Drying kinetics and quality characteristics of daylily dried by mid-infrared

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nan Wang ◽  
Shuaiyao Yang ◽  
Yifu Zhang ◽  
Lan Jiang ◽  
Xuechao Zheng ◽  
...  

Abstract Industrially, the use of far-infrared (FIR) as a heat source for drying daylily presents some issues, such as high energy consumption and large loss of nutrients. The use of mid-infrared (MIR) was performed to study the drying of daylily to explore its advantages, with the FIR drying as a comparison. Drying models were established by the drying kinetics, and the changes of nutrition, rehydration ratio (RR) and water migration pattern were researched. The results showed the best-fitting drying model was the Modified Henderson and Pabis model. Under the same temperature, compared with FIR drying, the drying time of MIR drying was shortened by 50%, the effective moisture diffusivity (D eff) was increased by 103%, the drying activation energy (E a) was reduced by 10%, the reducing sugar and ascorbic acid retention rate was increased by 13.9% and 9.7%, respectively. The MIR drying had better RR and water migration characteristics.

2016 ◽  
Vol 12 (8) ◽  
pp. 783-792 ◽  
Author(s):  
Hao-Yu Ju ◽  
Qian Zhang ◽  
A.S. Mujumdar ◽  
Xiao-Ming Fang ◽  
Hong-Wei Xiao ◽  
...  

Abstract The drying kinetics and mathematical modeling of hot-air drying of yam slices were investigated under two-stage relative humidity (RH) control strategy with 60 °C and 1.5 m/s as its constant drying temperature and air velocity, respectively. Results indicate high RH in the initial stage results in high sample’s temperature that enhances water diffusion in the falling rate drying period. Within the scope of current work, change in RH in the later drying period has insignificant influence on sample’s temperature rise while low RH can accelerate the drying rate. Compared to drying at constant 20 % RH at the same drying air temperature, the drying strategy of using 40 % RH over the first 15 min and then lowing to 20 % RH for the remainder time yields a shorter drying time. Weibull model adequately described the moisture content variation with time for all experiments with the scale parameter ranging from 105.02 to 122.38 min and the values of shape parameters from 0.988 to 1.183. The effective moisture diffusivity determined from the Weibull model varied from 2.032 to 2.610×10−8 m2/s. The rehydration ratio increased as the overall drying time was reduced. Microstructure examination shows that higher RH in the initial drying stage can lead to a more porous microstructure which enhances drying, while fast drying rate in the initial drying period generates a crust layer which hinders drying.


Author(s):  
Ignat Tolstorebrov ◽  
Trygve Magne Eikevik ◽  
Inna Petrova ◽  
Yulia Shokina ◽  
Michael Bantle

Drying kinetics of Saccharina latissima (raw and blanched) at low temperatures (10.0, 25.0 and 38.0 °C) was studied. The effective moisture diffusivity coefficient varied due to temperature alterations in the range between 1.4 and 4.5 10-10 m2/s for raw and 0.91 and 2.56 10-10 m2/s for blanched seaweeds. Significant changes in structural properties and chemical composition resulted in a much longer drying time of blanched seaweeds, when compared with raw. Drying temperature of 38.0 °C resulted in more brown color, when compared with other samples. Sorption characteristics of dried raw seaweeds depended on salt content and showed high accumulation of moisture at relative humidity of air of 80.0 %. The blanched seaweeds showed linear accumulation of moisture within increasing of relative humidity of drying air from 20.0 to 80.0 %, but high level of hysteresis was determined between sorption and desorption isotherms. The shrinkage development within dewatering of blanched and raw samples was also studied. Keywords: brown seaweeds, drying kinetics, sorption isotherms, color 


2018 ◽  
Vol 6 (2) ◽  
pp. 552-565 ◽  
Author(s):  
Eunice Akello Mewa ◽  
Michael Wandayi Okoth ◽  
Catherine Nkirote Kunyanga ◽  
Musa Njue Rugiri

The objective of the present study was to determine the drying kinetics, moisture diffusivity and sensory quality of convective air dried beef. The effect of temperature of drying (30-60°C) and thickness of samples (2.5-10 mm) on the convective thin-layer drying kinetics of beefdried in a cabinet dryer was evaluated. Five semi-theoretical models were fit to the drying experimentaldata with the aim of predicting drying characteristics of beef and fitting quality of models determined using the standard error of estimate (SEE)and coefficient of determination (R2). Determination ofeffective moisture diffusivity (Deff) from the experimental drying datawas done and sensory quality of the optimized dried cooked and uncookedbeef samplesevaluated. Drying time and rate of drying increased with an increasing temperature but decreased with increased slice thickness. However, there was overlapping of drying curves at 40-50°C. Among the selected models, Page model gave the best prediction of beef drying characteristics. Effective moisture diffusivity (Deff) ranged between 4.2337 x 10-11 and 5.5899 x 10-10 m2/s, increasing with an increase in air temperature and beef slice thickness.Of all the sensory parameters evaluated, texture was the only attribute that gave significantly different (P > 0.05) scores between the cooked and uncooked dried beef samples.


