Influence of Moisture Content,Variety and Parboiling on Milling Quality of Rice Grains

The effects of moisture content （8%, 10%and 12%）, variety （Tarom and Fajr） and parboiling on milling quality of rice as a function of milling recovery （MR）, head rice yield （HRY）, degree of milling （DOM） and whiteness were investigated. The parboiled grains was prepared with three soaking temperatures of 25 oC, 50 oC and 75 oC and three steaming times of 10, 15 and 20 min. As a result of parboiling, the increasing rates of MR and HRY values were 7.8%and 14.3%for Tarom and 9.8%and 10.0%for Fajr, respectively, and the decreasing rates for DOM and whiteness were 6.6%and 10.8%for Tarom and 6.8% and 10.5% for Fajr, respectively. Moreover, decreasing moisture content to 8%maximized MR （75.8% for Tarom and 74.3% for Fajr） and HRY （65.8% for Tarom and 57.0% for Fajr） while increasing that to 12%revealed maximum values of DOM （6.1%for Tarom and 6.2%for Fajr） and whiteness （24.8%for Tarom and 28.2%for Fajr）.

Effect of Milling and Parboiling Processes on Arsenic Species Distribution in Rice Grains

This study identified the role of milling and parboiling on arsenic(As)content and its species in large numbers of rice samples.Total As contents were 108±33μg/kg in polished rice grains(PR),159±46μg/kg in unpolished rice grains(UR),145±42μg/kg in parboiled polished rice grains(PPR)and 145±44μg/kg in parboiled unpolished rice grains(PUR).The percentages of inorganic As(iAs)were 66%±8%in PR and from 72%to 77%in other grain categories.The polishing process reduced the As content in the rice grains,removing outer part of the UR with high amount of As,whereas the parboiling technique transferred the semimetal content within the grain.Total As and iAs contents were not significantly different in UR,PPR and PUR,homogenizing its distribution inside the grains.The results allowed to understand how different operations affect As fate and its chemical forms in grains.

Parboiled rice supplementation alleviates high-fat diet-induced hyperlipidemia by regulating genes and gut microbiota in mice

Dietary parboiled rice(PR)has a low risk of disease,but little is known about the contribution of PR to the prevention of hyperlipidemia.The potential role and underlying mechanisms of PR in hyperlipidemia were evaluated in this study.Male C57BL/6J mice were fed with a normal diet,high-fat diet(HFD)containing refined rice(HFDRR)or PR(HFDPR).It was found that PR intervention improved lipid accumulation in mice.Transcriptomic data analysis revealed that 27 genes were up-regulated(mostly involved in lipid breakdown)and 86 genes were down-regulated(mostly involved in inflammatory responses)in the HFDPR group compared to the HFDRR group.And 15 differentially expressed genes(DEGs)were validated by quantitative real-time PCR(RT-qPCR),while protein interaction network showed that protein tyrosine phosphatase receptor type C(PTPRC)has a central role.The gut microbiota of mice was also altered after different dietary treatments,with higher ratio of Firmicutes and Bacteroidetes,increased abundances of Ruminococcaceae,Lachnospiraceae,Christensenellaceae,Porphyromonadaceae,Rikenellaceae and Prevotellaceae,and decreased abundances of Lactobacillaceae,Peptostreptococcaceae,Erysipelotrichaceae and Actinobacteria in the HFDRR group.In addition,it was observed that PPAR signaling pathway may act as a bridge between DEGs and differential gut microbiota.These results suggested that PR can prevent hyperlipidemia by modulating liver genes and gut microbiota.

