scholarly journals Effects of Infrared-Assisted Refractance Window™ Drying on the Drying Kinetics, Microstructure, and Color of Physalis Fruit Purée

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 343
Author(s):  
Luis Puente-Díaz ◽  
Oliver Spolmann ◽  
Diego Nocetti ◽  
Liliana Zura-Bravo ◽  
Roberto Lemus-Mondaca
Keyword(s):  
Statistical Tests ◽  
Coefficient Of Determination ◽  
Drying Process ◽  
Chi Square ◽  
Ir Radiation ◽  
Drying Time ◽  
Drying Curves ◽  
Effective Diffusivities ◽  
Drying Conditions ◽  
Fruit Purée

The objective of this work was to study the influence of the drying temperature, infrared (IR) radiation assistance, and the Mylar™ film thickness during Physalis fruit purée drying by the Refractance Window™ (RW™) method. For this, a RW™ dryer layout with a regulated bath at working temperatures of 60, 75, and 90 °C, Mylar™ thicknesses of 0.19, 0.25, 0.30 mm and IR radiation of 250 W for assisting RW™ drying process was used. Experimental curves data were expressed in moisture ratio (MR) in order to obtain moisture effective diffusivities (non-assisted RW™: Deff = 2.7–10.1 × 10−10 m2/s and IR-assisted RW™: Deff = 4.2–13.4 × 10−10 m2/s) and further drying curves modeling (Page, Henderson–Pabis, Modified Henderson–Pabis, Two-Term, and Midilli–Kucuk models). The Midilli–Kucuk model obtained the best-fit quality on experimental curves regarding statistical tests applied (Coefficient of Determination (R2), Chi-Square (χ2) and Root Mean Square Error (RMSE). Microscopical observations were carried out to study the RW™ drying conditions effect on microstructural changes of Physalis fruit purée. The main findings of this work indicated that the use of IR-assisted RW™ drying effectively accelerates the drying process, which achieved a decrease drying time around 60%. Thus, this combined RW™ process is strongly influenced by the working temperature and IR-power applied, and slightly by Mylar™ thickness.

scholarly journals Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Oven Drying ◽  
Sun Drying ◽  
Different Temperatures ◽  
Final Water Content ◽  
Drying Curves ◽  
Drying Conditions

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.

scholarly journals THE EFFECT OF THE FILLING RATIO ON THE OPERATING CHARACTERISTICS OF AN INDIRECT DRUM DRYER

2020 ◽  
Vol 60 (1) ◽  
pp. 49-55
Author(s):  
Jan Havlík ◽  
Tomáš Dlouhý ◽  
Michel Sabatini
Keyword(s):  
Specific Energy Consumption ◽  
Filling Ratio ◽  
Operating Characteristics ◽  
Drying Time ◽  
Green Wood ◽  
Operational Characteristics ◽  
Rotary Drum ◽  
Drying Curves ◽  
The One ◽  
Drying Conditions

This article investigates the effect of the filling ratio of the indirect rotary dryers on their operating characteristics. For moist biomass drying before combustion, the use of indirect drum dryers heated by a low pressure steam has proven to be highly suitable. Regarding the design of new dryers, it is necessary to experimentally verify the operating characteristics for specific materials and drying conditions. For this purpose, a set of experiments on a steam heated rotary drum dryer were carried out with green wood chips containing 60 to 66 wt% of moisture. The following operational characteristics of the dryer were experimentally determined: drying curves describing the process, square and volumetric evaporation capacities and drying heat consumptions. Based on the experimental results, the effect of various drum filling by dried material on the mentioned operating characteristics was analysed. On the one hand, higher drum filling ratio increases the drying time, on the other hand, the evaporation capacity also increases, while the specific energy consumption does not significantly alter. The maximum value of the evaporation capacity was reached when the drum was filled to 20 wt%. When the filling ratio was increased to 25 wt%, the evaporation capacity experienced almost no change.

