Nutrition and Applications of Rice Bran Oil: a Mini-overview

Rice bran oil is a healthy oil from many aspects.The oil has a balanced fatty acid profile comparing with many other vegetable oils.The key difference is the minor components or micronutrients or unsaponifiable matters contained in the oil that are very special and in larger percentages.The oil contains more than 1.5%oryzanol that gives nutritional and pharmaceutical functions from the studies so far.More studies are needed to demonstrate the wide functions in many aspects.The oil also contains large percentage of phytosterols which received huge amount of studies for nutritional applications.Furthermore,the oil contains tocopherols and tocotrienols,in which for the later particularly it gives many special functions including prevention of breast cancers for example.When the oil is properly processed and used in foods,those functions are more and more demonstrated in nutritional or biological studies.Thus the oil in food and pharmaceutical applications is in exploring both in academic studies and industrial practice.In this work,an overview of such progress is given.

Rice Bran Oil: Emerging Trends in Extraction, Health Benefit, and Its Industrial Application

Rice bran oil(RBO)is unique among edible vegetable oils because of its unique fatty acid composition,phenolic compound(γ-oryzanol,ferulic acid)and vitamin E(tocopherol and tocotrienol).It has become a great choice of cooking oil because of its very high burning point,neutral taste and delicate flavour.Non-conventional methods of RBO extraction are more efficient and environmentally friendly than conventional extraction methods.Advances in RBO extraction using innovative extraction strategies like super/sub-critical CO_(2),microwave-assisted,subcritical H_(2)O,enzyme-assisted aqueous and ultrasoundassisted aqueous extraction methods have proven to significantly improve the yields along with improved nutritional profile of RBO.The compositions and strategies for stabilization of RBO are well discussed.The constituents are present in the RBO contribute to antioxidative,anti-inflammatory,antimicrobial,antidiabetic and anti-cancerous properties to RBO.This has helped RBO to become an important substrate for the application in food(cooking oil,milk product and meat product)and non-food industries(polymer,lubricant,biofuel,structural lipid and cosmetic).This review provided comprehensive information on RBO extraction methods,oil stabilization,existing applications and health benefits.

Enzymatic Synthesis of Fatty Acid Methyl Esters from Crude Rice Bran Oil with Immobilized Candida sp. 99-125

The non-edible crude rice bran oil was extracted from white rice bran, and then was catalyzed by immobilized lipase for biodiesel production in this study. The effects of water content, oil/methanol molar ratio, temperature, enzyme amount, solvent,number of methanol added times and two-step methanolysis by using Candida sp. 99-125 as catalyst were investigated. The optimal conditions for processing 1 g rice bran oil were: 0.2 g immobilized lipase, 2 ml n-hexane as solvent, 20% water based on the rice bran oil mass, temperature of 40 °C and two-step addition of methanol. As a result, the fatty acid methyl esters yield was 87.4%. The immobilized lipase was proved to be stable when it was used repeatedly for 7 cycles.

Application of Taguchi’s Orthogonal Array in Multi Response Optimization of NO_xEmission of Crude Rice Bran Oil Methyl Ester Blend as a CI Engine Fuel

In this work an attempt was made to minimize the NOx emission of a crude rice bran oil methyl ester (CRBME) blend with less sacrifice on smoke density and brake thermal efficiency. Three factors namely fuel injection timing, percentage EGR and fuel injection pressure were chosen as the influencing factors for the set objective. Experiments were designed by employing design of experiments method and Taguchi’s L9 orthogonal array was used to test the engine. MRSN ratio was calculated for the response variables and the optimum combination level of factors was obtained simultaneously using Taguchi’s parametric design. ANOVA was employed to analyze the variance of MRSN and the most influencing factor for the set objective was taken from the ANOVA table. Obtained combination was confirmed experimentally and significant improvement was observed in the response variables.