Relationship Between Degree of Starch Gelatinization and Quality Attributes of Parboiled Rice During Steaming

Paddy rice samples were parboiled by soaking at 65℃ for 180 min and steaming at 96℃ for 2–10 min,and then dried to achieve the final moisture content of 11% ± 1%. The degree of starch gelatinization （DSG） andseveral quality attributes （head rice yield （HRY）, color value and hardness） of parboiled rice were measured.Results showed that DSG （46.8%–77.9%）, color value （18.08–19.04） and hardness （118.6–219.2 N） allincreased following steaming. In contrast, the HRY increased （64.8%–67.1%） for steaming times between 2–4min but decreased （67.1%–65.0%） for steaming times between 4–10 min. Linear relations between DSG andcolor value （R2 = 0.87）, and DSG and hardness （R2 = 0.88） were observed. The suitable DSG of parboiled riceleading to the highest HRY was found to be 62.5%, obtained following 4 min of steaming.

Effect of Soaking Temperature on Physical and Functional Properties of Parboiled Rice Cultivars Grown in Temperate Region of India

The physical and functional properties of seven parboiled rice cultivars (Jehlum, K-332, Koshar, Pusa-3, SKAU-345, SKAU-382 and SR-1) were investigated at different soaking temperatures of 60℃, 70℃ and 80℃ and it was compared with the brown raw rice of the respective cultivars. Parboiling was observed to decrease L* value and increase a* and b* values. The hardness of rice was significantly increased after parboiling and varied among the cultivars with the highest in Jehlum. Parboiling resulted in the decrease of pasting parameters with the increase in soaking temperature from 60℃ to 80℃. The pasting characteristics of parboiled rice sample showed the typical behaviour having high initial viscosity, but lower peak viscosity in comparison to raw rice. The water absorption index and water solubility indices were subsequently increased with the increase in soaking temperature.

Traditional Parboiled Rice-Based Products Revisited: Current Status and Future Research Challenges

Parboiling is an age old technique carried out to improve rice quality. Different grain parboiling techniques have been traditionally followed and scientifically developed for preparation and industrialization of rice. The state of Assam, India produces a large number of rice varieties, some of which are traditionally processed into peculiar parboiled rice products like Hurum, Komal chaul, Bhoja chaul and Sandahguri, which are of both ethnic and possible commercial importances. In spite of extensive research carried out on parboiled rice, these products and their special parboiling techniques have not been sufficiently explored. The status of research on parboiled rice as a whole with special attention to these lesser known speciality products of Assam is extensively reviewed. Future scope of research on these products is also identified.

Effects of Continuous Steaming on Milling Characteristics of Two Indica Rice Varieties

Parboiling improves milling characteristics of rice in a positive manner, which has been found to influence consumers demand and acceptability. A laboratory model of continuous steaming unit was fabricated and tested with two indica rice varieties, fine （ADT39） and coarse （CO43） rice, at three different soaking temperatures （50, 60 and 70 ~C） for 4 h and five residence times of steaming （1.0, 1.5, 2.0, 2.5 and 3.0 min）. The effects of continuous steaming on milling characteristics of rice were studied and compared with the values obtained from the control experiment （open steaming process under laboratory conditions）. The favourable conditions for continuous parboiling of the fine variety ADT39 were identified as soaking at 70 ~C for 4 h and 3.0 min residence time of Steaming. These conditions showed head rice outturn of 74.0%. The favourable processing conditions for the coarse variety CO43 were found to be 4 h of soaking at 60 ~C and steaming of 3.0 min residence time, and at these conditions the head rice outturn was 73.9%.

