Parameters optimization and quality evaluation of mechanical properties of infrared radiation thin layer drying of pumpkin samples

Abstract

This work aims to estimate quality characteristics of dried pumpkin samples in an infrared dryer under natural and forced drying air convection systems. Drying time, rehydration ratio, and shrinkage as a function of infrared intensity, sample thickness, sample distance from the infrared lamps, and air velocity were optimized using response surface methodology. Maximum rehydration ratio and minimum drying time and shrinkage were assumed as criteria for optimizing drying conditions of the samples. The optimum values of process variables were 1 m/s air velocity, a sample thickness of 2 mm, 2,000 W of infrared intensity, and sample to infrared lamps distance of 550 mm. Based on the significant effect, sample thickness was the most prominent factor. The optimal values of drying times, rehydration ratios, and shrinkages of the dried samples under natural and forced convection were 1.068 hr and 1.017 hr, 10.375 and 9.141 (g rehydrated sample/g dried sample), and 69.38 and 73.17 (%), respectively. Practical ApplicationsPumpkin as one of the tasty, valuable and healthy nutrition vegetables containing a lot of biologically active substances is rich in phenolics, polysaccharides, flavonoids, vitamins, mineral salts, and a good source of carotene and water-soluble vitamins.Because of the high initial moisture content, it is very sensitive to microbial spoilage.Thus, the drying can be greatly minimized microbial activities and deterioration chemical reaction by the removal of moisture up to a certain level. In addition, choosing the right type of dryer, design, simulation, and optimization of the drying process are largely dependent on the knowledge of the drying characteristics. It is worth mentioning, the developed statistical multivariate model equations accompanied by the optimal process conditions can be very useful for the design and operation of IR dryer when there is no certain multidimensional infrared drying model for high-value foodstuffs such pumpkin.

Drying of shrimp using hot air‐assisted continuous infrared drying system

“…The suitability of the quadratic model was evaluated using R 2 , adjusted‐ R 2 , predicted‐ R 2 , coefficient of variation (CV), and lack‐of‐fit of the model. Higher coefficient of determination ( R 2 ), the lesser difference between adjusted and predicted R 2 (<0.2), and adequate precision (>4) provide more adequacy (Sadeghi et al, 2020) to the regression equation which helps the model to predict the deviations during the drying. It is evident from Table 4 that the values of R 2 , adjusted‐ R 2 , and predicted‐ R 2 of all responses are high which represents a good relationship between the experimental and predicted values.…”

“…An increase in IRI up to 2,000 W/m 2 decreased the energy consumption initially because of the faster drying due to the high moisture removal rate from the product surface (Figure 6a,b). Increased SEC with an increase in IRI beyond the value of 2,000 W/m 2 can be attributed to the attainment of maximum drying rate and beyond which the additionally supplied IR SEC (Sadeghi et al, 2020). Similarly, a study on infrared convective drying of white mulberry fruit revealed that the AT had a positive effect on SEC, whereas the IR radiation was affected negatively.…”

The Quality of Infrared Rotary Dried Terebinth (Pistacia atlantica L.)-Optimization and Prediction Approach Using Response Surface Methodology

“…This is mainly due to the higher mass transfer rate, which leads to a decrease in the RR. It is very likely to contribute to the acceleration of shrinkage due to the inability of the terebinth texture to maintain its network structure [ 42 ]. For drying savory leaves in an infrared–hot air dryer, Darvishi et al [ 6 ] showed that the highest RR was obtained at the lowest infrared power, while the lowest RR was obtained at the highest infrared power, which is consistent with the results of this study.…”

Short- and Medium-Wave Infrared Drying of Cantaloupe (Cucumis melon L.) Slices: Drying Kinetics and Process Parameter Optimization

“…Researchers have found that the level of infrared radiation temperature, the thickness of the slices, and the distance between the infrared radiation emitter and the sample surface affect the color, hardness and nutrient retention of the product during the infrared radiation drying process [5,30]. Based on the material characteristics of the cantaloupe slices and the preliminary experiments, the radiation temperature X 1 (55, 60 and 65 • C), slice thickness X 2 (5, 7 and 9 mm) and radiation distance X 3 (80, 120 and 160 mm) were the independent variables in this design.…”