Optimization of Extraction Technology for Rice Bran Oil

[ Objective ] This study aimed to optimize the extraction technology for rice bran oil. [ Method ] Using rice bran as raw material, effects of ultrasonicassisted extraction technology and different organic solvents, extraction durations, solid-liquid ratios and extraction temperatures on extraction results of rice bran oil were investigated. Based on the results of single-factor experiment, L9 （34 ） orthngonal experiment with three factors at three levels was conducted to optimize the extraction technological parameters, thus obtaining the optimal technological conditions for extracting rice bran oil. [ Result] Anhydrous ethanol led to the best extraction result; after ultrasonic treatment, the extraction rate of rice bran oil from raw material was not enhanced. The optimized technological parameters were ： extraction temperature of 80 ℃, extraction duration of 20 rain and solid-liquid ratio of 1：24 （ g： ml）. Under the optimized technological conditions, the extraction rate of rice bran oil reached 19.33%. [ Conclusion] This study laid solid foundation for further investigation and development of rice bran oil.

Production of Rice Bran Oil in India: a Technical Evaluation

India has the highest utilization of rice bran oil in terms of the available resources in the country.Parboiled rice tradition has made the available rice bran in relatively good quality.This makes the quality of crude rice bran oil being also high.Therefore the following processing is made relatively simple comparing with those high free fatty acid content crude rice bran oils.In India,physical refining is commonly used.Thus the oil refining yield is usually high.The unsaponifiable content is also higher comparatively.For example,oryzanol content is usually 1%to 1.5%in weight.Although there are a large number of rice bran oil small plants in India,the technology is relatively mature for the production of relatively good quality rice bran oil.In this short overview of the production technology of rice bran oil in India,the state of the art has been elaborated in a simple form.Particularly,the problems and challenges of the production technology have been evaluated with the background of decades of research and technology development work in India.

Quantitative analysis of γ-oryzanol content in cold pressed rice bran oil by TLC-image analysis method

Objective:To develop and validate an image analysis method for quantitative analysis ofγ-oryzanol in cold pressed rice bran oil.Methods:TLC-densitometric and TLC-image analysis methods were developed,validated,and used for quantitative analysis of γ-oryzanol in cold pressed rice bran oil.The results obtained by these two different quantification methods were compared by paired t-test.Results:Both assays provided good linearity,accuracy,reproducibility and selectivity for determination of γ-oryzanol.Conclusions:The TLC-densitomelric and TLC-image analysis methods providett a similar reproducibility,accuracy and selectivity for the quantitative determination of γ-oryzanol in cold pressed rice bran oil.A statistical comparison of the quantitative determinations of γ-oryzanol in samples did not show any statistically significant difference between TLC-densitometric and TLC-image analysis methods.As both methods were found to be equal,they therefore can be used for the determination of γ-oryzanol in cold pressed rice bran oil.

Effects of Tocols Rich Fraction Isolated from Rice Bran Oil Deodorizer Distillate on Plasma and Hepatic Lipid Concentrations in Rats

A great deal of attention has been focused on the potential health benefits of using rice bran oil because it is a rich source of bioactive compounds. Rice bran oil deodorizer distillate (RBODD) is a byproduct obtained from distillation of rice bran oil. Elevated plasma cholesterol level is one of the major risk factors for coronary heart disease. The objective of this study was to investigate the effects of tocols (tocopherols + tocotrienols) rich fraction isolated from RBODD on plasma and liver lipid concentrations in rats. Male Sprague Dawley rats (6 weeks of age) were randomly assigned into three groups: normal fat control (NFC), high fat control (HFC) and high fat diet plus tocols rich fraction (RBODD). RBODD was administered daily for 3 weeks by oral gavage using 5% of Tween-80 as a vehicle. The rats in the control groups received 5% of Tween-80 alone in the same manner. Blood samples and livers were collected at the end of the feeding period. RBODD group had significantly lower plasma triglyceride levels compared to the HFC group (p < 0.05). However, no significant changes for plasma total and lipoprotein cholesterol levels were found in RBODD compared with HFC. Compared to the rat fed HFC, hepatic free fatty acids were significantly reduced in the rats with the RBODD treatment (p < 0.05). The results suggest that the tocols rich fraction isolated from RBODD is associated with decreased plasma triglyceride and hepatic free fatty acids concentrations. Further study is needed to investigate the mechanism and optimal dose by which isomers of tocols lower triglyceride concentrations.

