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

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.

Drying of Rough Rice in Oven: An Experimental Study

2015 ◽  
Vol 365 ◽  
pp. 77-81 ◽  
Author(s):  
J.V. Silva ◽  
E.M.A. Pereira ◽  
T.H.F. Andrade ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Experimental Study ◽  
Relative Humidity ◽  
Moisture Content ◽  
Product Quality ◽  
Air Temperature ◽  
Drying Rate ◽  
Rough Rice ◽  
Drying Conditions ◽  
Kinetics Of ◽  
Mechanical Movement

This paper aims to present an experimental study of rough rice (BRSMG CONAI cultivar) drying by using a stationary method. The grain was dried in an oven with air mechanical movement under controlled conditions of velocity, temperature and relative humidity. In order to obtain balanced moisture content, the samples studied were kept at 40 and 70°C. Results of the drying and heating kinetics of the grain during the process are shown and analyzed. It was found that higher drying rate and lower time for drying as higher air temperature (70°C) is used. It can be concluded that the reduction of the moisture content of the grain, is considered very complex and, depending on the method and drying conditions, can substantially provokes breaking and cracks, which reduces final product quality.

Numerical Simulation of the moisture content in rough rice drying process in a fixed bed

2019 ◽  
Author(s):  
Franciane Cristina Rodrigues Carvalho ◽  
José Leôncio Fonseca de Souza
Keyword(s):  
Numerical Simulation ◽  
Moisture Content ◽  
Fixed Bed ◽  
Drying Process ◽  
Rough Rice ◽  
Rice Drying

Fissuring Kinetics of Rough Rice during the Drying Process

2020 ◽  
Vol 36 (5) ◽  
pp. 639-645
Author(s):  
Zephania R. Odek ◽  
Terry J. Siebenmorgen ◽  
Ashok Saxena
Keyword(s):  
Relative Humidity ◽  
Time Interval ◽  
List Type ◽  
Drying Process ◽  
Milled Rice ◽  
X Ray ◽  
Rough Rice ◽  
Drying Conditions ◽  
Subsequent Storage ◽  
Kinetics Of

HighlightsDrying rough rice using harsh air conditions causes fissures to appear instantaneously during active drying.For mild drying air conditions, a time interval is required after the cessation of active drying before fissures appear.The majority of fissures due to active drying in rough rice kernels appear after drying has ceased.Abstract. Fissuring of rough rice kernels leads to breakage during milling, which results in head rice yield reductions. While other studies have addressed the fissuring kinetics of milled rice kernels, rice is normally dried and stored as rough rice. Thus, the objective of this research was to study the fissuring kinetics of rough rice kernels during the drying process and to characterize the configuration of the fissures. Rough rice kernels of cultivar CL XL745 with a bulk moisture content of 17% were dried using air at 40°C, 50°C, and 60°C each at relative humidity (RH) levels of 20%, 40%, and 60%. During the drying process (drying, tempering, and subsequent storage), X-ray images of rice kernels were recorded to enumerate fissures. As the drying air temperature was increased, the percentage of fissured kernels increased for all RHs evaluated. Conversely, as RH was increased, the percentage of fissured kernels decreased. Approximately 90% of fissures appeared after drying had ceased, increasing rapidly in the initial 6 h after drying. Kernels dried at high-temperature, low-RH drying air combinations had fissuring occur and appear instantaneously during active drying. In low-temperature drying conditions, fissures did not appear during active drying. Fissuring under such conditions required a time delay after active drying. This study shows the stages of the drying process when fissures appear in rough rice and the durations after active drying when fissures are expected to appear. Keywords: Glass transition, Post-drying, Relative humidity, Rice drying, Temperature, Tempering, X-ray imaging.

scholarly journals The Physical Quality of Milled Rice as Affected by Moisture Content and Relative Humidity during Delayed Rough Rice Drying

2017 ◽  
Vol 5 (11) ◽  
pp. 1261
Author(s):  
Tamrin Tamrin ◽  
Filli Pratama ◽  
Bagus Septian
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Block Design ◽  
Milled Rice ◽  
Physical Quality ◽  
Randomized Block Design ◽  
Rough Rice ◽  
Rice Milling ◽  
Rice Drying

