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The aim of this study has been to assess the composition and antioxidant activities of rice bran extracts submitted to a human simulated digestion, which extraction process was previously optimized. In order to adjust the optimum values for the extraction, D-optimal experimental design and response surface methodology have been applied. Phenolic compounds and γ-oryzanol contents have been used as response parameters. In this way, two different extracts have been obtained. The first one, was obtained with 100% water as solvent, and it was mainly composed by phenolic acids. Ferulic acid was the majority compound found with a concentration of 1.00 ± 0.03 mg/g extract, followed by p-coumaric acid (0.19 ± 0.02 mg/g), The second extract, extracted with ethanol as solvent, was a γ-oryzanol enriched fraction with a content of 14.41 ± 0.26 mg/g extract. The optimized rice bran extracts thus obtained were subjected to a process of human in-vitro digestion. In the first extract, with high polyphenol content, the phenolic content was oscillating during the digestion, like antioxidant activity. The oryzanol content found in this fraction (0.079 ± 0.002 mg/g) has not been detected in any phase of digestion. In the second extract, with a high oryzanol content at the beginning, oryzanol content was not detected in any of digestion steps. However, phenolic composition was stable in all phases of simulation (ranging from 0.117 and 0.094 mg/g in the case of ferulic acid). This fact evidence that oryzanol is not a bioavailability fraction, while phenolic compounds support to some extent, the conditions of digestion. [ABSTRACT FROM AUTHOR]

The aim of this study was to profile the polyphenol composition and antioxidant activity of 8 Australian-grown rice varieties. UHPLC with an online ABTS system was used to identify and quantify individual polyphenols present in the rice extract whilst simultaneously measuring their respective antioxidant activity. In addition, the synergistic antioxidant activity of the rice extracts was assessed using the ferric reducing ability of plasma assay (FRAP). The study found that the pigmented rice varieties had higher total antioxidant activity than the brown non-pigmented rice varieties. The red variety Yunlu29 had the highest FRAP total antioxidant activity (303.8 ± 16.16 mg 100 g −1 Trolox equivalents). UHPLC profile of Yunlu29 revealed a wide variety of active polyphenols. In particular, the chromatogram from the red rice variety Yunlu29, contained two unidentified peaks that exhibited the highest antioxidant activity. In the purple rice extract, cyanidin-3-glucoside and peonidin-3-glucoside were profiled as having the most free-radical scavenging activity. In comparison, the brown non-pigmented rice extracts did not exhibit substantial antioxidant activity in its polyphenol UHPLC profile. The results of this study demonstrate the antioxidant potential of polyphenols present in Australian-grown pigmented and non-pigmented rice varieties which may have a future role as a potential functional food ingredient. [ABSTRACT FROM AUTHOR]

This study investigated changes in the phenolic composition, total antioxidant activity (TAA) and starch digestibility in white and brown rice due to three different cooking procedures, and subsequent reheating of cooked rice after storage. Among the analyzed samples, brown rice showed the highest TAA and phenolic content (622.5 mg/kg DW). All cooking methods resulted in significant decrease of phenolic content and TAA of rice ( p < 0.05). The greatest loss was observed after processing in rice cooker, which reduced phenolic content of both brown and polished rice by ∼30% and ABTS radical-scavenging activity by 20 and 28%, respectively. In general, the levels of polyphenols and TAA of cooked rice tended to further decline after storage and reheating, but to a much lesser extent when rice was prepared using microwaves. The application of in vitro digestion system disclosed that the microwave cooking resulted in the highest starch digestibility among cooking methods used. Practical applications Rice is one of the most commonly consumed staple foods worldwide. Scientific and epidemiological studies have showed that their phytochemicals exhibit antioxidant, anti-inflammatory, antihypertensive and chemopreventive effects. Therefore, their high consumption, easy availability throughout the year and use as an additive to meat and high-fat foods may make rice, especially in the form of whole grains, potentially important chemopreventive component of the diet. The appropriate cooking procedure of rice is crucial for preservation of bioactive compounds as well as digestion of starch and thus duration of the glycemic response. Preferably, this study is focused on the evaluation of the effect of cooking methods on the health-related quality of rice. The results provide practical advice that the consumption of freshly cooked rice ensures its highest nutritional quality, while rice microwaving is recommended both when cooked rice will be reheated after storage (e.g., in restaurants) and accelerated starch digestion is in favor. [ABSTRACT FROM AUTHOR]