The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment

2014 ◽  
Vol 69 (9) ◽  
pp. 1859-1866 ◽  
Author(s):  
Hui-Ling Wang ◽  
Zhao-Hui Yang ◽  
Jing Huang ◽  
Li-Ke Wang ◽  
Cheng-Liu Gou ◽  
...  
Keyword(s):  
Sample Thickness ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
Dewatered Sludge ◽  
Drying Curves ◽  
Sludge Drying ◽  
The Impact

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm3 had the best drying performance at each level of temperature, which could save 35–45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm3 was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.

Thin Layer Drying Process of Some Leafy Vegetables under Open Sun

2007 ◽  
Vol 13 (1) ◽  
pp. 35-40 ◽  
Author(s):  
O. P. Sobukola ◽  
O. U. Dairo ◽  
L. O. Sanni ◽  
A. V. Odunewu ◽  
B. O. Fafiolu
Keyword(s):  
Thin Layer ◽  
Effective Diffusivity ◽  
Thin Layers ◽  
Leafy Vegetables ◽  
Drying Process ◽  
Chi Square ◽  
Thin Layer Drying ◽  
Rate Period ◽  
Drying Models ◽  
Drying Curves

Open sun drying experiments in thin layers of crain-crain (CC), fever (FV) and bitter (BT) leaves grown in Abeokuta, Nigeria were conducted. The drying process took place in the falling rate period and no constant rate period was observed from the drying curves. Eight thin layer mathematical drying models were compared using the multiple determination coefficients (R2), reduced chi-square (χ2) and root mean square error (RMSE) between the observed and predicted moisture ratios. Accordingly, Midilli et al. model satisfactorily described the drying curves of the three leaves with R2 of 0.9980, χ2 of 2.0×10-4 and RMSE of 1.09×10-2 for CC leaves; R2 of 0.9999, χ2 of 2×10-6 and RMSE of 1.11×10-3 for FV leaves; and R2 of 0.9998, χ2 of 1.9×10-5 and RMSE of 3.3×10-3 for BT leaves. The effective diffusivity was found to be 52.91×10-10, 48.72×10-10 and 43.42×10-10 m2/s for CC, BT and FV leaves, respectively.

Research on Constant-Temperature Drying Test of Cotton Straw and Regression Analysis of Drying Rate

2012 ◽  
Vol 472-475 ◽  
pp. 1645-1651
Author(s):  
Jian Jun Hu ◽  
Sheng Qiang Shen ◽  
Ting Zhou Lei ◽  
Hao Huang ◽  
Quan Guo Zhang
Keyword(s):  
Regression Analysis ◽  
Constant Temperature ◽  
Initial Moisture Content ◽  
Drying Rate ◽  
Regression Equations ◽  
Drying Time ◽  
Drying Curves ◽  
Drying Technology ◽  
Drying Conditions ◽  
Two Stages

Constant-temperature drying tests for cotton straw under different conditions were performed with an integrated thermal analyzer, and the influence of different drying conditions on the drying process was analyzed. The process was divided into preheating stage, constant-rate drying stage, and decelerating drying stage. Regression analysis was conducted for drying curves at the latter two stages, and then the drying time at the critical point was determined. Regression equations of drying rate at these stages were produced. Research results showed that the decelerating drying stage of cotton straw included two decelerating intervals, and the best ending point of the drying of the cotton straw that had an initial moisture content of 56.1% and a drying temperature of 100°Cwas 600s, thus providing experimental data and reference for research on drying technology of straws.

