Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process

2021 ◽  
Vol 114 ◽  
pp. 86-91
Author(s):  
Ladislav Dzurenda
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Bound Water ◽  
Free Water ◽  
Hot Air Drying ◽  
Air Drying ◽  
Water Steam ◽  
Color Changes ◽  
Hot Air ◽  
Relative Air Humidity

Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process. The paper presents a hot-air mode for drying steamed alder in the form of blanks with dimensions: 38x100x800 mm from the initial moisture content W1 ≈ 50 % to the final moisture content W2 = 10%, while maintaining the colour of wood obtained in the process of steaming with saturated water steam. The drying process is divided into two parts: (I) evaporation of free water from wet wood at drying medium temperatures td = 35 - 40 °C and relative air humidity φ = 70 – 60%, when there are no chemical changes in the lignin-saccharide complex of alder wood manifested by a change in colour; (II) evaporation of bound water from alder wood below the hygroscopicity limit is performed at temperatures td = 60 - 80 °C. The color coordinates of steamed alder wood after drying by a given mode in the CIE L* a* b* colour space are: L* = 62.5 ± 1.7; a* = 13.1 ± 0.8; b* = 18.5 ± 0.9. Total colour difference ∆E = 1.6. According to the categorization of wood color changes in thermal processes of wood , this change belongs to small (insignificant) color changes.

Hot Air Drying and Vacuum Drying Characteristics of Scarlet Runner Beans

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Yoshiki Muramatsu ◽  
Eiichiro Sakaguchi ◽  
Takahiro Orikasa ◽  
Akio Tagawa
Keyword(s):  
Diffusion Coefficient ◽  
Moisture Content ◽  
Initial Moisture Content ◽  
Vacuum Drying ◽  
Drying Method ◽  
Drying Process ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air

Abstract The drying characteristics and volume changes of scarlet runner beans were measured under various conditions to obtain useful basic information for the optimum drying method and conditions. The sample was dried using two drying methods: hot air drying and vacuum drying. The measured changes in moisture content of the sample with the hot air drying process were in good agreement with the exact solution of the infinite plane sheet model. The estimated diffusion coefficients were 3.8×10 -7 -7.4×10 -7 (m 2 h -1) for hot air drying and were related to absolute temperature by an Arrhenius-type equation. The hull of the scarlet runner bean is hard and thick, and the drying rate of the sample was much slower than that of other beans. To establish an efficient drying method without the quality loss, the vacuum drying characteristics of the sample were measured at several levels for temperature and initial moisture content. For the vacuum drying process, an exponential model could be used to estimate the changes in moisture content of the sample. The values of diffusion coefficient for vacuum drying were approximately twice as much as the values of diffusion coefficient for hot air drying at the same temperature. The effects of drying method, temperature, and initial moisture content on the sample quality were investigated, and the optimum drying method and conditions for scarlet runner beans were proposed. Volumetric changes in the sample were determined by measuring particle density. The specific volume of the sample was represented as a linear function of moisture content.

Detection of moisture and carotenoid content in carrot slices during hot air drying based on multispectral imaging equipment with selected wavelengths

2021 ◽  
Vol 17 (9) ◽  
pp. 727-735
Author(s):  
Jiamei Long ◽  
Jia Yang ◽  
Jing Peng ◽  
Leiqing Pan ◽  
Kang Tu
Keyword(s):  
Moisture Content ◽  
Prediction Model ◽  
Multispectral Imaging ◽  
Prediction Models ◽  
Projection Algorithm ◽  
Carotenoid Content ◽  
Support Vector ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air

