Comparative study on amount of nutraceuticals in by-products from solvent and cold pressing methods of rice bran oil processing.

Rice bran oil (RBO) has become a popular oil globally. However, the RBO extraction process leaves various residue products, which contain bioactive substances of varying potency which could be significant sources of functional ingredients for both food production and pharmaceutical manufacture. The objective of our study was to compare the bioactive substances in various by-products derived from the two rice bran oil processing methods; solvent extraction and cold pressing. The residues from solvent extraction processing contained up to 97.37 mg/100 g of γ-aminobutyric acid in defatted rice bran, and the rice acid oil contained high levels of vitamin E (tocopherols, tocotrienols), up to 120.59 mg/100 g, as well as γ-oryzanol (3829.65 mg/100 g), phytosterol (599.40 mg/100 g), and policosanol compounds (332.79 mg/100 g). All of these values are higher than in the residues derived from cold pressing. Importantly, high amounts of total nutraceuticals (8.3 kg/100 kg) were found in residues from both processing methods, indicating the commercial potential of these residues as a source of functional ingredients for food production, as dietary supplements, and in pharmaceutical manufacture.

Structure and rheology of oleogels made from rice bran wax and rice bran oil.

Structural and rheological properties of oleogels consisting of 0.5-25 wt% rice bran wax (RBX) in rice bran oil (RBO) were explored. RBX was an efficient, thermoreversible oleogelator capable of structuring RBO at concentrations as low as 0.5 wt% RBX. A qualitative temperature-composition phase diagram showed that oleogels containing higher concentrations of RBX were expectedly the most resistant to melting. In oleogels at higher RBX concentrations, polarized light microscopy revealed the presence of a network of interlinked, long aspect ratio wax crystal needles up to 50 µm long. Upon heating, RBX crystals did not undergo any structural transition, based on the constant short spacings at ~ 4.16 and ~ 3.73 Å, indicative of an orthorhombic subcell, and d001 long spacing at 74-76 Šthat persisted until RBX fusion. This long spacing was ascribed to the presence of wax esters consisting of long-chain saturated fatty acids (C24 and C22) esterified to C28 - C34 saturated fatty alcohols. During cooling from 90 to 20 °C, the increase in oleogel viscosity resulting from the RBX liquid-solid phase transition was corroborated by DSC-based crystallization onset and enthalpy data. Similarly, elastic moduli and hardness both rose with increasing RBX concentration. This study, which demonstrated that RBX can structure RBO with distinct concentration-dependent properties, serves as the foundation for the development of oleogel-based approaches to saturated and trans fats replacement in processed foods.

Some Strategies for Utilization of Rice Bran Functional Lipids and Phytochemicals.

Rice bran contains a great amount of functional lipids and phytochemicals including γ-oryzanols, tocotrienols, and tocopherols. However, utilization of those compounds is limited and needs some proven guidelines for better implementation. We introduce some effective strategies for the utilization of rice functional lipids, including an introduction of pigmented rice varieties for better bioactive compounds, biofortification of rice tocotrienols, plasma technology for improving rice phytochemicals, supercritical CO2 extraction of high quality rice bran oil, and an example on the development of tocotrienol-fortified foods.

Comparative Studies between Conventional and Microwave Assisted Extraction for Rice Bran Oil.

The present work deals with comparison of microwave assisted extraction to that of conventional solvent extraction for the extraction of rice bran oil (RBO); focusing on extraction yield and oil composition. Microwave assisted extraction act as a green process over other method and proved that it is effective method for extraction of oil. The investigation also focuses on the study of functional group and component present in oil. Natural antioxidant component; its activity was confirmed by DPPH assay. The oryzanol content was also determined by measuring the optical density of the sample at 315 nm in n-heptane using UV visible spectrophotometer.

Anthocyanin-rich Riceberry bran extract attenuates gentamicin-induced hepatotoxicity by reducing oxidative stress, inflammation and apoptosis in rats.

Liver plays an important role in the detoxification and metabolic elimination of various drugs and harmful substances. The damaging effects on the liver tissue treated with gentamicin are multi-factorial and their mechanisms remain unclear. This study aimed to investigate the possible protective effects of anthocyanin-rich Riceberry bran extract on gentamicin-induced hepatotoxicity in rats. Riceberry bran extract was given by oral administration 30min before gentamicin injection for 15 consecutive days. Serum levels of liver marker enzymes, AST and ALT, were significantly elevated and the total serum protein level was markedly reduced in gentamicin-treated rats. Gentamicin injection led to the significant increase in hepatic MDA level and decrease SOD expression. Liver inflammation and apoptosis were observed in gentamicin-treated rats as indicated by the increases in NF-κB, TNF-αR1, COX2, and iNOS, caspase-3, Bax, and decrease in Bcl-XL expressions. Riceberry bran extract significantly prevented gentamicin-induced the elevations of serum AST, ALT and the reduction of serum total protein. These were related to the inhibition of oxidative stress, inflammation and apoptosis in Riceberry bran extract treatment. These findings suggest that anthocyanin-rich Riceberry bran extract can prevent liver dysfunction and damage induced by gentamicin, possibly through its antioxidant, anti-inflammatory and anti-apoptotic effects.