Study on the splitting by hot-air drying of Camellia oleifera fruit

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Fenghe Wang ◽  
Zongxin Liu ◽  
Yechun Ding ◽  
Deyong Yang
Keyword(s):  
Air Temperature ◽  
Seed Quality ◽  
Seed Color ◽  
Camellia Oleifera ◽  
Hot Air Drying ◽  
Air Drying ◽  
Moisture Migration ◽  
Hot Air ◽  
Micro Channels ◽  
Drying Kinetic

Abstract In order to explore the feasibility of hot air splitting of Camellia oleifera fruit, the effect of hot air temperature on peel splitting, the moisture state and moisture migration in peel, the peel microstructure and the seed color were studied. The results showed that higher hot air temperature could accelerate the splitting rate, the optimum temperature for splitting C. oleifera fruit was 90–110 °C considering the seed quality. Page model was the most suitable for describing the drying kinetic characteristics of C. oleifera fruit. Nuclear magnetic resonance (NMR) revealed the changing of the dehydration rate, the migration rate of bound water, immobilized water and free water in peel during hot air drying. The expansion of micro-channels in peel was conducive to moisture migration in the early splitting stage, but microstructure damaged in the late splitting stage accompanied by loose disorder of micro pores, serious shrinkage and deformation of peel.

scholarly journals Optimisation of energy consumption of a solar-electric dryer during hot air drying of tomato slices

2019 ◽  
Vol 50 (3) ◽  
pp. 150-158 ◽  
Author(s):  
Nnaemeka R. Nwakuba
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
High Energy ◽  
Slice Thickness ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Drying Conditions ◽  
Desirability Index

High-energy demand of convective crop dryers has prompted study on optimisation of dryer energy consumption for optimal and cost effective drying operation. This paper presents response surface optimisation of energy consumption of a solar-electric dryer during hot air drying of tomato slices. Drying experiments were conducted with 1 kg batch of tomato samples using a 33 central composite design of Design Expert 7.0 Statistical Package. Three levels of air velocity (1.0, 1.5 and 2.0 ms–1), slice thickness (10, 15 and 20 mm) and air temperature (50, 60 and 70°C) were used to investigate their effects on energy consumption. A quadratic model was obtained with a high coefficient of determination (R2) of 0.9825. The model was validated using the statistical analysis of the experimental parameters and normal probability plot of the energy consumption residuals. Results obtained indicate that the process parameters had significant quadratic effects (P<0.05) on the energy consumption. The energy consumption varied between 5.42 kWh and 99.78 kWh; whereas the specific energy consumption varied between 5.53 kWhkg–1 and 150.61 kWhkg–1. The desirability index method was applied in predicting the ideal energy consumption and drying conditions for tomato slices in a solar-electric dryer. At optimum drying conditions of 1.94 ms–1 air velocity, 10.36 mm slice thickness and 68.4°C drying air temperature, the corresponding energy consumption was 5.6 8kWh for maximum desirability index of 0.989. Thermal utilisation efficiency (TUE) of the sliced tomato samples ranged between 15 ≤TUE ≤58%. The maximum TUE value was obtained at 70°C air temperature, 1.0 ms–1 air velocity and 10 mm slice thickness treatment combination, whereas the minimum TUE was obtained at 50°C air temperature, 2.0 ms–1 air velocity and 20 mm slice thickness. Recommendation and prospect for further improvement of the dryer system were stated.

Heat Transfer Characteristics and Kinetics of Camellia oleifera Seeds During Hot-Air Drying

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Dan Huang ◽  
Yuchao Tao ◽  
Wei Li ◽  
S. A. Sherif ◽  
Xiaohong Tang
Keyword(s):  
Heat Transfer ◽  
Camellia Oleifera ◽  
Heat Transfer Characteristics ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Hot Air ◽  
Rate Period ◽  
Kinetics Of

