Showing papers on "Brown rice published in 2022"

Genes and Their Molecular Functions Determining Seed Structure, Components, and Quality of Rice

Abstract: With the improvement of people's living standards and rice trade worldwide, the demand for high-quality rice is increasing. Therefore, breeding high quality rice is critical to meet the market demand. However, progress in improving rice grain quality lags far behind that of rice yield. This might be because of the complexity of rice grain quality research, and the lack of consensus definition and evaluation standards for high quality rice. In general, the main components of rice grain quality are milling quality (MQ), appearance quality (AQ), eating and cooking quality (ECQ), and nutritional quality (NQ). Importantly, all these quality traits are determined directly or indirectly by the structure and composition of the rice seeds. Structurally, rice seeds mainly comprise the spikelet hull, seed coat, aleurone layer, embryo, and endosperm. Among them, the size of spikelet hull is the key determinant of rice grain size, which usually affects rice AQ, MQ, and ECQ. The endosperm, mainly composed of starch and protein, is the major edible part of the rice seed. Therefore, the content, constitution, and physicochemical properties of starch and protein are crucial for multiple rice grain quality traits. Moreover, the other substances, such as lipids, minerals, vitamins, and phytochemicals, included in different parts of the rice seed, also contribute significantly to rice grain quality, especially the NQ. Rice seed growth and development are precisely controlled by many genes; therefore, cloning and dissecting these quality-related genes will enhance our knowledge of rice grain quality and will assist with the breeding of high quality rice. This review focuses on summarizing the recent progress on cloning key genes and their functions in regulating rice seed structure and composition, and their corresponding contributions to rice grain quality. This information will facilitate and advance future high quality rice breeding programs.

Genes and Their Molecular Functions Determining Seed Structure, Components, and Quality of Rice

Abstract: With the improvement of people's living standards and rice trade worldwide, the demand for high-quality rice is increasing. Therefore, breeding high quality rice is critical to meet the market demand. However, progress in improving rice grain quality lags far behind that of rice yield. This might be because of the complexity of rice grain quality research, and the lack of consensus definition and evaluation standards for high quality rice. In general, the main components of rice grain quality are milling quality (MQ), appearance quality (AQ), eating and cooking quality (ECQ), and nutritional quality (NQ). Importantly, all these quality traits are determined directly or indirectly by the structure and composition of the rice seeds. Structurally, rice seeds mainly comprise the spikelet hull, seed coat, aleurone layer, embryo, and endosperm. Among them, the size of spikelet hull is the key determinant of rice grain size, which usually affects rice AQ, MQ, and ECQ. The endosperm, mainly composed of starch and protein, is the major edible part of the rice seed. Therefore, the content, constitution, and physicochemical properties of starch and protein are crucial for multiple rice grain quality traits. Moreover, the other substances, such as lipids, minerals, vitamins, and phytochemicals, included in different parts of the rice seed, also contribute significantly to rice grain quality, especially the NQ. Rice seed growth and development are precisely controlled by many genes; therefore, cloning and dissecting these quality-related genes will enhance our knowledge of rice grain quality and will assist with the breeding of high quality rice. This review focuses on summarizing the recent progress on cloning key genes and their functions in regulating rice seed structure and composition, and their corresponding contributions to rice grain quality. This information will facilitate and advance future high quality rice breeding programs.

Comparing the LC-MS Phenolic Acids Profiles of Seven Different Varieties of Brown Rice (Oryza sativa L.)

Abstract: Brown rice, an important material of whole-grain food, is increasingly popular for its health benefits. Thus, seven varieties of brown rice from southern China were analyzed in this study, concerning the free and bound phenolic compounds in the extract. The phenolic profiles of different brown rice were obtained and compared by the combination of HPLC and LC-MS analysis, in which eleven phenolic acids were identified. It was indicated that the total phenolic contents of different brown rice varied from 92.32 to 196.54 mg of gallic acid equivalent (GAE)/100 g DW. Ferulic acid and p-coumaric acid, free and bound, dominated within the phenolic acids. To be mentioned, the total phenols of Luotiangongmi (a kind of red rice) were significantly higher than the other six varieties. The high phenolic content of brown rice can further guide us to explore the functional properties of the crops.

