Quality characterisation and estimation of phytochemicals content and antioxidant capacity of aromatic pigmented and non-pigmented rice varieties

Germination and biological adaptation approaches as salt-stress tolerance process in selected paddy cultivars under salinity stress

Cultivating productive paddy crops on salty soil to maximise production is a challenging approach to meeting the world's growing food demand. Thus, determining salinity tolerance rates in specific paddy cultivars is urgently needed. In this study, the salt tolerance traits of selected paddy cultivars, ADT45 and ADT39, were investigated by analysing germination, metabolites (pigments and biomolecules), and enzymatic (Superoxide dismutase (SOD), Catalase (CAT), and Peroxidase (POD) adaptation strategies as salt-stress tolerance mechanisms. This study found that salinity-induced reactive oxygen species (ROS) were efficiently detoxified by the antioxidant enzymes Superoxide dismutase (SOD), Catalase (CAT), and Peroxidase (POD) in ADT45 paddy varieties, followed by ADT39. Salinity stress had a significant impact on pigments and essential biomolecules in ADT45 and ADT39 paddy cultivars, including total chlorophyll, anthocyanin, carotenoids, ascorbic acid, hydrogen peroxide (H2O2), malondialdehyde, and proline. ADT45 demonstrated a significant relationship between H2O2 and antioxidant enzyme levels, followed by ADT39 paddy but not IR64. Morphological, physiological, and biochemical analyses revealed that ADT45, followed by ADT39, is a potential salt-tolerant rice cultivar.

Impact of soaking and cooking treatments on the physicochemical and antioxidant properties of parboiled and non-parboiled rice (Oryza sativa L.)

The effects of soaking and cooking on the physicochemical properties and bioactive compounds of two parboiled and non-parboiled rice cultivars (BRRI-28 and Katari bhog) were investigated in this study. Total phenolic content (TPC) increased significantly (p ≤ 0.5) after soaking, while total flavonoid content (TFC) and proanthocyanidin content (PC) decreased significantly (p ≤ 0.5) compared to untreated rice samples. TPC increased by around 23% and 20% in parboiled BRRI 28 and Katari bhog rice extracts, respectively, due to the cooking process, while TFC and PC decreased significantly. DPPH radical scavenging increased whereas reducing power activity decreased after soaking and cooking in parboiled BRRI 28. After processing, the protein, starch, and amylose content of all samples decreased in the majority of cases. After being soaked, all samples L * and b * values increased as compared to raw rice samples. As a result, it can be concluded that the treatment of soaking and cooking of parboiled rice (BRRI-28) was suitable to improve the antioxidant properties as compared to non-parboiled rice.

Anthocyanins: Potential Therapeutic Approaches towards Obesity and Diabetes Mellitus Type 2

Overweight and obesity are present in about three-quarters of the adult population in Mexico. The inflammatory mechanisms subjacent to visceral white adipose tissue are accountable for the initiation and development of cardiometabolic alterations, including type 2 diabetes. Lifestyle changes are pillars within its therapeutics and, thus, current dietary modifications should include not only hypocaloric prescriptions with balanced macronutrient intake, preferably by increasing the amount of whole grains, fruits, vegetables, nuts and legumes, but in concomitance, bioactive substances, such as anthocyanins, have been correlated with lower incidence of this disease.

Effects of Far-Infrared Radiation Drying on Starch Digestibility and the Content of Bioactive Compounds in Differently Pigmented Rice Varieties

