scholarly journals INFLUENCE OF DRYING TEMPERATURE AND PULP LAYER THICKNESS ON THE PHYSICAL AND PHYSICOCHEMICAL QUALITY OF PEQUI POWDER1

2021 ◽  
Vol 34 (4) ◽  
pp. 945-956
Author(s):  
ELISABETE PIANCÓ DE SOUSA ◽  
DANIELLE MARTINS LEMOS ◽  
ROSSANA MARIA FEITOSA DE FIGUEIREDO ◽  
JOSIVANDA PALMEIRA GOMES ◽  
ALEXANDRE JOSÉ DE MELO QUEIROZ
Keyword(s):  
Moisture Content ◽  
Layer Thickness ◽  
Water Activity ◽  
Physicochemical Characterization ◽  
Convective Drying ◽  
Drying Time ◽  
Drying Temperature ◽  
Different Temperatures ◽  
Gab Model ◽  
Fresh Pulp

ABSTRACT The objective of this work was to characterize the physical and physicochemical parameters of pequi powders obtained by means of convective drying at different temperatures (50, 60, 70 and 80 °C) and pulp layer thicknesses (0.5, 1.0 and 1.5 cm). Initially, the physicochemical characterization of fresh pulp was carried out, followed by convective drying under the conditions mentioned, until the equilibrium moisture content and subsequent disintegration to obtain the powders. Subsequently, the physical and physicochemical properties of the obtained powders were analyzed and the best powder was selected based on reduced moisture content and water activity and lower peroxide index. Pequi pulp showed a high fat content and a yellowish color; with the increase in drying temperature, there were reductions in the moisture content, water activity and protein content of the powders. As for the color parameters, the powder showed a darkening with the increase in drying time; the water adsorption isotherms of the selected pequi powder were classified as Type II, and the GAB model showed the best fits. The pequi powders showed good solubility and low cohesiveness. The powder that showed good flowability was produced at a drying temperature of 60 °C and with pequi pulp layer thickness of 0.5 cm.

scholarly journals Effect of drying temperature on the content and composition of hop oils

2018 ◽  
Vol 64 (No. 10) ◽  
pp. 512-516 ◽  
Author(s):  
Rybka Adolf ◽  
Krofta Karel ◽  
Heřmánek Petr ◽  
Honzík Ivo ◽  
Pokorný Jaroslav
Keyword(s):  
Moisture Content ◽  
Essential Oils ◽  
Experimental Chamber ◽  
Drying Time ◽  
Drying Temperature ◽  
Different Temperatures ◽  
Traditional Manner

In terms of content, the paper is aimed at analysing and comparing the quality of fresh green hops and hops dried at two drying temperatures – 55°C (in the traditional manner) and 40°C (using the so-called gentle drying), regarding the maximum preservation of hop essential oils. Comparative experiments were carried out in an experimental chamber dryer with two Czech hop cultivars Saaz and Harmonie. The moisture content of hops at the beginning of drying was 75% and at the end of drying it was 9–10%. By lowering the drying temperature from 55°C to 40°C, the drying time in cv. Saaz prolonged from 8 to 10 h and for the cv. Harmonie from 9 h to 12 h. Compared to fresh hops, the amount of hop oils decreased by 10% when dried at 40°C and by 36% (cv. Saaz) and 43% (cv. Harmonie) when dried at 55°C. These losses can be considered significant, especially for hops intended for late and dry beer hopping. However, by drying the hops at different temperatures, the ratios between various components of the essential oils and thus also their sensory character remained approximately unchanged. Due to the reduced amount of essential oils, the drying effect reduces the intensity of hop aroma depending on the drying temperature.

scholarly journals Modelling Thermodynamic Properties of Banana Waste by Analytical Derivation of Desorption Isotherms

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Harvey A. Villa-Vélez ◽  
Henry A. Váquiro ◽  
José Bon ◽  
Javier Telis-Romero
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Isosteric Heat ◽  
Effect Of Temperature ◽  
Agricultural Product ◽  
Different Temperatures ◽  
Desorption Isotherms ◽  
Gab Model ◽  
Processing And Storage ◽  
The Relationship

Banana is an agricultural product of great economic importance for various developing countries. The relationship between moisture content and water activity provides useful information for the processing and storage of banana waste. The water activity and moisture content of three banana (Mussa spp. Haploid AAB cv. Nanica) waste items were analyzed to determine the desorption isotherms at six different temperatures (20, 30, 40, 50, 60 and 70°C). The desorption isotherms of the peel, pedicel and pulp of overripe bananas were determined in wide ranges of moisture content (0.001–6.360 kg kg-1 d.b.) and water activity (0.02–0.907). The theoretical GAB model was used for modelling the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to compute the isosteric heat of sorption, the differential entropy and Gibbs’ free energy by way of the GAB model when the effect of temperature on the hygroscopic equilibrium was considered.

