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Pigmented rice is known to have nutritional and bioactive compounds which commonly concentrated in the bran layers. Solid-state fermentation is known to enhance the bioactive compounds of rice bran. The study aims to identify fermented rice bran's volatile compounds and aroma attributes from some pigmented rice (Inpari 24, Saodah, Cempo Ireng and Jeliteng). The rice brans were sterilized at 121°C for 15 minutes and produced non-fermented rice bran and some of them were fermented for 72 hours at 30°C using Rhizopus oligosporus. Both non-fermented and fermented rice brans were analysed using solid-phase microextraction-gas chromatography/mass spectrometry (GC/MS) and qualitative descriptive analysis (QDA). The result showed that a total 114 of volatile compounds were identified from fermented and non-fermented rice bran. They consisted of 14 aldehydes, 12 ketones, 14 alcohols, 15 hydrocarbons, 8 acids, 23 esters, 9 benzenes, 5 phenols, 6 furans, 2 lactones, 1 monoterpene, 1 sesquiterpene, 1 thiazole, 1 pyrazine and 1 pyridine. The aroma attributes of fermented rice brans obtained by 10 trained panellists in QDA were sweet, caramel, vanilla, grass, milky, fatty, nutty, smokey, rancid, acid, cereal, pungent, earthy and fermented. The nonfermented rice bran has the same aroma as the corresponding fermented rice bran except fermented aroma. Furthermore, Pearson's correlation test has resulted in several positive correlations between GC-MS results and QDA. These studies indicated that fermented rice bran might increase the volatile compound of rice bran; thus, it may provide opportunities to develop the production of fermented rice bran as a functional ingredient. [ABSTRACT FROM AUTHOR]

Rice bran (RB) corresponds to the outer layers of whole grain rice and contains several phenolic compounds (PCs) that make it an interesting functional food ingredient. PC richness is enhanced in pigmented RB varieties and requires effective ways of extraction of these compounds. Therefore, we investigated conventional and deep eutectic solvents (DES) extraction methods to recover a wide array of PCs from red and black RB. The RB were extracted with ethanol/water (60:40, v/v) and two DES (choline chloride/1.2-propanediol/water, 1:1:1 and choline chloride/lactic acid, 1:10, mole ratios), based on Generally Recognized as Safe (GRAS) components. Besides the quantification of the most typical phenolic acids of cereals, nontargeted metabolomic approaches were applied to PCs profiling in the extracts. Globally, metabolomics revealed 89 PCs belonging to flavonoids (52%), phenolic acids (33%), other polyphenols (8%), lignans (6%) and stilbenes (1%) classes. All extracts, whatever the solvents, were highly concentrated in the main phenolic acids found in cereals (37–66 mg/100 g in black RB extracts vs. 6–20 mg/100 g in red RB extracts). However, the PC profile was highly dependent on the extraction solvent and specific PCs were extracted using the acidic DES. The PC-enriched DES extracts demonstrated interesting DPPH scavenging activity, which makes them candidates for novel antioxidant formulations.

Consumption of pigmented rice as a staple food is rapidly increasing due to their healthy prospective and considered as functional food ingredients. Greater interest has been shown in many color rice varieties due to their multiple biological activities. The phenolic compounds have been found to consist of anthocyanidins, ferulic acid, diferulates, anthocyanins and polymeric proanthocyanidins. Anthocyanin is located in the bran layers of the rice kernel, while phenolic acids are mainly present in the bran layers of rice, existing as free, conjugated and bound forms. Keeping in view the several health benefits associated with the functional ingredients, such as anti-inflammatory, antioxidative and anticancer effects, pigmented rice is considered as a functional food and food ingredient in many Asian countries. The application and incorporation of bran into food products for the preparation of functional foods is increasing. Within the scope of this review, we highlighted the significant bioactive compounds from pigmented rice varieties and their potentials for medicinal and nutraceutical ingredients. The information provided from this could be of high benefit to the functional food industry and further research advance medicinal products.