Far infrared radiation (FIR) was applied to six rice varieties with different coloring of the pericarp (purple, red or non-pigment). Changes were determined in amylose content, in gelatinization parameters, in the content of bioactive compounds, in antioxidant activity and in the in vitro digestibility of pigmented rice as affected by FIR. The highest contents of amylose, total phenolic (TPC), total flavonoid (TFC) and total anthocyanins (TAC) were found in the purple and red varieties. Overall, FIR increased TPC, TFC and TAC, including antioxidant capacity. Quercetin and apigenin contents were increased while rutin and myricetin decreased significantly (p < 0.05) in all FIR-dried samples. Dephinidin, cyanidin-3-glucosides and pelargonidin increased after FIR treatment. Mostly, FIR-treated samples were found to have greater gelatinization enthalpy, compared with unheated rice samples. FIR-dried rice showed lower starch digestibility (25−40%) than unheated rice. This research suggested that the specific genotype of rice had the greatest influence on amylose content in pigmented rice, while FIR drying had no further effect. Our results suggest that FIR could enhance the content of the bioactive compounds capable of inhibiting α-amylase, thereby lowering starch digestibility. Hence, FIR may be considered as an appropriate drying method for pigmented rice regarding health benefits.

Investigation on Nutritional, Phytochemical, and Antioxidant Abilities of Various Traditional Rice Varieties

Rice (Oryza sativa L.) is a popular grain that is consumed by almost half of the world's population. Rice has several distinct breeds classified as traditional and ancient grains. The consumption of rice by 60% of the world's population is a staple food. Entire grain rice, often known as brown rice, is the unpolished counterpart of white rice, containing bran, germ, and endosperm. Eating whole-grain rice is linked to many health benefits; thus, scientists have focused on identifying and quantifying bioactive chemicals in this meal. The present study assessed the physio-chemical, cooking attributes, mineral contents, phytochemicals, and free radical scavenging capabilities of conventional rice cultivars using known approaches according to particle size analysis. Rice grain lengths varied between 4.10 ± 16 and 6.20 ± 007. The length and thickness ratios of rice were not substantially different (p > 0.05). Kattuyanam has the maximum protein content (9.99 ± 06%) of all the rice varieties that were physio-chemical investigated. It also has highest phenolic content and antioxidant properties compared to gallic acid equivalent (334.900 ± 61 g) (GAE)/100 g, followed by anthocyanins and flavonoids. Total phenolic content and phenolic fractions of the HPLC profile in tested landraces indicate the presence of bioactive substances derived from traditional rice cultivars and a range of phytonutrients, including phenol, revealing their healthy potentials in the present study.

New insight into the pigmented rice of northeast India revealed high antioxidant and mineral compositions for better human health

Northeast (NE) India possesses a rich diversity of rice cultivars including pigmented and non pigmented varieties. The pigmented rice is reported to possess a considerable amount of antioxidant compounds, free radical scavengers etc. In this study, eleven (black, red and white) rice cultivars of NE India were analyzed for antioxidant potentials, mineral and protein contents. Total phenolic content ranged from 94.8 (Idaw) to 900.90 mg GAE/100 g (Lumre). Total flavonoid content varied from 3.46 (Idaw) to 286.76 mg QE/100 g (Menil mibabaret). Total anthocyanin content varied from 0.23 (Farel) to 93.52 mg/100 g (Chakhao poireiton). The pigmented rice is also good sources of Catalase (CAT), Ascorbate peroxidase (APX) and Superoxide Dismutase (SOD) that can significantly reduce stress oxidative reactions. Chakhao poireiton possessed the highest Ni and Mn content, Tsulu tsuk had the highest Zn content, while Fazu and Tasung contained the highest Fe and Ca. The highest total protein was found in Chakhao poireiton (11.06%). And all the cultivars were found to be aromatic. Fourier Transformed Infra-Red spectroscopy (FTIR) identified various signature peaks and could discriminate the cultivars into pigmented and non pigmented. Principle Component Analysis (PCA) revealed the grouping of the cultivars based on the functional groups present. The present study could provide a better understanding of choosable rice lines for human consumption and also as germplasm resources for future rice improvement programs.

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

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.

