Polished Rice Research Articles

Metabolic engineering of rice endosperm towards higher vitamin B1 accumulation.

SummaryRice is a major food crop to approximately half of the human population. Unfortunately, the starchy endosperm, which is the remaining portion of the seed after polishing, contains limited amounts of micronutrients. Here, it is shown that this is particularly the case for thiamin (vitamin B1). Therefore, a tissue‐specific metabolic engineering approach was conducted, aimed at enhancing the level of thiamin specifically in the endosperm. To achieve this, three major thiamin biosynthesis genes, THIC, THI1 and TH1, controlled by strong endosperm‐specific promoters, were employed to obtain engineered rice lines. The metabolic engineering approaches included ectopic expression of THIC alone, in combination with THI1 (bigenic) or combined with both THI1 and TH1 (trigenic). Determination of thiamin and thiamin biosynthesis intermediates reveals the impact of the engineering approaches on endosperm thiamin biosynthesis. The results show an increase of thiamin in polished rice up to threefold compared to WT, and stable upon cooking. These findings confirm the potential of metabolic engineering to enhance de novo thiamin biosynthesis in rice endosperm tissue and aid in steering future biofortification endeavours.

Polishing conditions in rice milling differentially affect the physicochemical properties of waxy, low- and high-amylose rice starch

Effect of polishing condition during milling of rice on the properties of rice starch was investigated. Waxy, low- and high-amylose rice were polished with different milling speeds (750, 950 and 1050 r/min) and milling durations (20, 40 and 60 s) to obtain polished rice. Rice starches were extracted from the polished rice. Swelling power and solubility index of low- and high-amylose rice starches increased with milling speed and duration compared with unpolished rice starches. However, for waxy rice starch, there was no significant change. The peak, trough and final viscosities decreased for waxy rice starch and increased for high-amylose rice starch with increased polishing, whereas those of low-amylose rice starch increased first and then decreased. Polishing induced greater pseudoplasticity in starch relative to that from unpolished rice. Polishing duration during milling caused greater changes in swelling behavior and pasting properties, whereas polishing duration caused greater effects on structural properties. This study showed that both polishing speed and duration impacted the physicochemical and rheological properties of different rice starches, but to a different extent.

Remediation of Cd Contaminated Acidic Rice Fields Using the Combined Application of Lime and Organic Matter

Using an in-situ experiment in Cd contaminated paddy fields in Chongqing, the absorption and distribution of Cd in rice plants was examined following the combined application of lime and organic matter, and the mechanisms driving changes in Cd fractions in soil were also studied. The results showed that pH, OM content, and CEC in the soil were significantly enhanced, and OM and CEC were significantly positively correlated, as pH showed a significant positive correlation; pH and CEC was mainly associated with a change in Cd from the acidic extractable fraction to the reducible, oxidable, and residual fractions. The percentage of acidic extractable Cd dropped by 22.92%-31.25% with the application of the amendments, thus reducing the accumulation of Cd in rice plants in the followed order:CK (control group)≫B6 (lime and maize straw)≈B4 (lime and biochar)≈B3 (lime and activated humic acidic fertilizer) > B2 (lime and humic acidic fertilizer)≈B1 (lime) > B5 (lime and oil cake). On the other hand, for both the treatments and control conditions (CK), the Cd content of brown rice was higher than Chinese standard (GB 2762-2017), while that of polished (white) rice was lower than the Chinese standard after treatment. Overall, treatment using all of the remediation agents offers some benefit for the safe utilization of agricultural contaminated soil and safe food production. The combined application of lime and oil cake proved the best measure for treating Cd contaminated acidic rice fields, yielding a reduction in acidic extractable Cd (31.25%), a reduction in the Cd content of rice plants (33.32%), and the lowest Cd content (0.13 mg·kg-1) in polished rice (a 42.17% compared to the control).

