Lipidomics analysis unveils the dynamic alterations of lipid degradation in rice bran during storage

Recent explorations into rice bran oil (RBO) have highlighted its potential, owing to an advantageous fatty acid profile in the context of health and nutrition. Despite this, the susceptibility of rice bran lipids to oxidative degradation during storage remains a critical concern. This study focuses on the evolution of lipid degradation in RBO during storage, examining the increase in free fatty acids (FFAs), the formation of oxylipids, and the generation of volatile secondary oxidation products. Our findings reveal a substantial rise in FFA levels, from 109.55 to 354.06 mg/g, after 14 days of storage, highlighting significant lipid deterioration. Notably, key oxylipids, including 9,10-EpOME, 12,13(9,10)-DiHOME, and 13-oxoODE, were identified, with a demonstrated positive correlation between total oxylipids and free polyunsaturated fatty acids (PUFAs), specifically linoleic acid (LA) and α-linolenic acid (ALA). Furthermore, the study provides a detailed analysis of primary volatile secondary oxidation products. The insights gained from this study not only sheds light on the underlying mechanisms of lipid rancidity in rice bran but also offers significant implications for extending the shelf life and preserving the nutritional quality of RBO, aligning with the increasing global interest in this high-quality oil.

Arsenic contamination in rice, radiation and chemical methods of measurement, and implications for food safety

Rice products, including those given to infants, could be naturally polluted with arsenic. This issue for all age groups should be a top priority for the world food industry and the public. Food regulators assume incorrectly that infants' food and other rice products are safe, and health, agriculture and commerce authorities follow no clear guidelines. A common measure has been to place a ML on the amount of iAs in white rice and food intended for children and pregnant women. Although oAs is less toxic than iAs, it is still toxic; consequently, the ML of arsenic for the different age groups should be also specified. However, the ML of iAs in polished white rice for infants is very low (100 μg/kg for infants and 200 μg/kg for adults) and is difficult to measure. Using neutron activation for research is very useful in improving safety standards in the food industry. The second purpose of this review study is to report on the experimental results and methods used for measurements adopted at the Delft Reactor in the Netherlands with a colleague of the quantity of arsenic in 21 samples of different rice products from a variety of brands.

Rice bran oil supplementation protects swine weanlings against diarrhea and lipopolysaccharide challenge

Early weaned piglets suffer from oxidative stress and enteral infection, which usually results in gut microbial dysbiosis, serve diarrhea, and even death. Rice bran oil (RBO), a polyphenol-enriched by-product of rice processing, has been shown to have antioxidant and anti-inflammatory properties both in vivo and in vitro. Here, we ascertained the proper RBO supplementation level, and subsequently determined its effects on lipopolysaccharide (LPS)-induced intestinal dysfunction in weaned piglets. A total of 168 piglets were randomly allocated into four groups of seven replicates (42 piglets each group, (21±1) d of age, body weight (7.60±0.04) kg, and half males and half females) and were given basal diet (Ctrl) or basal diet supplemented with 0.01% (mass fraction) RBO (RBO1), 0.02% RBO (RBO2), or 0.03% RBO (RBO3) for 21 d. Then, seven piglets from the Ctrl and the RBO were treated with LPS (100 μg/kg body weight (BW)) as LPS group and RBO+LPS group, respectively. Meanwhile, seven piglets from the Ctrl were treated with the saline vehicle (Ctrl group). Four hours later, all treated piglets were sacrificed for taking samples of plasma, jejunum tissues, and feces. The results showed that 0.02% was the optimal dose of dietary RBO supplementation based on diarrhea, average daily gain, and average daily feed intake indices in early weaning piglets. Furthermore, RBO protected piglets against LPS-induced jejunal epithelium damage, which was indicated by the increases in villus height, villus height/crypt depth ratio, and Claudin-1 levels, as well as a decreased level of jejunal epithelium apoptosis. RBO also improved the antioxidant ability of LPS-challenged piglets, which was indicated by the elevated concentrations of catalase and superoxide dismutase, and increased total antioxidant capacity, as well as the decreased concentrations of diamine oxidase and malondialdehyde in plasma. Meanwhile, RBO improved the immune function of LPS-challenged weaned piglets, which was indicated by elevated immunoglobulin A (IgA), IgM, β‍‍-defensin-1, and lysozyme levels in the plasma. In addition, RBO supplementation improved the LPS challenge-induced dysbiosis of gut microbiota. Particularly, the indices of antioxidant capacity, intestinal damage, and immunity were significantly associated with the RBO-regulated gut microbiota. These findings suggested that 0.02% RBO is a suitable dose to protect against LPS-induced intestinal damage, oxidative stress, and jejunal microbiota dysbiosis in early weaned piglets.