Anticancer and Cytotoxicity Activity of Native and Modified Black Rice Flour on Colon Cancer Cell Lines

This study is intended to evaluate the cytotoxicity of native and dual-modified black rice flour against the colon cancer cell line (HCT116) and mouse embryo cell line (3T3-L1) by using the MTT assay. The modification techniques applied to prepare rice flour samples were enzymatic modification and heat moisture treatment. In this study, the IC50 of native black rice flour and modified black rice flour was 255.78 µg/mL and 340.85 µg/mL, respectively. The result confirms that the native black rice flour has significant cytotoxic and anticancer potential against human colon cancer cells. In addition, the IC50 of native black rice flour and modified black rice flour on the 3T3-L1 cell line was found to be 345.96 µg/mL and 1106.94 µg/mL, respectively. The results showed that the native black rice flour had weak cytotoxicity, and modified black rice flour was nontoxic in both the cell lines. The active component of phytochemicals present in black rice flour has a potential role in preventing colon cancer.

Multi-Mechanistic In Vitro Evaluation of Antihyperglycemic, Antioxidant and Antiglycation Activities of Three Phenolic-Rich Indian Red Rice Genotypes and In Silico Evaluation of Their Phenolic Metabolites

The study evaluated the antidiabetic potential of three traditional Indian red rice genotypes/RR (Kattuyanam/KA, Chennangi/CH & Karungkuruvai/KU) using a combination of in vitro, metabolomics (Quadrupole-Time of Flight-Liquid chromatography-Mass spectrometry/Q-TOF-LC-MS/MS), and in silico techniques. In terms of antihyperglycemic potential, KA exhibited the highest inhibitory activity against α-amylase; CH against α-glucosidase; and KU against DPPIV and PTP1B enzymes. KA exhibited the highest antioxidant activity (DPPH, FRAP, and ABTS) and greater inhibition of protein glycation compared to other RR indicating its potential to mitigate diabetic complications. The metabolomic analysis confirmed the presence of 99 phenolics in the sample extracts (KU-71, KA-70, CH-68). Molecular docking studies revealed seven metabolites to be good inhibitors of the four target enzymes and activators of insulin receptor substrate/IRS. The antihyperglycemic and oxidation-glycation reduction composite index revealed KA to have the highest overall antidiabetic potential. Hence, the RR could be utilized in functional foods with a multi-barrelled strategy for diabetes prevention/management.

The nutritional profile and human health benefit of pigmented rice and the impact of post-harvest processes and product development on the nutritional components: A review

Pigmented rice has attracted considerable attention due to its nutritional value, which is in large conferred by its abundant content of phenolic compounds, considerable micronutrient concentrations, as well as its higher resistant starch and thereby slower digestibility properties. A wide range of phenolic compounds identified in pigmented rice exhibit biological activities such as antioxidant activity, anti-inflammatory, anticancer, and antidiabetic properties. Post-harvest processes significantly reduce the levels of these phytochemicals, but recent developments in processing methods have allowed greater retention of their contents. Pigmented rice has also been converted to different products for food preservation and to derive functional foods. Profiling a large set of pigmented rice cultivars will thus not only provide new insights into the phytochemical diversity of rice and the genes underlying the vast array of secondary metabolites present in this species but also provide information concerning their nutritional benefits, which will be instrumental in breeding healthier rice. The present review mainly focuses on the nutritional composition of pigmented rice and how it can impact human health alongside the effects of post-harvest processes and product development methods to retain the ambient level of phytochemicals in the final processed form in which it is consumed.

Computer Vision and Machine Learning Analysis of Commercial Rice Grains: A Potential Digital Approach for Consumer Perception Studies

Rice quality assessment is essential for meeting high-quality standards and consumer demands. However, challenges remain in developing cost-effective and rapid techniques to assess commercial rice grain quality traits. This paper presents the application of computer vision (CV) and machine learning (ML) to classify commercial rice samples based on dimensionless morphometric parameters and color parameters extracted using CV algorithms from digital images obtained from a smartphone camera. The artificial neural network (ANN) model was developed using nine morpho-colorimetric parameters to classify rice samples into 15 commercial rice types. Furthermore, the ANN models were deployed and evaluated on a different imaging system to simulate their practical applications under different conditions. Results showed that the best classification accuracy was obtained using the Bayesian Regularization (BR) algorithm of the ANN with ten hidden neurons at 91.6% (MSE = <0.01) and 88.5% (MSE = 0.01) for the training and testing stages, respectively, with an overall accuracy of 90.7% (Model 2). Deployment also showed high accuracy (93.9%) in the classification of the rice samples. The adoption by the industry of rapid, reliable, and accurate methods, such as those presented here, may allow the incorporation of different morpho-colorimetric traits in rice with consumer perception studies.