Simulation of Drying Hevea brasiliensis Wood

2015 ◽  
Vol 1088 ◽  
pp. 802-806 ◽  
Author(s):  
Cláudio de Conti ◽  
Andrea Cressoni de Conti ◽  
Maristela Gava ◽  
Luiz Oliveira Veriano dalla Valentina ◽  
Glaucia Aparecida Prates
Keyword(s):  
Moisture Content ◽  
Statistical Method ◽  
Temperature Increase ◽  
Gravimetric Method ◽  
Average Moisture Content ◽  
Drying Process ◽  
Chi Square ◽  
Drying Time ◽  
Kiln Temperature ◽  
Drying Curve

The Simpson model proposes that the rate of wood drying is directly proportional to average moisture content. In this work was done the fitting and the reproduction of drying curve forHeveabrasiliensiswood through of Simpson model and the chi-square statistical method. The curves were obtained by drying 108 specimensHeveabrasiliensiswood with size 10 mm x 20 mm x 100 mm that were drying in a laboratory kiln. The drying control was performed through gradual temperature increase in order to minimize the errors arising due the drastic loss of moisture by wood. The gravimetric method was used to evaluate the drying process, the specimens have theirs mass measured every 6 hours until the timber reached the theoretical anhydrous state. The drying curve of rubber wood obtained here can be used to estimate the drying time of this species for different kiln temperature settings.

scholarly journals Mathematical modeling of the foam-mat drying curves of guava pulp

2017 ◽  
Vol 21 (10) ◽  
pp. 721-725 ◽  
Author(s):  
Roberta M. G. Maciel ◽  
Marcos R. A. Afonso ◽  
José M. C. da Costa ◽  
Leandro S. Severo ◽  
Natália D. de Lima
Keyword(s):  
Experimental Data ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Albumin Concentration ◽  
Mean Square ◽  
Liquid Food ◽  
Chi Square ◽  
Foaming Agent ◽  
Chi Square Test ◽  
Drying Curves

ABSTRACT In foam-mat drying, the liquid food is foamed by the addition of a foaming agent, for example, albumin. The aim of this study was to evaluate the adjustment of mathematical models to foam mat drying curves of guava pulp. The fits were evaluated using samples with 4 and 8% albumin (m m-1) and drying temperatures of 75, 80 and 85 °C. The samples were placed on aluminum trays. Drying was carried out in a tray dryer. The Lewis, Page, Midilli and Logarithmic models were fitted to the experimental data and evaluated based on the coefficient of determination (R2), root-mean-square error (RMSE) and chi-square test. All models fitted well to experimental data and Midilli was the best. Albumin concentration and temperature influenced the drying rate; the lowest drying times occurred for the highest albumin concentration and highest drying temperature.

scholarly journals Kinetic parameters identification of conductive enhanced hot air drying process of food waste

2020 ◽  
pp. 223-223
Author(s):  
Mihailo Milanovic ◽  
Mirko Komatina ◽  
Ivan Zlatanovic ◽  
Nebojsa Manic ◽  
Dragi Antonijevic
Keyword(s):  
Food Industry ◽  
Convective Drying ◽  
Diffusivity Coefficient ◽  
Drying Method ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Drying Curves

The efficient utilization of waste from food industry is possible after thermal treatment of the material. This treatment should be economically feasible and compromise the energy efficient drying process. The main goal of this investigation is to determine drying characteristics of nectarine pomace as a waste from food industry. The measurements were performed in an experimental dryer by combined conductive-convective drying method with disk-shaped samples of 5, 7 and 10mm thickness and 100 mm in diameter at the air temperatures of 30, 40, 50, 60 and 70oC, hot plate temperatures of 50, 60 an 70oC and air velocity of 1.5 m/s. The drying curves were compared to a few semi-theoretical mathematical models. The Logarithmic model showed the best correspondence. On the basis of experiments, it is determined that the drying process takes place in a falling rate period and it is accepted that the main mechanism of moisture removal is diffusion. The effective coefficient of diffusion was determined using experimental results by calculating the slope of the drying curves. Drying time and equilibrium moisture are determined for each experiment. Analysis of drying curves showed that the conductive-enhanced drying method reduces drying times and increases the diffusivity coefficient. The character of drying rate curves for conductive-enhanced drying was analyzed and compared with pure convective drying of nectarine pomace.

