of predicting drying characteristics of beef and fitting quality of models determined using the standard error of estimate (SEE)and coefficient of determination (R2). Determination ofeffective moisture diffusivity (Deff) from the experimental drying datawas done and sensory quality of the optimized dried cooked and uncookedbeef samplesevaluated. Drying time and rate of drying increased with an increasing temperature but decreased with increased slice thickness. However, there was overlapping of drying curves at 40-50°C. Among the selected models, Page model gave the best prediction of beef drying characteristics. Effective moisture diffusivity (Deff) ranged between 4.2337 x 10-11 and 5.5899 x 10-10 m2/s, increasing with an increase in air temperature and beef slice thickness.Of all the sensory parameters evaluated, texture was the only attribute that gave significantly different (P > 0.05) scores between the cooked and uncooked dried beef samples.


Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1840
Author(s):  
Aleksandra Matys ◽  
Artur Wiktor ◽  
Magdalena Dadan ◽  
Dorota Witrowa-Rajchert

The conditions of convective drying induce a negative effect on the quality of the dried products, and thus, innovative solutions, such as the utilization of ultrasound and dehumidified air are gaining importance. Therefore, the aim of this study was to evaluate the impact of ultrasound pretreatment and variable air temperature on the kinetics of convective drying with dehumidified air and the quality of dried apples. Apples were dried with dehumidified and non-dehumidified air at 55, 70 and 85 °C. Preliminary ultrasound treatment was conducted by immersion for 60 min. The effect of both ultrasound and dehumidified air utilization was more prominent in the terms of drying time reduction, when lower drying temperatures were used. Drying of apples with dehumidified air, preceded by ultrasound pretreatment, resulted in a greater rehydration capacity of the products, and limited the browning process. Dehumidified air increased the lightness of the dried products, while sonication darkened them. The use of ultrasound before drying coupled with a drying with dehumidified medium at a temperature of 70 °C reduced the exposure of the product to a high temperature and oxygen. Products treated before dehumidified air drying with ultrasounds were characterized by high total phenolic content and the greatest antioxidant activity. This was because such technological treatment reduced exposure of the product to a high temperature and oxygen.


2020 ◽  
Vol 9 (11) ◽  
pp. e73791110583
Author(s):  
Leandro Levate Macedo ◽  
Jefferson Luiz Gomes Corrêa ◽  
Hugo Calixto Fonseca ◽  
Cintia da Silva Araújo ◽  
Wallaf Costa Vimercati ◽  
...  

Butiá (Butia capitata) is a typical Brazilian Cerrado fruit, rich in several bioactive compounds. This work aimed to study the influence of air temperature on drying kinetics and quality parameters of butiá pulp. The pulps were dried at 50 and 70 °C. Mathematical models were fitted to the moisture ratio data. The effective moisture diffusivity (Deff) and the drying rate (DR) were calculated. The fresh and dried pulps were characterized in terms of moisture content (MC), water activity (aw), total carotenoids content (TCC), yellow flavonoids, total phenolic content (TPC), antioxidant capacity and color. The Page model was the one that best fitted to the moisture ratio data. Drying reduced MC, aw and the bioactive compounds content and altered colorimetric parameters. The higher temperature resulted in lower TCC and higher total color difference. However, it reduced the drying time (from 300 to 180 min), with higher Deff and DR and resulted in samples with higher retention of yellow flavonoids, TPC and total antioxidants and a lower browning index. Therefore, 70 °C was the most suitable temperature for drying butiá pulp.


2019 ◽  
Vol 56 (1) ◽  
pp. 34
Author(s):  
Parul Bora ◽  
Asha Kawatra

<em>Experiments were conducted on pre treated dehydrated oyster mushroom with steeping in citric acid and sodium chloride and blanching to investigate the effect of pre treatments and drying methods on drying characteristics of mushroom and quality of dried oyster mushroom. Drying was accomplished in a cabinet dryer using hot air at 40<sup>O </sup>C, 60<sup>O</sup>C and by sun drying. The drying characteristics of mushroom were not affected by the pre-treatments significantly. However, the rate of drying increased with the increase in drying temperature. Increase in drying temperature significantly reduced the total drying time. Pre treatments and drying temperature had adverse influence on the rehydration ratio, hardness and colour of the dehydrated mushrooms. Blanching improves the colour of the dehydrated mushroom but increased hardness also. A loss of protein was observed during blanching</em>


2018 ◽  
Vol 192 ◽  
pp. 03040 ◽  
Author(s):  
Sahachart Sansak ◽  
Jiraporn Sripinyowanich Jongyingcharoen