Genetic Architecture and Anthocyanin Profiling of Aromatic Rice From Manipur Reveals Divergence of Chakhao Landraces

Aromatic rice of Manipur popularly known as Chakhao is a speciality glutinous rice, for which protection under geographical indication in India has been granted recently. The agronomic and nutraceutical variability of the Chakhao rice germplasm is yet to be genetically characterized. To address this gap, characterization of ninety-three landraces for agro-morphological traits, grain pigmentation, antioxidant properties, and molecular genetic variation was carried out to unravel their population genetic structure. Two major groups were identified based on pericarp color, namely, purple and non-purple, which showed a significant variation for plant height, panicle length, and grain yield. Molecular marker analysis revealed three subpopulations that could be associated with pericarp pigmentation. Deep purple genotypes formed POP3, japonica genotypes adapted to hill environment formed POP1, while POP2 comprised of both indica and aus types. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed two major anthocyanin compounds in pigmented rices, namely, cyanidin-3-O-glucoside (C3G) and peonidin-3-O-glucoside (P3G). The total anthocyanin content among pigmented genotypes ranged from 29.8 to 275.8 mg.100g-1 DW. Total phenolics ranged from 66.5 to 700.3 mg GAE.100g-1 DW with radical scavenging activity (RSA) varying between 17.7 and 65.7%. Anthocyanins and phenolics showed a direct relationship with RSA implying the nutraceutical benefits of deep pigmented rice such as Manipur black rice. Aromatic rices from Manipur were found to be genetically diverse. Therefore, efforts need to be made for maintaining the geographic identity of these rice and utilization in breeding for region-specific cultivar improvement.

Anthocyanins in Whole Grain Cereals and Their Potential Effect on Health

Coloured (black, purple, blue, red, etc.) cereal grains, rich in anthocyanins, have recently gained a lot of attention in the food industry. Anthocyanins are water-soluble flavonoids, and are responsible for red, violet, and blue colours in fruits, vegetables, and grains. Anthocyanins have demonstrated antioxidant potential in both in vitro and in vivo studies, and the consumption of foods high in anthocyanins has been linked to lower risks of chronic diseases. As such, whole grain functional foods made with coloured grains are promising new products. This paper will review the characteristics of cereal anthocyanins, and assess their prevalence in various commercially relevant crops including wheat, barley, maize, and rice. A brief overview of the antioxidant potential, and current research on the health effects of cereal-based anthocyanins will be provided. Finally, processing of coloured cereals in whole grain products will be briefly discussed. A full understanding of the fate of anthocyanins in whole grain products, and more research targeted towards health outcomes of anthocyanin supplementation to/inclusion in cereal food products are the next logical steps in this research field.

Differential expression of flavonoid biosynthesis genes and biochemical composition in different tissues of pigmented and non-pigmented rice

Ever since the flavonoids and other antioxidants in rice were demonstrated with immense health benefits, much interest has been diverted to study the native indigenous rice landraces. In the present investigation, three pigmented rare Indian rice landraces and two non-pigmented rice varieties were analyzed for their phytoconstituents like total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content and antioxidant potential using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The phytochemical profile was compared between seed, seedling, stem, leaf and root tissues of the different varieties. Pigmented rice cultivars demonstrated higher levels of bioactive compounds as compared to the non-pigmented cultivars exhibiting a strong correlation between the antioxidant activity of the grain and their phenolic and flavonoid content. Among the five different rice studied, black navara was found to be superior in terms of its phytochemical composition. Further, the expression levels of flavonoid genes among pigmented and non-pigmented rice was studied. Higher gene expression profiles were observed in the 8 flavonoid genes studied in pigmented rice varieties as compared to non-pigmented varieties. The colorlessness of non-pigmented rice and its lower levels of phytoconstituents correlated with the low transcript levels of flavonoid genes recorded in them. This study provides a basis for understanding the health-promoting properties of pigmented rice over non-pigmented rice at the biochemical and molecular levels.