High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively proved that rice cultivar Kanchana respond to different environmental signals independently and tolerance mechanisms to individual stress factors was also varied. [ABSTRACT FROM AUTHOR]

The effects of polishing on proximate compositions, physico-chemical characteristics, mineral compositions and antioxidant properties of the rice flours obtained from three different pigmented rice varieties (Chak-hao Angangba, Chak-hao Amubi and Chak-hao Poireiton) were investigated. The rice varieties were significantly ( P < 0.05) different in the contents of the test characteristics. Lipids, ash, minerals, phytochemicals (phenolic acids and flavonoids) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity of rice flours were decreased after polishing (9% degree of milling), while amylose content and lightness were increased. X-ray diffraction pattern of rice flours exhibited A-type crystalline pattern with reflections at 15.1°, 17.1°, 18.2° and 23.0°. Pasting properties and transition temperatures were decreased after polishing treatment. Polishing resulted in changes in the crystallinity, enthalpy and morphology of rice flours. [ABSTRACT FROM AUTHOR]

Epidemiological and clinical studies suggest that the additive/synergistic effects of several bioactive compounds are responsible for the health benefits of rice. Among the leading contenders are phenolic acids, flavonoids, anthocyanins, proanthocyanidins, tocotrienols, tocopherols, λ-oryzanol, and phytic acid, which all possess strong antioxidant activities in vitro. In this review, data related to health effects of rice antioxidants using cultured cells, rodents and humans models are first summarized. The evidence is strong that consumption of rice tocotrienols translates into improved health outcomes. Current research, however, does not strongly support the health-promoting effects of rice tocopherols and phenolic acids. The crucial limitations in studies using rice flavonoids, anthocyanins, proanthocyanidins, λ-oryzanol and phytic acid appear to be the appropriateness of the substance tested (i.e., purity), and the scarcity of animal and human interventions. In a second part, rice antioxidants are reviewed with an emphasis on their composition and contents. Taking into account the bioavailability of these compounds, it is evident that a number of factors affect the antioxidant composition of rice, making it difficult to estimate dietary intake. Before harvest, factors including soil type, atmospheric CO2, chemical inputs, temperature, and degree of ripening are important. After harvest, rice is subjected to processing methods that include drying, parboiling, storage, irradiation, milling, stabilization, soaking, germination, fermentation, boiling, steaming, roasting, baking, and extrusion. Quantitative knowledge about the effects of these processes is summarized in this review. Surprisingly, a high level of agreement was found among study results, which could be useful in manipulating the growing and processing techniques of rice grains to facilitate efficient and safe consumption of antioxidant compounds. [ABSTRACT FROM PUBLISHER]

The paper was to explore the effect of rice blast resistance induced by Ag-antibiotic 702 on antioxidant enzyme activities and malondialdehyde (MDA) content. At three-leaf and one-hearL stage of Luliangyou 996, 15 μg/mL Ag-antibiotic 702 was sprayed, while Validamycin and distilled water were sprayed as positive control and negative control, respectively. The antioxidant enzyme (SOD, POD, PPO, CAT and PAL) activities and malondialdehyde (MDA) content in rice leaves were determined every 24 h within 168 h post spraying. Compared with CK, the MDA content and activities of the five antioxidant enzymes increased in Ag-antibiotic 702 treatment, Validamycin treatment and Af. grisea inoculation treatment. The MDA content and SOD, CAT and POD activities in Ag-antibiotic 702 treatment were significantly higher than those in M. grisea inoculation treatment in early stage, and the APX and LOX activities increased more remarkably and rapidly. The induction effect of Ag-antibiotic 702 could reach or exceed that of Validamycin treatment. Ag-antibiotic 702 enhanced the resistance to rice blast because MDA content and antioxidant enzymes activities were improved in rice leaves. Therefore, the increase of rice blast resistance induced by Ag-antibiotic 702 in rice was positively correlated with the increase of MDA content and antioxidant enzymes activities in rice leaves. [ABSTRACT FROM AUTHOR]