Genome-wide association study reveals useful QTL and genes controlling the fatty acid composition in rice bran oil using Vietnamese rice landraces

In rice (Oryza sativa L.), rice bran contains valuable nutritional constituents, such as high unsaturated fat content, tocotrienols, inositol, γ-oryzanol, and phytosterols, all of which are of nutritional and pharmaceuticals interest. There is now a rising market demand for rice bran oil, which makes research into their content and fatty acid profile an area of interest. As it is evident that lipid content has a substantial impact on the eating, cooking, and storage quality of rice, an understanding of the genetic mechanisms that determine oil content in rice is of great importance, equal to that of rice quality. Therefore, in this study, we performed a genome-wide association study on the composition and oil concentration of 161 Vietnamese rice varieties. Five categories of fatty acids in rice bran were discovered and the bran oil concentration profile in different rice accessions was identified. We also identified 229 important markers related to the fatty acid composition of bran oil, distributed mainly on chromosomes 1 and 7. Seven quantitative trait loci and five potential genes related to unsaturated fatty acid content were detected, including OsKASI, OsFAD, OsARF, OsGAPDH, and OsMADS29. These results provide insights into the genetic basis of rice bran oil composition, which is pivotal to the metabolic engineering of rice plants with desirable bran oil content through candidate genes selection.

Anti-inflammatory and antioxidant properties of rice bran oil extract in copper sulfate-induced inflammation in zebrafish (Danio rerio)

Tocotrienols have strong antioxidant properties; however, tocotrienol has not been investigated in detail in aquatic products. In this study, the anti-inflammatory and antioxidant activities of the tocotrienol-rich fraction from rice bran oil and its potential mechanism were verified in a zebrafish CuSO₄ inflammation model. The in vitro antioxidant activity was evaluated using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) stable radical method. The copper chelating activity was determined using the pyrocatechol violet method. Intracellular reactive oxygen species in zebrafish were detected using a fluorescent ROS probe. Transgenic Tg (lyz: DsRed2) zebrafish were used for neutrophil transmigration assays. The mRNA expression levels of antioxidant and pro-inflammatory factor genes were measured using quantitative real-time reverse transcription PCR. In the concentration range tested, 100 μg/mL TRF had the highest copper chelating activity (10%). TRF showed DPPH-free radical scavenging ability, which was 53% at 100 μg/mL TRF. TRF effectively repressed ROS generation and inhibited neutrophil migration to the inflamed site. Moreover, TRF upregulated the expression of antioxidant genes sod and gpx4b, inhibited the expression of pro-inflammatory factors tnfa and il8, and suppressed CuSO₄-induced inflammation. In conclusion, TRF has significant anti-inflammatory and antioxidant properties, which supports the use of TRF as an aquatic feed additive to improve the anti-inflammatory and antioxidant capacity of aquatic products.

Deacidification of high-acid rice bran oil by the tandem continuous-flow enzymatic reactors

Rice bran oil (RBO) contains a variety of nutrients, but the high acid values largely hinder its processing into edible oil. Thus, the tandem continuous-flow reactors are proposed and developed for the enzymatic deacidification of RBO and simultaneous production of functional oils. The results indicate that the Candida antarctica lipase B (CALB) immobilized on the hydrophobic ordered mesoporous silicon (OMS-C₁₈) increased 6.6 times of the catalytic activity and improved at least 20 ℃ of temperature tolerance compared to the commercial Novozym 435. The tandem continuous-flow enzymatic reactors removed 91.4% of free fatty acid and increased 9 and 12 times of phytosterol ester and diacylglycerol in RBO, respectively. Moreover, the retention rate of γ-oryzanol was at least 40% higher than that obtained by traditional alkali refining. This study provides an effective and sustainable method to continuously convert the low-value RBO into value-added products, which brings huge potential to cleaner industrial production.

Physicochemical properties of rice bran blended oil in deep frying by principal component analysis

This study aimed to obtain a rice bran blended oil with good quality in deep frying. The thermal stability, nutrients and harmful substances of rice bran oil (RBO) and other four oils (palm oil, PO; cottonseed oil, CO; sunflower oil, SuO; soybean oil, SO) were analyzed. Besides, the blended oil formulas were established by the principal component analysis method, and their physicochemical properties, frying characteristic indicators, nutrients, and harmful substances were compared. The results provided that two suitable blended oil formulas (F1: 50% RBO + 40% PO + 10% CO; F2: 60% RBO + 35% PO + 5% CO) of good frying performance were attained by principal component analysis. The acid value (1.19 mg/g), peroxide value (0.09 meq/kg), residual oil rate (8.07%), 3-MCPD ester reduction content (2.33 mg/kg), benzopyrene concentration content (0.95 μg/kg) and vitamin E consumption rate (67.86%) in F2 were lower than that in F1. Moreover, the oryzanol retention rate (87.84%) of F2 was higher than that of F1. In summary, F2 was more conducive to human health and more suitable than F1 in deep-frying. This information had an important directive on the industrial production of rice bran blend oil.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05472-7.