Comparative study of conventional steam cooking and microwave cooking on cooked pigmented rice texture and their phenolic antioxidant

The impact of two different cooking processes (microwave and steaming) on cooked rice quality (i.e., texture), and changes in the bioactive compounds (total phenolic content [TPC] and total anthocyanin content [TAC]) and antioxidant activities (DPPH and FRAP assays) of black and red (nonwaxy) and purple (waxy) pigmented rice were investigated. No significant difference in the firmness between microwave-cooked rice and steam-cooked rice was found, except for cooked purple rice. However, microwave cooking promoted an increase in the cooked rice adhesiveness, which approximately higher 2- ~ 3-fold than that of steam cooking with varying among rice cultivars. Microwave cooking also exhibited significantly higher TPC (1.2- ~ 2.0-fold), TAC (2.0- ~ 3.2-fold), DPPH (1.3- ~ 2.5-fold), and FRAP (1.5- ~ 2.4-fold) than steam cooking for black and purple rice cultivars. There was a strong positive correlation among these bioactive compounds and the antioxidant activities (p < .01). Our study indicated that the TPC, TAC, DPPH, and FRAP of all rice examined were remarkably decreased after cooking, and the extent of the decrease depended on the rice cultivar and cooking method.

Nano/Submicrometer Milled Red Rice Particles-Stabilized Pickering Emulsions and Their Antioxidative Properties

Nano/submicrometer red rice particles were obtained through processing a type of red rice using media-milling. The diameters of red rice were gradually reduced as processing time increased. After 4 h of processing, the particle size of milled red rice was reduced to around 692 nm. Microscopic observation and SEM analysis confirmed the presence of nano/submicrometer particles. The phytochemical contents of milled red rice were analyzed. The total anthocyanin content of red rice increased after milling process. Its phenolic and flavonoid contents were slightly decreased after the milling process. All milled red rice exhibited good ferric reducing antioxidant property (FRAP) and DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The emulsifying ability of milled red rice particles with different milling time was characterized. Milled red rice starch particles with a concentration of 0.8-3.5% were able to form stable Pickering emulsions, and milled red rice particles retarded the oil oxidation process when being used as Pickering emulsions stabilizers. This pioneer study directly modifies whole grain materials to submicrometer particles that can form stable food grade Pickering emulsions with intrinsic antioxidant properties.

Impact of physicochemical properties on duration and head rice yield during abrasive and friction milling of rice

The physicochemical properties of four rice varieties representing high amylose (Jyothi and IR64), intermediate amylose (Taraori Basmati) and waxy (Agonibora) were evaluated to understand their influence on milling. Based on the grain dimensions, Jyothi and Agonibora were classified as long and medium, IR64 as long and slender, and Basmati as extra-long and slender. The head rice yield (HRY) was higher with abrasive milling (61-75%) compared to friction milling (10-60%) although it required longer milling duration. Lower grain thickness, hardness and, amylose and higher bran fat content reduced the friction milling duration while these properties prolonged the duration in abrasive milling. Agonibora variety with low amylose content and high-fat content exhibited the highest HRY in both the types of milling. The study revealed that the selection of milling process should be made with due importance to grain geometry as well as its chemical properties.

Process-Structure-Function in Association with the Main Bioactive of Black Rice Flour Sieving Fractions

The aim of this work was to advance knowledge on the potential use of black rice different sieving fractions for various functional applications, through proximate analysis, thermal degradation kinetics of phytochemical and characterization of the thermal behavior of the main proteins, from the perspectives of their use as a food ingredient. The results indicated that the thermal degradation of phytochemicals followed a first-order reaction kinetics for all the tested fractions. The temperature-dependent degradation was adequately modeled according to the Arrhenius equation. The calculated activation energies (E_a) and k values were different among the four studied parameters. The kinetic parameters depended on the grinding and sieving degree, the anthocyanins being the most thermolabile compounds, thus affecting the antioxidant activity. Three protein fractions were identified by electrophoresis with different molecular weight, such as albumin, globulin, and glutelin. The fluorescence spectroscopy experiments revealed the sequential character of the heat-induced conformational changes, different molecular events being suggested, such as folding in the lower temperature range and unfolding at higher temperature. The significance of the study is evidenced by the need to identify and advance the process-structure-function relationships for various biologically active compounds from the perspective of obtaining food or ingredients nutritionally optimized.

