Impact of drying deep beds of rice with microwave set at 915 MHz frequency on rice microbial community responses

Smith, Deandrae Lynette; Atungulu, Griffiths G.

doi:10.1002/cche.10018

Cited by 10 publications

(10 citation statements)

References 19 publications

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“…Parameters for calculation of specific energy are shown in Table 1. The choice of specific energy used was based on the findings of previous research which showed that the use of 360–630 kJ/kg‐grain microwave specific energy for rice drying does not cause damage to the rice kernels (Bruce et al, 2021; Olatunde et al, 2017; Smith & Atungulu, 2018). Following microwave treatment, samples were immediately transferred into glass jars and tightly sealed.…”

Section: Methodsmentioning

confidence: 99%

“…So far, studies have been conducted to determine the 915 MHz microwave's drying potential, energy consumption, microbial load reduction, and impacts on rice physicochemical properties (Atungulu et al, 2016; Olatunde et al, 2017; Smith & Atungulu, 2018). Furthermore, Bruce et al (2021) determined microwave parameters for drying different rice cultivars with the 915 MHz microwave.…”

Section: Introductionmentioning

confidence: 99%

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Aging characteristics of rice dried using microwave at 915 MHz frequency

Bruce¹,

Atungulu²,

Sadaka

et al. 2022

Cereal Chem

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Background and Objectives Rice aging is an intrinsic phenomenon that leads to physicochemical changes in rice kernels. The goal of this study is to determine the physicochemical properties of rice dried using a 915 MHz microwave and then aged. Two rice cultivars, a medium grain cultivar Titan and long grain hybrid cultivar XL753, with a harvest moisture content of 20% ± 1% (wet basis) were used for the study. The rice samples were treated with two different drying methods, natural air drying as control and microwave heating at 915 MHz frequency followed by tempering and natural air cooling at 25°C and 56% relative humidity (RH). Microwave‐dried samples were treated at specific energies ranging from 360 to 630 kJ/kg of initial wet grain mass (kJ/kg‐grain). Head rice samples were stored for 6 months at 4°C and 25°C representing nonaged and aged samples, respectively. Physicochemical properties of the samples were determined. Findings Aged microwave‐dried rice had significantly higher setback viscosity, cooked rice hardness and gumminess, and significantly lower peak viscosity and solid loss than nonaged rice. The changes in the viscosity profiles of aged microwave‐dried rice were generally similar to the trends recorded for aged control rice. Furthermore, aging significantly increased the water uptake and kernel elongation ratio of microwave‐dried rice cultivar XL753 but had no significant impact on rice cultivar Titan. Statistical models indicate that the solid loss of microwave‐dried rice decreases by 0.083% while the final viscosity, kernel elongation ratio, and hardness increase by 30 cP, 0.014, and 41 g respectively, with every degree Celsius increase in aging temperature (between 4°C and 25°C), when all other variables are kept constant. Also, aged microwave‐dried rice that were treated at 360 and 525 kJ/kg‐grain were practically equivalent in terms of hardness and solid loss. Conclusions Natural aging of microwave‐dried rice (dried at 915 MHz frequency) led to changes in some physicochemical properties which were generally similar to the aging patterns of the control rice. Microwave specific energy of 525 kJ/kg‐grain is recommended for rice drying because it produces rice with desirable drying and aging properties. Significance and Novelty This study provides processing recommendations that can be used to select microwave parameters for rice drying, which will achieve desirable rice properties.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aging characteristics of rice dried using microwave at 915 MHz frequency

Bruce¹,

Atungulu²,

Sadaka

et al. 2022

Cereal Chem

Self Cite

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“…Physical methods are used to control the inactivation of fungi at all stages of grain harvesting and storage where fungi can be produced, including superheated steam sterilization (Spicher et al 1999), irradiation treatment techniques (Huang et al 2008), infrared radiation technology (Yi et al 2014) and microwave sterilization (Li et al 2003). Radiation treatment has a signi cant effect on the inactivation of fungi (Assatarakul et al 2012) and the reduction of mycotoxins (Smith and Atungulu 2018). Chemical methods are a class of methods that use chemical reagents to remove mycotoxins (Faugere and Antalick 1984).…”