Fate and health risks assessment of some pesticides residues during industrial rice processing in Argentina

The residues of deltamethrin, penconazole, kresoxim-methyl, cyproconazole, epoxiconazole and azoxystrobin were determined in husk rice, brown rice, husk and bran, fifty samples of each matrix, obtained from industrial rice facilities, to estimate the distribution of contamination levels during industrial rice processing; and to estimate the exposure to these pesticides through rice intake. The analytical methodologies required were validated. QuEChERS extraction and gas chromatography-mass spectrometry were used. All methods showed good linearity (r2 > 0.9996), adequate recoveries (between 80.0–102.0%) and relative standard deviations lower than 9.9 %. A total of 250 samples were analyzed, finding that the polishing stage reached the greatest pesticide reduction. Considering the overall process, the initial concentration of pesticides in husk rice was reduced in the range of 66.1–74.7%. Process factors were lower than 0.69 and 0.36 for brown and polished rice, respectively. Estimated Dietary Intake were below 0.83 %, 2.34 % and 3.70 % of ADI, for men, women, and children, respectively. Hazard quotient was estimated, and it was lower than 1 in all cases, showing a low potential risk for human health in terms of residue ingestion.

Effects of Various Rice-Based Raw Materials on Enhancement of Volatile Aromatic Compounds in Monascus Vinegar.

Monascus vinegar (MV), during whose brewing process Monascus spp. and polished rice (PR) are normally used as the starter and the raw material, respectively, is one of the traditional vinegars in China. In this study, the effects of three raw materials, including PR, unhusked rice (UR), and germinated UR (GR), on MV volatile compounds have been investigated. The results revealed that MV of GR (GMV), and its intermediate Monascus wine (GMW), exhibited the highest amount of aroma, not only in the concentrations but also in the varieties of the aromatic compounds mainly contributing to the final fragrance. Especially after three years of aging, the contents of benzaldehyde and furfural in GMV could reach to 13.93% and 0.57%, respectively, both of which can coordinate synergistically on enhancing the aroma. We also found that the filtering efficiency was significantly improved when UR and GR were applied as the raw materials, respectively. Therefore, GR might be more suitable raw materials for MV.

Heavy metal contamination and health risk assessment in grains and grain-based processed food in Arequipa region of Peru

Heavy metals (HMs) in crops and processed foods are a concern and pose a potential serious health hazard. This study investigated possible presence of HMs in grains and processed products in the Region of Arequipa in Peru. Concentrations of Cd, As, Sn, Pb, and Hg were determined for commonly consumed grains in 18 districts of the region and processed products from 3 popular markets of Arequipa city, using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Cold Vapor Atomic Absorption Spectroscopy (CVAAS). HM concentrations above the Codex General Standard limits were found for As (0.17 mg kg−1) and Cd (0.11 mg kg−1) in cereal grains. Elevated Pb concentrations of 0.55, 0.75, and 5.08 mg kg−1 were found for quinoa, maize, and rice products, respectively; and attributed to processing conditions. The Total Hazard Index (HI) for polished rice and rice products had values between 1 and 10, showing non-carcinogenic adverse effects. Total Target Cancer Risk (TRT) and uncertainty analysis of percentile P90% for polished rice and quinoa products gave values above permissible limit of 10−4, indicating an unacceptable cancer risk. The Nemerow Composite Pollution Index method (NCPI) showed that processed products had a significant pollution level due to the presence of Pb. While most crops grains had acceptable low HM levels, this is the first report of concerning HM concentrations in some consumed grains and processed products in southern Peru and indicates the necessity to find ways to decrease certain toxic metals in foods.

Diversity analysis of the rice cultivars ( Oryza sativa L.) by utilizing SSRs rice diversity by SSRs

This study was carried out to analysis of genetic diversity of rice marketed in Turkey. Sixty rice varieties used as a material. A total of 50 SSR markers distributed to all 12 rice chromosomes were used for the diversity analysis of the genotypes. Out of these, 43 SSRs produced clear, distinct polymorphic bands among the rice varieties, and a total of 227 alleles were obtained. The number of alleles per locus ranged from 9 to 1. The mean number of alleles per locus was 5.25, and 22 markers (51%) had 6 or more alleles. Clustering of 60 varieties based on 43 SSR markers was carried out. While aromatic varieties were placed into an out-group Rocca and Baldo which are parents of many rice varieties and 47 varieties were placed into the same clusters. This SSR polymorphism analysis revealed genomic relationships in rice marketed in Turkey. Practical applications Results of this study could be used to diversity analysis of rice and other crops and rice breeding programs. It could be used to study genetic diversity of polished rice at the market and consumer preference by countries.