Goethite modified biochar simultaneously mitigates the arsenic and cadmium accumulation in paddy rice (Oryza sativa) L

Abstract: Cadmium (Cd) and arsenic (As) contamination of paddy soils is a serious global issue because of the opposite geochemical behavior of Cd and As in paddy soils. Rice plant (Oryza sativa L.) cultivation in Cd- and As- contaminated paddy soil is regarded as one of the main dietary cause of Cd and As entry in human beings. This study aimed to determine the impact of goethite-modified biochar (GB) on bioavailability of both Cd and As in Cd- and As- polluted paddy soil. Contrary to control and biochar (BC) amendments, the application of GB amendments significantly impeded the accumulation of both Cd and As in rice plants. The results confirmed an obvious reduction in Cd and As content of rice grains by 85% and 77%, respectively after soil supplementation with GB 2% amendment. BC 3% application minimized the Cd uptake by 59% in the rice grains as compared to the control but exhibited a little impact on As accumulation in rice grains. Sequential extraction results displayed an increase in immobile Cd and As fractions of the soil by decreasing the bioavailable fractions of both elements after GB treatments. Fe-plaque formation on the root surfaces was significantly variable (P ˂ 0.05) among all the amendments. GB 2% treatment significantly increased the Fe content (10 g kg-1) of root Fe-plaque by 48%, which ultimately enhanced the sequestration of Cd and As by Fe-plaque and minimized the transport of Cd and As in rice plants. Moreover, GB treatments significantly changed the relative abundance of the microbial community in the rice rhizosphere and minimized the metal(loid)s mobility in the soil. The relative abundance of Acidobacteria, Firmicutes and Verrucomicrobia increased with GB 2% treatment while those of Bacteroidetes and Choloroflexi decreased. Our findings confirmed improvement in the rice grains quality regarding enhanced amino acid contents with GB application. Overall, the results of this study demonstrated that GB amendment simultaneously alleviated the Cd and As concentrations in edible parts of rice plant and provided a new valuable method to protect the public health by effectively remediating the co-occurrence of Cd and As in paddy soils.

Combined amendment reduces soil Cd availability and rice Cd accumulation in three consecutive rice planting seasons

Abstract: The scientific application of stabilized materials has been considered an effective method for the in situ remediation of Cd-contaminated soil. This study aimed to investigate the persistence of the effect of a combined amendment of limestone and sepiolite (LS) on soil Cd availability and accumulation in rice grown in a mildly Cd-contaminated paddy field (0.45 mg/kg of Cd) over three consecutive rice seasons. 1125–4500 kg/ha of LS was applied to the soil before the first rice planting season and 562.5–2250 kg/ha of LS was supplemented before the third rice planting season. The application of LS (1125–4500 kg/ha) increased the soil pH by 0.44–1.09, 0.18–0.53, and 0.42–0.68 in the first, second, and third season, respectively, and decreased the soil acid-extractable Cd content by 18.2–36.4%, 17.7–33.5%, and 9.6–17.6%. LS application significantly decreased the Cd contents in the rice tissues. The application of 4500 kg/ha of LS decreased the Cd content in brown rice to below the National Food Limit Standard of 0.2 mg/kg (GB 2762-2017) in the three consecutive rice seasons. However, the effect of LS on the soil-rice system was significantly weakened in the third season. The supplementary application of 562.5–2250 kg/ha of LS further decreased the Cd content in brown rice by 26.1–56.5% and decreased the health risk index by 23.7–43.8%. Therefore, it was recommended to apply 4500 kg/ha of LS in the first season and to supplement 2250 kg/ha of LS in the third season to effectively guarantee the clean production of rice in three consecutive rice seasons.

Combined amendment reduces soil Cd availability and rice Cd accumulation in three consecutive rice planting seasons

Abstract: The scientific application of stabilized materials has been considered an effective method for the in situ remediation of Cd-contaminated soil. This study aimed to investigate the persistence of the effect of a combined amendment of limestone and sepiolite (LS) on soil Cd availability and accumulation in rice grown in a mildly Cd-contaminated paddy field (0.45 mg/kg of Cd) over three consecutive rice seasons. 1125-4500 kg/ha of LS was applied to the soil before the first rice planting season and 562.5-2250 kg/ha of LS was supplemented before the third rice planting season. The application of LS (1125-4500 kg/ha) increased the soil pH by 0.44-1.09, 0.18-0.53, and 0.42-0.68 in the first, second, and third season, respectively, and decreased the soil acid-extractable Cd content by 18.2-36.4%, 17.7-33.5%, and 9.6-17.6%. LS application significantly decreased the Cd contents in the rice tissues. The application of 4500 kg/ha of LS decreased the Cd content in brown rice to below the National Food Limit Standard of 0.2 mg/kg (GB 2762-2017) in the three consecutive rice seasons. However, the effect of LS on the soil-rice system was significantly weakened in the third season. The supplementary application of 562.5-2250 kg/ha of LS further decreased the Cd content in brown rice by 26.1-56.5% and decreased the health risk index by 23.7-43.8%. Therefore, it was recommended to apply 4500 kg/ha of LS in the first season and to supplement 2250 kg/ha of LS in the third season to effectively guarantee the clean production of rice in three consecutive rice seasons.