scholarly journals Drying of ‘yacon’ pretreated by pulsed vacuum osmotic dehydration

2021 ◽  
Vol 25 (8) ◽  
pp. 560-565
Author(s):  
Letícia F. Oliveira ◽  
Jefferson L. G. Corrêa ◽  
Paula G. Silveira ◽  
Marina B. Vilela ◽  
João R. de J. Junqueira
Keyword(s):  
Water Activity ◽  
Osmotic Dehydration ◽  
Drying Kinetics ◽  
The Other ◽  
Convective Drying ◽  
Vacuum Drying ◽  
Second Law ◽  
Drying Time ◽  
Different Temperatures

ABSTRACT In this study, the ‘yacon’ was dried using pulsed vacuum osmotic dehydration as pretreatment followed by vacuum drying (at different temperatures) or convective drying. The use of osmotic dehydration and vacuum drying had their influence evaluated concerning drying kinetics and quality of the final product, considering fructan retention, color, and water activity. Fick’s second law and Page’s equation were suitable for the fitting of drying evolution. It was observed that higher temperatures (60 °C) resulted in shorter drying time, higher diffusivity, and higher fructan retention when compared to 40 and 50 °C. The osmotic pretreatment and the vacuum drying differed in fructan retention (p ≤ 0.05). Moreover, the dried product, osmotically pretreated, presented a shorter drying time. The best condition was vacuum drying at 60 ºC, preceded by pulsed vacuum osmotic dehydration that resulted in fructan retention of approximately 38% in a quicker, higher diffusivity and lighter color product concerning the other tested conditions.

scholarly journals Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Oven Drying ◽  
Sun Drying ◽  
Different Temperatures ◽  
Final Water Content ◽  
Drying Curves ◽  
Drying Conditions

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.

scholarly journals CURVAS DE SECAGEM E AVALIAÇÃO DA ATIVIDADE DE ÁGUA DA BANANA PASSA

2004 ◽  
Vol 22 (1) ◽  
Author(s):  
MILTON CANO-CHAUCA ◽  
AFONSO M. RAMOS ◽  
PAULO C. STRINGHETA ◽  
JOSÉ ANTONIO MARQUES ◽  
POLLYANNA IBRAHIM SILVA
Keyword(s):  
Experimental Data ◽  
Linear Regression ◽  
Moisture Content ◽  
Water Activity ◽  
Linear Regression Analysis ◽  
Sorption Isotherms ◽  
Exponential Model ◽  
Drying Time ◽  
Non Linear ◽  
Drying Curves

Curvas de secagem de banana passa foram determinadas, utilizando-se três temperaturas do ar de secagem. Os resultados indicaram que para reduzir o teor de umidade do produto até 23,5% foram necessários tempos de secagem de 51, 36 e 30 horas paras as temperaturas de 50, 60 e 70ºC, respectivamente. O modelo exponencial U/Uo = exp(-kt) foi ajustado para os dados experimentais mediante análise de regressão não-linear, encontrandose alto coeficiente de regressão linear. Determinou-se a atividade de água do produto ao longo do processo de secagem para as três temperaturas testadas. Estudou-se a correlação entre a atividade de água e o teor de umidade do produto, determinando-se as isotermas de dessorção da banana passa a 25ºC. Observou-se que a atividade de água diminuiu em função do tempo de secagem e do teor de umidade para as três temperaturas de secagem. Os dados experimentais foram ajustados mediante regressão não-linear ao modelo polinomial e a seguinte equação foi obtida: U = -1844,93 + 7293,53Aa – 9515,52Aa2 + 4157,196Aa3. O ajuste mostrou-se satisfatório (R2 > 0,90). DRYING CURVES AND WATER ACTIVITY EVALUATION OF THE BANANA-PASSES Abstract Banana drying curves were determined by utilizing three drying air temperatures. The results indicated that to reduce the moisture content of the product until 23.5% it were necessary drying times of 51, 36 and 30 hours for temperatures of 50, 60 and 70ºC, respectively. The exponential model U/Uo = exp(-kt) was adjusted for the experimental data by means of non linear regression analysis, and a high coefficient of linear regression was found. The water activity of the product was determined throughout the drying process for the three tested temperatures. The correlation between the water activity and moisture content of the product was studied, and the sorption isotherms were determined at 25º C. It was observed that the water activity decreased in function to the drying time and moisture content for the three drying temperatures. The experimental data were adjusted by means of non linear regression to the polynomial model and the following equation was obtained: U = - 1844.93 + 7293.53A a – 9515.52 Aa 2 + 4157.196A a 3. The final adjust was satisfactory (R2 > 0.90).