The objective of this study was to determine drying characteristics and quality of rice bran pellet subjected to hot air assisted infrared (HA-IR) drying at different levels of infrared (IR) intensity (750 – 3750 W/m2) and air temperature (40 – 80°C). The rice bran pellets were dried from 0.18 to 0.08 g water/g dry matter. The maximum drying rate (DR) and drying time were in the ranges of 0.0030 – 0.0165 g water/g dry matter·min and 8 – 54 min, respectively. Higher IR intensity and air temperature resulted in greater maximum DR and shorter drying time. The same trend was also observed for the effective moisture diffusivity (Deff) values which were between 0.3103×10-7 and 2.7603×10-7 m2/s. As compared to the commercial reference sample of dried rice bran pellets, the products of this study had higher oil content and lower FFA content. The oil content was affected by IR intensity only while the FFA content was affected both by IR intensity and air temperature. HA-IR drying could improve drying characteristics of the rice bran pellets and produce better quality of the dried products.


2019 ◽  
Vol 16 (1-2) ◽  
Author(s):  
Joanna Zubernik ◽  
Magdalena Dadan ◽  
Joanna Cichowska ◽  
Dorota Witrowa-Rajchert

AbstractThe aim of this study was to investigate the effects of pre-treatment in ethanol solution carried out in variable time with and without ultrasound (US) assistance on convective drying kinetics, total phenolic content (TPC) and hygroscopicity of an apple. The drying time after immersion in ethanol solution was shorter up to 13.4 (without US) and 18.3 % (with US) in comparison to intact slices. The most appropriate model that described kinetics of drying was the one proposed by Sledz et al. Drying of the untreated apple resulted in a decrease of the TPC by 18 %, compared with raw apples and the pre-treatment led to further losses. The tissue after ethanol pre-treatment was less hygroscopic, which proves the possibility to maintain a characteristic texture of the dried apple with prolonged storage stability. The best quality of dried apples was obtained after 1 min of ethanolic pre-treatment with US.


Author(s):  
S. K. Chin ◽  
Y. H. Lee ◽  
B. K. Chung

In this research, a Coulomb force assisted heat pump (CF-HP) dryer was invented for the purpose of improving the drying characteristics and product quality of biomaterials. As compared to heat pump drying alone, the assistance of Coulomb force in heat pump dryer enhanced the drying rates and effective moisture diffusivity of lemon slices up to 26%, which eventually shortened the total drying time to 40%. This saved the total energy consumption of HP drying by 31.5%. High retention of vitamin C and TPC were also found in CF-HP dried slices due to mild drying temperature and fast drying rate. Keywords: Coulomb force; Heat pump drying; Drying rate; Vitamin C; Total Phenolic Content (TPC).  


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 226
Author(s):  
Katarzyna Rybak ◽  
Artur Wiktor ◽  
Dorota Witrowa-Rajchert ◽  
Oleksii Parniakov ◽  
Małgorzata Nowacka

It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.


Author(s):  
Ronaldo Elias de Mello-Júnior ◽  
Nathane Silva Resende ◽  
Jefferson Luiz Gomes Corrêa ◽  
Leila Aparecida Salles Pio ◽  
Elisângela Elena Nunes Carvalho

Dekopon or Hallabong (Citrus reticulate “Shiranui”) is a hybrid fruit that belongs to the citrus fruits. The scientific and commercial interests in dekopon is due to its nutritional composition. The objective of the study was to verify the influence of ethanol as a pretreatment in reducing drying time as well as maintaining nutritional quality (vitamin C, total phenolic compounds, and antioxidant activity) of dekopon slices. The drying with ethanol at 70 °C promoted the greatest reduction in drying time, but the processed pretreated samples at 50 °C presented the highest level of nutritional quality parameters. Keywords: drying time; vitamin C; phenolic compounds; antioxidant activity 


2020 ◽  
Vol 42 ◽  
pp. e40570
Author(s):  
Ibrahim Doymaz

Kiwifruit slices were dried at four different air drying temperatures of 50, 55, 60 and 70ºC and at 2 m s-1 air velocity by using a cabinet dryer in this study. The drying, rehydration and colour characteristics were significantly influenced by pretreatment and drying temperature. The drying time decreased with the increase in drying temperature. The drying rate curves showed that the entire drying process took place in the falling rate period. Five well-known thin-layer models were evaluated for moisture ratios using nonlinear regression analysis. The results of regression analysis indicated that the Midilli & Kucuk model the best to describe the drying behaviour with the lowest c2 and RMSE values, and highest R2 value. The effective moisture diffusivity of the dried kiwifruit slices was calculated with Fick’s diffusion model, in which their values varied from 4.19×10–10 to 6.99×10-10 m2 s-1 over the mentioned temperature range. The dependence of effective diffusivity coefficient on temperature was expressed by an Arrhenius type equation. The calculated values of the activation energy of moisture diffusion were 10.37 and 19.08 kJ mol-1 for citric acid and control samples, respectively


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