Effect of slightly acidic electrolyzed water on amino acid and phenolic profiling of germinated brown rice sprouts and their antioxidant potential

Abstract: This study investigated the effectiveness of slightly acidic electrolyzed water (SAEW ACC-10 ppm) on the accumulation of total flavonoids content, total phenolic content, antioxidants, and bioactive compounds over the tap and distilled water during germination. Germination was carried out with moisture content (20–30%) at 35 ± 1 °C in Co2 incubator using tap water, distilled water, and SAEW pH-5.5, ACC-10 ppm. SAEW was used to decontaminate natural microbiota from the rice outer layer and to check its effect on rice bioactive components. Nevertheless, after 48 h, SAEW germination showed detrimental effects on germination potential and germination rate in brown rice. The germination enhanced GABA content from 1.8 mg/L to 7.35 mg/L showing an increase of about three times. HPLC-FLD-MS/MS and UHPLCQ-TOF- MS/MS approaches were applied to analyze amino acids & phenolics in brown rice samples. In our study, germination using SAEW affected GABA content and enhanced other amino acids, antioxidants, and phenolic compounds such as ferulic acid, p-coumaric acid, quercetin, and ascorbic acid as compared with the raw, tap, and distilled water germination. Results indicated that SAEW in germination might enhance the bioactive compounds of grains so it can be utilized for germination and functional food production safely in the food sector.

Impact of germination alone or in combination with solid-state fermentation on the physicochemical, antioxidant, in vitro digestibility, functional and thermal properties of brown finger millet flours

Abstract: The impact of germination alone or in combination with solid-state fermentation on the physicochemical, antioxidant, in vitro digestibility, functional, and thermal characteristics of brown finger millet were evaluated. Germination and fermentation increased (p ≤ 0.05) the protein, crude fiber, minerals, resistant starch (7.64–9.69 g/100g), total flavonoid content, total phenolic content, antioxidant properties (ABTS, DPPH and FRAP), majority of the amino acids as well as in vitro protein digestibility (67.72–89.53%), while antinutritional factors and digestible starch (from 45.17 to 35.58 g/100 g) content decreased significantly. Germination and fermentation significantly increased water absorption capacity and protein solubility, and slightly modified the pasting and thermal characteristics of brown finger millet flour while bulk density decreased. Among the treatments, combined germination and fermentation greatly improved the physicochemical, antioxidant, functional and processing properties of the flour with reduced antinutrients. Such combined process could enhance the use of brown finger millet as a novel flour in food product development.

Impact of germination alone or in combination with solid-state fermentation on the physicochemical, antioxidant, in vitro digestibility, functional and thermal properties of brown finger millet flours

Abstract: The impact of germination alone or in combination with solid-state fermentation on the physicochemical, antioxidant, in vitro digestibility, functional, and thermal characteristics of brown finger millet were evaluated. Germination and fermentation increased (p ≤ 0.05) the protein, crude fiber, minerals, resistant starch (7.64–9.69 g/100g), total flavonoid content, total phenolic content, antioxidant properties (ABTS, DPPH and FRAP), majority of the amino acids as well as in vitro protein digestibility (67.72–89.53%), while antinutritional factors and digestible starch (from 45.17 to 35.58 g/100 g) content decreased significantly. Germination and fermentation significantly increased water absorption capacity and protein solubility, and slightly modified the pasting and thermal characteristics of brown finger millet flour while bulk density decreased. Among the treatments, combined germination and fermentation greatly improved the physicochemical, antioxidant, functional and processing properties of the flour with reduced antinutrients. Such combined process could enhance the use of brown finger millet as a novel flour in food product development.

