Pigmented rice (Oryza sativa L.) genotypes become increasingly important in the agroindustry due to their bioavailable compounds that have the ability to inhibit the formation and/or to reduce the effective concentration of reactive cell-damaging free radicals. This study aimed at determining the concentrations of free, and bound phytochemicals and their antioxidant potential (DPPH and ABTS assays) as well as the vitamin E and carotenoids contents of non-pigmented and pigmented rice genotypes. The results confirmed that the content of total phenolics and flavonoids contents, as well as the antioxidant capacity (DPPH and ABTS assays) of pigmented rice was several-fold greater than non-pigmented ones (4, 4, 3 and 5 times, respectively). Compounds in the free fraction of pigmented rice had higher antioxidant capacity relative to those in the bound form, whereas the non-pigmented rice cultivars exhibited the opposite trend. Ferulic acid was the main phenolic acid of all rice genotypes, whereas black rice contained protocatechuic and vanillic acids in higher contents than red rice and non-pigmented rice genotypes. For vitamin E (tocopherols and tocotrienols) and carotenoids (lutein, zeaxanthin and β-carotene) contents, no obvious concentration differences were observed between non-pigmented and pigmented rice, with the black rice exhibiting the highest carotenoid content. Overall, pigmented rice genotypes contain a remarkable amount of bioactive compounds with high antioxidant capacity; therefore, they have great potential as a source of bioactives for developing functional food products with improved health benefits.
Authors:S. Genieva, S. Turmanova, A. Dimitrov, P. Petkov, and L. Vlaev
blackrice husk ash (BRHA) or so-called “black ash” which contains different amounts of amorphous carbon incorporated with silica. This material has very high porosity and may be used as an adsorbent for adsorption of non-polar molecules, such as
Authors:S. Genieva, S. Turmanova, A. Dimitrova, and L. Vlaev
Rice husk is a by-product of rice milling process and are a major waste product of the agricultural industry. They have now
become a great source as a raw biomass material for manufacturing value-added silicon composite products, including silicon
carbide, silicon nitride, silicon tetrachloride, pure silicon, zeolite, fillers of rubber and plastic composites, adsorbent
and support of catalysts. The bulk and true densities of raw rice husk with different moisture and sizes were determined.
The rice husk was subjected to pyrolysis in fluidized-bed reactor in air or nitrogen atmosphere.
The products obtained were characterized by thermogravimetric and X-ray powder analysis, IR-spectroscopy, scanning electron
microscopy and nitrogen adsorption at 77 K. The specific surface area of the products is comparable with this of γ-Al2O3. The kinetics of H2SeO3 adsorption out of aqueous solutions at 298 K was studied. The adsorption capacity of white rice husks ash was found to be
higher than that of black rice husk ash and the adsorption kinetics obeyed the second order kinetic equation.
Authors:A-C. Tecucianu, O. Drăghici, and S. Oancea
of polyphenols–a comprehensive review . Trends Food Sci. Tech. , 88 , 302 - 315 . 10.1016/j.tifs.2019.03.029 Hou , Z. , Qin , P. , Zhang , Y. , Cui , S. & Ren , G. ( 2013 ): Identification of anthocyanins isolated from blackrice
Authors:Xue-Gang Chen, Shuang-Shuang Lv, Ping-Ping Zhang, Lu Zhang, and Ying Ye
–A750 (ashed in air, white rice hull ash, WRHA) or N300–N750 (ashed in nitrogen, blackrice hull ash, BRHA), respectively, according to the ashing temperatures and atmospheres.
The phase purity and