Recently, the isolation of new health-related bioactive molecules derived from agro-food industrial by-products by means of environment-friendly extraction processes has become of particular interest. In the present study, a protein by-product from the rice starch industry was hydrolysed with five commercial proteolytic enzymes, avoiding the use of solvents or chemicals. The digestion processes were optimised, and the digestates were separated in fractions with four different molecular weight ranges by using a cross-flow membrane filtration technique. Total hydrolysates and fractions were tested in vitro for a wide range of biological activities. For the first time rice-derived peptides were assayed for anti-tyrosinase, anti-inflammatory, cytotoxicity and irritation capacities. Antioxidant and anti-hypertensive activities were also evaluated. Protamex, Alcalase and Neutrase treatments produced peptide fractions with valuable bioactivities without resulting cytotoxic or irritant. Highest levels of bioactivity were detected in Protamex-derived samples, followed by samples treated with Alcalase. Based on the present results, a future direct exploitation of isolated peptide fractions in the nutraceutical, functional food and cosmetic industrial fields may be foreseen. [ABSTRACT FROM AUTHOR]

Black and red rices ( Oryza sativa L.) were analysed for total flavonoids and phenolics and the HPLC profile including both free and bound phenolic fractions. Moreover, antioxidant activity and in vitro digestibility was determined. Content of flavonoids and polyphenols as well as antioxidant activity was higher in free phenolic fractions. Bound flavonoids in black rices were not significant contributors to antioxidant activity. The main free phenolics in black rices were ferulic, protocatechuic and trans - p -coumaric acids, while the major free phenolics in red rices were catechin, protocatechuic and caffeic acids. The main bound phenolics in black rices were ferulic and vanillic acids and quercetin, in red rice types, they were ferulic, syringic, trans - p -coumaric acids and quercetin. Newly, the presence of m -coumaric acid in red rices was detected. Steam cooked rices showed very high levels of organic matter digestibility, whereas red rices were significantly more digestible than black rices ( p < 0.05). [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to focus on the antioxidant properties of two phenolic-rich varieties of Nigerian local rice and their anti-cholinesterase potential after in vitro-simulated gastrointestinal digestion, with the aim of establishing their actual antioxidant and nutraceutical potential after their passage through the gastrointestinal tract upon consumption. Design/methodology/approach – Two local rice varieties, commonly referred to as “Gboko” and “Ofada” rice commonly grown in Benue State, a middle belt region of Nigeria and south western regions of Nigeria, respectively, were locally processed. Each of the processed grains were divided into two portions; one portion was left uncooked, while the second portion was boiled conventionally as eaten, dried and subsequently milled into powder. The milled samples of the raw and boiled rice were treated with acidified methanol to obtain the methanol extracts; another portion of each samples was subjected to in vitro enzyme digestion using standard methods to mimic human digestion; and the third portion was treated using the same scheme of in vitro digestion without the sets of enzyme which was used to serve as a control for enzyme treatment. The quali-quantitative phenolic profiles of the two local varieties were carried out with the aid of high-performance liquid chromatography with diode-array detection (HPLC-DAD) method. The antioxidant potential and anti-cholinesterase action of the methanolic extracts, the simulated in vitro digested model and the enzyme-treated controls of the rice samples were determined using standard methods and data obtained were subjected to ANOVA; the differences of means were separated using Duncan’s multiple range test (DMRT). Findings – The quali-quantitative assessment of phenolic compounds in the two studied local varieties revealed the presence of some phenolic acids and flavonoids, with a decreased level of most of the identified phenolic compounds after boiling. In vitro enzyme-digested rice for both raw and boiled rice samples showed significantly higher total phenolic content, total flavonoid content, ferric-reducing antioxidant power, 2, 2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS+) scavenging and NO− inhibitory activities than the aqueous-methanolic extracts and the enzyme-treated controls. The aqueous-methanolic extracts displayed a higher 1, 1 diphenyl-2-picrylhdrazyl radical scavenging activity and inhibited Fe2+-induced lipid oxidation in rat’s brain and liver homogenate than that displayed by the in vitro enzyme-digested samples. In vitro enzyme-digested and boiled “Gboko” and “Ofada” rice and raw “Ofada” rice have the potential of inhibiting acetylcholine esterase (AChE) activity. While methanolic extracts of raw and boiled “Ofada” and “Gboko” rice exhibited the potential to inhibit butrylcholinesterase activity. The result of this paper indicates that the selected rice varieties possess antioxidant capacities which are better released after the simulated in vitro enzyme digestion; the result also showed the anti-cholinesterase potential of the studied rice grains and, therefore, they can be considered as nutraceutical health supplements. Originality/value – The paper has demonstrated the antioxidant potentials of the phenolic-containing two Nigerian local rice varieties and established their anti-cholinesterase potential after simulated in vitro enzyme digestion. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the effects of polishing and parboiling on proximate composition, structure, phenolic compounds, antioxidant activity, cooking time and hardness of IAC-600 black rice cultivar and MPB-10 red rice lineage. Proximate analysis and light micrographs revealed higher migration of red rice proteins than black rice proteins to the endosperm as a result of parboiling. Parboiling reduced the ash content of red rice while no difference was determined in black rice. Gelatinized starch granules from both genotypes showed similar appearance. There was a decrease in relative crystallinity on both black and red rice subjected to parboiling, which was an indicative of crystallites disruption. Polishing removed more than 90% of free phenolics for both genotypes, while parboiling allowed the partial preservation of free phenolics content in polished rice. Parboiling induced an increase in the cooking time of red rice, but a decrease in the cooking time of black rice. [ABSTRACT FROM AUTHOR]