Abstract Moisture content and carotenoid content are important indicators for evaluating the drying process of carrot slices. There are growing attention to develop non-destructive methods as effectively analytical tools in quality assurance of drying carrot slices. In this study, the characteristic wavelengths of moisture and carotenoid content in carrot slices during hot air drying were extracted based on hyperspectral imaging technology. A multispectral imaging equipment was built after that, and the wavelengths of filters were determined according to the characteristic wavelengths. Based on the successive projection algorithm (SPA), the optimal wavelengths of moisture and carotenoid content were further determined, and prediction models of both were established based on the system. There were 12 filters selected in this study. The results showed that a support vector machine (SVM) prediction model for moisture content was established based on seven optimal wavelengths with 0.991 for the coefficient of determination of prediction set (R 2 p ) and 10.318 for the residual prediction residual (RPD). Based on eight optimal wavelengths, a SVM prediction model for carotenoid content was also established with 0.968 for R 2 p and 5.337 for RPD. The prediction performance is close to or even better than that based on hyperspectral. The study confirmed the feasibility of using the multispectral imaging equipment to measure the moisture and carotenoid content of carrot slices during drying based on selected wavelengths, laying a foundation for the further preparation of a portable multispectral detector for the quality of dry products.

scholarly journals Effects of Freeze Vacuum Drying Combined with Hot Air Drying on the Sensory Quality, Active Components, Moisture Mobility, Odors, and Microstructure of Kiwifruits

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Lihui Zhang ◽  
Yu Qiao ◽  
Chao Wang ◽  
Li Liao ◽  
Lu Liu ◽  
...  
Keyword(s):  
Sensory Quality ◽  
Antioxidant Properties ◽  
Bound Water ◽  
Principal Component ◽  
Vacuum Drying ◽  
Active Components ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air

In this study, freeze vacuum drying (FVD), hot air drying (AD), and FVD combined with AD (FVD-AD) were used to dry kiwifruits. Dried products were analyzed comprehensively on their sensory quality, active components, moisture mobility, odors, and microstructure. Results showed that the FVD-AD saved time by 38.22% compared with FVD while maintaining an acceptable product quality. The antioxidant properties of FVD-AD were lower than those of FVD but significantly higher than those of AD. Moreover, compared with FVD products, FVD-AD products were moderately hard (5252.71 ± 33.53 g) and improved in color, bound water, and microstructure. Additionally, FVD-AD consumed lesser drying time and energy than FD. According to cluster analysis, the odors of FVD-AD products were similar to those of the fresh ones. Principal component analysis of physicochemical and drying cost indicated that FVD-AD was a promising processing technique for functional kiwifruit snacks.

scholarly journals Effect of drying methods on properties of green curry powder

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.

Analysis of Equilibrium moisture content and L-ascorbic acid during hot air drying for sweet potato

2008 ◽  
Author(s):  
Takahiro Orikasa ◽  
Daisuke Nei ◽  
Poritosh Roy ◽  
Nobutaka Nakamura ◽  
Takeo Shiina ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Moisture Content ◽  
Sweet Potato ◽  
Equilibrium Moisture Content ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air

scholarly journals Influence of Different Hot Air Drying Temperatures on Drying Kinetics, Shrinkage, and Colour of Persimmon Slices

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo
Keyword(s):  
Moisture Content ◽  
Quadratic Model ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Hot Air

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.

Experiment on the Mechanics Properties of Hot-Pepper in the Process of Hot-Air Drying

2013 ◽  
Vol 395-396 ◽  
pp. 571-576
Author(s):  
Xue Bi Zhang ◽  
Si Yu Chen ◽  
Wen Fu Wu ◽  
Ya Qiu Zhang ◽  
Chun Shan Liu ◽  
...  
Keyword(s):  
Moisture Content ◽  
Tensile Strain ◽  
Maximum Load ◽  
Hot Pepper ◽  
Hot Air Drying ◽  
Air Drying ◽  
Damage Rate ◽  
Hot Air ◽  
Variation Tendency

In order to reduce the damage rate of hot-pepper in the process of drying and transportation, and to improve the quality of dried hot-pepper. In this paper, the mechanical properties of hot-pepper were studied in the process of hot-air drying. The experimental results showed that the hot-pepper’s compressive ability dropped with the decrease of moisture content after the moisture content reached the safe moisture content. With the moisture content decreasing, the variation tendency of the elastic modulus and tensile strain of hot-pepper were first increased and then decreased and finally tended to be stable when it reached 12％. Effect of hot-pepper’s shape on tensile strain is greater than on the maximum load and displacement in the process of drying.