Influence of parboiling of red paddy varieties by simple hot soaking on physical, nutrient, phytochemical, antioxidant properties of their dehusked rice and their mineral, starch, and antioxidant's bioaccessibility studies

The objective of this study was to know about the effect of simple parboiling on physical properties, proximate composition, phenolic compounds, and antioxidant activity.  These were  studied in raw and parboiled paddy varieties as well as bioaccessibility of specific nutrients (minerals, starch, and antioxidants). The pigmented rice paddy varieties such as Jyothi, Meter & Athikaraya were parboiled by hot soaking treatment after soaking for 2, 2½, and 3 hr. Athikaraya rice showed high protein, low ash in raw and parboiled than other varieties. Amylose equivalents of all three varieties exhibited in the range of 24%-27% (d.b). Whereas, the soluble amylose content showed 12.7, 8.7, and 7.7% (d.b) in Athikaraya, Meter and Jyothi rice varieties, respectively. Jyothi rice showed less cooking time and more cooking volume. Athikaraya showed high phenolic content and antioxidant properties compared to other two varieties. The dialysability of minerals, starch, and antioxidants were increased due to simple hot soaking parboiling. PRACTICAL APPLICATIONS: The present study has the significance in assessing the variation among different pigmented rice varieties after parboiling by simple hot soaking with various soaking periods. The industrial advantage of this method is, there is no usage of boiler for cooking the paddy by steam, which was economically better. The information gained by this study might be beneficial for consumers and suppliers regarding the quality of the selected pigmented rice varieties with respect to nutrient composition, antioxidant activities, and bioaccessibility of minerals, starch, and antioxidants. Ultimately, the present study can lead to better appreciation of pigmented rice and assist food processors in selecting rice variety with unique characteristics for specialty food preparations.

Evaluation of sensory, physicochemical properties and Consumer preference of black rice and their products

This study was aimed to evaluate the physicochemical, textural, sensory and antioxidative attributes of various rice products such as boiled rice, beaten rice, popped rice, puffed rice and raw milled rice, prepared from the Indian black rice cultivars Chakha (CH), Kalobhat (KB), Mamihunger (MA) and Manipuri Black (MN). A popular white rice variety Swarna Sub-1 (SW) was considered as control. Significant differences in most of the physicochemical and cooking parameters of raw rice were observed across different cultivars. The head rice recovery, amylose content, elongation ratio (ER) and kernel length after cooking of MA were most satisfactory among the black rice cultivars and are found to be 50.67%, 17.6%, 1.87 and 10.10 mm respectively, while popped rice of MA recorded highest length (10.83 mm) and elongation ratio (ER; 2.01). MA showed the highest adhesiveness (11.18 mJ) in boiled rice but hardness (183.53 N) was medium in raw rice. Other textural quality varied differentially according to the various products and cultivars. The highest a* value was obtained from puffed rice of MA (6.61) but L value was highest in raw rice of MN. Popped and boiled rice of MA displayed higher DPPH-antioxidant activity (88.74% and 84.74% respectively) as compared to all other products. The raw rice of KB registered higher anthocyanin (57.23 mg/100 g) content while boiled rice of SW recorded the least (0.21 mg/100 g). A survey on the consumer preference of these products indicated that boiled rice was usually preferred in lunch and dinner by most of the consumers whiles other products in breakfast. With respect to most of the traits, MA showed the good potential for rice Industry as well as for breeding material.

