Drying kinetics, proximate composition, dietary fiber, total phenolic compounds, pigments, amino acid profile, and antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical ...absorbance capacity) of a red edible seaweed (
Pyropia orbicularis
) subjected to vacuum drying at five temperatures (40–80 °C) were evaluated. The experimental drying curves were satisfactorily fitted to the Weibull model. The total dietary fiber (TDF) of this seaweed presented a value of 64.37 g (100 g)
−1
d.m. The ratio IDF:TDF was 81.1%. The values for protein ranged between 22.34 and 24.92 g (100 g)
−1
d.m. in dried seaweed, and His, Thr, and Pro were the most abundant amino acids. The chlorophyll
a
content was higher than that for chlorophyll
b
. Total phenolic content (TPC), phycoerythrin and phycocyanin contents, and carotenoid content as well as antioxidant capacity showed an increase at 70 °C. Moreover, at 70 °C, Δ
E
presented a value of 15.66. Correlations between the TPC and DPPH values (
r
2
= 0.899) as well as lightness and hue angle (
r
2
= 0.776) were found during food drying. This work provides important information about the chemical composition and nutraceutical properties of the Chilean edible red seaweed,
P. orbicularis
.
The drying of carrot slices in a microwave-assisted fluidized-bed drying (MWFBD) system was investigated. The drying conditions such as the initial microwave power density and the inlet air ...temperature were optimized. The effects of different pretreatment processes such as water blanching, osmotic drying with 20% sugar solution, and 1% citric acid solution on the drying of carrot slices were investigated under the optimized drying conditions. The drying kinetics and the physical properties of the dried carrot slices were analyzed. Different mathematical models of the drying process were explored and fitted to the drying of carrot slices in MWFBD. The pretreatment of the carrot slices reduced the drying time required and improved the qualities such as color and textural strength of the dried carrot slices.
Rosemary leaves (
Rosmarinus officinalis L., Lamiaceae) were dried by using sun, oven (50
°C) and microwave oven (700
W, 2450
MHz) drying methods. Microwave oven drying shortened the drying time more ...than 99% when compared to the sun and oven drying methods. K, Ca, Na, Mg and P were the most abundant elements in the rosemary samples. The mineral content of oven dried rosemary leaves was higher than that of the sun and microwave dried samples. The logarithmic and Midilli and Küçük models were shown to give a good fit to the sun and oven drying. The Page, Modified Page and Midilli and Küçük models have shown a better fit to the experimental microwave oven drying data of rosemary leaves. Microwave oven drying revealed optimum colour values. Oven drying resulted in a considerable decrease in the colour quality of the rosemary leaves.
Moisture greatly affects the performance of Li-ion batteries, so LiNi1/3Co1/3Mn1/3O2 (NCM111) powder is usually dried in vacuum before the slurry preparation. In this paper, vacuum-drying experiments ...of NCM111 powder were performed first and the effects of different conditions were investigated. Then, the experimental data were fitted to nine mathematical models, and the Weibull model was the best one to describe the drying kinetics. The relationship between model parameters and drying conditions was established and verified. Moreover, effective diffusivities were determined using the Fick’s equation and the activation energy was calculated using the Arrhenius equation. The energy consumption was also discussed in the end. The result shows that increasing drying temperature can not only improve drying performance but also reduce energy consumption. However, reducing thickness of NCM111 powder is beneficial to elevate the drying rate but has little effect on saving energy.
•Drying kinetics were well described considering a compositional diffusion model.•Effective diffusivity for pits fraction was higher than in pulps and peels one.•Drying at high temperatures led to an ...improved antioxidant potential.•Long drying times at high temperatures increased antioxidant potential.•An efficient extraction can be achieved in only 5h.
This work aims to evaluate the influence of olive pomace drying (a solid by-product of the olive oil industry) on both antioxidant potential and drying kinetics. The two main fractions of olive pomace (pits, PI and pulps+peels, P+P) were characterized by image analysis and density measurement. The drying process was analyzed in experiments carried out at different temperatures (from 50 to 150°C) and mathematically described from the diffusion and Weibull models. The antioxidant potential of the extracts (ethanol–water 80:20 v/v, 22±1°C, 170rpm for 24h) obtained from the dry product was analyzed by measuring the total phenolic content and antioxidant capacity and the main polyphenols were quantified by HPLC–DAD/MS–MS.
The drying behavior of olive pomace was well described by considering the diffusion in the PI and P+P fractions separately and the influence of temperature on effective moisture diffusivities was quantified by an Arrhenius type equation. The antioxidant potential was only mildly influenced by the drying temperature. However, long drying times at the highest temperature tested (150°C) significantly (p<0.05) increased the antioxidant potential.
Water removal rate during drying depends on the microstructural pathways of water migration from inside the food materials. The water removal rate also depends on the mechanical properties of plant ...tissue. There is no literature that shows the interrelationship between viscoelastic property and transport phenomena during drying. In this study, the influence of viscoelastic property of plant-based food material on transport phenomena during drying has been experimentally investigated. Granny Smith apple, pears, and beet root has been taken as the sample in this study. A 2 kN Instron universal testing machine and ImageJ software were used in order to measure and analyze the viscoelasticity of the samples. Three different fruits Granny Smith apple, pears, and beet root show different viscoelastic properties along with different energy loss due to hysteresis. A positive relationship was found between energy loss due to viscoelastic nature of materials and drying kinetics. This correlation can be explained by the nature of the cell wall stiffness that facilitates or hinders the water migration in mechanical and thermal energy applications.
In this work, a transient macroscopic model is proposed for studying the conjugated heat and mass transfer phenomena that occur inside a single rice grain during the superheated steam drying process. ...The governing equations of this model are derived based on the volume-averaging approach. Since rice is a highly hygroscopic material, more than 80% of water is accumulated as bound water in rice grain. Both the bound water diffusive flow in the solid matrix and the convective flow of water vapor and liquid water in the void volume are taken into account in this model. Thermophysical properties of rice which serve as model inputs are measured, except the absolute permeability and the bound-water diffusivity coefficients. These two properties are determined by minimizing the square of residuals between simulation results and experimental data, which were obtained by means of a magnetic suspension balance system at a drying temperature of 160 °C. The validity of these two estimated parameters is reflected by a good agreement between the numerical and the experimental data at drying temperatures of 120 and 140 °C. Finally, a model-based sensitivity analysis is carried out, from which quantitative guidelines for the relationship between both the absolute permeability and the bound-water diffusivity and drying kinetics are proposed.
The research was aimed to prepare muffins using groundnut milk residue. Groundnut or
Peanut (Arachis hypogaea) is one of the most consumed legumes in the world. Groundnut
is also a prominent source ...of plant-based milk. The groundnut milk was prepared by the
conventional method with 1:2 ratio of water. The residue was tray-dried at different
temperatures (60, 70, 80°C) to study the drying kinetics. Physical and chemical properties
of optimized groundnut milk residue powder were analysed. Muffins were developed
using milk residue. Quality parameters and sensory analyses were also done for the
product obtained from milk residue. The results indicated that groundnut milk residue
dried at 70ºC had less water absorption capacity and more water solubility index. Also, the
powder retained colour when dried at 70°C. The experimental data were fitted to five
mathematical models. Wang and Singh's model was found to have the best fit with R2
value of 0.9932. The increase in temperature promotes drying at a faster rate.
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