Patient-Centric Assessment of Thiamine Status in Dried Blood Volumetric Absorptive Microsamples Using LC-MS/MS Analysis.

Many populations in low- and middle income countries are at a higher risk of thiamine deficiency, mainly due to the lack of dietary diversification and their reliance on staple crops low in thiamine content, such as polished rice. Unfortunately, symptoms of thiamine deficiency are variable and clinical determination of thiamine status is essential for early diagnosis. Currently, the diagnosis of thiamine deficiency in remote regions is hampered due to several drawbacks related to venous blood collection, for example, cold chain transport. Therefore, we here describe the first liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of thiamine diphosphate (TDP) in dried blood, using volumetric absorptive microsampling (VAMS). Moreover, by setting up an additional method in liquid blood, the results in VAMS samples could be compared to liquid blood samples. Both methods, employing a simple one-step extraction and fast (2 min) chromatography, were fully validated based on international guidelines. Accuracy (% bias) was below 6.5% for all QC levels. The total imprecision (% CV) was below 13% for both QCs and native blood samples. The recovery of the VAMS samples was not impacted by the hematocrit, within the hematocrit range of 0.20-0.60. Additionally, we showed improved TDP stability in dried blood compared to liquid blood. VAMS samples were stable for 1 week at 60 °C or at high humidity (80%) and for at least 1 month at room temperature. Finally, we demonstrated the commutability of commercial calibrators with authentic blood samples. The validity and applicability of both methods were demonstrated via their successful application on blood samples from healthy volunteers.

Effect of Total Mixed Ration Based Complete Pellet Feed on the Performances of Stall Fed Native Sheep

A complete pellet feed was developed using 40 % roughage (Rice straw) and 60 % concentrate (Rice polish 50 %, Maize crush 16 %, Soybean meal 20 %, Molasses 10 %, Salt 2 %, DCP 1 %, Vitaminmineral premix 0.5 %, Pellet binder 0.5 %) for commercial sheep production under stall feeding system. To know the effect of complete pellet feed on animal performances, both on-station and on-farm trials were conducted in growing sheep. The results of the experiment demonstrated that in the traditional system of rearing; only 22.42 g daily weight gain was observed. While, feeding of complete pellet feed achieved 84.98 g, and 100.67 g daily weight gain at on-farm and on-station condition respectively suggesting that pelleting enhanced the efficiency of utilization of feed. However, no differences were observed for the feed cost per kg weight gain, feed conversion ratio (FCR) and benefit-cost ratio (BCR) among the pellet feeding group and other group. But results suggest that complete pellet feed would be more economical for commercial sheep production under the stall-fed condition and farmers would be more benefited using complete pellet feed compared to conventional grass or urea molasses straw (UMS) and concentrate based feeding system. No disease or clinical symptoms were observed in the animals during the experimental period, suggesting that pellet feeds are well accepted by the sheep and results in better growth rate.
 SAARC J. Agri., 18(2): 157-166 (2020)

A Short Review: Bioactivity of Fermented Rice Bran.

Rice bran is a by-product of the rice milling process, which refers to the processing of brown rice into polished rice. It contains a considerable amount of functional bioactive compounds. However, the utilization of these compounds is limited and calls for an effort to ferment rice bran. One of the methods that can significantly increase the added value of rice bran as well as its bioactivity is the solid-state fermentation. It can also be one of the strategies that help in the production of rice bran as a functional ingredient with higher bioactivity for health promotion.

Detection and Analysis of the Quality Characters of Yunnan Soft Rice in South Henan Province

Taking the 38 Yunnan soft rice germplasm resources introduced from South Henan as experimental materials, the appearance quality, grinding quality, nutrition quality, cooking and eating quality of soft rice in South Henan were tested and analyzed by huller, rice polisher and near-infrared grain analyzer, combined with biochemical and physical-chemical analysis techniques. The results showed that there were rich variation types in chalkiness rate, chalkiness area, chalkiness degree, grain length, grain width, length width ratio, brown rice rate, milled rice rate, whole milled rice rate, protein content, total amino acid content, total essential amino acid content, amylose content, taste value and gelatinization temperature. In particular, the total amino acid content, the total essential amino acid content, chalkiness character, grain type and gelatinization temperature in soft rice varied widely.

