Red Rices Research Articles

Determination of contents and antioxidant activity of free and bound phenolics compounds and in vitro digestibility of commercial black and red rice (Oryza sativa L.) varieties

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).

Variation of Functional Materials and Antioxidant Activity as Affected by Cultivation Environment in Pigmented Rice Varieties

Production of high quality pigmented rice contained with high content of anthocyanin, and polyphenol was significantly influenced by cultivation environments like transplanting date and cultivation location. This study was carried out to establish an optimum transplanting date and cultivation region to produce maximum content of anthocyanin, polyphenol and antioxidant activity of pigmented rice varieties (black, red colored). Three transplanting times (May 20, June 5, June 20) and four different sites (Miryang, Uiseong, Sangju, Bonghwa) were evaluated with five pigmented rice cultivars. Anthocyanin and total polyphenol index to average temperature during 30 days after heading (DAH) of black, red pigmented rice varieties showed that anthocyanin and total polyphenol contents were decreased by 10% and 9%, respectively, with increasing average temperature of . The optimum ripening temperature of the 30 DAH for the production of high anthocyanin and total polyphenol was 22 to for early maturity black rice, 21 to for mid-late maturity of black and red rices, respectively. On the other hand, an estimated heading date of pigmented rices in return according to the optimum ripening temperature of the 30 DAH was ranged Aug. 11 to 17 for early maturity black rice, Aug. 25 for mid-late maturity black, red rice variety in Jecheon, Aug. 27 to Sep. 2 for early maturity type, Sep. 3 to 6 for mid-late type in Daegu. It seemed that Jecheon, Boeun, Mungyeong, and Yeongju were optimum regions for cultivation of pigmented rices. The estimated sowing date of pigmented rices for high anthocyanin and total polyphenol production based on the optimum heading date was May 18 to 26 for early maturity black rice variety, April 11 for mid-late black, red variety in Jecheon, May 23 to 28 for early type, April 9 to 26 for mid-late type in Boeun, respectively.

Phenolics characterization and antioxidant activity of six different pigmented Oryza sativa L. cultivars grown in Piedmont (Italy)

The three principal black rice varieties grown in Piedmont (Artemide, Venere, Nerone) have been studied in comparison with other three at different pigmentations: red (Ermes, Russ) and white, partially refined (Selenio). The extracts from these six different cultivars, processed as “husked” rices, were analyzed by high-performance liquid chromatography coupled with diode array detection and electrospray ionization-mass spectrometry (HPLC-DAD-ESI-MS/MS). Both qualitative and quantitative characterizations of the flavonoids (anthocyanins, flavonols, and flavan-3-ols) and non-flavonoid (hydroxycinnamic acids) phenolic compounds were achieved. 2,2-Diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity and total phenolic content were evaluated to determine the antioxidant properties of different rices. Black rice showed higher contents of phenolics, flavonoids, and anthocyanins showing higher antioxidant activity when compared to white and partially if compared to red rices. Cyanidin-3-glucoside was the major anthocyanin in black rice grains, followed by peonidin-3-glucoside and cyanidin-3-rutinoside. With respect to the diglycosyl anthocyanins, cyanidin-3-O-gentiobioside was confirmed and quantified in black varieties. Significant differences in phytochemical content and antioxidant activity were achieved also among the three black varieties. The results demonstrate that the black rice varieties contain a rich heterogeneous mixture of phytochemicals which may provide a basis for the potential health benefits, and highlights the rice as a functional food.