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.

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.

Comparison of Drying Kinetics of Maize in Oven and in Pilot Silo Dryer: Influence on Moisture Content and Physical Characteristics

2016 ◽  
Vol 12 (6) ◽  
pp. 599-606 ◽  
Author(s):  
Flávia Daiana Montanuci ◽  
Raphaela Mulato Cavalcante ◽  
Camila Augusto Perussello ◽  
Luiz Mario de Matos Jorge
Keyword(s):  
Moisture Content ◽  
Temperature Increase ◽  
Drying Kinetics ◽  
Final Moisture Content ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Temperature ◽  
Design And Optimization ◽  
Process Kinetics ◽  
Kinetics Of

Abstract The study of process kinetics may aid the design and optimization of drying systems. This paper evaluated the influence of drying temperature (40, 60 and 80 °C) on the moisture content, drying rate, density, shrinkage and breakage of maize dried in two different dryers: oven and silo dryer. In both dryers, the temperature increase reduced drying time, final moisture content and shrinkage of the grains, however increased breakage. Drying rate was higher in the oven (6.4×10−4±2.3×10−4s−1 versus 5.4×10−4±1.2×10−4s−1), while shrinkage (15.2±4.7 % versus 24.4±5.6 %) and density increase (16.6±5.9 % versus 33.4±5.8 %) were more intense in the silo. There was a large release of husk in the silo dryer and the moisture content was slightly smaller in the lower layers respective to the upper ones.

scholarly journals Quality of Milled Rice from Large-Scale Dried Paddy Rice by Hot Air Combined with Radio Frequency Heating

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2277
Author(s):  
Karn Chitsuthipakorn ◽  
Sa-nguansak Thanapornpoonpong
Keyword(s):  
Moisture Content ◽  
Radio Frequency ◽  
Block Design ◽  
Specific Energy Consumption ◽  
Brown Rice ◽  
Convective Drying ◽  
Control Treatment ◽  
Rf Heating ◽  
Drying Time ◽  
Hot Air

A scaled-up process for paddy drying was developed using hot air (HA) combined with radio frequency (RF) heating. The study was conducted using hot air (control treatment) arranged in descending order in four temperature levels, namely 80 °C at moisture content of 25–26%, 70 °C at moisture content of 20–25%, 60 °C at moisture content of 17–20%, and 50 °C at moisture content of 13–17%, as well as with hot air combined with radio frequency (HA/RF) at different paddy temperatures (45–60 °C) by adjusting the appropriate RF energy when passing through RF heating chamber, namely HA/RF45, HA/RF50, HA/RF55, and HA/RF60. Each treatment was performed in three replicates and data were statistically analyzed in a randomized complete block design. The quality attributes of paddies affected by the drying process were assessed: fissure percentage, color, milling quality, and sensory evaluation. The drying efficiency showed that the drying time and the specific energy consumption could be decreased by up to 54.44% and 23.17% at HA/RF60 and HA/RF45, respectively. As the RF heating temperature increased, the fissure percentage of brown rice kernels at HA/RF45 and HA was not significantly impacted. Regarding color evaluation, combining RF heating and convective drying at all given conditions could be statistically applied in terms of the b*, WI, and ΔE* value. Considering the milling yield of HA as the baseline, head rice yield was maximized at HA/RF45, while bran yield reached the maximum at HA/RF60. The liking score of cooked rice after it was dried using the HA method was the highest. This study concludes that the HA/RF45 was the most appropriate drying condition, and this may provide preliminary exposure to the industrial drying of paddies.

scholarly journals Influence of the temperature and ultrasound application in drying kinetics of apple skin

2018 ◽  
Author(s):  
Juan A. Cárcel ◽  
Matheus P. Martins ◽  
Edgar J. Cortés ◽  
Carmen Rosselló ◽  
Ramón Peña
Keyword(s):  
Physical Structure ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Different Temperatures ◽  
Ultrasound Application ◽  
Quality Of Products ◽  
Drying Conditions ◽  
Kinetics Of ◽  
By Products

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

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