Sake (Rice Wine) Brewing Hydrolyzes Highly Polar Sphingolipids to Ceramides and Increases Free Sphingoid Bases.

In plants and fungi, sphingolipids, characterized by the presence of a sphingoid base (SB), comprise neutral classes, including ceramide (Cer) and glucosylceramide (GlcCer), and acidic classes, including glycosyl inositol phosphoryl ceramide (GIPC). The major class of plant and fungal sphingolipids is GIPC; however, owing to their complicated extraction and analysis, there is still little information regarding the food characteristics of GIPC compounds. In the present study, we evaluated the content and SB composition of highly polar sphingolipids (HPS) in materials that had been obtained from our previous food processing study for GlcCer and Cer. This assessment was based on the changes that occur in HPS containing GIPC in sake rice (saka-mai) during the rice polishing and sake (rice wine) brewing process. In addition, we report a new investigation into the composition of sphingolipids in koji rice and sake yeast. HPS levels were the highest among the sphingolipid classes in brown rice cultivars and highly polished rice. Sake and sake lees (sake-kasu) were produced using three different starter cultures. In sake lees, Cer levels were the highest among the classes, while HPS was greatly reduced based on the amount of highly polished rice and koji rice, and these HPS were mainly composed of sphinganine (d18:0), which is a minor SB in highly polished rice, koji rice, and sake yeast. In addition, considerable levels of free SBs, mainly comprising d18:0, were detected in sake lees. The levels of HPS and free SBs in sake lees were dependent on the starter culture. These results suggest that HPS was hydrolyzed to Cer and that sake yeast also affected the levels of Cer and free SBs during brewing. One interesting question raised by these results is whether changes in the class and base compositions of sphingolipids during brewing contribute to taste of the final product and other food functions.

Sphingolipid Properties in Sake Rice Cultivars and Changes During Polishing and Brewing.

Sphingolipids, including ceramide (Cer) and glucosylceramide (GlcCer), have the characteristic structural units called sphingoid bases, and are constituents of cell and vacuole membranes. Plant sphingolipids bear highly diverse base structures and the base composition differs depending on the plant species. It is thought that the composition of sphingolipid classes and sphingoid bases is related to membrane fractions. However, there is little information about differences in sphingolipids among plant cultivars and the changes occurring in sphingolipids during food processing. This study investigated sphingolipids in sake rice (saka-mai) cultivars grown for sake (rice wine), and the changes in sphingolipids during polishing and brewing. In six brown rice samples, there were no large differences of the base composition among Cer or GlcCer of cultivars, whereas there were differences in their sphingolipid contents. When compared to brown rice, highly polished rice contained lower levels of sphingolipids, especially Cer. For three rice brans from different polishing steps, the Cer content was higher in the outer bran than in the inner bran. Sake and sake lees (sake-kasu) were produced by three different starter cultures (shubo preparations: the mixture of koji rice as an enzyme cocktail containing amylases, sake yeast, and adding rice as a carbohydrate source). The Cer/GlcCer ratio in sake and sake lees depended on the starter culture; Cer and GlcCer in sake lees possessed a fungi-specific base, 9-methyl-trans-4,trans-8- sphingadienine. In addition, sake lees had a higher Cer/GlcCer ratio when compared to highly polished rice as a sake source. These results suggest that the sphingolipid content of brown rice differs depending on the rice cultivar; further, the sphingolipids and the sphingolipid composition in sake and sake lees are affected by fungal sphingolipids and self-digestion during brewing.

Impact of degree of polishing on technological and biochemical grain quality traits of rice varieties of Russian breeding

The article presents the results of evaluation of rice varieties grown in the conditions of Krasnodar region by technological and biochemical quality traits in connection with the degree of grain polishing. The experiments were carried out in the laboratory of grain quality of Federal Scientific Rice Centre, Krasnodar. Grain of four rice varieties of Russian breeding (Rapan, Flagman, Polevik and Olimp) was subjected to five different degrees of polishing (0 %, 10 %, 12 % and 14 %). The degree of polishing significantly (P≤0.05) influenced the total yield of polished rice, head rice content, and the content of protein and amylose. An increase in the degree of polishing led to a further decrease in the protein content, total yield of polished rice and head rice content in it. However, an increase in the amylose content was found for simulated samples. With an increase in the degree of polishing to 14%, the amylose content increased in varieties Rapan, Flagman, Polevik and Olimp, respectively, by 1.3 %, 1.4 %, 1.5 % and 1.2 %, the protein content decreased by 1.5 %, 1.7 %, 1.6 %, 1.7 %.

