A study on drying models and internal stresses of the rice kernel during infrared drying

Wu, Jiansheng; Zhang, Hengwei; Li, Fan

doi:10.1080/07373937.2016.1201834

Cited by 40 publications

(11 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The stress and strain distribution of the core was shown in Figure 15. From the stress and strain distribution based on the EMD, it could be seen the near surface area was subject to tensile stress, while the central area was subject to compressive stress, which was similar to the stress distribution in rice kernels and apple slices during drying (Wu et al, 2017; Yuan et al, 2019). The strain around the upper and lower surfaces was higher, while the interior strain was lower.…”

Section: Resultssupporting

confidence: 54%

Determination and comparison of effective moisture diffusivity of carrot (core and cortex) during hot air drying

Zheng

Wei

Xie

et al. 2022

J Food Process Engineering

View full text Add to dashboard Cite

The moisture content and shrinkage of a sample are often ignored when determining its effective moisture diffusivity (EMD), which will result in a larger error in simulating the dynamic moisture diffusion process during drying. This work aimed to determine the EMDs of cortex and core in axial and radial directions considering the combined influence of moisture content and shrinkage of material. The drying and shrinkage characteristics of cortex and core were investigated under different hot air drying conditions, and the EMDs of the cortex and core in different drying stages were determined by the slope method considering the moisture content and shrinkage. The results showed that the EMDs were dependent on the carrot component rather than its directions. The EMDs of the core and cortex were different. It decreased slowly at the early drying stage, and decreased sharply at the later drying stage, and increased with the hot air temperature increasing. A third order polynomial relationship was established to correlate the EMDs with the moisture content and hot air temperature (R2 > 0.9460), and was verified by experiments. The maximum weighted absolute percentage error of the moisture content from simulation and experiment was only 6.11%, more accurate than that based on a constant effective moisture diffusivity (CEMD) for characterizing the intrinsic moisture diffusion in carrot during drying. Practical applications The EMD is an important parameter that characterizes intrinsic moisture diffusion in material and often used for modeling and calculation in food drying. The investigation methods developed in this study can be applied for determining the EMD of samples with shrinkage and variable moisture content. This study would be helpful for understanding the moisture transfer mechanism and optimizing operation conditions in carrot drying industry.

show abstract

Section: Resultssupporting

confidence: 54%

Determination and comparison of effective moisture diffusivity of carrot (core and cortex) during hot air drying

Zheng

Wei

Xie

et al. 2022

J Food Process Engineering

View full text Add to dashboard Cite

show abstract

“…Even with an increasing degree of gelatinization, the lower HRY observed in grains heated at higher temperatures is due to fissure formation in rice grains (Lang et al, 2018). These fissures occur in the endosperm of the grains due to the occurrence of tensile stress in the peripheral region of rice and compression stress in the central region of rice (Wu et al, 2017). At the lower heating temperatures with infrared radiation, the lower HRY occurred due to the lower degree of gelatinization of the grains.…”

Section: Resultsmentioning

confidence: 99%

Effects of infrared radiation heating temperature and time on starch gelatinization and technological, thermal, and pasting properties of parboiled rice

et al. 2023

View full text Add to dashboard Cite

Background and Objectives: The improvement of the physical, chemical, and sensorial parameters of parboiled rice is constantly sought by the industry.Thus, the objective was to evaluate the effects of infrared radiation heating temperature (80°C, 100°C, 120°C, and 140°C) and time (2, 6, 10, and 14 min) on starch gelatinization and technological, thermal, and pasting properties of parboiled rice. Findings:The degree of gelatinization of rice starch subjected to infrared radiation heating ranged from 5.73% to 39.13% and the relative crystallinity from 49.70% to 42.30% in the treatments at 80°C for 6 min and 140°C for 14 min, respectively. The increase in head rice yield is related to an increase in the degree of gelatinization and a reduction in the relative crystallinity of the starch, making the grains more resistant to breakage. There was a tendency to reduce the cooking time at temperatures of 80°C and 140°C, regardless of the heating time. As for hardness, the opposite behavior was observed, with a tendency to increase at temperatures of 80°C and 140°C, regardless of the heating time.Conclusions: Infrared radiation heating can be used to produce parboiled rice. It is recommended to use temperatures between 100°C and 120°C for 6-10 min. Significance and Novelty:The method validated in this study presented to the rice processing industry a new way to produce parboiled rice. The study showed that it is possible to use infrared radiation heating to gelatinize rice starch. The use of infrared radiation in rice processes is widely used in the industry as a source of heating, whether in drying or parboiling, with previous studies showing a reduction of up to 4.6 times in energy consumption compared to conventional sources of heating.

show abstract

“…Consequently, it is assumed that there are free boundaries around the corn kernels, and the kernels can expand or shrink freely around its geometric center. The initial and boundary conditions for solving the drying model are illustrated in the below equation (Wu et al, 2016).

\left\{\begin{array}{c}t=0,{\sigma }_{T}=0,{\sigma }_{M}=0;\\ t\ge 0,u(0,0,0)={[0,0,0]}^{T},\end{array}\right.

where, u is the deformation of corn kernels, mm.…”

Section: Methodsmentioning

confidence: 99%

Hot‐air drying of corn kernels: Drying kinetics and quality improvement

et al. 2023

View full text Add to dashboard Cite

Background and Objectives: During the hot-air drying process of corn kernels, excessive stress can cause cracks to develop. For this reason, it's essential to identify the optimum parameters that can minimize stress during hot-air drying. Findings: In this study, a three-dimensional fitness model was established based on the average geometric size of corn kernels. Additionally, a hot-air drying model was constructed on the basis of heat and mass transfer, stress-strain theory, and conservation law of heat and mass transfer. Simulated calculations of heat and mass transfer were performed to obtain the temperature and moisture gradient distribution. This distribution was then coupled with a stress model to reveal the variation of drying stress. Verification experiments were conducted on the drying model. The results indicated that the temperature and moisture gradient were symmetrically distributed about the geometric center of corn kernels. At symmetrical positions about the geometric center, their sizes were almost equal but their directions are opposite. The thermal stress and moisture gradient stress showed the fact of larger surface but smaller interior of corn kernels. Furthermore, they both increased rapidly in the initial stage and then slowly decreased. The maximum value of thermal stress was 4.57 kPa, and the maximum value of moisture gradient stress was 0.49 MPa.Conclusions: Mass transfer plays a significant role in the hot-air drying process, and cracks can develop as a result of excessive moisture gradient stress.To mitigate these issues, it's important to increase the air humidity in a controlled manner to significantly reduce the total stress. The maximum error in temperature between simulated and experimental results was 8.5%. This suggests that our drying model can be effectively utilized to explore temperature gradient, moisture gradient, and stress distribution of corn kernels.Significance and Novelty: This study provides insights into the mechanism of stress generation that occurs during the hot-air drying process of corn kernels. Our analysis indicates that properly increasing the air humidity can significantly reduce drying stress and consequently prevent the formation of cracks. This ultimately leads to improved product quality and economic value.

show abstract

A study on drying models and internal stresses of the rice kernel during infrared drying

Cited by 40 publications

References 30 publications

Determination and comparison of effective moisture diffusivity of carrot (core and cortex) during hot air drying

Determination and comparison of effective moisture diffusivity of carrot (core and cortex) during hot air drying

Effects of infrared radiation heating temperature and time on starch gelatinization and technological, thermal, and pasting properties of parboiled rice

Hot‐air drying of corn kernels: Drying kinetics and quality improvement

Contact Info

Product

Resources

About