Mathematical modeling of the drying of orange bagasse associating the convective method and infrared radiation

ABSTRACT Mathematical modeling enables dimensioning of dryers, optimization of drying conditions and the evaluation of process performance. The aim of this research was to describe the behavior of orange bagasse drying using Page's and Fick's second law models, and to assess activation energy (using Arrhenius equation), moisture content, water activity and bulk density of product at the end of the process. The drying experimental assays were performed in 2011 with convective air temperature between 36 and 64 ºC and infrared radiation application time in the range from 23 to 277 s in accordance with the experimental central composite rotatable design. Analysis of variance and F-test were applied to results. At the end of the drying process, moisture content was about 0.09 to 0.87 db and water activity was between 0.25 and 0.87. Bulk density did not vary under studied conditions. Empirical Page's model demonstrated better representation of experimental data than the Fick's model for spheres. Activation energy values were about 18.491; 14.975 and 11.421 kJ mol-1 for infrared application times of 60; 150 e 244 s, respectively.

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Optimization of Drying Process for Squid-Laver Snack by a Combined Method of Fuzzy Synthetic and Response Surface Methodology

Journal of Food Quality ◽

10.1155/2017/9761356 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Chang-Cheng Zhao ◽

Gui-Hun Jiang ◽

Jong-Bang Eun

Keyword(s):

Response Surface Methodology ◽

Moisture Content ◽

Response Surface ◽

Water Activity ◽

Shear Force ◽

Process Conditions ◽

Drying Process ◽

Drying Temperature ◽

Overall Acceptability ◽

Drying Conditions

The aim of this study was to investigate the effects of drying temperature (50–70°C) and drying time (3–5 h) on the physical properties and quality of squid-laver snack (SLS) using response surface methodology combined with a synthetic evaluation method to optimize the drying process conditions. Moisture content, water activity, color (L⁎, a⁎, b⁎), shear force, and overall acceptability were evaluated as responses. Increased drying times and higher temperatures significantly reduced the moisture content and water activity of SLS from 9.07% to 4.76% and 0.136 to 0.056, respectively (p<0.05). There was no significant difference in the L⁎ and a⁎ values under different drying conditions. The quadratic effect of temperature and time was observed for the b⁎ value and overall acceptability of SLS. For shear force, a quadratic and interaction term for drying temperature and time on shear force was observed. In conclusion, the recommended optimal hot air-drying conditions for SLS are temperature and time of 70°C and 3 h, respectively.

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Effects Of Variables On The Production Of Red-Fleshed Pitaya Powder Using Response Surface Methodology

Jurnal Teknologi ◽

10.11113/jt.v56.51 ◽

2011 ◽

pp. 15-29

Author(s):

Mohd Azizi Che Yunus ◽

Ching Yaw Lee ◽

Zuhaili Idham

Keyword(s):

Response Surface Methodology ◽

Moisture Content ◽

Bulk Density ◽

Response Surface ◽

Spray Drying ◽

Air Temperature ◽

Flow Rate ◽

Feed Flow Rate ◽

Drying Conditions ◽

Central Composite

Teknik reka bentuk komposit pusat dalam kaedah gerak balas permukaan (RSM), telah dipilih untuk memeriksa pengaruh parameter-parameter pengeringan sembur terhadap kandungan lembapan dan ketumpatan pukal serbuk buah naga. Pemboleh ubah-pemboleh ubah tak bersandar dengan julat seperti yang disebutkan telah diuji kaji: suhu masukan (156-224°C), kadar aliran suapan (16.6-33.4 ml/min) dan kepekatan maltodextrin (31.6-48.4%). Keputusan menunjukkan bahawa data eksperimen dapat diwakili oleh bentuk polinomial tertib kedua. Bagaimanapun, hanya istilah linear mempunyai pengaruh mutlak terhadap keadaan serbuk. Parameter-parameter terbaik untuk mencapai nilai kandungan lembapan terendah adalah suhu masukan 224°C, kadar aliran suapan 22.9 ml/min dan kepekatan maltodextrin 40%, dengan jangkaan 3.88% kandungan lembapan. Nilai ketumpatan pukal yang maksimum iaitu 0.45 g/ml dicapai pada suhu masukan 156°C, kadar aliran suapan 16.6 ml/min dan kepekatan maltodextrin 48.4%. Kata kunci: Kaedah gerak balas permukaan; sembur kering; buah naga Central Composite Design technique from Response Surface Methodology (RSM) was used to investigate the effects of spray drying conditions on red-fleshed pitaya powder moisture content and bulk density. The spray drying independent variables and ranges are inlet air temperature (156-224°C), feed flow rate (16.6-33.4 ml/min) and maltodextrin concentration (31.6-48.4 %). Results showed that the data were adequately fitted to second order polynomial model. However, only linear terms proved to be significant for powder attributes. The best spray drying conditions within the experimental ranges for minimum powder moisture content of 3.88% would be inlet air temperature, feed flow rate and maltodextrin concentration of 224°C, 22.9 ml/min and 40% respectively. The maximum powder bulk density of 0.45 g/ml was obtained at inlet air temperature of 156°C, 16.6 ml/min feed flow rate and 48.4% maltodextrin concentration. Key words: Response surface methodology; spray-drying; red-fleshed pitaya

