Physicochemical Properties of Rice Dried in a Single Pass Using High Temperatures

Ondier, George; Siebenmorgen, T. J.; Mauromoustakos, A.

doi:10.1094/cchem-09-12-0110-r

Cited by 8 publications

(17 citation statements)

References 29 publications

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“…The breakdown values indicates how fragile the starch granules are and are good indices for studying the susceptibility of starch to disintegrate (Juliano, ). It was also reported that the breakdown viscosity increased with increasing drying air temperature (Dang & Copeland ; Ondier, Siebenmorgen, & Mauromoustakos, ). The authors speculated that high drying temperature caused cross linking of starch granules with unfolded proteins or lipids, making the granules resistant to breakdown hence the high breakdown viscosity.…”

Section: Resultsmentioning

confidence: 89%

“…There was marginal decrease in the peak viscosity values registered in this experiment; it is speculated that the reason could be the short intermittent IR treatment duration of 30 s. Otherwise, longer exposure durations may result in interaction of amylose and amylopectin chains of starch with unfolded structures of the denatured proteins (Dang & Copeland, ) forming complexes that may increase peak viscosity. As mentioned previously, it is also possible that soluble proteins in the corn influenced water access to the starch granule by reducing water uptake, limiting starch granule swelling (Baxter, Zhao, & Blanchard, ; Ondier, Siebenmorgen, & Mauromoustakos, ), and thereby lowering the peak viscosity.…”

Section: Resultsmentioning

confidence: 99%

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Radiant heat treatments for corn drying and decontamination

Wilson¹,

Okeyo²,

Olatunde³

et al. 2017

Journal of Food Processing and Preservation

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Freshly harvested corn at moisture content of 24% wet basis (w.b.) was intermittently dried with infrared (IR) at intensities 2.39, 3.78, and 5.55 kW/m2 for 30, 50, and 180 s to safe storage‐moisture content of 13% (w.b). Microbial load reduction, energy use and corn sensory and pasting qualities were evaluated. Experiments were carried out at product‐to‐emitter gap size of 450 mm. Increasing IR intensity from 2.39 to 5.55 kW/m2 resulted in average microbial load reductions of 2.6 and 2.9 log CFU/g at 180 and 30 s of intermittent IR heating, respectively. IR treatments reduced corn paste viscosity and stress cracks (p < .05), but insignificantly impacted corn color (p > .05). Drying corn to storage‐moisture content with IR intensities 2.39 and 5.55 kW/m2, required 7.5 and 15.0 MJ/kg of water removed, respectively. Accelerated, Scaled‐up IR drying and decontamination was achieved without affecting the corn quality; optimized treatments could potentially improve throughput and energy efficiency. Practical applications Freshly harvested, high moisture content corn must be dried within short duration to about 12–14% (w. b.) to prevent mold growth and preserve the overall corn quality. This research presents the following practical applications: Scaled up infrared (IR) treatment of corn with efficacy to significantly reduce drying time (9 to 22 min depending on infrared intensity and intermittent IR drying duration to dry freshly harvested corn at moisture content 23–13% wet basis). Capability of using intermittent IR heating to combine corn drying and decontamination in a single step while maintaining the quality of finished product. Potential of IR heating to inactivate heat resistant, mycotoxin‐producing mold spores that are liable to survive conventional drying methods.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Radiant heat treatments for corn drying and decontamination

Wilson¹,

Okeyo²,

Olatunde³

et al. 2017

Journal of Food Processing and Preservation

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“…The highest peak viscosity was observed in CL 271 samples dried with IR in a two-pass treatment for 30 s (3,206 cP). Ondier et al (2013) reported peak viscosities of 2,400-3,100 cP and final viscosities of 2,650-3,100 cP for Wells, Jupiter, and CL XL729 exposed to temperatures of 60, 70, and 80°C. Similar increases in final and peak viscosities with increasing air temperatures were also reported by Dhaliwal et al (1991).…”

Section: Resultsmentioning

confidence: 99%

“…High final and peak viscosities are associated with increased cohesiveness caused by increased water binding capacity of the starch granules as well as subsequent disintegration during cooking (Wang et al 2004). Setback viscosity is the difference in viscosity between the trough and the final viscosity value, and is a measure of the degree of retrogradation of amylose and amylopectin upon cooling of the gelatinized starch (Ondier et al 2013). Ambardekar and Siebenmorgen (2012) also reported similar increases in final and peak viscosities for samples that were exposed to elevated temperatures, which they attributed to the modification of starch granule structures.…”