scholarly journals Modelling the Drying Characteristics and Kinetics of Hot Air-Drying of Unblanched Whole Red Pepper and Blanched Bitter Leaf Slices

2017 ◽  
Vol 5 (1) ◽  
pp. 24
Author(s):  
Samuel Enahoro Agarry
Keyword(s):  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Red Pepper ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Curves ◽  
Kinetics Of

The objective of this study was to investigate the drying characteristics and kinetics of red pepper and bitter leaf under the influence of different drying temperatures. The drying experiments were carried out at dry bulb temperature of 35, 45, 55 and 75oC, respectively in an oven dryer. The results showed that as drying temperature increased, drying rate also increased and the drying time decreased. It was observed that un-sliced red pepper and sliced bitter leaf would dry within 2.5-12 h and 1.67-7 h, respectively at temperature ranging from 75 to 35oC. The drying of red pepper and bitter leaf was both in the constant and falling rate period. Four semi-empirical mathematical drying models (Newton, Page, Henderson and Pabis, and Logarithmic models) were fitted to the experimental drying curves. The models were compared using the coefficient of determination (R^2) and the root mean square error (RMSE). The Page model has shown a better fit to the experimental drying data of red pepper and bitter leaf, respectively as relatively compared to other tested models. Moisture transport during drying was described by the application of Fick’s diffusion model and the effective moisture diffusivity was estimated. The value ranges from 15.69 to 84.79 × 10-9 m2/s and 0.294 to 1.263 × 10-9 m2/s for red pepper and bitter leaf, respectively. The Arrhenius-type relationship describes the temperature dependence of effective moisture diffusivity and was determined to be 37.11 kJ/mol and 32.86 kJ/mol for red pepper and bitter leaf, respectively. A correlation between the drying time and the heat transfer area was also developed.

scholarly journals Sıcaklık Kontrollü Mikrodalga Kurutma Yönteminin Alıç (Crataegusspp. L.) Meyvesinin Kuruma Karakteristikleri ve Renk Değerleri Üzerine Etkisi

2017 ◽  
Vol 5 (10) ◽  
pp. 1130 ◽  
Author(s):  
Hakan Polatcı ◽  
Muhammed Taşova
Keyword(s):  
Mathematical Model ◽  
Quality Criterion ◽  
Drying Time ◽  
Drying Temperature ◽  
Significant Difference ◽  
Hawthorn Fruit ◽  
Fresh Products ◽  
Drying Curves ◽  
Drying Conditions ◽  
Microwave Dryer

In this study, the hawthorn fruit was dried in a controlled temperature microwave dryer and determined the mathematical model that best predicts the drying time, color value and product drying curves. Since the horticultural fruit contains important nutritional values, when it is desired to be dried and consumed, optimum drying conditions should be determined. Productions were dried in a temperature controlled microwave dryer under at temperatures of 50, 60 and 70ºC. Drying times lasted 129, 66, and 45 minutes for drying temperatures of 50, 60 and 70ºC, respectively. The shortest drying time was at a drying temperature of 70ºC, while the longest drying is at a drying temperature of 50ºC. The Yağcıoğlu, Midilli-Küçük and Page’s mathematical model were used to predict the drying curves, and Midilli- Küçük model was determined as the best model to predict the drying curves. In addition, the color values of fresh and dried hawthorn fruit as a quality criterion were investigated. In terms of L brightness and a red color values, there was a statistically significant difference between dried and fresh products at all three drying temperatures, while there was no statistically significant difference between fresh and dried products at temperatures of 50 and 70ºC in terms of b yellowness value. The chroma, hue angle and brown values of the fresh products and chroma and brown values of the dried products are not differentiating from each other numerically. However, the values closest to the fresh product’s chromium and brown values were determined at a drying temperature of 70ºC.

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