This study was aimed the extraction of total flavonoids, anthocyanins and phenolics, as well as the antioxidant activity of black rice ( Oryza sativa ) and to study the stability in relation to pH, light and copigmentation. Variations in temperature (10–50 °C), time (20–80 min), and solid–solvent ratio (1:15–1:45) were studied using a Box–Behnken design. The regression models were significant ( P < 0.001) and determination coefficients ⩾0.900. Extraction at 34.7 °C for 80 min using a solid:solvent ratio of 1:30 rendered an extract with 51.26 mg 100 g −1 of flavonoids, 116.58 mg 100 g −1 of anthocyanins, 520.17 mg 100 g −1 of phenolics and 46.50% inhibition of the DPPH radical. A decrease in the color intensity was observed when pH values were changed while anthocyanins were reversible in the process of protonation/deprotonation. The addition of glucose, phytic and gallic acids in the optimized extract exposed to light displayed an intermolecular copigmentation. The main anthocyanin identified in black rice was cyanidin-3-glucoside. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of puffing process on the physical, antioxidant properties and mineral composition of brown rice. Bulk density significantly varied ( P < 0.05) among the puffing stages and was lowest in expanded rice. From Hunter colour analysis, the lowest L ∗ value and highest a ∗ and b ∗ values were observed for parboiled rice ( P < 0.05). A-type of diffraction pattern, observed in raw rice was altered by puffing process and led to the formation of B- and V-type patterns. Raman spectrum showed the intense peaks in raw rice and the intensity of those peaks was decreased during the puffing process. Scanning electron microscopy revealed a highly porous structure of expanded rice kernel. Significant decrease in the antioxidant properties was observed upon puffing process as compared to raw rice samples. Hence the present study demonstrates that the puffing process leads to the significant changes in the properties of brown rice. [ABSTRACT FROM AUTHOR]