Pilot Scale Mill Characterization and Evaluation of Rice Bran Oil Concentration of Jazzman Rice

The demand for aromatic rice has increased in the United States during the last two decades. Jazzman, the first US-bred jasmine-type rice variety, was released by the Louisiana State University (LSU) AgCenter Rice Research Station in 2008 to compete for a market share of jasmine-type rice. Jazzman, a long grain aromatic rice variety, was developed from a cross between Ahrent and an unreleased aromatic Chinese rice line 96a-8. In pre-release field tests and laboratory scale evaluation, Jazzman rice yield and milling quality compared favorably with two high-yielding and good-milling non-aromatic long grain varieties, Cypress and Cheniere. Pilot scale evaluation of Jazzman for milling quality supported laboratory scale evaluation while providing additional data for milling optimization. Pilot scale milling uses larger rice samples than laboratory scale testing and employs a continuous process instead of the batch process used at laboratory scale. As a result, pilot scale milling offers more comprehensive information regarding the milling yield and quality of rice varieties as they are considered for industrial scale release. Another consideration for new rice varieties involves their potential for value-added processing, in which waste streams during processing can be used to create valuable products. The oil from rice bran is one such product. The objective of this study was to use pilot scale milling to determine the potential of Jazzman for industrial scale release, including its potential for value-added processing. Results showed that bran was easily removed during milling;the head rice recovery ranged from 66% to 74% as a function of milling flow rate. Water polishing had little effect on head rice recovery, but improved the final degree of milling (DOM) to a commercially acceptable level of 87 - 90. Additionally, rice bran oil concentration decreased as pilot scale flow rate increased, indicating that oil was concentrated in the outer bran layer of Jazzman. Pilot scale milling shows that Jazzman is a high-yielding and good-milling aromatic long grain rice variety.

Oxidative Stability of Green Tea Extract-Enriched Rice Bran Oil During Storage

Adding green tea extract to rice bran oil was expected to improve its oxidative stability,so this study was conducted to investigate oxidative stability of green tea extract-enriched rice bran oil(RBOG) during storage at 60℃ for 15 days compared to rice bran oil(RBO),olive(OL),canola(CN),and grape-seed oil(GS).Acid values did not increase during storage,and the highest value was found for OL.The peroxide values of RBOG,RBO,CN,OL,and GS increased for up to 15 days.The highest average rate constant for the change in peroxide value was found for RBO(0.282).TBARS increased continually during storage of RBOG,RBO,CN,and OL;however,the value increased for up to 9 days and then decreased for GS.The highest average rate constant of change in TBARS was found for CN.Overall,the results suggest that green tea extract improves oxidative stability of rice bran oil.

Liquefied dimethyl ether as alternative extraction solvent for high γ-oryzanol rice bran oil:Systematic HSP theory and experimental evaluation

This study aimed to systematically find an alternative solvent to replace hexane for the extraction of bio-oil with high𝛾-oryzanol content from rice bran(RB).The selection involved predicting solubility through Hansen solubility theory,experimental validation,determination of suitable extraction conditions,and comparison of oil quality with that of conventional hexane.A wide variety of solvents:subcritical water(SCW),supercritical carbon dioxide(SCCO_(2)),bio-based sol-vents(alcohols and terpenes),and liquefied dimethyl ether(LDME),were initially assessed for rice bran oil(RBO)and𝛾-oryzanol solubility using Hansen solubility spheres.Solvents demon-strating high solubility for both RBO and𝛾-oryzanol,including LDME,ethyl acetate,acetone,and others(alcohols and SCCO_(2))known for effective vegetable oil extraction,were selected/identified for experimental extraction comparison.Among these,LDME performed better overall,affording greater solubility and requiring less solvent,shorter duration,lower pressure,and no additional co-solvents for equivalent extractions.Optimal conditions for LDME extraction were identified as 30℃ with a solvent-to-sample ratio of 10 mL/g and an extraction time of 10 min.Oils extracted with LDME and hexane displayed similar fatty acid compositions and no adverse effects on RB protein and carbohydrate structures after LDME extraction were observed.This study demon-strates LDME as a promising alternative to replace hexane for RBO extraction to further valorize this abundant low-cost RB residue into bio-oil and its𝛾γ-oryzanol and de-oil RB co-products.