Abstract The heat transfer characteristics and kinetics of Camellia oleifera seeds under hot-air drying were investigated at different temperatures (40, 60, and 80 °C) and loading densities (0.92, 1.22, and 1.52 g/cm2) with a constant air velocity of 1 m/s. Twelve common drying kinetic models were selected to fit the experimental data. The most suitable model was chosen to describe the hot-air drying process of C. oleifera seeds and help in its optimization. The results showed that the drying temperature has a significant influence on the hot-air drying characteristics of C. oleifera seeds. As the drying air temperature increases, the drying time decreases. The effect of the loading density on the drying characteristics of C. oleifera seeds is much smaller than that of temperature. With the increase in the loading density, the drying time slightly increases. The hot-air drying curve of C. oleifera seeds consists of a very short acceleration rate period at the beginning and a long falling rate period, indicating that the drying of C. oleifera seeds is mainly controlled by the diffusion of moisture inside the material. An effective moisture diffusion coefficient of C. oleifera seeds was estimated to range from 0.81256 × 10−9 to 3.28496 × 10−9 m2/s within the temperature range studied. The average activation energy was 28.27979 kJ/mol. The logarithmic model was found to be the best model to describe the kinetics of hot-air drying of C. oleifera seeds.

scholarly journals Optimization of energy consumption of a solar-electric dryer during hot air drying of tomato slices

2019 ◽  
Author(s):  
Nnaemeka R. Nwakuba
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
High Energy ◽  
Utilization Efficiency ◽  
Slice Thickness ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Drying Conditions ◽  
Desirability Index

High-energy demand of convective crop dryers has prompted study on optimization of dryer energy consumption for optimal and cost effective drying operation. This paper presents response surface optimization of energy consumption of a solar-electric dryer during hot air drying of tomato slices. Drying experiments were conducted with 1kg batch of tomato samples using a 33Central Composite Design (CCD) of Design Expert 7.0 Statistical Package. Three levels of air velocity (1.0, 1.5 and 2.0ms–1), slice thickness (10, 15 and 20mm) and air temperature (50, 60 and 70oC) were used to investigate their effects on energy consumption. A quadratic model was obtained with a high coefficient of determination (R2) of 0.9825. The model was validated using the statistical analysis of the experimental parameters and normal probability plot of the energy consumption residuals. Results obtained indicate that the process parameters had significant quadratic effects (p < 0.05) on the energy consumption. The energy consumption varied between 5.42kWh and 99.78kWh; whereas the specific energy consumption varied between 5.53kWhkg–1and 150.61kWhkg–1. The desirability index method was applied in predicting the ideal energy consumption and drying conditions for tomato slices in a solar-electric dryer. At optimum drying conditions of 1.94ms–1air velocity, 10.36mm slice thickness and 68.4oC drying air temperature, the corresponding energy consumption was 5.68kWh for maximum desirability index of 0.989. Thermal utilization efficiency (TUE) of the sliced tomato samples ranged between 15 ≤ TUE ≤ 58%. The maximum TUE value was obtained at 70oC air temperature, 1.0ms–1air velocity and 10mm slice thickness treatment combination, whereas the minimum TUE was obtained at 50oC air temperature, 2.0ms–1air velocity and 20mm slice thickness. Recommendation and prospect for further improvement of the dryer system were stated.

Study on Drying Technology of Sargassum Fusiforme

2011 ◽  
Vol 361-363 ◽  
pp. 764-769
Author(s):  
Shu Xing Liu ◽  
Li Li Zhu ◽  
Shu Meng Zhang
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Raw Materials ◽  
Variable Temperature ◽  
High Quality ◽  
Hot Air Drying ◽  
Air Drying ◽  
Sargassum Fusiforme ◽  
Hot Air ◽  
Drying Technology

A convenient and nutritious dried instant Sargassum fusiforme was developed by the study on the technology of drying with the raw materials of Sargassum fusiforme. The result indicated that the optimum drying technology of Sargassum fusiforme is: on the condition of 95°C for 90s,to blanching, then by means of variable temperature for hot air drying at the 3m/s wind speed, which is air temperature 80°C in first hour,70°C for another 3.5 hours, that we can get high quality Sargassum fusiforme in Rehydration shape,color, and taste .etc.

