scholarly journals Drying Rate and Product Quality Evaluation of Roselle (Hibiscus sabdariffa L.) Calyces Extract Dried with Foaming Agent under Different Temperatures

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mohamad Djaeni ◽  
Andri Cahyo Kumoro ◽  
Setia Budi Sasongko ◽  
Febiani Dwi Utari

The utilisation of roselle (Hibiscus sabdariffa L.) calyx as a source of anthocyanins has been explored through intensive investigations. Due to its perishable property, the transformation of roselle calyces into dried extract without reducing their quality is highly challenging. The aim of this work was to study the effect of air temperatures and relative humidity on the kinetics and product quality during drying of roselle extract foamed with ovalbumin and glycerol monostearate (GMS). The results showed that foam mat drying increased the drying rate significantly and retained the antioxidant activity and colour of roselle calyces extract. Shorter drying time was achieved when higher air temperature and/or lower relative humidity was used. Foam mat drying produced dried brilliant red roselle calyces extract with better antioxidant activity and colour qualities when compared with nonfoam mat drying. The results showed the potential for retaining the roselle calyces extract quality under suggested drying conditions.

2015 ◽  
Vol 365 ◽  
pp. 77-81 ◽  
Author(s):  
J.V. Silva ◽  
E.M.A. Pereira ◽  
T.H.F. Andrade ◽  
Antônio Gilson Barbosa de Lima

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.


2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana

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.


Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro

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.


2021 ◽  
Vol 02 ◽  
Author(s):  
Thanh V. Ngo ◽  
Christopher J. Scarlett ◽  
Michael C. Bowyer ◽  
Rebecca McCullum ◽  
Quan V. Vuong

Background: S. chinensis extract contains bioactive compounds, which exhibit high antioxidant activities. However, for commercial uses, it is necessary to encapsulate the extract to protect it from degradation. Objective: This study aimed to optimise spray-drying conditions and then compare with freeze-drying to identify the most suitable conditions for encapsulation of Salacia chinensis L. root extract. Method: Three factors of spray-drying encapsulation, including maltodextrin concentration, inlet temperature and feed rate, have been tested for the impacts on the physical and phytochemical properties of S. chinensis root extract. Based on the optimal conditions, the spray-drying was then compared with freeze-drying. Results: The results showed that maltodextrin concentration, inlet temperature and feed rate had significant impacts on recovery yield, phenolics, mangiferin and antioxidant activity of the spray-dried extract. The optimal spray-drying encapsulation conditions were maltodextrin concentration of 20 %, inlet temperature of 130ºC and feed rate of 9 mL/min. Under these optimal conditions, the encapsulated extract had comparable solubility, total phenolics, mangiferin, and antioxidant activity, lower bulk density, moisture content, and water activity as compared to encapsulated extract made using the freeze-drying technique. These optimal spray-drying conditions are recommended to encapsulate the extract of S. chinensis root. Conclusion: Spray-drying was found to be more effective for encapsulation of S. chinensis root extract than freeze-drying. Therefore, spray-drying is recommended for further applications.


2017 ◽  
Vol 39 (2) ◽  
pp. 225 ◽  
Author(s):  
Guilherme Euripedes Alves ◽  
Flávio Meira Borém ◽  
Eder Pedroza Isquierdo ◽  
Valdiney Cambuy Siqueira ◽  
Marcelo Ângelo Cirillo ◽  
...  

The objective of this study was to evaluate the correlation between a group of physiological variables (electrical conductivity, potassium leaching, and germination percentage) and a group of drying kinetics variables (drying time and drying rate) in addition to verifying the relation between drying kinetics variables and coffee quality as a function of processing type, temperature, and drying airflow. Coffee drying was conducted in a fixed-layer dryer at two temperatures and two airflows. After drying, an evaluation of the physiological and sensorial quality was conducted. Based on the results obtained, the following conclusions were drawn: coffee that is processed via a dry method is more sensitive to mechanical drying with heated air than coffee processed via a wet method, resulting in poor physiological performance; airflow does not interfere with the physiological quality of pulped and natural coffees; a temperature increase from 40 to 45°C resulted in a decrease in the physiological quality only for pulped coffee; and an increase in the drying rate as a result of an increase in the drying temperature to 40°C had a negative effect on the sensorial quality of pulped coffee. 