Empirical Model and Artificial Neural Network Model Approach for Air Dried Sheets (ADS) Rubber

2012 ◽  
Vol 622-623 ◽  
pp. 69-74
Author(s):  
T. Ninchuewong ◽  
S. Tirawanichakul ◽  
Y. Tirawanichakul
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Moisture Content ◽  
Neural Network Model ◽  
Artificial Neural Network Model ◽  
Hot Air Drying ◽  
Air Drying ◽  
Rubber Sheet ◽  
Hot Air ◽  
Drying Behavior

The objective of this research was to predict drying behavior of hot air drying using an empirical model (EM) and an artificial neural network model (ANN). Rubber sheet with initial moisture content ranging of 23-40% dry-basis was dried by temperature ranging of 40-70°C and air flow rate of 0.7 m/s. The desired final moisture content was set at 0.15% dry-basis. The results showed that drying rate of rubber sheet dried with hot air convection was faster than conventional natural aeration. The EM and ANN were simulated to describe the drying behavior of products. Furthermore, prediction results between EM and ANN were compared with the experimental data. In this research, it was obviously found that ANN can describe the drying behavior effectively. Additionally, it was also found that predicted results of Multilayer feed forward Levenberg-Maqurdt’s Back-propagation ANN were good agreement with the experimental results compared to those results of EM. It is the optimum architecture for prediction the evolution of moisture transfer for hot air drying.

scholarly journals Hot air drying combined vacuum-filling nitrogen drying of apple slices: Drying characteristics and nutrients

2018 ◽  
Author(s):  
Xiaoli Huang ◽  
T. Li ◽  
S.N. Li ◽  
Z.H. Wu ◽  
J. Xue
Keyword(s):  
Moisture Content ◽  
Drying Rate ◽  
Slice Thickness ◽  
Relative Pressure ◽  
Hot Air Drying ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air ◽  
Apple Slices ◽  
Apple Slice

In this paper, hot air drying (HAD) was applied when moisture content of apple slices range from 50% to 86%, and then vacuum-filling nitrogen drying (VFND) was used till moisture content reaching 7%. Results showed that, the drying rate of apple slice during VFND period increased with temperature increment and decreased with increment of slice thickness; compared to freezing dried samples,  samples dried in this research were owned lower Vc and higher flavonoid; when HAD (70℃,3.0m/s)+VFND(relative pressure 0.08MPa, 50℃) and thickness of 6.0mm, nutrients reached better levels: retentions of Vc, total phenolics and flavonoid were 1.63mg/100g, 4.07mg/100g and 2.10mg/100g, respectively. Keywords: apple slices, hot air drying, vacuum-filling nitrogen drying, drying rate, nutrients

Potato Shrinkage During Hot Air Drying

2010 ◽  
Vol 16 (4) ◽  
pp. 337-341 ◽  
Author(s):  
A. Frías ◽  
G. Clemente ◽  
A. Mulet
Keyword(s):  
Image Analysis ◽  
Moisture Content ◽  
Volumetric Shrinkage ◽  
Air Velocity ◽  
Volume Changes ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Physical Changes

Shrinkage is one of the most important physical changes that occur during the dehydration of foods. In this work, the effect of the temperature (35, 40, 50, 60 and 70 °C) and air velocity (7, 8, 9 and 10 m/s) on bulk volumetric shrinkage was investigated. Volume changes were evaluated by image analysis. It was found that neither temperature nor air velocity had any significant effects on bulk shrinkage in this system. The bulk shrinkage of the potato cubes was well correlated with the moisture content of the sample during drying (R2 = 97.28). Volume varied linearly with the moisture content changes under the studied conditions. The volume of lost water and the decrease in volume of the samples during dehydration were similar.

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