The antioxidative compounds were extracted by ultrasonic treatment of bran extracts of seven pigmented (completely) and non pigmented (sparsely) colored rice cultivars followed by assessment of their in vitro antioxidative capacity by LC-MS and oxidation/reduction assay based methods. A total of 40-compounds, 7-phenolic, 9-flavonoids, 9-hydroxycinammic acid derivatives, 3-hydroxybenzoic acid derivatives and other glucosides specifically, pro-anthocyanidin trimer and procyanidin-B 1 (dimer) were indentified in completely colored rice cultivars. Higher DPPH radical scavenging activity of pigmented cultivars was due to higher percentage of phenolics like thymol, quinicquinic-caffeicacid ester and polar dicaffeoylquinic acid; whereas higher lipid peroxidation inhibition was attributed to the presence of polar substances such as p-hydroxybenzoicacid, procyanidin B 1 and quercetin-3 -O- rutinoside. The phosphomolybdenum reduction capacity was attributed to luteolin-7- O- glucoside, apigenin-7- O- glucoside, caffeicacid, myrecitin and phloreticacid. Whereas, grater reducing power of pigmented bran was attributed to presence of multiple-OH groups containing phenols, flavonoid and hydracinammicacid depicting potential health and nutritional effects of these rice cultivars. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the antioxidant activities and phenolic compounds of pigmented rice (black, red, and green rice) and brown rice brans. Antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, 2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) radical cation assay, reducing power, and chelating ability. Phenolic compounds were measured by using HPLC. Pigmented rice brans were extracted by using aqueous mixtures of acetone, ethanol, and methanol to determine the most effective extraction solvent. Of all solvents examined, extract from 40:60 acetone-water mixtures (v/v) provided the highest DPPH radical assay as well as the highest total phenolic and flavonoid content. We finally selected 40% acetone as an extraction solvent for antioxidant study of pigmented rice bran. Antioxidant activities of 40% acetone extracts of pigmented rice bran, measured in the range of 0 to 1500 μg/mL. At 500 μg/mL concentration, red rice bran, which had the highest total phenolic (259.5 μg/mg) and total flavonoid (187.4 μg/mg) contents, showed the highest antioxidant activity: 83.6%, 71.5%, 1.2%, and 16.4% for DPPH radical assay, ABTS radical cation assay, reducing power, and chelating ability, respectively. Red rice bran showed a lower EC50 value (112.6 μg/mL) than that of butylated hydroxytoluene (144.5 μg/mL) from the DPPH radical assay. The major phenolic acids of red rice bran were ferulic, vanillic and p-coumaric acids. The results indicated pigmented rice bran might be used as a natural antioxidant. Practical Application: The present study revealed black and red rice bran shows high antioxidant activities and they contain high amount of phenolic compounds. Indeed, black and red rice bran could be better raw materials for manufacturing the food with high antioxidant activity. [ABSTRACT FROM AUTHOR]

Rice bran (RB) corresponds to the outer layers of whole grain rice and contains several phenolic compounds (PCs) that make it an interesting functional food ingredient. PC richness is enhanced in pigmented RB varieties and requires effective ways of extraction of these compounds. Therefore, we investigated conventional and deep eutectic solvents (DES) extraction methods to recover a wide array of PCs from red and black RB. The RB were extracted with ethanol/water (60:40, v/v) and two DES (choline chloride/1.2-propanediol/water, 1:1:1 and choline chloride/lactic acid, 1:10, mole ratios), based on Generally Recognized as Safe (GRAS) components. Besides the quantification of the most typical phenolic acids of cereals, nontargeted metabolomic approaches were applied to PCs profiling in the extracts. Globally, metabolomics revealed 89 PCs belonging to flavonoids (52%), phenolic acids (33%), other polyphenols (8%), lignans (6%) and stilbenes (1%) classes. All extracts, whatever the solvents, were highly concentrated in the main phenolic acids found in cereals (37–66 mg/100 g in black RB extracts vs. 6–20 mg/100 g in red RB extracts). However, the PC profile was highly dependent on the extraction solvent and specific PCs were extracted using the acidic DES. The PC-enriched DES extracts demonstrated interesting DPPH scavenging activity, which makes them candidates for novel antioxidant formulations. [ABSTRACT FROM AUTHOR]

Consumption of pigmented rice as a staple food is rapidly increasing due to their healthy prospective and considered as functional food ingredients. Greater interest has been shown in many color rice varieties due to their multiple biological activities. The phenolic compounds have been found to consist of anthocyanidins, ferulic acid, diferulates, anthocyanins and polymeric proanthocyanidins. Anthocyanin is located in the bran layers of the rice kernel, while phenolic acids are mainly present in the bran layers of rice, existing as free, conjugated and bound forms. Keeping in view the several health benefits associated with the functional ingredients, such as anti-inflammatory, antioxidative and anticancer effects, pigmented rice is considered as a functional food and food ingredient in many Asian countries. The application and incorporation of bran into food products for the preparation of functional foods is increasing. Within the scope of this review, we highlighted the significant bioactive compounds from pigmented rice varieties and their potentials for medicinal and nutraceutical ingredients. The information provided from this could be of high benefit to the functional food industry and further research advance medicinal products. [ABSTRACT FROM AUTHOR]