scholarly journals 3D Model-Based Simulation Analysis of Energy Consumption in Hot Air Drying of Corn Kernels

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Shiwei Zhang ◽  
Ninghua Kong ◽  
Yufang Zhu ◽  
Zhijun Zhang ◽  
Chenghai Xu
Keyword(s):  
Mass Transfer ◽  
Energy Consumption ◽  
Air Temperature ◽  
Hot Air Drying ◽  
Air Drying ◽  
Body Model ◽  
Transfer Processes ◽  
Hot Air ◽  
Mass Transfer Processes ◽  
Corn Kernels

To determine the mechanism of energy consumption in hot air drying, we simulate the interior heat and mass transfer processes that occur during the hot air drying for a single corn grain. The simulations are based on a 3D solid model. The 3D real body model is obtained by scanning the corn kernels with a high-precision medical CT machine. The CT images are then edited by MIMICS and ANSYS software to reconstruct the three-dimensional real body model of a corn kernel. The Fourier heat conduction equation, the Fick diffusion equation, the heat transfer coefficient, and the mass diffusion coefficient are chosen as the governing equations of the theoretical dry model. The calculation software, COMSOL Multiphysics, is used to complete the simulation calculation. The influence of air temperature and velocity on the heat and mass transfer processes is discussed. Results show that mass transfer dominates during the hot air drying of corn grains. Air temperature and velocity are chosen primarily in consideration of mass transfer effects. A low velocity leads to less energy consumption.

scholarly journals Optimization of Microwave Coupled Hot Air Drying for Chinese Yam Using Response Surface Methodology

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 745 ◽  
Author(s):  
Hanyang Wang ◽  
Dan Liu ◽  
Haiming Yu ◽  
Donghai Wang ◽  
Jun Li
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Power Density ◽  
Air Temperature ◽  
Microwave Power ◽  
Slice Thickness ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air

The effect of microwave coupled hot air drying on rehydration ratio (RR) and total sugar content (TSC) of Chinese yam was investigated. Single factor test and response surface methodology were used for process parameter optimization with hot air temperature, hot air velocity, slice thickness, and microwave power density as variables and RR and TSC of dried products as responses. The effect of variables on RR followed the order: slice thickness > hot air temperature > microwave power density > hot air velocity. The effect of variables on TSC followed the order: slice thickness > microwave power density > hot air velocity > hot air temperature. The optimized process parameters were hot air velocity of 2.5 m/s, hot air temperature of 61.7 °C, slice thickness of 8.5 mm, and microwave power density of 5.9 W/g. Under the optimal conditions, the predicted values of RR and TSC were 1.90 g/g and 5.74 g/100 g, respectively, which is very close to corresponding actual values (1.83 g/g and 5.72 g/100 g). The desirability of 0.913 further validated the effectiveness of the model. The findings from this work may apply to other agricultural products.

Characteristics and Process Optimization of Hot-Air Drying Pepper

2012 ◽  
Vol 490-495 ◽  
pp. 3074-3078
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Song ◽  
Ya Qiu Zhang ◽  
Jun Xing Li ◽  
...  
Keyword(s):  
Wind Speed ◽  
Moisture Content ◽  
Air Temperature ◽  
Drying Process ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Primary Parameter ◽  
Hot Air ◽  
Pre Treatment

In order to solve the drying problems in the deep-processing of pepper, peppers were dried through blanching pre-treatment and hot-air drying process. Orthogonal test designs were carried out to investigate factors influencing the quality and moisture content of pepper. The results showed that the whole drying process was a reduction speed drying, hot-air temperature and wind speed have significantly affected on the drying rate of pepper, but the impact of hot-air temperature was more prominent than wind speed; hot-air temperature was found to be the primary parameter to affect the quality of the pepper, wind speed was the secondary one and followed by packing thickness; drying time was found to be the primary parameter to affect the moisture content of the pepper in the drying process, the best drying conditions were as follows: wind temperature was 80°C, wind speed was 10 m/s, packing thickness was 80 cm, drying time was 12 h after 100°C steam blanching pre-treatment