Author(s):  
Monica Premi ◽  
Harish Sharma ◽  
Ashutosh Upadhyay

Abstract The present study examines the effect of air velocity on drying kinetics of the drumstick leaves in a forced convective dryer. The drumstick leaves were dried in the temperature range of 50–800 C, at different air velocity (Dv) of 0.5 and 1.3 m/s. The results indicated that drying temperature and air velocity are the factors in controlling the drying rate. Experimental data obtained for the samples for color, drying rate and drying time proved that air velocity of 1.3 m/s yielded the product superior in terms of both quality and energy efficiency as compared to the samples at 0.5 m/s. Activation energy for drumstick leaves dried with air velocity, 0.5 and 1.3 m/s was 12.50 and 32.74 kJ/mol respectively. The activation energy relates similarly with the effective moisture diffusivity which also increased with increase in air velocity and temperature.


Foods ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 216 ◽  
Author(s):  
Aslı Aksoy ◽  
Salih Karasu ◽  
Alican Akcicek ◽  
Selma Kayacan

This study aimed to investigate the effect of different drying methods, namely ultrasound-assisted vacuum drying (USV), vacuum drying (VD), and freeze-drying (FD), on the drying kinetics and some quality parameters of dried minced meat. In this study, USV was for the first time applied to the drying of minced meat. The USV and VD methods were conducted at 25 °C, 35 °C, and 45 °C. The different drying methods and temperatures significantly affected the drying time (p < 0.05). The USV method showed lower drying times at all temperatures. The rehydration values of the freeze-dried minced meat samples were higher than those obtained by the USV and VD techniques. The samples prepared using USV showed higher rehydration values than the vacuum dried samples for all temperatures. The effects of the different drying techniques and drying conditions on the microstructural properties of the minced meat samples were investigated using scanning electron microscope (SEM). The USV method resulted in higher porosity and a more open structure than the VD method. Total color differences (ΔE) for VD, USV, and FD were 8.27–20.81, 9.58–16.42, and 9.38, respectively, and were significantly affected by the drying methods and temperatures (p < 0.05). Higher drying temperature increased the ΔE value. Peroxide values (PV) significantly increased after the drying process, and samples treated with USV showed lower PV values than the VD treated samples. This study suggests that USV could be used as an alternative drying method for minced meat drying due to lower drying times and higher quality parameters.


Food Research ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 431-440
Author(s):  
O.T. Bolaji ◽  
P.A. Adepoju ◽  
E.O. Adelana ◽  
B.S. Adesina

The drying kinetics of ogi produced from six varieties of maize at varying soaking period (12, 24 and 36 hrs) and drying temperature of 40, 50 and 60oC, respectively were studied. Seven common thin layer models were evaluated, and the best models were selected. The moisture content of ogi decreased with increased drying temperature and drying time while the drying rate increased with an increase in drying temperature and decreased with an increase in drying time. Logarithmic and two term models best fitted about 40.77% (22 samples each). However, where two term models were selected best, the R2 values ranged from 0.9858-0.99999999, χ 2 = 0.03715-0.000412, RMSE = 0.02206-0.0000677, unlike Logarithmic model that ranged from 0.8876-0.9964, χ 2 = 0.07045-0.001447, RMSE = 0.1084-0.01098. There was no definite pattern for effective moisture diffusivity (Deff) and Activation energy (Ea). This research work strongly suggests that the drying process was predominantly in the falling rate period (FRP) and was significantly affected by the change in temperature and moisture gradient. The activation energy obtained for ogi at varying soaking period and drying temperature ranged from 2.58-12.00 kJ/mol (A4Y), 7.72-44.95 kJ/mol (A4W), 14.53-35.88 kJ/mol (S7Y), 6.02-20.10 kJ/mol (D2Y), 14.024- 45.31 kJ/mol (DIY) and 19.34-64.22 kJ/mol (T3W). It was obviously indicated in this research that the soaking period had less or no impact on the drying behavior of ogi compared with the influence of drying temperature, drying time and initial moisture content.


