Effect of presoaking high hydrostatic pressure on the cooking properties of brown rice

Abstract

Effects of presoaking-high hydrostatic pressure (PHHP) on cooking time, hardness, gumminess, springiness, and microstructure of brown rice were evaluated. Compared with traditional soaking treatment, PHHP significantly shorten the cooking time of brown rice from 34 to 14 min. The hardness of brown rice treated by PHHP reduced remarkably, which is lower than that treated by soaking process and similar to that of white rice. The gumminess and springiness of brown rice dramatically decreased under pressure above 500 MPa. However, the water uptake capacity of brown rice treated by PHHP was not obviously affected, whose moisture contents were much lower than that of soaked samples. The analysis of thermal properties revealed that the enthalpy of brown rice was influenced by PHHP, and the denaturation of brown rice components generated. These results and microstructure analysis revealed that the structures of pericarp and aleurone layer of brown rice were damaged by PHHP, which allows water to be easily absorbed by the rice kernel during cooking process. PHHP treatment could be a potentially applicable pretreatment for improving cooking properties of brown rice.

Effect of soaking and single/two cycle high pressure treatment on water absorption, color, morphology and cooked texture of brown rice

“…However, the effect of HPT on the color and textural properties of brown rice is limited. In a previous study from our lab (Yu et al 2015), it was found that single cycle HPT could shorten the cooking time and reduce the hardness of brown rice. However, this study was somewhat limited for concept testing with a single cycle HPT and lacked details on the influence on appearance, texture, morphology and market potential of HPT that might be possible with a two cycle HPT.…”

Innovative processing techniques for altering the physicochemical properties of wholegrain brown rice (Oryza sativa L.) – opportunities for enhancing food quality and health attributes

“…In this line, Ahromrit, Ledward, and Niranjan (2006) investigated HP-induced water uptake characteristics of glutinous rice (polished form), concluding that the equilibrium moisture content (EMC) and water uptake rates increased with pressure intensities (100-600 MPa) and temperature (20-70 ºC). Regarding WBR grains, however, the values for EMC fluctuated within the applied pressures of 100-500 MPa, which was related to the histochemical difference and the formed cracks at the RB surface (Yu et al, 2015). Yu et al (2015) reported that the HP-mediated pre-soaking contributed to shortening about 60% of the cooking time of WBR grains; and more importantly, the palatability was largely improved due to the damaged structure of pericarp and aleurone layer under pressures.…”

“…Regarding WBR grains, however, the values for EMC fluctuated within the applied pressures of 100-500 MPa, which was related to the histochemical difference and the formed cracks at the RB surface (Yu et al, 2015). Yu et al (2015) reported that the HP-mediated pre-soaking contributed to shortening about 60% of the cooking time of WBR grains; and more importantly, the palatability was largely improved due to the damaged structure of pericarp and aleurone layer under pressures. These changes in cooking and textural attributes were greatly dependent on the applied pressure intensities (holding times and pressures) and processing patterns.…”

“…After combined treatments (Zhang et al, 2015a) WBR flour was mixed Combining enzyme -Enzymatic extrusion contributed to higher retention After combined (Zeng et al, 2017); treatments (Zeng et al, 2018) WBR (Yu et al, 2015) Soaking (30-50 o C/30 min), followed by one-cyle or two-cycles HHP treatments (100-500 MPa/10 min)…”

Characterization of Volatile Compound Profiling of Germinated Brown Rice Revealed by Headspace Solid-phase Micro Extraction Coupled to Gas Chromatography Mass Spectrometry

“…GBR grains were boiled for 30 min and no white spots leaching were observed [5]. The cooked rice was placed in a 20-ml autosampler vial with a screw cap and the internal standard (IS), n-heptadecane, was added.…”