Effect of novel combination processing technologies on extraction and quality of rice bran oil

Rice bran, a primary by-product from the rice processing industries, containing 10-15% oil, attracts significant attention from consumers due to its many health-promoting effects. The extraction methodology used is one of the most critical factors affecting the quality and yield of oil from rice bran. Using solvents is the current commercial process for rice bran oil extraction, which has its setbacks. It is challenging and expensive, and there is a risk of traces of solvent residue in the oil. Emerging combination extraction technologies offer zero to minimal solvent residues or chemical deformation while considering increasing environmental and energy footprint. Emerging combination processing technologies include new-age methods like supercritical fluid extraction, sub-critical fluid extraction, ultrasound-assisted enzymatic extraction, ohmic heating, and microwave-assisted extraction. These techniques have been reported to extract oil from rice bran, improving extraction efficiency and quality. These techniques demonstrate solid prospects for future applications. The present review discusses and compares these emerging technologies for oil extraction from rice bran commercially.

Application of magnetic immobilized enzyme of nano dialdehyde starch in deacidification of rice bran oil

Glutaraldehyde is usually used as a cross-linking agent in the immobilization of enzymes, but this will have a negative effect on the enzyme. Dialdehyde starch can effectively replace glutaraldehyde as a cross-linking agent, but the large particle size of dialdehyde starch affects the performance of immobilized enzyme. In this study, dialdehyde starch nanoparticles (DSNP) were combined with modified Fe₃O₄ to obtain magnetic carrier (MDSNP), and Candida Antarctica lipase B (CALB) was crosslinked to the carrier to obtain magnetic immobilized enzyme (MDSNPCALB). The characterization results show that the functional groups of each material have obvious characteristic absorption peaks, strong diffraction peaks and typical crystal structures, high magnetism, no coercivity, relatively good dispersion and nano particle size. MDSNPCALB was added to degummed rice bran oil (RBO) and ethanolamine was used as an acyl receptor for acylation and deacidification. After repeated use for 10 times, MDSNPCALB remained highly active, indicating that MDSNPCALB can be effectively used for the deacidification of RBO.

Life cycle assessment of rice bran oil production: a case study in China

Environmental problems caused by the food processing industry have always been one of the concerns for the public. Herein, for the first time, a gate-to-gate life cycle assessment (LCA) was employed to evaluate the environmental impact of rice bran oil production. Four subsystems, namely, transportation of the raw rice bran to oil factory, crude oil extraction, oil refining, and oil storage, were established. The product sustainability software GaBi and the method CML 2001-Jan. 2016 were used to calculate and analyze the environmental burdens at each stage of the rice bran oil production chain. The results show the oil refining stage had the greatest environmental impact, followed by the oil extraction stage. High demands for coal and electricity make a critical difference in generating vast majority of environmental impacts. Modifying the electricity source and replacing traditional fuels with cleaner ones will do bring benefits to the sustainable development of the industry.

Characterization of encapsulated γ-oryzanol powder by spray drying using whey protein and maltodextrin as wall materials

Characterizations of encapsulated γ-oryzanol powder (EOP) using whey protein concentrate (WPC) and maltodextrin as wall materials were studied. Rice bran oil (RBO) with 2% γ-oryzanol was encapsulated using different concentrations of WPC (0.2-1.0%) combined with 10% of maltodextrin before spray drying. The physicochemical characteristics and reconstitution of EOP were investigated. The results found that different concentrations of WPC affected EOP characteristics. The EOP coated 1% WPC exhibited low moisture content and water activity (a_w) containing high γ-oryzanol content and encapsulation efficiency. Morphology of EOP using SEM displayed spheroid shape with smooth and crack-free surface. However, EOP emulsion had relatively larger particle size and lower solubility index than the fresh emulsion after reconstitution, but a good creaming stability of reconstituted EOP was observed. Therefore, it can be concluded that using 1% WPC combined with 10% maltodextrin provided good performance of encapsulated RBO with 2% γ-oryzanol using spray drying. According to physicochemical characteristics, the EOP has good potential as a food ingredient for food industry and as an excipient for pharmaceutical and cosmetic industries.