Laboratory studies of rice bran as a carbon source to stimulate indigenous microorganisms in oil reservoirs

There is a great interest in developing cost-efficient nutrients to stimulate microorganisms in indigenous microbial enhanced oil recovery（IMEOR） processes.In the present study,the potential of rice bran as a carbon source for promoting IMEOR was investigated on a laboratory scale.The co-applications of rice bran,K2HPO4 and urea under optimized bio-stimulation conditions significantly increased the production of gases,acids and emulsifiers.The structure and diversity of microbial community greatly changed during the IMEOR process,in which Clostridium sp.,Acidobacteria sp.,Bacillus sp.,and Pseudomonas sp.were dominant.Pressurization,acidification and emulsification due to microbial activities and interactions markedly improved the IMEOR processes.This study indicated that rice bran is a potential carbon source for IMEOR.

Rice Bran Oil Extraction by Screw Press Method:Optimum Operating Settings,Oil Extraction Level and Press Cake Appearance

The appearance of rice bran ＇cake＇ or discharge from a screw press corresponds to the level of oil produced in the extraction process. The relationships between operating settings, oil extraction level and cake appearance were studied. Cake characteristics reliably indicate the expected oil recovery extraction level. These conclusions applyed to both Chainat 1 rice bran and parboiled rice bran. Variables were the speed of the screw press （set at five levels from 8.5 to 19.8 r/min） and corresponding clearance distances between the screw and barrel （set between 1.0 and 1.9 cm）. Results showed that the maximum levels of extraction were 4.17% for the rice bran and 8.20% for the parboiled rice bran. At the maximum extraction level, the apparatus continuously discharged cake that were hard, crispy, flaky, shiny and polished on one side but dull and coarse on the other.

Effect of Blended Rice Bran and Olive Oil on Cardiovascular Risk Factors in Hyperlipidemic Patients

The present study was designed to evaluate the effectiveness of blended rice bran and olive oil on hyperlipidemic subjects. A total of 60 moderately hyperlipidemic patients (Total Cholesterol (TC) >200 mg/dl and/or Triglycerides (TG) >150 mg/dl) with an age range of 45 - 60 were selected from Mediciti Hospital of Ludhiana and were divided into two groups: Group A and Group B containing 30 subjects each. The subjects of Group B were given blended rice bran and olive oil for a time period of 45 days and were asked to continue with their routine eating and physical activity pattern. The subjects of Group A were kept on their regular cooking oil. The serum lipid values were assessed before and after the study. Additional parameters assessed included anthropometry, dietary fat intake and physical activity pattern. The results showed that there was an insignificant change in the average body mass index (BMI) of the subjects of Group B before (27.0 kg/m2) and after (26.9 kg/m2) the study respectively. Also, there was an insignificant change in the lipid levels of the subjects of Group B after the study. The levels of TC and LDL cholesterol decreased by 3.7 and 9.0 percent respectively. Whereas, the levels of TG and VLDL cholesterol increased by 9.5 percent in the subjects of Group B after the feeding trials. Further, systolic and diastolic blood pressure of the subjects of Group B reduced by 2.9 and 2.3 percent respectively. An insignificant change was observed in all the parameters of selected subjects. So, the present study recommends carrying out more long duration research studies to evaluate the effectiveness of this blended oil.

Anti-tumor activity of rice bran hydrolysates on migration, invasion and angiogenesis