Profiles of Fatty Acid Distribution of Different Acyl Lipids from Red and Black Rices

&lt;p&gt;The present study is focused on the variation in fatty acid (FA) composition of the different acyl lipids in red and black rices. Total lipids were fractionated by TLC into eight subfractions. Significant differences (&lt;em&gt;P&lt;/em&gt; &amp;lt; 0.05) in FA distribution were found among the different acyl lipids when the two cultivars were compared. There were no significant differences (&lt;em&gt;P&lt;/em&gt; &amp;gt; 0.05) in the positional distribution of FA in triacylglycerols; unsaturated FA was predominantly concentrated in the &lt;em&gt;sn&lt;/em&gt;-2 position while saturated FA primarily occupied the &lt;em&gt;sn&lt;/em&gt;-1 position or &lt;em&gt;sn&lt;/em&gt;-3 position in the oils. Significant differences (&lt;em&gt;P&lt;/em&gt; &amp;lt; 0.05) in FA distribution existed when the individual phospholipids were compared. Based on the FA composition of the different acyl lipids, it seems that red and black rices are very similar to each other with a few exceptions. The results suggest that these rice lipids may be well incorporated into our daily diet to improve value of the Japanese diet.&lt;/p&gt;

Free and bound total phenolic concentrations, antioxidant capacities, and profiles of proanthocyanidins and anthocyanins in whole grain rice (Oryza sativa L.) of different bran colours

Abstract To study the polyphenols in whole grain rice varying in bran colour, the total phenolics, flavonoids and antioxidant capacities of the solvent-extractable (Free) and cell-wall bound (Bound) fractions and the profiles of proanthocyanidins and anthocyanins were determined. Red and purple bran rices had significantly higher total (sum of Free- and Bound-) phenolic (PC) and flavonoid (FC) concentrations and antioxidant capacities than light-coloured bran rice or other cereals ( P P 10 mers), respectively. Cyanidin-3-glucoside was the predominant anthocyanin and peonidin-3-glucoside was the second highest; the profiles varied between purple bran cultivars. Whole grain rice differing in bran colour contained unique polyphenol subgroups, which have been proposed to positively impact human health.

Composition and Regiodistribution of Fatty Acids in Triacylglycerols and Phospholipids from Red and Black Rices

ABSTRACTRegiospecific profiles of fatty acids (FA) of triacylglycerols (TAG) and phospholipids (PL) isolated from red and black rices were investigated. The lipids extracted from red and black rices were separated by thin‐layer chromatography (TLC) into eight subfractions, respectively. With a few exceptions, the major lipid components were TAG (76.4–80.5%), free FA (7.2–9.8%), and phospholipids (3.5–3.6%), while hydrocarbons, steryl esters, diacylglycerols (1,3‐DAG and 1,2‐DAG), and monoacylglycerols were present in minor proportions (0.1–4.1%). The PL components isolated from the two cultivars were phosphatidyl choline (52.3–53.7%), phosphatidyl ethanolamine (22.3–23.1%), phosphatidyl inositol (20.6–21.3%), and others (&lt;3.4%). No significant differences (P &lt; 0.05) in FA distribution were found when these cultivars were compared. The principal characteristics of the FA distribution in the TAG and PL were evident in the rices between the two cultivars: unsaturated FA were predominantly located at the sn‐2 position (77.3–96.8%), while saturated FA primary occupied the sn‐1 or the sn‐3 position (35.0–78.7%) in these lipids. The results of this study could provide useful information to both consumers and producers during manufacture of traditional rice foods in Japan.

Genetic resources of rice in the Western Himalayan region of India: current status

The Western Himalayan region of India possesses rich genetic diversity of rice (Oryza sativa L.). Rice landraces having withstood the rigors of biotic and abiotic stresses, suit to the local conditions of farms and reflect socio-cultural preferences can still be found in crop fields located distantly in rural and tribal areas. This region is known for growing World fame basmati in the foot hills and many varieties of red rices grown at higher elevations, known for cold tolerance and medicinal properties. Genetic resources of rice were collected for about 8 years (1999-2006) and 1069 germplasm accessions including 154 named landraces were collected. Prominent landraces such as Begumi, Ramjwain, Thapachini, Naurang, Hansraj, Tilakchandan, Lalsati, Jhini, Mushakbudji, Jattoo, Barpasso, Qadirbeigh, Safedbrez, Shahie known for their special quality attributes were collected. The change in land use, cropping patterns and aggressive introduction of modern varieties in the region has resulted in the loss of a large number of landraces especially from irrigated lands. The present paper looks at the status of rice genetic resources, genetic variability, genetic erosion and future strategies to conserve rice germplasm on farm and to maximize its use in rice breeding.