Effect of rice variety and modification on antioxidant and anti-inflammatory activities

The effects of variety and modification of rice on its antioxidant and anti-inflammatory activities were investigated. White rice varieties; Jasmine (JM) and Saohai (SH), and pigmented rice varieties; Doisket (DS) and Homnil (HN) were used. The modified rice samples were obtained from chemical modification using etherification reaction. The activities of the modified rice samples were compared with the ethanol extracts of the raw rice at the same rice concentration. Antioxidant activity was measured by the free radical scavenging activity tests and ferric reducing power assay. Results indicated that the ethanol extracts of raw rice had higher antioxidant activity than the modified rice. Among the raw rice tested, the pigmented rice showed higher antioxidant activity than white rice. Trolox equivalent antioxidant capacity values from free radical scavenging activity test were revealed that 50% ethanol extracts of HN and DS possessed the highest antioxidant activity. Ferric reducing power assay showed that 50% ethanol extracts of DS had the highest antioxidant activity. The anti-inflammatory activity was evaluated in vitro using a lipopolysaccharide-stimulated RAW264.7 macrophage cell model with enzyme-linked immunosorbent assay. Absolute ethanol extracts of HN reduced interleukin-6 secretion whereas that of DS suppressed interleukin-6 and tumor necrosis factor -α secretion. These results indicate that variety of rice, chemical modification, and extracting solvent were the factors that play an important role on antioxidant and anti-inflammatory activity. This study supports the potential use of the pigmented rice, especially DS, as a promising choice of a natural source because of its antioxidant and anti-inflammatory activities.

Factors influencing antioxidant compounds in rice

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.

Cultivars effect on the physical characteristics of rice (rough and milled) (Oryza Sativa L.) of temperate region of Kashmir (India)

The aim of present research was to evaluate physical and engineering properties of traditional paddy and rice cultivars native to temperate region of India. Length, width, thickness, equivalent diameter, surface area, aspect ratio, volume, bulk density, true density, porosity, thousand kernels weight, angle of repose and coefficient of friction were evaluated, which are required in designing of various post harvest operations and storage structures. The low bulk density of cultivars, Mushki budgi, Mushki tujan and Kaw kareed may be due to the presence of long awns possessed by these cultivars which were bulky and occupied more space. The wide variations were found in rice kernels with respect to colour, which determined the functional properties and energy requirement during polishing of these cultivars. Results indicated significant differences in the physical properties among various paddy and brown rice cultivars when compared with earlier reported results. Thousand kernel weight, width, arithmetic mean diameter and equivalent diameter showed significant positive correlations with spherecity, surface area, volume, true density, and angle of repose; but negatively correlated with bulk density. These desirable characteristics exploit agriculturists/institutions to preserve these races and encourage farmers to cultivate these cherished rice cultivars.

Changes in the Bioactive Compounds Content of Soybean as a Function of Grain Moisture Content and Temperature during Long-Term Storage

Soybean is a rich source of bioactive compounds, such as phenolic acids, flavonoids, isoflavones, carotenoids, and tocopherols. The amount of bioactive compounds in freshly harvested soybeans and their derived products has been determined; however, when they are used in the food industry, soybeans are generally stored prior to being processed. This study aimed to evaluate the effects of soybean moisture content (12%, 15%, and 18%) and storage temperature (11, 18, 25, and 32 °C) on the free phenolic, total flavonoid, vanillic acid, total carotenoid, and δ- and γ-tocopherol content of soybeans stored for 12 mo. Moreover, the ABTS and DPPH radical scavenging activities of phenolic extracts were determined. There was an increase in free phenolics and total flavonoids in the stored grains compared with the grains on the 1st d of storage. Vanillic acid showed a decrease in soybeans stored at 15% and 18% moisture content and 25 or 32 °C, which indicated some degradation into other metabolites. Total carotenoid content decreased as a function of storage temperature and showed some temperature-dependent degradation. The δ- and γ-tocopherol content also tended to decrease in grains stored at 15% or 18% moisture content or 25 or 32 °C, regardless of the moisture content studied.