scholarly journals Effect of temperature and mode of drying on bioactive compounds and quality of germinated parboiled rice

Author(s):  
Busarakorn Mahayothee ◽  
Supaporn Klaykruayat ◽  
Marcus Nagle ◽  
Joachim Müller

Germinated parboiled rice (GPR) is recognized as a functional food because it is rich in bioactive compounds, especially gamma-aminobutyric acid (GABA). GPR was produced by soaking, incubating, steaming, and then drying using a high-precision hot air dryer. The results indicated that air flow mode and drying temperature had significant effects on the quality of GPR. Drying at higher temperatures and shorter times conserved GABA content. Using through-flow mode decreased drying time and prevented color change. However, a slightly lower percentage of head rice yield was observed. Moreover, using through-flow mode negatively affected the hardness loss after cooking.Keywords: Germinated parboiled rice; Drying mode; Gamma-aminobutyric acid; Head rice yield  

2015 ◽  
Vol 11 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Ebrahim Taghinezhad ◽  
Mohammad Hadi Khoshtaghaza ◽  
Saeid Minaei ◽  
Asefeh Latifi

Abstract Iranian paddy (Fajr) is the most popular rice for export and consumption in Iran but it has poor milling yield. To solve this problem, parboiling has been used for improving its milling quality. In this study, the effect of various parboiling conditions (soaking at temperatures of 55–75°C and steaming times for 2–10 min) on some quality properties of Fajr paddy was investigated. After parboiling, the physical properties (degree of milling, head rice yield, lightness and color value) and mechanical properties (rupture force) of parboiled rice were measured. Head rice yield and mean value of rupture force increased significantly (p < 0.05) from 50.10% to 62.11–67.05% and from 108.6 to 128.93–227.30 N, respectively. Also, the color value of parboiled rice increased significantly (p < 0.05) by increasing the length of steaming time. The milling degree of unparboiled rice (17.03%) was significantly (p < 0.05) higher than that of the parboiled rice (15.1–16.9% range). Soaking at 65°C and 4 min steaming time gave the highest values of head rice yield, lightness and rupture force. So, this treatment was found to provide the most desirable quality of Fajr parboiled rice.


2018 ◽  
Vol 192 ◽  
pp. 03017
Author(s):  
Thatchapol Chungcharoen ◽  
Naruebodee Srisang ◽  
Siriwan Srisang

The steaming process with revolved sieve was studied as a function of steaming time and revolution velocity. The quality of parboiled rice in terms of thermal property, head rice yield and color was investigated and compared to the conventional steaming process such as fixed sieve. The experimental results showed that the steaming process with revolved sieve had advantage over the steaming process with fixed sieve. It led to a steamed sample with higher DG higher head rice yield and lower whiteness value. The required steaming time for a regularity quality by a steaming process with revolved sieve was also shorter. Moreover, the steaming time affected the qualities of parboiled rice. The long steaming time provided the higher DG and head rice yield and lower whiteness value of parboiled rice. Considering revolution velocity, it was found that the revolution velocity did not affect the qualities of parboiled rice. However, the revolution velocity of 5 rpm with steaming time of 5 min provided the difference of quality at each layer.


2020 ◽  
Vol 187 ◽  
pp. 01002
Author(s):  
Asadayuth Mitsiri ◽  
Somkiat Prachayawarakorn ◽  
Sakamon Devahastin ◽  
Wathanyoo Rordprapat ◽  
Somchart Soponronnarit

A more simple methodology of producing parboiled rice is subject to be investigated in this work with proposed the method, the gelatinization of rice starch, commonly taking place at the steaming step in the traditional process, and drying are combined and replaced by a hot air fluidized bed dryer. A pilot-scale continuous fluidized bed, with a maximum capacity of 140-150 kg/h, has been designed, constructed and tested. Suphanburi 90 paddy variety with high amylose content was dipped into hot water at temperatures of 70, 80, 83°C for 4.0, 3.3, 3.2 h, respectively, to get the moisture content around 47-55% db and dried at 150-170°C using air speed of 3.5 m/s. The paddy bed depth within the dryer was 3 and 5 cm. In the dryer operation, the exhaust air was fully recycled and reheated again by 30 kW electrical heaters to the desired temperature. The experimental result has shown that parboiled rice with a different degree of starch gelatinization could be produced by this technique. The degree ranged between 80-100% as examined by differential scanning calorimeter. The exit moisture content was given in a range of 14-21% db, relying on the drying temperature and soaking time. The aforementioned exit moisture contents were not a detrimental effect on head rice yield although the tempering was not included. The head rice yield was given in the range of 59-66%, depending on the degree of starch gelatinization. The starch granules lost their original shape as revealed by scanning electron microscope.