Section: Resultsmentioning

confidence: 99%

“…The pasting properties Fig. The soluble proteins such as albumin may obstruct water access to the starch granule through preferential binding of the starch hydrophilic region, thus reducing water uptake and limiting starch granule swelling (Baxter et al 2010;Ondier et al 2013). Final viscosity (in centipoises [cP]) after one-pass infrared heating for 30, 50, 90, and 180 s (A) and two-pass infrared heating for 30 and 50 s (B) followed by tempering at 60°C for 4 h. Each value is an average of three replicate measurements.…”

Section: Resultsmentioning

confidence: 99%

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Infrared Drying Characteristics of Long‐Grain Hybrid, Long‐Grain Pureline, and Medium‐Grain Rice Cultivars

Okeyo¹,

Olatunde²,

Atungulu³

et al. 2017

Cereal Chem

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Cereal Chem. 94(2):251-261The objective for this study was to investigate the effectiveness of scaled-up infrared (IR) heating followed by tempering steps to dry freshly harvested rough rice. An industrial-type, pilot-scale, IR heating system designed to dry rough rice was used in this study. The heating zone of the equipment had catalytic IR emitters that provided heat energy to the sample as it was conveyed on a vibrating belt. The sample comprised freshly harvested rough rice of long-grain pureline (Cheniere), long-grain hybrid (6XP 756), and medium-grain (CL 271) cultivars at initial moisture contents of 23, 23.5, and 24% wb, respectively. Samples at a loading rate of 1.61 kg/m 2 were heated with IR of radiation intensity 5.55 kW/m 2 for 30, 50, 90, and 180 s followed by tempering at 60°C for 4 h, at a product-toemitter-gap size of 450 mm, in one-and two-pass drying operations. Control samples were gently natural air dried in an equilibrium moisture content chamber set at relative humidity of 65% and temperature of 26°C to moisture content of 12.5% wb. The effects of IR treatments followed by tempering on percentage points of moisture removed, head rice yield, energy use, rice color, and pasting characteristics were evaluated. For all cultivars, percentage point moisture removed increased with increase in IR drying duration. For all rice cultivars, one-pass IR treatments for 180 s resulted in head rice yield significantly lower than that of rice dried with natural air in the controlled-environment conditions (P < 0.05). Energy required to dry rice increased with increase in drying duration. Viscosity values of all the experimental samples were significantly greater (P value < 0.05) than that of the control samples for all the cultivars, except those treated with IR for 180 s. There was a significant difference (P < 0.05) in the color index (DE) of treated milled samples and the controls. In conclusion, the study provided information crucial to understanding the effects of scaled-up radiant heating and tempering of rough rice on drying rates and rice quality for long-grain pureline, long-grain hybrid, and medium-grain rice cultivars.

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Rice paste viscosities and gel texture resulting from varying drying and tempering regimen

Graham‐Acquaah

Siebenmorgen

2020

Cereal Chem

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Background and objectives Heated‐air drying followed by tempering (HAT) is effective for increasing rough rice drying rates without compromising head rice yield (HRY). However, relatively little is known about the specific nature of the effects of HAT regimens on end‐use properties of rice. This study determined the effects of drying air conditions (air temperature and relative humidity) and tempering durations on changes in rice paste viscosities and gel texture. Findings Rice paste viscosities and gel texture were not only dependent on drying air temperature but also on how long the rice was exposed to a given temperature during drying and tempering. Air relative humidity (rh) had an indirect effect on rice end‐use properties. Using different HAT regimens, peak viscosity was altered by 16%, final viscosity by 21%, breakdown by 24%, and setback by >500% compared with control samples. Gel strength was increased by approximately 40% with HAT regimens. Conclusions Heated‐air drying and tempering conditions must be carefully selected, not only to minimize HRY reductions but also to minimize variations in the functional properties of rice intended for specified end uses. Likewise, HAT regimens could be selected to produce desired properties for specified end uses. Significance and novelty Inconsistencies in rice flour functionality are a hindrance to an expansive use of rice in end‐use, gluten‐free product development. This study shows that drying, a critical postharvest operation, could introduce variations in rice flour quality, which also implies that HAT regimens could deliberately be utilized to produce flour for various end‐use applications.

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Physicochemical Properties of Rice Dried in a Single Pass Using High Temperatures

Cited by 8 publications

References 29 publications

Radiant heat treatments for corn drying and decontamination

Radiant heat treatments for corn drying and decontamination

Infrared Drying Characteristics of Long‐Grain Hybrid, Long‐Grain Pureline, and Medium‐Grain Rice Cultivars

Rice paste viscosities and gel texture resulting from varying drying and tempering regimen

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