Modelos de predição da cinética de secagem dos grãos de guandu

Silva, Luzia Marcia de Melo; Sousa, Francinalva Cordeiro de; Sousa, Elisabete Piancó de; Mata, M. E. R. M. C.; Duarte, M. de L. R.

doi:10.1590/1981-6723.3014

Cited by 10 publications

(15 citation statements)

References 18 publications

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“…Similar results were observed by Sousa, Sousa, Mata, and Duarte (2014) in the prediction of the drying kinetics of pigeon pea grains. However, despite the obtained data, these authors affirmed that the coefficient "n" represents the gradient existing between the vapor pressures of the air and of the material, which points to the fact that increasing the temperature used in the process should naturally increase this coefficient, which in turn leads to a higher rate of water removal.…”

Section: Discussionsupporting

confidence: 88%

Red rice (Oryza sativa L.) use in flour production: Convective drying and bioactive quality

Santos

Silva

Barros

et al. 2020

J Food Process Engineering

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This study aimed to develop red rice flours in order to provide alternatives to replace conventional flours in the production of gluten-free foods for people who suffers from celiac disease. To obtain the flour, red rice grains were dried at temperatures of 40, 50, 60, 70, and 80 C and air velocity of 1.5 m/s. Mathematical models (empirical and diffusive) were fitted to the experimental data obtained and, subsequently, the dehydrated grains were ground to obtain the flour, which was subjected to physicochemical and bioactive characterization to verify the impact of the applied temperatures on the final product quality. It was found that the Page model is more reliable to describe the drying kinetics of red rice, since it showed higher coefficients of determination (R 2) and lower chi-square (χ 2). The diffusion model showed satisfactory fit, with coefficient of determination (R 2) higher than 0.99 and chi-square (χ 2) lower than 0.0146659. Higher drying rate was found at the temperature of 80 C, but cracks were observed in the grains and there was greater degradation of anthocyanins. The pH, total titratable acidity, and flavonoids did not differ between the temperatures applied. Lower values of moisture content, water activity, total phenolic compounds, and antioxidant activity were obtained in the grains subjected to temperature of 80 C. Therefore, the temperature of 40 C was the one that ensured greatest conservation of all bioactive compounds analyzed and greater antioxidant activity for all three methods. Practical applications: The diffusion model provides a realistic and physical interpretation of the drying operation, stimulating the correct time needed to reduce the moisture content of the material, of initial value at the equilibrium value. In this way, it is possible to save energy and reduce the degradation of bioactive compounds promoted by thermal damage, which material is submitted, in addition to aiming at the optimization of drying equipment projects. 1 | INTRODUCTION Rice (Oryza sativa L.) has several types of cultivars and is a widely consumed food in the world, with different colors, such as white, black, red, and brown. Red rice is thus called because of the reddish color of the pericarp of the grains, which in turn is due to the accumulation of tannins and anthocyanins (Agostineto, Fleck, Rizzardi,

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Section: Discussionsupporting

confidence: 88%

Red rice (Oryza sativa L.) use in flour production: Convective drying and bioactive quality

Santos

Silva

Barros

et al. 2020

J Food Process Engineering

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show abstract

“…Thus, the highest drying rates showed the highest values of diffusivity. Silva et al (2014), evaluating the diffusivity of pigeon pea grains at temperatures from 40 to 70 °C, found values ranging from 2.1 to 6.8 × 10 -10 m 2 s -1 . For red rice grains, Sousa et al (2016) obtained values which varied from 2.33 to 6.45 × 10 -11 m 2 s -1 .…”

Section: Resultsmentioning

confidence: 99%

Study on Drying of Black Rice (Oryza sativa L.) Grains: Physical-Chemical and Bioactive Quality

Santos¹,

Silva²,

Barros³

et al. 2019

JAS

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The present study aimed to assess the drying kinetics of black rice and fit different mathematical models (empirical and diffusive) to the experimental data, and evaluate the effect of drying air temperature on the physical-chemical and bioactive compounds quality of black rice. Drying air temperatures ranged from 40 to 80 ºC and the drying air speed was 1.5 m/s. Physical-chemical characterization of the product was based on the following parameters: moisture, water activity, ashes, total protein content, pH, total acidity, lipids, total carbohydrates, total anthocyanins, flavonoids, total phenolic compounds and antioxidant activity. Among the empirical models, Page showed the lowest mean squared deviations (MSD) and highest coefficients of determination (R2). For the diffusion model, the values of effective mass diffusivity and convective heat transfer coefficient increased with increasing drying air temperature, and the Biot number indicated that the first-type boundary condition would also describe well the drying process. Physical-chemical parameters and bioactive compounds differed between the temperatures used, and the temperature of 60 ºC led to the best relationship between drying time and preservation of product characteristics.

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“…Ea (kJ mol -1 ) Product Baptestini et al (2015) 33.10 Soursop foam Goneli et al (2014a) 62.89 Cordia Verbenacea leaves Silva et al (2014) 34.51 Pigeon pea seeds Ferreira et al (2012) 24.512 Fermented grape pomace Costa et al (2011), 37.07 crambe Sousa et al (2011) 24.78 Turnip feed Resende et al (2010) 38.94 Adzuki beans Martinazzo et al (2007) 63.47 Lemon grass leaves to be unleashed in the product (Goneli et al, 2014a;Jangam et al, 2010).…”

Section: Referencesmentioning

confidence: 99%

Kinetics drying of Spirulina platensis

Melo¹,

Devilla²,

Lisbôa³

et al. 2016

Afr. J. Agric. Res.

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Spirulina platensis is a blue-green multicellular photosynthetic cyanobacterium and it is used in many countries as human and animal feed. The aim of this work is to determine and set kinetics drying for S. platensis at different temperatures (30, 40, 50 and 60°C). A completely randomized design was adopted and the treatments were the drying temperatures. S. platensis was furnished by the company, Brasil Vital, located in Anápolis-Goiás. The initial water content from the product was determined according to analytical norm from Association of Official Analytical Chemists (AOAC). The product was subjected to drying in a heater at temperatures of 30, 40, 50 and 60°C. The samples were placed on stainless steel removable trays with background screen; they consisted of three replications. The temperature and relative humidity from the air in the environment were monitored with a thermo-hygrometer. During the process of drying, the trays with samples were periodically weighed to obtain a constant weight. Afterwards, the math models were set on the experimental drying data, using Statistica 12.0 software. The criteria for the selection of the estimative statistics were: R 2 close to 100%, P < 10% and SE close to zero. The effective diffusion coefficient was obtained from the mathematical model of liquid diffusion. One can conclude that the necessary time for S. platensis to reach constant weight was 7.00, 4.58, 3.83, and 3.25 h, at temperatures of 30, 40, 50, and 60°C, respectively. The recommended model used to predict the drying phenomenon for S. platensis was the Midilli Mathematical model at temperatures of 30, 40, and 50°C, and the model Approach of Diffusion at temperature of 60°C. The diffusion coefficient increased with increased temperature; its values were from 3.343 × 10-8 to 14.881 × 10-8 m 2 s-1 at temperature ranging from 30 to 60°C. It activates energy for liquid diffusion at 39.52 kJ.mol-1 .

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Modelos de predição da cinética de secagem dos grãos de guandu

Cited by 10 publications

References 18 publications

Red rice (Oryza sativa L.) use in flour production: Convective drying and bioactive quality

Red rice (Oryza sativa L.) use in flour production: Convective drying and bioactive quality

Study on Drying of Black Rice (Oryza sativa L.) Grains: Physical-Chemical and Bioactive Quality

Kinetics drying of Spirulina platensis

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