Delayed rough rice drying was often found in tidal low land in Indonesia due to rice harvesting used to be in rainy season. Moisture re-absorption of rough rice during delayed drying caused fissures and breakage after rice milling. This experimental works condition the rough rice in some different moisture content and relative humidity during delayed drying. This aim of this study was to develop an alternative condition of delayed rough rice for drying so as not to significantly affect the physical quality of milled rice. The experiment was arranged as a factorial-randomized block design. Each treatment was repeated three times. Rough rice of IR42 variety was selected at three level of moisture content (24.89%, 18% and 22%), and was stored in a closed vessel at the relative humidity of 76% and 86%. The percentage of whole grain, head rice, large broken grain, and small broken grain were daily assessed until 7 days of delayed drying duration. The results showed that the moisture content and relative humidity had a significant effect on all parameters on each day of delayed rough rice drying duration. Rough rice would be better delayed for drying at the conditions for moisture content of 22% and relative humidity of 86%.

scholarly journals Drying of Sisal Fiber: A Numerical Analysis by Finite-Volumes

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2514
Author(s):  
Jacqueline F. B. Diniz ◽  
João M. P. Q. Delgado ◽  
Anderson F. Vilela ◽  
Ricardo S. Gomez ◽  
Arianne D. Viana ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Sisal Fiber ◽  
Moisture Removal ◽  
Drying Process ◽  
Porous Bed ◽  
Bed Porosity ◽  
Long Time ◽  
Sisal Fibers ◽  
Drying Conditions

Vegetable fibers have inspired studies in academia and industry, because of their good characteristics appropriated for many technological applications. Sisal fibers (Agave sisalana variety), when extracted from the leaf, are wet and must be dried to reduce moisture content, minimizing deterioration and degradation for long time. The control of the drying process plays an important role to guarantee maximum quality of the fibers related to mechanical strength and color. In this sense, this research aims to evaluate the drying of sisal fibers in an oven with mechanical air circulation. For this purpose, a transient and 3D mathematical model has been developed to predict moisture removal and heating of a fiber porous bed, and drying experiments were carried out at different drying conditions. The advanced model considers bed porosity, fiber and bed moisture, simultaneous heat and mass transfer, and heat transport due to conduction, convection and evaporation. Simulated drying and heating curves and the hygroscopic equilibrium moisture content of the sisal fibers are presented and compared with the experimental data, and good concordance was obtained. Results of moisture content and temperature distribution within the fiber porous bed are presented and discussed in details. It was observed that the moisture removal and temperature kinetics of the sisal fibers were affected by the temperature and relative humidity of the drying air, being more accentuated at higher temperature and lower relative humidity, and the drying process occurred in a falling rate period.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

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.

Drying technology of mesquite pods (Prosopis laevigata) and microstructural insights

2020 ◽  
Vol 122 (9) ◽  
pp. 2953-2963
Author(s):  
Sadoth Sandoval Torres ◽  
Daniel Lopez Cravioto ◽  
Juan Rodríguez Ramírez ◽  
Lilia L. Méndez Lagunas ◽  
Luis Gerardo Barriada Bernal ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Food Industry ◽  
Characteristic Curve ◽  
Drying Process ◽  
Sem Images ◽  
Content Type ◽  
Milling Operation ◽  
Drying Technology ◽  
First Time