Microwave Assisted Convective Air Drying of Sugarloaf Pineapples (Ananas Comosus)

2021 ◽  
Vol 37 (5) ◽  
pp. 763-774
Author(s):  
Ernest Ekow Abano
Keyword(s):  
Air Temperature ◽  
Microwave Power ◽  
Moisture Diffusivity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Microwave Assisted ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Conditions

HighlightsMicrowave pretreatment before drying reduced drying time significantly.Microwave-assisted drying increased the effective moisture diffusivity coefficient.Microwave pretreatment before convective hot-air drying improved quality parameters.The Middili et al. (2002) model best fitted the microwave-assisted drying of sugarloaf pineapples.Abstract. This study’s objective was to provide the optimum drying conditions to produce quality dried sugarloaf pineapples using microwave pretreatments before the conventional hot air drying. For this, the effect of microwave power (385 to 697 W), microwave time (2 to 4 min), and air temperature (50°C to 70°C) on the drying kinetics and quality of sugarloaf pineapple were evaluated using the Box Behnken response surface methodology. To reach a 17.44±0.09% kg/kg dry matter moisture content, we found the optimum drying conditions for sugarloaf pineapples to be 697 W microwave power for 2.26 min before convective hot air drying at a temperature of 64.75°C. The predicted drying time, ascorbic acid content, and browning index were 13.68 h, 20.89 mg/100 g, and 0.099 Abs unit at this optimum condition, respectively. The pineapple slices’ effective moisture removal rate pretreated with microwave before drying was higher than the control and was between 6.42 × 10-10 m2/s and 11.82 × 10-10 m2/s while ones without a microwave were between 3.54 × 10-10 m2/s and 8.78 × 10-10 m2/s for drying at air temperature between 50°C and 70°C. It was discovered that the Midilli et al. (2002) model was the most appropriate thin layer model for microwave-assisted drying of sugarloaf pineapples. The pineapple slices’ drying rate potential generally increased with microwave power and pretreatments time but not the corresponding increase in the air temperature. Drying time for microwave-assisted drying was in the range of 11 to 20 h, while the ones without microwaves were between 18 and 24 h. Therefore, microwaves should be considered a pretreatment step to the industrial production of sugarloaf pineapple to reduce drying time and produce better quality products. Keywords: Drying, Hot air, Microwave, Moisture diffusivity, Sugarloaf pineapple.

scholarly journals Effects of air temperature and blanching pre-treatment on phytochemical content, antioxidant activity and enzyme inhibition activities of Thai basil leaves (Ocimum basilicum var. thyrsiflorum)

Food Research ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 337-342
Author(s):  
N.L. Le ◽  
T.T.H. Le ◽  
N.B. Ma
Keyword(s):  
Air Temperature ◽  
Low Cost ◽  
Ocimum Basilicum ◽  
Hot Air Drying ◽  
Fresh Sample ◽  
Air Drying ◽  
Phytochemical Content ◽  
Hot Air ◽  
Inhibitory Activities ◽  
Antioxidant Characteristics

Thai basil leaves (Ocimum basilicum var. thyrsiflorum) have been used in food flavoring and traditional medicine. Hot-air drying is a convenient and low-cost method to preserve them for long-term use but causes the loss of their bioactive compounds during the process. In this work, the effect of pre-blanching on preserving these characteristics of Thai basil leaves dried at different air temperatures was studied. The antioxidant characteristics were evaluated by the contents of total phenolics, total flavonoids and total chlorophylls and the scavenging capacity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. In addition, the inhibitory activities against starch-digesting enzymes were assessed with α-amylase and amyloglucosidase. At the air temperature of 50oC, antioxidant characteristics of dried leaves with pre-blanching were proven better than those without blanching and came close to those of the fresh sample. The drying temperature had more evident effects on inhibitory activities against starch-digesting enzymes than blanching. These activities of hot-air dried leaves were comparable to those of the fresh one. This study could provide insights into the integration of blanching and hot-air drying to preserve medicinal plants.

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