Objective:To investigate anti-tumor effect of rice bran hydrolysates(RBH)on proliferation,migration,invasion,and angiogenesis of cholangiocarcinoma(CCA)cells,and elucidate the underlying mechanisms.Methods:RBH was prepared from Tubtim Chumprae rice(Oryza sativa L.)by hydrothermolysis followed by protease digestion.Phenolic content in RBH was analyzed by high-performance liquid chromatography.Human CCA cells,KKU-156,KKU-452,and KKU-100,were used to study the effects of RBH on proliferation,migration,invasion,and adhesion by wound healing,Transwell chamber,and fibronectin cell adhesion assays.Angiogenesis was evaluated using human umbilical vein endothelial cells.Proteins associated with cancer progression were analyzed by immunobloting assays.Results:RBH contained carbohydrates,proteins,lipids,and various phenolic compounds and flavonoids.RBH did not inhibit CCA proliferation,but strongly suppressed migration,invasion,adhesion of CCA cells,and the formation of tube-like capillary structures of human umbilical vein endothelial cells.Moreover,RBH downregulated phosphorylation of FAK,PI3K,and Akt,suppressed NF-κB nuclear translocation,decreased the expression of ICAM-1,vimentin and vascular endothelium growth factor(VEGF),and increased the expression of E-cadherin.Conclusions:RBH suppresses CCA cell migration and invasion and decreases expression of proteins involved in cancer metastasis.RBH is a potential food supplement for cancer prevention.

Sang-Yod rice bran hydrolysates alleviate hypertension, endothelial dysfunction, vascular remodeling, and oxidative stress in nitric oxide deficient hypertensive rats

Objective:To evaluate the potential therapeutic effect of Sang-Yod rice bran hydrolysates(SRH)and in combination with lisinopril against hypertension,endothelial dysfunction,vascular remodeling,and oxidative stress in rats with nitric oxide deficiency-induced hypertension.Methods:Hypertension was induced in male Sprague-Dawley rats by administration of a nitric oxide synthase inhibitor,Nω-nitro-L-arginine methyl ester(L-NAME)in drinking water for 6 weeks.Hypertensive rats were administered daily with SRH(500 mg/kg/day),lisinopril(1 mg/kg/day),or the combination of SRH and lisinopril by gastric lavage for the last 3 weeks of L-NAME treatment.Hemodynamic status,vascular reactivity to vasoactive agents,and vascular remodeling were assessed.Blood and aortic tissues were collected for measurements of oxidative stress markers,plasma angiotensin-converting enzyme(ACE)activity,plasma angiotensinⅡ,and protein expression.Results:L-NAME induced remarkable hypertension and severe oxidative stress,and altered contents of smooth muscle cells,elastin,and collagen of the aortic wall.SRH or lisinopril alone reduced blood pressure,restored endothelial function,decreased plasma ACEs and angiotensinⅡlevels,alleviated oxidant markers and glutathione redox status,and restored the vascular structure.The effects were associated with increased expression of endothelial nitric oxide synthase and decreased expression of gp91phox and AT1R expression.The combination of SRH and lisinopril was more effective than monotherapy.Conclusions:SRH alone or in combination with lisinopril exert an antihypertensive effect and improve endothelial function and vascular remodeling through reducing oxidative stress and suppressing elevated renin-angiotensin system.

Reactive oxygen species and senescence modulatory effects of rice bran extract on 4T1 and NIH-3T3 cells co-treatment with doxorubicin

Objective:To determine the effect of rice bran extract(RBE)in combination with doxorubicin on 4 T1 triple-negative breast cancer cells and NIH-3 T3 cells.Methods:RBE was obtained by maceration with n-hexane.The phytochemical profile of RBE was observed using highperformance liquid chromatography.Cytotoxic effect of RBE was evaluated through MTT assay.In addition,flow cytometry was used for cell cycle and apoptosis analysis.Cellular senescence was observed using SA-β-Gal assay and intracellular reactive oxygen species(ROS)levels were evaluated using DCFDA staining.The pro-oxidant property of RBE was also evaluated through 1-chloro-2,4-dinitrobenzene spectrophotometry and molecular docking.Results:RBE was obtained with a yield of 18.42%w/w and contained tocotrienols as the major compound.RBE exerted no cytotoxic effect on 4 T1 and NIH-3 T3 cells.However,RBE in combination with doxorubicin decreased 4 T1 cell viability synergistically(combination index<0.9)and induced apoptosis and senescence on 4 T1 cells.RBE significantly decreased senescence in doxorubicin-treated NIH-3 T3 cells.Additionally,RBE did not increase ROS levels in doxorubicin-treated 4 T1 cells.Meanwhile,the combination of RBE and doxorubicin reduced ROS levels in NIH-3 T3 cells.RBE significantly reduced glutathione-S-transferase activity and alpha-tocotrienol interacted with glutathione-Stransferase in the glutathione binding site.Conclusions:Rice bran may be used as a co-chemotherapeutic agent to improve the therapeutic effectiveness of doxorubicin while protecting against the cellular senescence effects of doxorubicin on healthy cells.