2019 ◽  
Vol 25 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Azmi Kipcak ◽  
İbrahim Doymaz ◽  
Emek Moroydor-Derun

As an alternative to fish and beef, blue mussels (Mytilus edulis) can be consumed due to their high protein content. In this study, the drying kinetics and quality changes (cook loss, area shrinkage and colour change) in whole blue mussels were investigated with several infrared power levels between 88?146 W. Various thin-layer drying models were applied to the blue mussel and the Midilli et al., model best fits the experimental data (R2: 0.999150?0.999750, ?2: 0.000104?0.000030, RMSE: 0.008309?0.004797). The effective moisture diffusivity was determined to be between 4.24?10-9 and 1.10?10-8 m2/s. The activation energy was found to be 20.85 kW/kg. The cook loss and area shrinkage increased with increasing power level and drying time. Most cook loss (30%) and area shrinkage (30%) were obtained between 15-23 min and 8-20 min of drying time, respectively. The colour change was slightly affected by the change in infrared power level.


2020 ◽  
Vol 44 (6) ◽  
pp. 543-556
Author(s):  
Bige İNCEDAYI

In this study, the effect of pretreatments (hot water blanching, microwave blanching, and ohmic heating) on the drying kinetics and quality characteristics of red pepper, dried at 60 and 70 °C, was investigated. The drying times varied between 205–290 min, depending on the pretreatment and temperature applied. The drying rate also changed based on the pretreatment and the falling rate period was observed. Four mathematical models were fitted to experimental data and the logarithmic model was found to be the best for all of the samples. Effective moisture diffusivity values obtained from Fick’s second law of diffusion ranged from 6.11 × 10–10 to 9.31 × 10–10 m2 s–1. The total phenolic contents, antioxidant capacities, and red pigment amounts of the dried peppers varied between 6.95 and 9.45 mg GAE g–1dry matter (DM), 2610.43 and 4463.96 mmol AEAC 100 g–1DM, and 184 and 443mg 100 g–1DM, respectively. Rehydration ability of pretreated samples was similar to or slightly lower than that of the untreated samples. As a result, it can be suggested that ohmic heating before drying at a temperature of 70 °C could be a promising alternative pretreatment to decrease drying time and produce high-quality dried red pepper.


Author(s):  
Tamás Antal ◽  
Judit Tarek-Tilistyák ◽  
Zoltán Cziáky ◽  
László Sinka

Abstract This article provides results of an experimental investigation of hybrid- (MIR-FD), mid-infrared- (MIR) and freeze drying (FD) on the drying characteristics, energy consumption and quality parameters of pear. Rehydration ratio, color, texture, water activity, phenolic content and antioxidant activity were measured to evaluate the quality of dried pear products. Mid-infrared-freeze drying (MIR-FD) had the higher drying rate, which reduced the drying time by 14.3–42.9 % compared with FD method. Two empirical models were chosen to fit the drying curves and the models had the suitable R2 and RMSE values. Temperature characteristics of MIR and MIR-FD dried pear were determined in terms of interior temperature variation. The MIR-FD pear had darker color, better rehydration capacity, similar water activity, lower hardness (except of MIR-FD70°C) and highest content of chemical composition than single stage of FD products. Above all, the MIR50-60°C-FD was suggested as the best drying method for pear in this study.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mohamed A. ElKhodiry ◽  
Shaima R. Suwaidi ◽  
Melika Taheri ◽  
Hams Elwalid ◽  
Dina ElBaba ◽  
...  

The drying kinetics of eggplant were studied experimentally in a laboratory-scale fluidized bed dryer. Experiments were conducted at drying temperatures of 60, 70, and 80°C and at constant air velocity of 3.10 ms−1. The drying rate and moisture ratio were determined as a function of time. At any given temperature, only the falling rate period was observed during the drying process. Effective moisture diffusivity was in the range 2.667–4.311 × 10−8 m2/s while activation energy of 23.5 kJ mol−1 was obtained from the Arrhenius equation. The experimental moisture ratio data was fitted to ten mathematical models. Statistical analysis showed that the by Demir et al. has the best fit quality. In terms of product quality, the dried samples had low rehydration ratio of 4.889. In addition, compared to direct sunlight drying, the dried product from the fluidized bed dryer exhibited better color quality.


Sign in / Sign up

Export Citation Format

Share Document