2018 ◽  
Vol 21 (1) ◽  
pp. 1-7
Author(s):  
Fatemeh Rahimi-Ajdadi ◽  
Ezzatollah Askari Asli-Ardeh ◽  
Adel Ahmadi-Ara

AbstractVarious conditions of a parboiling process affect the qualitative parameters of paddy milling. In this study, the effects of drying temperature (45 and 60 °C), moisture content (8, 10 and 12% w.b.), steaming time (10, 20 and 30 min) and paddy varieties (Hashemi and Alikazemi) were investigated on head rice yield (HRY). The samples were husked using a rubber roller husker and whitened by a laboratory abrasive whitener. Results showed that the main effects of all parameters were significant onHRY(P<0.01). The utilization of higher temperature (60 °C), in comparison with non-parboiled rice, without reducing the milling quality was found as one of the advantages of parboiling. Among all experiments, the highestHRY(68.647%) was achieved in the combination of Alikazemi/45 °C/10 min/8%. In the majority of cases, the combinations including Alikazemi variety had higherHRYthan Hashemi. For Hashemi variety, the highestHRY(67.297%) was achieved in combination 45 °C/10 min/8%. In terms ofHRY, parboiling causes an increase of 25.8% and 43.3% respectively for Hashemi and Alikazemi. Therefore, it is highly recommended in processing of Alikazemi variety.


2001 ◽  
Vol 47 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Germán Elbert ◽  
Marcela P Tolaba ◽  
Constantino Suárez

2018 ◽  
Vol 55 (1) ◽  
pp. 132-142 ◽  
Author(s):  
SOM BUNNA ◽  
HOURN SEREYVUTH ◽  
YIM SOMALY ◽  
NGON NGOY ◽  
LOAN MENGSRY ◽  
...  

SUMMARYExperiments were conducted across 2 years to determine the effect of harvesting methods – combine harvester and hand harvesting – and harvest time during ripening on milling quality of long grain rice grown in the rainfed lowland ecosystem in Cambodia. Head rice yield (HRY) was highest when rice was harvested 25 days after flowering and decreased with delay in harvesting at 35 and 45 days after flowering. This was accompanied by a general decline in grain moisture content at harvest, although it was still high at 24–25% at 35 days after flowering. The decline in HRY was associated with increases in fissured grain percentage observed immediately after harvest. Hand harvesting produced 2–6% higher HRY than combine harvesting. Fissured grain in hand harvested crops was lower in year 1, but was similar to combine harvested crops in year 2. Both hand and combine harvested crops were sun-dried but rough rice harvested by combine was dried on plastic sheet and this may have contributed to reduction in HRY. Maximum HRY percentage was only about 44% and the factors contributing to this low HRY were discussed. Harvesting time and methods had no significant effect on grain yield, but the field grain loss during the harvesting operation was 2–5% higher in combine than hand harvesting.


Author(s):  
Thatchapol Chungcharoen ◽  
◽  
Anupong Meekotekong ◽  
Warunee Limmun ◽  
Naruebodee Srisang

A modified steaming method (steam using the revolved sieve; SRS) was applied to produce parboiled rice and the qualities of parboiled rice, namely, thermal properties (enthalpy; ΔH and degree of starch gelatinization: DG), head rice yield (HRY) and whiteness index (WI) were investigated under various steaming times and temperatures. The experimental results indicated that time and temperature during steaming step affected the parboiled rice qualities significantly. Prolonged time and increase of temperature during steaming provided the higher initial moisture content and grain temperature of rice sample after steaming, leading to longer time in drying process for decreasing the moisture content in the rice sample to 22% (d.b.). This provided the decrease of ΔH, leading to increase in the DG and resulting in the higher HRY and lower WI values.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ayenew Meresa ◽  
Ayalew Demissew ◽  
Seifu Yilma ◽  
Getu Tegegne ◽  
Kiber Temesgen

Most locally cultivated rice varieties in Ethiopia have low physical (low head rice yield, high broken rice yield, and high percentage of chalkiness) and cooking qualities (low water uptake ratio and swelling ratio). Parboiling, a process which involves soaking, steaming, and drying, has been identified as a key technique to improve cooking and milling quality of rice. The current study is aimed at elucidating the effect of parboiling on physical and cooking qualities of three rice varieties (Gumara, Edget, and Narica4) collected from Fogera National Rice Research and Training Center, Amhara region, Ethiopia. Each rice variety was subjected to different soaking temperatures (40°C, 50°C, 60°C, 70°C, and 80°C) and steaming time (10, 20, 30, 40, and 50 minutes). The treatment effect results indicated that parboiling has a significant effect (P<0.05) on head rice yield and percentage of broken rice with increased soaking temperature and steaming time as compared to the control. For instance, percent head rice yield increased as soaking temperature (from 40 to 80°C) and steaming time (from 10 to 50 min) increased: for Gumara, from 4.07 to 93.6%, for Edget, 9.47 to 96.53, and from 3.20 to 91.67 for Narica4. Percentage chalkiness had decreased as soaking temperature and steaming time increased: 97.33% to 0.00% for Gumara, 97.80% to 0.00% for Edget, and 100.00% to 0.13% for Narica4 as compared to 100% for control of all varieties. The minimum cooking time was identified as 16-23 min for Gumara, 16-23 min for Edget, and 15-20 min for Narica4 rice varieties. The result of the present study clearly showed that parboiling with high soaking temperature and steaming time increased the head rice yield, water uptake ratio, decreased percentage chalkiness, and enhanced the overall quality of the rice varieties.


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