Arsenic (As) is posing serious health concerns in South East Asia where rice, an efficient accumulator of As, is prominent crop. Salicylic acid (SA) is an important signaling molecule and plays a crucial role in resistance against biotic and abiotic stress in plants. In present study, ameliorative effect of SA against arsenate (AsV) toxicity has been investigated in rice (Oryza sativa L.). Arsenate stress hampered the plant growth in terms of root, shoots length, and biomass as well as it enhanced the level of H2O2 and MDA in dose dependent manner in shoot. Exogenous application of SA, reverted the growth, and oxidative stress caused by AsV and significantly decreased As translocation to the shoots. Level of As in shoot was positively correlated with the expression of OsLsi2, efflux transporter responsible for root to shoot translocation of As in the form of arsenite (AsIII). SA also overcame AsV induced oxidative stress and modulated the activities of antioxidant enzymes in a differential manner in shoots. As treatment hampered the translocation of Fe in the shoot which was compensated by the SA treatment. The level of Fe in root and shoot was positively correlated with the transcript level of transporters responsible for the accumulation of Fe, OsNRAMP5, and OsFRDL1, in the root and shoot, respectively. Co-application of SA was more effective than pre-treatment for reducing As accumulation as well as imposed toxicity. [ABSTRACT FROM AUTHOR]

Light buckwheat flour was used to substitute rice flour at the level of 10, 20 and 30 % to produce gluten-free cookies. The substitution of gluten-free cookie formulation with light buckwheat flour contributed to the significantly higher mineral content, especially magnesium, potassium, iron and copper, in comparison with the control rice cookies (p<0.05). Gluten-free cookies made with rice flour and buckwheat flour exhibited significantly higher total phenolic and rutin content, scavenging activity against 1,1-diphenyl-2-picrylhy-drazyl radicals (DPPH·), antioxidant activity and reducing power than the control cookies (p<0.05). Comparing all evaluated sensory properties, cookies containing 20 % of light buckwheat flour had the most acceptable sensory properties. The obtained results of principal component analysis showed that the cookies with 20 and 30 % buckwheat flour had better antioxidant and sensory properties in comparison with other two cookie samples. [ABSTRACT FROM AUTHOR]

BACKGROUND Two cultivars of black rice were investigated for the effects of different cooking methods on anthocyanins, total phenolic compounds and antioxidant activities. RESULTS There was a significant loss of anthocyanins during cooking: roasting resulted in the greatest decrease (94%), followed by steaming (88%), pan-frying (86%) and boiling (77%). Contents of phenolic compounds decreased drastically after cooking, with significantly lower retention in the black rice cultivar that had higher amylose content. DPPH radical-scavenging activity of black rice decreased after cooking. In contrast, metal-chelating activity increased significantly after cooking. Anthocyanins showed a high positive correlation with total phenolic compounds ( r2 = 0.936) but a significant negative correlation with metal-chelating activity ( r2 = 0.6107). CONCLUSION The results indicate that cooking degraded anthocyanins and other phenolic compounds, but with a concomitant increase in phenolics from possible degradation of anthocyanins, which resulted in the enhancement of metal-chelating activity. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Ten pigmented landraces of rice were analyzed for chemical composition and antioxidant properties. The results of proximate composition and calcium, iron, zinc content showed intra variability among landraces. The amylose, total anthocyanin (TAC) and phytate contents were found to be in the range of 22.01 - 44.38%, 28.73 - 193.36 mg cyanidin-3-glucoside/100 g and 1.16 - 24.49 mg Fe/100 g respectively. Total phenol and polyphenol contents were in the range of 233.92 - 251.38 mg ferulic acid equivalent/100 g and 252.43 - 284.36 mg gallic acid equivalent/100 g, respectively. Antioxidant assays of landraces showed free radical scavenging activity. [ABSTRACT FROM AUTHOR]