An HS-GC-IMS analysis of volatile flavor compounds in brown rice flour and brown rice noodles produced using different methods

Abstract: In this study, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and principal component analysis (PCA) were used to analyze the volatile flavor compounds in brown rice flour (BRF) and brown rice noodles (BRNs) prepared by different methods. White rice flour (WRF) and white rice noodles (WRNs) were used for comparison. The results revealed significant differences in volatile flavor compounds between BRFs and BRNs, and the types of volatile flavor compound in BRF were more than WRF. Compared with WRF, aldehydes increased in the BRF produced by refilling. The primary volatile flavor compounds of brown rice flour made by crushing brown rice fully (BRF-F) were 2-acetyl-1-pyrroline, 6-methyl-5-hepten-2-one, 2-heptanone, 2,3-butanedione, 2-octanone, 2-butanone, 1-hexanol, 1-pentanol, ethanol, 2-methylbutanol, 3-methylbutanol, and 2-methylpropanol. Ethyl acetate was found in all rice flour and rice noodle samples. The contents of 2-methylpropanol, 2-hexanone, 2-methylbutanal, 3-methylbutanal, ethanol and acetone increased after processing rice flour into rice noodles, while the contents of 2-acetyl-1-pyrroline, 6-methyl-5-hepten-2-one, 1-hexanol, 2-heptanone, 1-pentanol and 2,3-butanedione decreased. This research demonstrated the promising application of extrusion in fabricating brown rice flour with satisfactory flavor preservation for refilling in WRF.

In vitro gastric digestion and emptying of cooked white and brown rice using a dynamic human stomach system

Abstract: In this study, a dynamic in vitro human stomach system was employed to elucidate the influence of structural differences between white and brown rice on gastric emptying and starch digestion. The evolution of gastric digesta particle size distribution, pH, viscosity and starch hydrolysis was investigated during digestion. Due to the protective effect of the outer bran layer against structural breakdown, brown rice showed higher pH buffering capacity, larger digesta particle size and greater rheology, resulting in a delayed gastric emptying and consequently, lower starch hydrolysis in an overall starch digestibility in the stomach than the white rice. The current study has provided quantitative evidence regarding the importance of macrostructure (i.e. the bran layer) in rice gastric digestion that may further impact intestinal absorption. Meanwhile, the particle size was significantly smaller in the digesta emptied out of the stomach in both white and brown rice throughout the digestion compared to that retained in the stomach. This demonstrates an effective size reduction and sieving efficiency exhibited by the in vitro system. It is practically meaningful to use the in vitro system to track the dynamic changes in structural and physicochemical properties of food materials during digestion in the stomach.

Germination of five Indonesian brown rice: evaluation of antioxidant, bioactive compounds, fatty acids and pasting properties

Abstract: Germination can alter the physicochemical, nutritional, and nutraceutical value of brown rice. This study aimed to evaluate some characteristic changes from five Indonesian brown rice varieties during germination. The germination was carried out through a complete soaking method for up to 120 h, and the samples were taken and analyzed every 24 h. The results showed that germination increased GABA (γ-aminobutyric acid) content in brown rice. The highest level of GABA, up to 126.55 mg/100 g, obtained in rice var. Inpari 43, after 120 h. Germination also affected the changes in phenolic content, antioxidant capacity, and γ-oryzanol, while fatty acid compositions showed no changes. The pasting properties changed significantly after germination, especially in peak viscosity, final viscosity, breakdown, and setback. In conclusion, the changes in brown rice characteristics during germination, especially for increased GABA content and shifting of pasting properties, are valuable information for developing functional rice-based food products.

Functional properties, antioxidant activity and in-vitro digestibility characteristics of brown and polished rice flours of Indian temperate region

Abstract: The present investigation was aimed to study functional properties, antioxidant activity and in-vitro digestibility characteristics of brown and polished flours obtained from four rice cultivars (SR-4, K-39, Mushq Budij and Zhag) of Kashmir. Brown rice flours had higher total dietary fibre (3.08%–3.68%), oil absorption (116.0%–139.0%), emulsion capacity (4.78%–9.52%), emulsion stability (87.46%–99.93%) and resistant starch content (6.80%–9.00%) than polished flours. However, polished flours presented greater water absorption (102.0%–122.0%), foaming capacity (8.00%–13.63%), apparent amylose (19.16%–22.62%), peak (2260.0–2408.0 cP), trough (1372.0–1589.0 cP) and breakdown (714.0–978.0 cP) viscosities than their brown counterparts. Brown rice flours depicted highest total phenolic content (4.40–6.40 mg GAE/g) and inhibition of lipid peroxidation (19.50%–33.20%). However, equilibrium starch hydrolysis percentage (C∞) and predicted glycemic index of brown rice flours were lower than their polished counterparts. Among rice cultivars, brown Zhag flour had the highest total dietary fibre (3.68%), emulsion capacity (9.52%), emulsion stability (99.93%), resistant starch (9.00%), DPPH radical scavenging activity (85.45%) and inhibition of lipid peroxidation (33.20%), respectively. Emulsion capacity and emulsion stability were positively correlated with protein content of rice flours. However, peak, trough, breakdown and setback viscosities were negatively correlated with protein and fat contents of rice flour. The present investigation will be helpful in identifying nutritive role of rice flours from studied cultivars in human diet.