Section: Introductionmentioning

confidence: 99%

Prediction and optimal control of fungal contamination of food under the influence of temperature and water content

Wang

Feng

Zheng

et al. 2023

Preprint

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The mildew phenomenon and mycotoxin pollution caused by the mass reproduction of grain fungi seriously endanger food security and people's health. The existing fungal growth models are difficult to accurately describe and predict the fungal growth trend, and can't optimally control the temperature and water content of grain storage environment. This paper constructs a fungal growth model with temperature and water content as the influencing factors to predict the fungal growth trend, and puts forward the optimal control method of temperature and water content during grain storage. Firstly, on the basis of the existing temperature-based microbial growth dynamics model, water influencing factors were added, and the transformation relationship model between colony diameter and fungal spore number was put forward by improving the two-dimensional normal distribution model. Then, the growth trend of fungi was predicted by discretizing and incrementing the model. On this basis, according to the characteristics of grain fungus pollution, the predictive control theory was improved, and the optimal control objective function with fungus growth as the predictive variable and temperature and water as the control variables was established. The fixed point method was used for iterative solution to achieve the global minimization of colony growth rate, temperature and water control cost. The experimental data of rice storage were used to verify the proposed method, and it was verified that the prediction accuracy of the established fungal growth model was high, and by optimizing the control of temperature and water content, the fungal growth could be significantly reduced.

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“…Among the emerging technologies to eliminate fungal contamination in high‐moisture rice, microwave (MW) treatment is fast, safe, effective, and environment friendly (Smith & Atungulu, 2018). MW is a high‐frequency electromagnetic wave between 1 mm and 1 m and frequency between 3 × 10 2 and 3 × 10 5 MHz.…”

Section: Introductionmentioning

confidence: 99%

Characterization of differences between microwave and traditional thermal sterilization to prevent fungal spoilage during storage of high‐moisture paddy rice

et al. 2020

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Background and objectives Characteristic difference between microwave (MW; 2.45 GHz, 1.5 W/g) and traditional thermal (TT; water bath, 100°C) sterilization on representative fungi (Aspergillus candidus, Aspergillus glaucus, Penicillium chrysogenum, Alternaria alternata, and Fusarium nivale) on high‐moisture paddy rice was evaluated by observing heat absorption of rice surface, fungal mortality, growth, and cell permeation. Findings Using MW (2.45 GHz, 1.5 W/g) can inhibit the growth of fungi, such as Aspergillus candidus. Under our experimental conditions, MW radiation was effective for safe storage of high‐moisture rice with fungal mortality of 95%. Fungal dehydrogenase activities after MW treatment were nearly 50% lower than fungal dehydrogenase activities after TT. Both MW and TT at the same temperature (60°C) can inhibit the growth of fungal spores. However, MW had better inhibitory effect, which is conducive to the safe storage of high‐moisture paddy rice. Conclusions Microwave and TT sterilization destroy fungal cell, causing substantial cell leakage and death. MW is more destructive to organisms on high‐moisture paddy rice than TT, which may be due to the nonthermal effects of MW. Significance and novelty Compared with TT, MW has better sterilization and could prevent fungal contamination in high‐moisture paddy rice storage and other cereals.

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Impact of drying deep beds of rice with microwave set at 915 MHz frequency on rice microbial community responses

Cited by 10 publications

References 19 publications

Aging characteristics of rice dried using microwave at 915 MHz frequency

Aging characteristics of rice dried using microwave at 915 MHz frequency

Prediction and optimal control of fungal contamination of food under the influence of temperature and water content

Characterization of differences between microwave and traditional thermal sterilization to prevent fungal spoilage during storage of high‐moisture paddy rice

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