PurposeMesquite pods offer a high nutritional content; A flour can be produced from them; nevertheless, the moisture content makes the milling process difficult. Then, before the milling operation a drying process must be implemented, but drying technology must be studied in order to characterise the process and identify the effect of drying temperature on the magnitude of drying rate.Design/methodology/approachProsopis Laevigata pods were collected in Oaxaca (Southern of Mexico) and they were dried. Three stages of maturity were identified and pods in the stage three of maturity were dried by forced convection. The internal structure of the pods was analyzed by scanning electron microscopy (SEM). The pods were dried in a tunnel dryer at 40, 50, 60 and 70° C, 10% relative humidity and air velocity of 2.6 m/s. From experimental data, a lumped analysis was conducted for drying.FindingsWe found that the internal microstructure of this material is a limiting factor for moisture migration. In order to reduce the moisture content in the pods, a minimum air temperature of 60° C must be applied. The characteristic drying curve shows a good agreement with the experimental drying kinetics. The nutritional composition (carbohydrates, sugar and protein) of pods reveals important applications for the food industry.Practical implicationsThe mesquite pods are important ethnic foods. In order to obtain flour, the drying of pods is mandatory. Drying must be applied in stage three of maturity which can be identified based on color changes and moisture content. The moisture content affects the performance of milling operation, then a minimum drying temperature of 60° C and low relative humidity must be applied. SEM images show the complex microstructure of the pods which hinders the moisture diffusion. The drying characteristic curve was deduced for the first time; it helps to understand the drying behavior of pods. The chemical composition of mesquite pods reveals interesting applications for the food industry. The methodology for drying is useful for researchers and producers.Originality/valueMezquite pods is an interesting ethnic food for people with celiac disease. This is the first time a research paper describes the drying process at detail. The SEM images, the convective drying operation and the characteristic curve are presented for the first time. The information will be useful for the industry and academia.

Effect of Drying on Physical Qualities and Sensory Evaluation of Herbal Germinated Brown Rice by Hot Air: Turmeric and Roselle

2013 ◽  
Vol 372 ◽  
pp. 420-423
Author(s):  
Khwanruedi Sangchum ◽  
Yutthana Tirawanichakul ◽  
Supawan Tirawanichakul
Keyword(s):  
Moisture Content ◽  
Sensory Evaluation ◽  
Initial Moisture Content ◽  
Brown Rice ◽  
Ambient Air ◽  
Drying Rate ◽  
Germinated Brown Rice ◽  
Rice Drying ◽  
Drying Conditions ◽  
Cie Lab

The object of this project was to study the effect of drying temperature on physical quality and sensory evaluation of germinated brown rice soaking with tumeric and roselle. The drying was run under the conditions of drying temperatures of 80-100°C and air velocity of 7.3 m/s. Initial moisture content of brown rice samples was of 54-55% dry-basis and was dried until the final moisture content reached to 20-25% dry-basis. After drying, the rice was tempered and then was ventilated by ambient air until its moisture content reached to 14-15% dry-basis. The experiment showed that highest drying rate is incident at 100°C. For physical qualities analysis, the results showed that the drying air temperature does not affect to head rice yield, fissured kernels, chalky grain and color (L*, a*, b* CIE-lab unit) of herbal germinated brown rice. In addition, herbal germinated brown rice drying can maintain low percentage of chalky grain compared to commercial brown rice. The soaking solution was not affect to drying rate. Finally, the sensory evaluation showed that the herbal germinated brown rice dried with all drying conditions was acceptable taste (>5).

The creep of wood destabilized by change in moisture content. Part 1: The creep behaviors of wood during and immediately after drying

Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 261-267 ◽  
Author(s):  
C. Takahashi ◽  
Y. Ishimaru ◽  
I. Iida ◽  
Y. Furuta
Keyword(s):  
Elastic Modulus ◽  
Relative Humidity ◽  
Moisture Content ◽  
Stable State ◽  
Unstable State ◽  
Drying Process ◽  
Temperature Creep ◽  
Long Time ◽  
Content Part

Abstract To better understand mechano-sorptive creep, creep behaviors were compared in wood samples during the drying process, immediately after drying, and after a long conditioning under constant humidity and temperature. Creep was greater in the sample tested immediately after drying than in the sample conditioned for a long time under relative humidity equal to that after drying, despite the fact that these samples had almost the same moisture content (MC). While the wood that has been moisture-conditioned for a long time is in a stable state, the wood tested immediately after the drying is presumed to be in an unstable state. Moreover, creep of the sample tested during the drying process was greater than that of the sample tested immediately after the drying. It has also been found that the instability decreased with time, indicating that stabilization and destabilization occur simultaneously during the drying process. In recent studies, a decrease in the elastic modulus and an increase in the fluidity of wood immediately after a change in MC or temperature have been reported. These findings are attributed to the instability caused by changes in MC or temperature. Based on the results of the present study and recent studies, we consider the increase in the fluidity of wood as the MC changes to be attributable to instability.

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