Purpose – The paper aims to investigate the iron, zinc, carotenoid, vitamin E, anthocyanin, and phenolic contents, antioxidant activity and the effect of the boiling of rice on such parameters. Design/methodology/approach – Iron and zinc content were investigated using atomic absorption spectrometry. Meanwhile, simultaneous extraction and detection methods using high performance liquid chromatography were applied for carotenoids, tocopherol, and tocotrienol analyses. For anthocyanin and phenolic determination, pH differential method and Folin Ciocalteu method were used, respectively. Antioxidant activity of samples was examined using ferric reducing antioxidant power (FRAP) and superoxide radical scavenging methods. Findings – The n790 cultivar has a higher iron, zinc γ tocopherol (1,869.64 mg/kg), α tocopherol (1,883.97 mg/kg), anthocyanin (205.54 mg cyanidin 3 glucoside equivalent/100 g dry matter), and phenolic (728.9 mg catechin equivalent/100 g dry matter) contents. Jowo cultivar has higher lutein (1,314.21 mg/kg), α carotene (823.29 mg/kg), and β carotene (71.73 mg/kg) contents. Meanwhile, γ tocotrienol is the most abundant tocotrienol found in all samples. N790 cultivar had the highest antioxidative potential in FRAP, and superoxide radical methods. Boiling did not significantly affect the zinc content, however, different response was found in carotenoid, tocopherol, and tocotrienol content. Moreover, boiling decreased the antioxidant activity of extract. Practical implications – Black- and red-colored rice could substitute white rice in Indonesian diet to achieve better nutrient intake. Originality/value – Providing information on nutrient and bioactive compound of Indonesian underutilized colored rice can help to change the dietary habit and to alleviate nutrient deficiency in Indonesia. [ABSTRACT FROM AUTHOR]

Abstract: There have been no studies conducted with the objective of investigating the effect of elevated CO2 concentrations ([CO2]) on antioxidants in grains. Therefore, a two-year field experiment was conducted using open-top chambers with two levels of atmospheric CO2 (375 and 550 μmol/mol) to evaluate their effects on rice grain antioxidants. Following exposure to high [CO2], the total phenolic content of all rice milling fractions decreased (3%–18%), with the highest reduction in the brown rice for sinapic acid (167%), and in the white rice for p-hydroxybenzoic acid (100%). The total flavonoid content also decreased under elevated [CO2] in all rice milling fractions (8%–14%), with apigenin (25%) being highly affected in the white rice, and tricin (12%) in the bran. The same trend was found for γ-oryzanol, with decreases of 35%, 32%, 25%, and 2% in the white rice, brown rice, husk, and bran, respectively. In the white and brown rices, tocopherols and tocotrienols were all lower under elevated [CO2], with reductions larger for α-tocotrienol (69%), γ-tocotrienol (46%), and α-tocopherol (38%). Good correlations between antioxidant contents and DPPH radical scavenging capacities indicated that these decreases may be meaningful in the preventive ability of rice against free radical-mediated degenerative diseases. [Copyright &y& Elsevier]

Abstract: The present work evaluated the concentration of total soluble phenolic compounds (TSPCs) and antioxidant activity (AOA) of rice grains with light brown, red and black pericarp colors and the processing effect on the concentration of TSPCs in the grain. Brown rice grains of ten ecotypes and six cultivars with red pericarp, one with a black pericarp and one with a light brown pericarp color, were evaluated. The concentration of TSPCs and AOA of rice grains with different processing (brown, polished, parboiled brown and parboiled polished) was determined, and the concentration of TSPCs was also determined in raw and cooked grains. Significant differences were observed in the concentrations of TSPCs and AOAs among genotypes with higher values obtained for grains with red and black pericarp colors, and a positive and significant correlation between these parameters was found. Parboiling reduced the TSPCs concentration in the grains due to the loss of part of them in the processing water, thermal decomposition and, possibly, interaction with other components. This reduction is related to the lower AOA in these grains. In a similar way, cooking also reduced the concentration of TSPCs, especially in brown and polished grains. [Copyright &y& Elsevier]