Micronutrients and phytochemicals content in various rice (Oryza sativa Linn.) samples control carbohydrate digestion variedly and present differential antioxidant activities: an in vitro appraisal

High starch and carbohydrate content in rice ( Oryza sativa Linn.) disparages this food responsible for postprandial hyperglycemic excursions. However, rice is an Asian food synonym. Additionally, in traditional Indian healing practices, rice is used for treatment of various disorders. In this research, we analyzed micronutrient and phytochemical contents in different rice samples available in market. Effect of aqueous-ethanol extract of each type of rice was evaluated against intestinal α-glucosidase to examine extract’s influence on carbohydrate digestion. Free-radicals scavenging activities as a measure of antioxidant potential in different rice were also examined. Brown-rice presented highest (54%) α-glucosidase inhibition followed by parboiled-rice (52%), idly-rice (48%), hand-pounded rice (42%), dosa-rice (40%) and basmati-rice (39%). Polished white sona-masoori rice presented least enzyme inhibitory (31%) activity. Presence of higher α-glucosidase inhibitory activity was regarded as slow digesting rice that would impart lesser postprandial glycemic excursion. Brown and parboiled-rice presented highest ABTS֗ + radical scavenging (74%) activity whereas; idly-rice displayed highest DPPH scavenging (50%) activity. Higher polyphenol and niacin contents in rice were found significantly (p<0.0001 and p<0.01 respectively) correlated with enzyme inhibitory activity. Higher polyphenol content was found responsible for enhanced free-radicals scavenging activity. Increasing concentrations of niacin and pantothenic acid correlated with ABTS֗ + radical scavenging activity.

Fate of Organophosphorus Flame Retardants in Polished Rice during the Cooking Process

The fate of organophosphorus flame retardants (PFRs) in polished rice during the cooking process was examined. After adding PFRs to polished rice (500 ng/g), the rice was washed with water and cooked in a rice cooker. Among the seven kinds of PFRs, approximately 68-86% of the PFRs residues were removed after washing with water three times. In the first washing with water, approximately 50-70% of the PFRs residues were removed from rice. By the subsequent heating in an electric rice cooker or in a microwave rice cooker, the removal rates of PFRs in the cooked rice were 74-94 and 78-96%, respectively. The removal rates in musenmai (500 ng/g) which need not to wash before cooking were lower than those in the washed rice. In the cooked musenmai, 10-50% of the PFRs residues were removed after heating in the electric rice cooker, and 10-70% were removed in the microwave rice cooker. The washing process is effective to reduce the intake of PFRs from rice.