Impact of parboiling conditions on Maillard precursors and indicators in long-grain rice cultivars

The effect of steaming conditions (mild, intermediate and severe) during parboiling of five different long-grain rice cultivars (brown rice cultivars Puntal, Cocodrie, XL8 and Jacinto, and a red rice) on rice colour, and Maillard precursors and indicators was investigated. Rice colour increased with severity of parboiling conditions. Redness increased more than yellowness when parboiling brown rice. Parboiling turned red rice black. It changed the levels of glucose, fructose, sucrose, and maltose. Losses of the non-reducing sugar, sucrose were caused by both leaching into the soaking water and enzymic conversion, rather than by thermal degradation during steaming. Concentrations of the reducing sugars, glucose and fructose, in intermediately parboiled rice were higher than those of mildly parboiled rice. After severe parboiling, glucose levels were lower than those of intermediately parboiled rice, while fructose levels were higher. These changes were ascribed to the sum of losses in the Maillard reaction (MR), formations as a result of starch degradation and isomerisation of glucose into fructose. It was clear that the ε-amino group of protein-bound lysine was more affected by parboiling conditions and loss in MRs, than that of free lysine. Low values of the MR indicators furosine and free 5-hydroxymethyl-2-furaldehyde (HMF) in processed brown and red rices were related to mild parboiling, whereas high furosine and low free HMF levels were indicative of rices being subjected to intermediate processing conditions. High furosine and high free HMF contents corresponded to severe hydrothermal treatments. The strong correlation (r=0.89) between the free HMF levels and the increase in redness of parboiled brown rices suggested that Maillard browning was reflected more in the red than in the yellow colour.

여러 가지 특수미의 항산화 활성 및 항산화 성분

Dept. of Food Science and Technology, Chungbuk National University, Cheongju 361-763, KoreaAbstractThe objectives of this study were to determine antioxidant activity of the methanolic extracts from some specialty rices and to investigate relationships between antioxidant activities and antioxidant contents in the extracts. ABTS (2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) radical cation scavenging activity, inhibitory effect on lipid peroxidation, chelating activity, reducing power and inhibitory effect on xanthine oxidase have been used to investigate the relative antioxidant activity of the extracts from specialty rices. The concentrations of total polyphenolics, phytic acid, and anthocyanin in the extracts were measured by spectrophotometric methods and vitamin E analysis was carried out by HPLC. The methanolic extracts prepared from black and red rices showed higher antioxidant activities and contained higher antioxidant compounds compared with other rices, apparently due to their intense red-purple color. The correlation coefficient between total polyphenolic content of methanolic extracts and ABTS radical cation scavenging activity, reducing power, and inhibitory effect of xanthine oxidase were 0.9921, 0.9856, and 0.8032, respectively.Key words: rice, antioxidant activity, antioxidant compound, correlation

Characterization of antioxidant compounds of red and white rice and changes in total antioxidant capacity during processing

Although most rice cultivars have whitish kernel, some varieties have a red testa. Aim of this work was to compare the total antioxidant capacity (TAC) and the antioxidant chemical composition (namely tocols, gamma-oryzanols, and polyphenols) of red and white rices. In addition, the effect of milling and cooking on antioxidants was investigated in both rices. Dehulled red rice showed a TAC more than three times greater than dehulled white rice and its high TAC was essentially characterized by the presence of proanthocyanidins (PA) and associated phenolics. Milling caused a significant loss of TAC, even if red rice maintained a higher TAC. Cooking caused a further loss of antioxidants, but when there was a full uptake of cooking water by the grains ("risotto") this loss was limited. Thus, the consumption of whole or partially milled rice cooked as risotto would be preferred to preserve its nutritional properties.