Influences of the conditions of raw rice storage and cooking on parameters related to colour and antioxidant activities of organic hulled red fragrant rice were investigated. Raw rice samples were vacuum-packed in oriented polypropylene/aluminium/linear low-density polyethylene or nylon/linear low-density polyethylene pouches and stored at ambient temperature or 15 °C up to 12 months. Cooked samples were prepared from aged raw samples. Kernel colour, total anthocyanin content ( TAC) of acidic methanolic extracts as well as total phenolic content ( TPC), reducing power ( RP) and radical scavenging activity ( RSA) of methanolic extracts and enzymatically digested samples were maintained during 12-month storage, regardless of packaging materials and storage temperatures. Cooked kernels had larger L value, lower a and b values, and greater TAC (dry basis), comparing with the raw rice. Cooking caused drastic decrease in TPC, RP and RSA of methanolic extracts. Nevertheless, less negative impacts of cooking were found for enzymatically digested samples. [ABSTRACT FROM AUTHOR]

Abstract: To investigate the effects of copper (Cu), rice plant (Oryza sativa. L. var. MSE-9) was treated with different Cu concentrations (0, 10, 50 and 100μM) for 5 days in hydroponic condition. Gradual decrease in shoot and root growth was observed with the increase of Cu concentration and duration of treatment where maximum inhibition was recorded in root growth. Cu was readily absorbed by the plant though the maximum accumulation was found in root than shoot. Hydrogen peroxide (H2O2) production and lipid peroxidation were found increased with the elevated Cu concentration indicating excess Cu induced oxidative stress. Antioxidant enzymes superoxide dismutase (SOD), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) and glutathione reductase (GR) were effectively generated at the elevated concentrations of Cu though catalase (CAT) did not show significant variation with respect to control. Ascorbate (ASH), glutathione (GSH) and proline contents were also increased in all the Cu treated plants compared with the control. SOD isoenzyme was greatly affected by higher concentration of Cu and it was consistent with the changes of the activity assayed in solution. The present study confirmed that excess Cu inhibits growth, induced oxidative stress by inducing ROS formation while the stimulated antioxidative system appears adaptive response of rice plant against Cu induced oxidative stress. Moreover proline accumulation in Cu stress plant seems to provide additional defense against the oxidative stress. [Copyright &y& Elsevier]

Abstract: In the present study, chemical compositions, phytochemicals, and antioxidant activity of rice bran (contained bran layer and rice germ) rice bran layer (without germ), and rice germ of four indica rice cultivars (waxy and non waxy) were investigated. The yield of rice bran, bran layer, and rice germ of all rice types were ranged between 17.59 -21.75%, 14.63-17.14%, and 2.81- 3.19% of the whole kernel, respectively. Rice germ fraction was high in protein, lipid, and fiber, whilst rice bran layer fraction was a good source of carbohydrate and ash. In the phytochemical compositions and antioxidant activity study, rice germ contained highest amount of α-tocopherol, γ-tocopherol, and indicated the strongest antioxidant activity. The rice bran layer showed highest level of γ-oryzanol with the amount ranged from 5.07mg/g in RD 6 to13.55mg/g in black waxy rice. [Copyright &y& Elsevier]

Rice (Oryza sativa L.) contains generous amounts of carbohydrates, proteins, vitamins, and dietary fibers, in addition to secondary metabolites such as phenols and flavonoids that act as antioxidants. The phenolic compounds detected in rice (organic rice (OR), conventional rice (CR), and pesticide-free rice (PFR)), namely, protocatechuic, gentisic, p-hydroxybenzoic, p-coumaric, ferulic, salicylic, and caffeic acids, are notable free radical scavengers. The sum of these phenolic compounds was found to be higher in PFR, followed by CR and OR (p < 0.0001), when the rice types were classified based on the farming system employed. In addition, significant differences were observed in the p-hydroxybenzoic acid levels for the OR and CR groups compared with the PFR groups (p < 0.01). Furthermore, greater quantities of p-coumaric acid were found in CR-08 and OR-02, although these groups contained overall higher and lower sums of phenolic compounds, respectively. Moreover, significance was observed in the sum of the phenolic compounds, although only small quantities were found in polished rice. Further research is thus required to provide a clearer picture regarding the phenolic profiles of different rice brands. [ABSTRACT FROM AUTHOR]