Development of thiamine-rich snacks from brown rice using extrusion technology

PurposeSnack industry is one of the fastest growing food sectors globally, and people are nowadays conscious about intake of healthy snacks on regular basis. There is enormous variety of ready-to-snacks available in the market. Brown rice though highly nutritious in comparison to polished rice is consumed meagerly by masses. Each raw material/ingredient used in extrusion cooking requires specific control of processing variables to meet acceptable product characteristics and consumer demands, which in turn necessitates the need to optimize the conditions for development of brown-rice-based snacks. The aim of this study was to optimize the extrusion cooking conditions for development of brown-rice-based extrudates.Design/methodology/approachExtrusion conditions were optimized through design expert using central composite rotatable design (CCRD) experimental design. The effect of feed moisture (10–22%), screw speed (215–385 rpm) and barrel temperature (95–160 °C) on specific mechanical energy (SME), bulk density (BD), water absorption index (WAI), water solubility index (WSI), expansion ratio (ER), breaking strength (BS) and instrumental color (L*, a*, b*) was evaluated.FindingsAll the system and product responses were significantly (p < 0.01) affected by independent variables. Regression models obtained were highly significant with high coefficient of determination (R2 = 0.992). The optimum extrusion conditions obtained by numerical optimization for development of snacks were moisture content of 12%, screw speed of 350 rpm and temperature of 133 °C. The vitamin B1 content of brown-rice-based snacks was 0.45 mg/100 (50% of RDA) whereas no vitamin B1 was detected in white-rice-based snacks used as control.Practical implicationsThe developed snacks contain 0.45 mg/100 g of vitamin B1. If a person on an average consumes 150 g of snacks in a day, 50% of RDA (1.2 mg/day) for vitamin B1 can be sufficed. Therefore, developed snacks can prove to be a viable vehicle to reduce the vitamin B1 deficiency burden among the target population. Large-scale production and consumption of such type of snacks could improve the nutritional status of vitamin B1 deficient people. Furthermore, it can also provide a good opportunity for snack industry to develop nutritious snacks through utilization of brown rice.Originality/valueBrown rice flour contains nutrients such as iron, calcium, zinc, sodium and vitamin B1 in appreciable portions and was thus explored for development of nutritious snacks. Moreover, developed snacks recorded an overall acceptability of 4.70 out of 5, which depicts it is acceptable for mass production and consumption.

Determination and Evaluation of Se-Rich High-Quality Rice Produced by Compound Nutrient Solution

Rice is one of the most important food crops in the world. Its biggest flaw is the low content of protein and essential amino acids, which severely limits its nutritional value. In order to produce high-quality rice with rich Se, we sprayed different concentrations of compound nutrient solution (containing Se (selenium), amino acid compound, zinc and boron) on the rice at different growth stages; and then determined the main nutrient content of their polished rice. The results showed that spraying low concentration compound nutrient solution (Each liter contained 20 mg of Se, 333 mg of complex amino acids, 33 mg of zinc and 33 mg of boron) to rice in the heading stage produced rice with the highest total starch and fat content and lower amylose content. Spraying high concentration compound nutrient solution to rice during the filling stage produced rice with the highest Se content. Multiple sprays of compound nutrient solution produced rice with low protein and low starch. Spraying low concentration compound nutrient solution on rice in milky stage significantly increased the content of protein, total starch, fat, all essential amino acids (Lysine increased by more than 57%), amylopectin and Se in rice; significantly reduced amylose content; significantly improved the nutritional value and taste quality of rice. The conclusion is that spraying low concentration compound nutrient solution on rice in the milky stage can produce rice with the highest content of protein and essential amino acids, higher content of total starch, fat and Se, and the lowest amylose content; significantly improve the nutritional value and taste quality of rice. The technical solution can comprehensively and effectively improve the nutritional value and flavor quality of rice, and has great development and application value.

Aktivitas Antioksidan, Kadar Serat dan Karakteristik Fisik Beras Hitam Pecah Kulit Pratanak dengan Variasi Lama Waktu Perendaman

Black rice has a better bioactive component than white rice. The quality of black rice can be increased, among others, through the process of the broken skin grinding . B lack br oken r ice has a better nutritional and bioactive component than polished rice. But b lack b roken rice skin is easily damaged. One that can be done is processing into parboiled rice. The purpose of this study in general was to determine antioxidant activity, fiber content and the characteristics of black rice broken pre pared skin. The experimental design used was a monofactor Completely Randomized Design (RAL) with variations in the length of immersion time (0, 30, 60, 90, 120, 150 and 180 minutes). Analysis was carried out on antioxidants, fiber content and physical characteristics (cage density, air absorbency, development ratio, bulk angle and broken grain) black broken rice skin with parboiled. The results of the study stated that the treatment of soaking black rice caused a decrease in antioxidant activity and crude fiber. The highest decreased in the 180 minutes immersion treatment with a decrease in presentation was 35% and 10,2% respectively, the results of testing on physical characteristics showed immersion treatment had an effect on decreasing in the kamba density test, development ratio, bulk angle and broken grain. However, the water absorption test experienced an increase. The best treatment is in a variation of 30 minutes soaking time.

Effect of replacement of corn in feed with polished rice or combined polished rice and rice bran feeding on pork quality

Effect of replacement of corn in feed with polished rice or combined polished rice and rice bran feeding on pork quality