Rice Husk Extract Research Articles

Corrosion Inhibition and Adsorption Characteristics of Rice Husk Extracts on Mild Steel Immersed in 1M H2SO4 and HCl Solutions

Corrosion Inhibition and Adsorption Characteristics of Rice Husk Extracts on Mild Steel Immersed in 1M H2SO4 and HCl Solutions

English

Rice husk extract (RHE), bamboo extract (BE) and wood extract (WE) at different concentration levels (0.0, 0.1, 0.5, 1.0 and 1.5%) were evaluated (in completely randomized design) in vitro as an antagonist to mycelial growth of selected fungal pathogens of maize. Botanical preparations were utilized singly (rice husk, bamboo and wood extracts) and in combinations (RHE x BE, RHE x WE, BE x WE and RHE x BE x WE). RHE at 1.0% concentration and in combination- RHE x BE x WE at 1.5% concentration, completely inhibited mycelial growth of Fusarium solani, Fusarium equiseti, Fusarium verticilloides and Macrophomina phaseolina. Other botanical preparations, either singly or in combinations showed significant (p<0.05) reduction in mycelial growth of the fungal pathogens. Thus, these botanicals have phytofungicidal potentials towards controlling pathogenic fungi of maize, hence, could be useful in the control and management of maize diseases on large scale farming. Key words: Rice husk, bamboo, wood, extract, maize, mycelial growth, fungal pathogens.

Monitoring of oxidation behavior in mineral base oil additized with biomass derived antioxidants using FT-IR spectroscopy

The antioxidant potential of methanolic extract of rice husk and sawdust in mineral base oil is investigated by FT-IR spectroscopy during oxidation at 100 and 200 °C. The Rice husk extract is found to be more efficient than saw dust extract.

Evaluation of plant extracts as an antagonist to mycelial growth of Mycosphaerella fijiensis morelet

Three plant extracts (rice husk, wood and bamboo) at different concentration were evaluated in vitro as an antagonist to mycelial growth of Mycosphaerella fijienesis on different culture media using spread plate and mycelia dry weight method. The plant extracts had significant effects on the mycelial growth of Mycosphaerella fijiensis. Rice husk extract at concentration of 1, 1.5, 2.5 and 5% completely inhibited the mycelia growth of M. fijiensis in malt extract broth (MEB) and at 2.5 and 5% on malt extract agar (MEA). Wood extract at concentration of 1 and 1.5% inhibited the mycelial growth of M. fijiensis and completely at concentration of 2.5 and 5% on MEA. Although complete inhibition was only observed at 5% concentration on MEA for bamboo extract, the evaluated plant extracts could be recommended for the control of M. fijiensis on a large-scale farming.

Evaluation of Biological Activities of Rice Husk Extracts

This study was conducted to determine the biological activities of 70% ethanol extracts from rice husks of nine rice cultivars in Korea. The relative antioxidant activities of rice husk extracts were evaluated by determining DPPH, ABTS radical scavenging activity and reducing power. The contents of total polyphenol, flavonoid and r-oryzanol were measured by spectrophotometric methods. Among the extracts of rice husks, Nokmi rice husks tended to have the most effective antioxidant activities compared to other rice husk varieties. Seolgaeng rice husk extract showed anti-proliferative activity against cancer cell lines (MCF7 and NCI-H460), and Hongjinju rice husk extract significantly exhibited mitogenic activity.

Structural Characterization and Antioxidant Activity Evaluation of Lignins from Rice Husk

In recent years, lignin and extractives from herbaceous plants and crops are receiving increasing attention for their renewability and large annual biomass stock. It is worth noting that only a few studies deal with the chemical characterization of rice husk, a side product of one of the most important crops with regard to human nutrition. Thus, in this study lignin from rice husk was isolated and characterized. Two different extraction procedures were optimized and tested: acidolysis and alkaline enzymatic (AE). The different lignins isolated were fully characterized by means of gravimetric, chromatographic (GPC), and spectroscopic (31P NMR, 2D-HSQC-NMR) analyses with the aim to compare yields, sample purity, and chemical properties, recognized as key parameters for future development. Notwithstanding the extraction procedure, the results highlighted that rice husk lignin is mainly formed by guaiacyl and p-hydroxyphenyl units. The acidolytic approach showed an appreciable lignin recovery and high purity, whereas the AE lignin sample was found to be rich in residual polysaccharides and oxidized functionalities. Moreover, different rice husk extracts, along with acidolysis lignin and AE lignin specimens, were assayed for their antioxidant activity by means of a DPPH radical scavenging test.

Efeito de extratos de cascas de café e de arroz na emergência e no crescimento do caruru-de-mancha

Este trabalho objetivou determinar influências dos extratos aquosos de cascas de café e de arroz na emergência e no crescimento inicial do caruru-de-mancha (Amaranthus viridis L.). O delineamento experimental foi em blocos casualizados, com quatro repetições, em esquema fatorial (2x2x5), sendo dois tipos de casca, em dois solos (lavoura de café e terra de barranco) e cinco concentrações dos extratos (0, 5, 10, 15 e 20%). Extratos aquosos de cascas de café e de arroz, nas concentrações entre 10 e 20%, proporcionaram, respectivamente, maior estímulo e inibição na emergência. O extrato de casca de café proporcionou maior crescimento inicial e massa da matéria seca do caruru-de-mancha, enquanto a velocidade e a porcentagem de emergência foram mais inibidas por extrato de casca de arroz.