2012 ◽  
Vol 10 (1) ◽  
pp. 87-97 ◽  
Author(s):  
M. S. Islam ◽  
M. A. Haque ◽  
M. N. Islam

The present study quantifies the drying kinetics of green banana during mechanical dehydration. The effect of loading density (sample thickness) and the temperature on the drying rate constant and drying time were investigated and quantified. Drying rate increased with increasing temperature but decreased with increase in loading density. The values of exponent ‘n’ of the two parameters power law model describing the drying rate constant (as a function of thickness) were less than 2 which indicated the presence of significant external resistance to mass transfer despite the dominance of internal mass transfer resistance.  Investigation with three drying air temperatures (55, 60 and 65oC) at constant air velocity (0.6 m/sec) resulted that the increase in drying air temperature increased the drying process.  The moisture diffusivity values were 1.25×10-10, 1.67×10-10 and 2.19×10-10 m2/sec at 55, 60 and 65oC respectively. The activation energy (Ea) indicating the temperature dependence of the diffusivity was 51.21 KJ/mole obtained using Arrhenius model. Mixing of green banana flour in the potato chips formulation enhanced the fiber and mineral content in the product.DOI: http://dx.doi.org/10.3329/agric.v10i1.11069The Agriculturists 2012; 10(1): 87-97


2012 ◽  
Vol 472-475 ◽  
pp. 1645-1651
Author(s):  
Jian Jun Hu ◽  
Sheng Qiang Shen ◽  
Ting Zhou Lei ◽  
Hao Huang ◽  
Quan Guo Zhang

Constant-temperature drying tests for cotton straw under different conditions were performed with an integrated thermal analyzer, and the influence of different drying conditions on the drying process was analyzed. The process was divided into preheating stage, constant-rate drying stage, and decelerating drying stage. Regression analysis was conducted for drying curves at the latter two stages, and then the drying time at the critical point was determined. Regression equations of drying rate at these stages were produced. Research results showed that the decelerating drying stage of cotton straw included two decelerating intervals, and the best ending point of the drying of the cotton straw that had an initial moisture content of 56.1% and a drying temperature of 100°Cwas 600s, thus providing experimental data and reference for research on drying technology of straws.


Author(s):  
Juan A. Cárcel ◽  
Matheus P. Martins ◽  
Edgar J. Cortés ◽  
Carmen Rosselló ◽  
Ramón Peña

The great amount of waste produced by food industry contains interesting bioactive compounds. The extraction of these compounds requires the by-products previous stabilization being the convective drying one of most used techniques to this end. Drying conditions can affect both drying kinetics and final quality of products. The apple skin, byproduct of apple juice or cider industries, is rich in functional compounds such as polyphenols or vitamin C. The main goal of this contribution was to quantify the influence of temperature and ultrasound application in drying kinetics of apple skin. For this purpose, drying experiments at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) and without application of ultrasound were carried out. Drying kinetics were modelled by using a diffusion based model. As can be expected, the higher the temperature the faster the drying. Ultrasound application accelerated the process at every temperature tested being the influence slightly lower than found from the literature for other products. This can be attributed at the physical structure of the apple skin, less porous than the pulp. In any case, the application of ultrasound significantly reduced the drying time. Keywords: by-products; dehydration;diffusivity; mass transfer


2021 ◽  
Vol 11 (24) ◽  
pp. 11803
Author(s):  
Thi-Van-Linh Nguyen ◽  
Quoc-Duy Nguyen ◽  
Thi-Thuy-Dung Nguyen ◽  
Phuoc-Bao-Duy Nguyen

In this study, avocado pulp with a good nutritional profile and economic value was dehydrated using infrared drying to produce pulp powder, which shows potential application in nutritional supplements. An experimental design with two factors, namely maltodextrin level (0% and 9%) and infrared temperature (ranging from 65 to 80 °C), was used. Responses related to the physicochemical properties of the resulted powder were observed, including peroxide value, total polyphenols, total chlorophylls, antioxidant activity, and color parameters (L*, a*, and b* values). The quality of dried products may be harmed by drying either at a high temperature or for an extended period of time. The coating substance maltodextrin was found to be beneficial in limiting unexpected changes in avocado pulp subjected to infrared drying. The highest quality of dried avocado could be obtained via infrared drying of avocado pulp with 9% maltodextrin at 70 °C, as illustrated by the exceptional retention of total polyphenols, total chlorophylls, and antioxidant activity, being 95.1, 95.2, and 94.4%, respectively. Moreover, the short drying time (35–55 min) led to the minimization of lipid oxidation and the absence of peroxide compounds in all samples.


2013 ◽  
Vol 561 ◽  
pp. 341-346
Author(s):  
Meng Wang ◽  
Ze Guang Lu ◽  
Wan Da Jia ◽  
Huai Yan Zhao ◽  
Feng Shuang Wang

The moisture evaporation amount and drying velocity of monocomponent sealer on the maple-veneered panels as base materials, under the drying conditions of constant temperature of 30°C and relative humidity varied from 30% to 70%, were measured in this study. The results indicated that the moisture evaporation amount increased, and drying velocity decreased with drying time under the same relative humidity, while the moisture evaporation amount decreased with the increase of relative humidity. The drying velocities were remarkable different under different relative humidities. During the same period of drying time, the difference degree of moisture evaporation amount within the relative humidity range of 30% to 50% was smaller than that within the relative humidity range of 50% to 70%.


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