여러 가지 특수미의 일부 항산화 성분 분석

The objective of this study was to determine antioxidant compounds in specialty rice including milled rice, brown rice, red rice, giant embryonic rice, black rice, green rice, and Goami consumed in Korea. The concentrations of total polyphenols (insoluble and soluble polyphenols), phytic acid, and anthocyanin in the samples were measured using spectrophotometric methods and vitamin E analysis was carried out by HPLC. The contents of the total polyphenolic compounds were 565 ㎎/100 g for black rice, 405 ㎎/100 g for red rice, 140 ㎎/100 g for giant embryo rice, 138 ㎎/100 g for Goami, 133 ㎎/100 g for brown rice, 127 ㎎/100 g for green rice, and 66 ㎎/100 g for white rice. The black and red rices were significantly high in polyphenolic contents compared with the other rices, apparently due to their intense red?purple color. Black rice, red rice, and Goami showed significantly higher vitamin E and phytic acid contents compared with other rices. Anthocyanins were determined in only black rice (302 ㎎/100 g) due to the detection limits of spectrophoto-metric assay. Although vitamin E and anthocyanin contents were relatively lower than polyphenolics among the samples, the specialty rice may contribute to the significant supply of antioxidant compounds to prevent oxidative stress due to the fact that rice is used as a staple food and consumed in large amounts in our diets. The results can be used to increase rice consumption by enhancing consumer awareness on health benefits of the rice.

Anthocyanin Composition in Black, Blue, Pink, Purple, and Red Cereal Grains

Anthocyanin pigments from a wide variety of edible and ornamental black, blue, pink, purple, red, and white wheat, barley, corn, rice, and wild rice were identified and quantified to evaluate their potential as natural colorants or functional food ingredients. The total anthocyanin contents varied significantly and exhibited a range of 7-3276 microg/g. Some grains, such as red rice and black rice, contained a limited number of pigments, whereas others, such as blue, pink, purple, and red corns, had complex anthocyanin profiles. Of the 42 anthocyanin compounds observed, 9 were characterized by comparison of the spectroscopic and chromatographic properties with those of authentic standards. The remaining compounds were tentatively identified on the basis of spectroscopic properties and electrospray ionization mass spectra. The most abundant anthocyanins were cyanidin 3-glucoside in black and red rices and in blue, purple, and red corns, pelargonidin 3-glucoside in pink corn, and delphinidin 3-glucoside in blue wheat.

Determination of trace element concentrations in ancient rices (red and black rices) and a present-day rice (Koshihikari) : Relationship among the trace element concentrations, species, harvest site and rice parts

Determination of trace element concentrations in ancient rices (red and black rices) and a present-day rice (Koshihikari) : Relationship among the trace element concentrations, species, harvest site and rice parts

Antioxidative Properties of Extracts from Ancient Rice Brans

In this study, the superoxide dismutase (SOD)-like activity and the ROS (superoxide anion, hydroxyl radical, singlet oxygen, t-butylperoxyl radical) scavenging activities were evaluated for the extracts from 2 varieties (black and red rices) of ancient rice brans (8 types) by the nitro-blue tetrazolium (NBT) and ESR-spin trapping methods. All the extracts from ancient rice brans (black and red rice) had SOD-like activity, which was stronger than those from present-day rice brans (Koshihikari, Akitakomachi, Haenuki). It was proven by NBT method that the activities of ancient rice brans were significantly stronger than those of L-ascorbic acid, however, L-ascorbic acid exhibited higher scavenging activity as evaluated by ESR spin-trap method. The ancient rice brans have remarkably strong ROS scavenging activities compared with those of the present-day rice brans (Koshihikari, etc.). The ROS scavenging activities and SOD-like activities of the extracts varied depending on the rice species and the planting region. In addition, the extracts from ancient rice brans inhibited the Maillard reaction, which is known to be involved in physiological aging processes. Thus, the present results suggest the utility of the extracts from ancient rice brans as antioxidative materials.