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Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽

10.3390/horticulturae7030040 ◽

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.

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Microwave Nondestructive Sensing of Moisture Content and Water Activity of Almonds

Transactions of the ASABE ◽

10.13031/trans.14338 ◽

2021 ◽

Vol 64 (4) ◽

pp. 1373-1379

Author(s):

Samir Trabelsi

Keyword(s):

Dielectric Constant ◽

Dielectric Properties ◽

Dielectric Loss ◽

Moisture Content ◽

Bulk Density ◽

Water Activity ◽

Free Space ◽

Loss Factor ◽

Dielectric Loss Factor ◽

List Type

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.

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Impact of Initial Moisture Content on the Drying Process of Wood Exposed to Infrared Radiation

BioResources ◽

10.15376/biores.8.3.4283-4287 ◽

2013 ◽

Vol 8 (3) ◽

Author(s):

Erzsébet Cserta ◽

Gergely Hegedűs ◽

Gergely Agócs ◽

Róbert Németh

Keyword(s):

Moisture Content ◽

Infrared Radiation ◽

Initial Moisture Content ◽

Drying Process

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Effect of drying methods on properties of green curry powder

MATEC Web of Conferences ◽

10.1051/matecconf/201819203023 ◽

2018 ◽

Vol 192 ◽

pp. 03023

Author(s):

Natthacha Chaloeichitratham ◽

Pornkanya Mawilai ◽

Thadchapong Pongsuttiyakorn ◽

Pimpen Pornchalermpong

Keyword(s):

Moisture Content ◽

Bulk Density ◽

Water Activity ◽

Freeze Drying ◽

Total Phenolic ◽

Drying Methods ◽

Hot Air Drying ◽

Air Drying ◽

Drying Temperature ◽

Hot Air

In this study, the effects of two drying methods: hot-air and freeze drying for Thai green curry paste in a terms of drying time and qualities have been investigated. The hot-air drying was carried out in tray dryer at temperature of 50, 60 and 70 °C. The freeze drying was carried out in freeze dryer at freezing temperature of -20°C, primary drying temperature of -10°C and secondary drying temperature of 50°C. Moisture content, water activity, colour, bulk density, and total phenolic content (TPC) were determined in samples. Freeze dried sample had significantly (p<0.05) lower moisture content, water activity, bulk density, total colour difference and browning index than hot air dried samples. For antioxidant activity, the results showed hot-air drying at 70°C effected highest TPC similar to freeze drying.

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Dielectric properties of hops – an effect of bulk density

Research in Agricultural Engineering ◽

10.17221/34/2017-rae ◽

2017 ◽

Vol 63 (Special Issue) ◽

pp. S18-S23

Author(s):

Lev Jakub ◽

Kumhála František

Keyword(s):

Dielectric Properties ◽

Moisture Content ◽

Bulk Density ◽

Relative Permittivity ◽

Loss Factor ◽

Drying Process ◽

Material Loss ◽

Measuring Device ◽

Temperature Changes ◽

Strong Linear Correlation

Continuous detection of basic physical properties of freshly picked and cleaned wet hop cones would be very helpful for better control and automation of harvesting processes. That is why the main aim of this article was to determine the effects of bulk density changes on dielectric properties of freshly picked hop cones. Relative permittivity and loss factor were measured using a newly developed capacitance measuring device. A strong linear correlation between fresh hops relative permittivity and bulk density was found. This finding could be used e.g. for consequent hop drying process control. Significant differences between tested hop varieties were observed for both relative permittivity and loss factor measurements. These differences cannot be explained only by a slightly different moisture content of the measured varieties and ambient temperature changes. Measured material loss factor was only slightly affected by bulk density changes. However, relative permittivity was affected by bulk density changes significantly. These facts could be used for other properties of wet hop cones estimation.