Selenium Decreases the Cadmium Content in Brown Rice: Foliar Se Application to Plants Grown in Cd-contaminated Soil

Abstract: Abstract Cadmium (Cd) contamination in agricultural soils has become a serious issue owing to its high toxicity threat to human health through the food chain. The purpose of this paper is to explore the availability of foliar selenium (Se) application in reducing Cd enrichment in brown rice. A field experiment from 2017 to 2019 was conducted to investigate the effects of foliar Se application on the physiology and yields of three rice cultivars and their accumulation of Cd in low-Cd and high-Cd soils. The grain protein contents and yields of rice plants grown in the high-Cd soil were lower than those of plants cultivated in the low-Cd soil by 27.85% and 6.82%, whereas the malondialdehyde (MDA) and Cd contents were higher by 66.06% and 91.47%, respectively. Se application reduced Cd translocation from the stems and leaves to the spikes, decreasing the Cd content in brown rice by 40.36%. Additionally, Se enhanced the antioxidative activity, glutathione and protein contents, and rice yield (7.58%) and decreased the MDA and proline contents. However, these Se effects weakened under the high-Cd soil. Foliar Se application can alleviate Cd-induced physiological stress in brown rice while improving its yield and reducing its Cd content.

Health-promoting germinated rice and value-added foods: a comprehensive and systematic review of germination effects on brown rice.

Abstract: Over the last 30 years, thousands of articles have appeared examining the effects of soaking and germinating brown rice (BR). Variable germination conditions and methods have been employed to measure different health-beneficial parameters in a diverse germplasm of BR. Research results may therefore appear inconsistent with occasional anomalies, and it may be difficult to reach consensus concerning expected trends. Herein, we amassed a comprehensive review on germinated brown rice (GBR), attempting to codify 133 peer-reviewed articles regarding the effects on 164 chemical parameters related to health and nutrition in BR and in value-added food products. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-2020) approach was used to direct the flow of the literature search. A pair-wise comparison t-test was performed to deliver an overall approach indicating when a given compound has been found to significantly increase or decrease through germination, which was grouped into GABA and polyamines, γ-Oryzanol and phytosterols, phenolic compounds, vitamins, proteins and amino acids, starchy carbohydrates, free sugars, lipids, minerals and phytic acid. This resource will stimulate interest in germinating rice and optimistically help increase both production and consumption of highly nutritious, health-beneficial rice with pigmented bran.

Effect of Large-Scale Paddy Rice Drying Process Using Hot Air Combined with Radio Frequency Heating on Milling and Cooking Qualities of Milled Rice

Abstract: The objectives of the study on a continuous flow hot air dryer combined with radio frequency heating at different temperatures (HA/RF) (38 °C, 42 °C, 46 °C, and 50 °C) in a large-scale process compared with conventional continuous flow hot air drying (HA) were (1) to investigate the drying characteristics, drying kinetics, and milling quality of the process and (2) to observe the cooking quality and compare the sensory differences of the cooked rice after treatment. The drying characteristics and moisture diffusivity showed that the higher the radio frequency (RF) heating temperature, the shorter the drying time. The specific energy consumption and energy cost decreased when the RF heating temperature increased. The optimal condition in terms of fissure percentage was HA/RF42. In addition, there were no significant differences in head rice yield and white rice color determination, amylose content, texture profiles, and pasting properties in all HA/RF treatments. In the triangle test, it was found that at least 6% of the population could perceive a difference between HA and HA/RF50. In conclusion, this study proposes the further development of the HA/RF drying process at low-temperature profiles and shows the great potential of RF technology for commercial drying in rice industry.