Hydration Characteristics of Selected Varieties of Paddy Rice from Nigeria

In this study, water absorption characteristics of some rice varieties (Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44) from Nigeria were studied at 30°C, 45°C, 60°C and 75°C by determining the increase in grain weight as a function of time during soaking. Differences in moisture content among the selected varieties of paddy during soaking were significant (P < 0.05) at all temperatures considered. Using the experimental moisture data, a non-linear regression procedure was applied to an analytical solution of the Fick’s second law of the diffusion for an infinite cylinder. The predicted values of instantaneous moisture contents were in good agreement with the experiential data with R2 of (0.834 - 0.997). Water absorption rate was found to increase with soaking temperature, while water saturation time decreased with temperature. Average values of diffusion coefficients of moisture during soaking of paddy rice at different temperatures (30°C, 45°C, 60°C and 75°C) were estimated as 6.25 × 10 -11, 6.28 × 10 -11, 7.02 × 10 -11, and 5.51 × 10 -11 and 5.52 × 10 -11 m2/s for Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44, respectively. The activation energies of the diffusivity through different varieties of rice grains werecalculated using Arrhenius-type equation for diffusion dependence on temperature and were determined as 41.96, 38.69, 40.16, 34.05 and 42.12 kJ/mole for Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44 for the respectively rice variety above.

Iron Fortification in Parboiled Rice—A Rapid and Effective Tool for Delivering Iron Nutrition to Rice Consumers

Parboiled rice production accounts for nearly half of the world’s rice production. Its markets and consumer base are firmly established in South Asia and Africa where Fe-deficient populations are mostly concentrated. Our research group has pioneered the technology of Fe-fortification in parboiled rice and demonstrated its feasibility in significantly increasing Fe concentration in the endosperm (white rice) and its bioavailability in rice based diet. Fortification with Fe-EDTA during parboiling resulted in 10 to 50 folds increase in grain Fe concentration, depending on the grain properties among different rice varieties. However, the broken rice of Fe-fortified parboiled rice contained 5 times the Fe concentration of the full grain, which is often bought and consumed by people in low income category. The bioavailability of the fortified Fe is closely correlated with increasing Fe concentration in white rice (r = 0.90, p 50% to almost 100%, despite repeated rinsing before cooking depending on rice varieties. Perls’ Prussian blue staining and prolonged polishing showed that the in vitro Fe penetrated into the interior of the endosperm. Fortification at the rate up to 250 mg Fe kg–1 paddy rice has no deleterious effects on appearance, color and sensory quality and overall acceptance by parboiled rice consumers. It increased Fe concentration up to 27 mg Fe kg–1 of in white rice, compared with 5 mg Fe kg–1 in unfortified parboiled and raw white rice. As a result, we can conclude that parboiled rice is a ready and effective tool for improving Fe nutrition of rice consumers in these regions.

Effect of processing on the antioxidant activities of porridges and Pittu prepared from finger millets (Eleusine coracana)

Finger millets are important coarse grains that exhibit high levels of phenolic compounds and antioxidant activities among other cereals. Grains are subjected to a number of thermal treatments and this could affect the contents and bioactivities of phenolic compounds. The aim of the present study was to determine the phenolic contents and antioxidant activities of finger millet flour and foods, namely porridges and Pittu subjected to several thermal treatments such as roasting, parboiling, and parboiled roasting of flour and open boiling and steaming of foods prepared using flour. The effect of the addition of spices on phenolic content and antioxidant activities to open boiled foods was determined. Antioxidant activities of phenolic extracts obtained from finger millet flour and foods were studied for their total phenolic, flavonoids and proanthocyanidins contents, radical scavenging capacities, reducing power, ferrous ion chelating capacity, and antioxidant activity in a β-carotene/linoleate emulsion. The roasted flour and foods had higher total phenolic content (TPC) than other counterparts and ranged from 21.58 to 28.63 µmol ferulic acid equivalents/g dry matter. All flour and food preparations exhibited effective inhibition of radicals, reducing power, ferrous ion chelating activity, and antioxidant activity in the β-carotene/linoleate emulsion and the degree of activity depended on the processing conditions adopted in food preparations.Foods prepared using steaming showed lower phenolic content and antioxidant activities in general than those of open-boiled counterparts. The addition of spices, namely garlic and cinnamon improved the phenolic contents and antioxidant activities of open-boiled porridges. The knowledge generated from this study may help to exploit the use of finger millets as a functional food ingredient to promote health and wellness.