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Effect of the Freeze-Drying Process on the Physicochemical and Microbiological Properties of Mexican Kefir Grains

Processes ◽

10.3390/pr7030127 ◽

2019 ◽

Vol 7 (3) ◽

pp. 127 ◽

Cited By ~ 3

Author(s):

Alicia Conde-Islas ◽

Maribel Jiménez-Fernández ◽

Denis Cantú-Lozano ◽

Galo Urrea-García ◽

Guadalupe Luna-Solano

Keyword(s):

Moisture Content ◽

Water Activity ◽

Freeze Drying ◽

Survival Rates ◽

Freezing Temperature ◽

Freezing Time ◽

Residual Moisture Content ◽

Drying Process ◽

Residual Moisture ◽

Kefir Grains

The purpose of this study was to investigate how the properties of Mexican kefir grains (MKG) are affected by the operating parameters used in the freeze-drying process. The factors investigated were the freezing time (3–9 h), freezing temperature (−20 to −80 °C), pressure (0.2–0.8 mbar), and lyophilization time (5–20 h). The maximum range of change and one-way analysis of variance showed that lyophilization time and freezing time significant affects (p < 0.05) the response variables, residual moisture content and water activity, and pressure had a significant effect on the color difference and survival rate of probiotic microorganisms. The best drying conditions were a freezing time of 3 h, a freezing temperature of −20 °C, a pressure of 0.6 mbar, and a lyophilization time of 15 h. Under these conditions, we obtained a product with residual moisture content below 6%, water activity below 0.2, and survival rates above 8.5 log cfu per gram of lactic acid bacteria and above 8.6 log for yeast.

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A Proposed Method for Quantifying Thermal Exposure Incurred during Rough-Rice Drying

Transactions of the ASABE ◽

10.13031/trans.14063 ◽

2021 ◽

Vol 64 (2) ◽

pp. 475-484

Author(s):

Seth Graham-Acquaah ◽

Terry J. Siebenmorgen

Keyword(s):

Relative Humidity ◽

Moisture Content ◽

Thermal Desorption ◽

Thermal Exposure ◽

Drying Process ◽

Rough Rice ◽

Thermal Sterilization ◽

End Use ◽

Rice Drying ◽

Drying Conditions

HighlightsDrying conditions affect rice end-use functionality.Thermal exposure incurred by rough rice may differ depending on drying conditions.A framework is proposed for deriving an index that can show how much heat exposure rough rice incurs during drying.Abstract. Heated air is used to dry most rice in the U.S. Thus, commercial rice drying can be considered a thermal process that aims to remove moisture from rough rice until a desired moisture content is reached. Parallels can be drawn between rice drying and thermal sterilization that is targeted at reducing microbial load because moisture content reduction during drying follows similar decay rate kinetics as the reduction in microbial load during thermal sterilization. Given the different combinations of drying air conditions (air temperature and relative humidity), as well as drying and tempering durations, employed in various dryer designs for rice drying and the impact that these conditions have on rice end-use functionality, this study sought to derive a thermal treatment index (drying process values) that is similar to the F0 value concept used in thermal sterilization for quantifying and comparing the thermal exposure incurred by rice during drying under various scenarios. Using data collected from rough-rice drying experiments, a decimal desorption value (Dmv) that represents the duration required to cause a 90% reduction in moisture ratio during drying at a specified temperature was determined, from which a thermal desorption constant (Zmv) that represents the increase in temperature necessary to cause a 90% reduction in Dmv during drying was established. Subsequently, a thermal desorption value (Fmv) was derived to express the duration that a rice lot would have been heat treated at a reference temperature during drying to produce an equivalent effect on moisture content as that produced by the actual drying process. Keywords: End use, Moisture content, Peak viscosity, Postharvest, Relative humidity, Rice, Temperature.

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