Protective effects of rice bran hydrolysates on heart rate variability,cardiac oxidative stress,and cardiac remodeling in high fat and high fructose diet-fed rats

Objective:To examine the ameliorative effect of rice bran hydrolysates(RBH)on metabolic disorders,cardiac oxidative stress,heart rate variability(HRV),and cardiac structural changes in high fat and high fructose(HFHF)-fed rats.Methods:Male Sprague-Dawley rats were daily fed either standard chow diet with tap water or an HFHF diet with 10%fructose in drinking water over 16 weeks.RBH(500 and 1000 mg/kg/day)was orally administered to the HFHF-diet-fed rats during the last 6 weeks of the study period.At the end of the treatment,metabolic parameters,oxidative stress,HRV,and cardiac structural changes were examined.Results:RBH administration significantly ameliorated metabolic disorders by improving lipid profiles,insulin sensitivity,and hemodynamic parameters.Moreover,RBH restored HRV,as evidenced by decreasing the ratio of low-frequency to highfrequency power of HRV,a marker of autonomic imbalance.Cardiac oxidative stress was also mitigated after RBH supplementation by decreasing cardiac malondialdehyde and protein carbonyl,upregulating eNOS expression,and increasing catalase activity in the heart.Furthermore,RBH mitigated cardiac structural changes by reducing cardiac hypertrophy and myocardial fibrosis in HFHFdiet-fed rats.Conclusions:The present findings suggest that consumption of RBH may exert cardioprotective effects against autonomic imbalances,cardiac oxidative stress,and structural changes in metabolic syndrome.

Rapid semi-quantification of triacylglycerols,phosphatidylcholines,and free fatty acids in the rice bran of one grain

We developed a microplate assay method for determining the contents of triacylglycerols（TAGs）, phosphatidylcholines（PCs）, and free fatty acids（FFAs） in the rice bran of one grain using enzymatic reactions. In this method, enzymes from commercially available kits were used. Optimum reaction conditions were established. It was found that Nonidet P-40 was the optimal among the three surfactants used（Triton X-100, Tween 40, and Nonidet P-40） when lipid was dissolved in a reaction solution. Using this method, it was possible to quantify TAGs, PCs, and FFAs in concentration ranges of 7–150, 5–70, and 8–200 mg L-（–1）, respectively. Furthermore, when the TAG contents in the rice bran were measured, the values closely corresponded to those obtained by extracting from large amounts of rice bran. However, sufficient data on the PC and FFA contents in rice bran are not available for valid comparisons. Although this method can accurately quantify the TAG contents in the rice bran of one grain, the accuracy of the PC and FFA contents has not been verified. Hence, future study is necessary.

Chemical,Sensorial and Rheological Properties of a New Organic Rice Bran Beverage

Rice bran is a solid residue from rice polishing that is used in animal nutrition and rice oil production. Cultivation conditions with agro-toxics, lipids instability, and tendency for mycotoxin contamination restrict its application in human nutrition. Therefore, organic agriculture is an alternative to use the properties of rice bran. Rice bran beverage is a new cereal product from organic rice. This work presents the preliminary results of the chemical and rheological studies of a bath pasteurized rice bran beverage. Compared with integral defatted milk, soy extracts, and brown rice low-fat milk, the rice bran beverage studied in this work presents itself as an important source of minerals and unsaturated lipids. All essential amino acids were found in this product. Glutamic and aspartic acids were predominant. Bath pasteurization at boiling water temperature for 15 and 30 min was adequate for microbiological safety. Refrigeration storage for 20 days, evaluated by pH and acidity variations, was ideal for assessment of the beverage conservation time. The beverage viscosity was of the Newtonian standard behavior, and its viscosity during storage was not a good parameter to evaluate shelf life. Sensory preference tests showed positive perspectives for this new beverage.