Rice bran oil could favorably ameliorate atherogenicity and insulin resistance indices among men with coronary artery disease: post hoc analysis of a randomized controlled trial

BACKGROUND

Despite recent advances in recognizing more reliable indicators to estimate the coronary artery disease (CAD) patients' response to treatment and prognosis, less attention has been paid to evaluating them in clinical trials. Hence, the present research was conducted to study the impact of rice bran oil (RBO) versus sunflower oil (SFO) on various atherogenicity and insulin resistance markers.

METHODS

In the present 8-week randomized controlled trial, 40 CAD men with an average age of 56 years were allocated randomly into the intervention or control group to use RBO or SFO (30 g/day) plus a standardized dietary plan. As a further analysis, eight atherosclerosis-related indices were calculated before and after the study.

RESULTS

Analysis of covariance test in which potential confounders and baseline levels were considered, indicated that using RBO compared to SFO reduced Castelli's risk index I and II (adjusted means:3.29, 1.52 vs. 4.61, 2.20, respectively), atherogenic coefficient (2.29 vs. 3.61), lipoprotein combine index (6.54 vs. 17.53), and cholesterol index (0.46 vs. 1.20) after the trial (P-value ≤ 0.002). Also, the RBO group yielded significantly lower triglyceride glucose index (8.73 vs. 9.13) (P-value = 0.010). Further, marginally significant amelioration in triglyceride/HDL ratio and atherogenic index of plasma (1.48 and 0.13 vs. 1.86 and 0.24 respectively) were noted (P-value = 0.07). Spearman correlation analysis detected significant positive correlations between alterations in TNF-α serum levels (ng/L) and the majority of evaluated indices (P-value < 0.05).

CONCLUSION

Taken together, incorporating 30 g of RBO into the patient's usual diet appeared effective in ameliorating atherogenicity and insulin resistance indicators among men with CAD, probably in relation to its anti-inflammatory properties.

TRIAL REGISTRATION

The protocol of the current trial was retrospectively recorded in the Iranian clinical trial registration system (IRCT) with the registration number of IRCT20190313043045N1 (URL: https://en.irct.ir/trial/38346 ; Registration date: 2019-04-27).

Supercritical CO2 extraction of lycopene from pink grapefruit (Citrus paradise Macfad) and its degradation studies during storage

Lycopene was extracted from pink grapefruit using SC-CO₂ and rice bran oil as co-solvent. Response surface methodology was employed to evaluate the individual and interactive effects of three process parameters varied at five levels i.e. pressure (250, 300, 375, 450 & 500 bar), temperature (55, 60, 70, 80 & 85 °C), and extraction time (60, 90, 135, 180 & 210 min). Single optimum point for multiple response variables was achieved at 325 bar, 64 °C, and 143 min with overall desirability of 0.92 at which 70.52 ± 3.65% (lycopene extraction efficiency) and 11154 ± 148 ppm (γ-oryzanol) were predicted. Extraction temperatures of more than 80 °C and time beyond 180 min led to the isomerization of lycopene. Lycopene storage at 3 °C, 10 °C, & 25 °C showed average k and half-life values as 0.018, 0.030, & 0.075 and 40, 23, & 9 days, respectively for first-order degradation kinetics; depicting faster degradation at higher storage temperatures.

Determination of singlet oxygen quenching rate and mechanism of γ-oryzanol

Photooxidation is one of the causes of quality deterioration in food. An antioxidant or singlet oxygen quencher is urgently needed to prevent photooxidation. γ-Oryzanol was recognized as a naturally present antioxidant in rice bran products. This research aimed to calculate the singlet oxygen quenching rate and its mechanism of γ-oryzanol to evaluate the potency of γ-oryzanol as singlet oxygen quencher. A series of linoleic acid (50 and 100 mM) or γ-oryzanol (0.7 and 1.5 mM) were prepared separately in ethanol: chloroform (96:4, v/v) containing 25 ppm of erythrosine. High-Performance Liquid Chromatography quantified the degradation of γ-oryzanol. Meanwhile, Gas Chromatography determined the changes in linoleic acid content during photooxidation. The singlet oxygen quenching rate was calculated by steady-state. The singlet oxygen quenching rate of γ-oryzanol was 3.04 × 106/M/s by physical and chemical quenching mechanism. Photooxidation caused the declined of γ-oryzanol by 0.1421 mM/h. Based on singlet oxygen quenching rate calculation, it suggests that γ-oryzanol can perform as a singlet oxygen quencher with slightly dominated by physical quenching mechanism (52.28%). The rest it performed via a chemical quenching mechanism.

Preparing spray-dried cholesterol free salad dressing emulsified with enzymatically synthesized mixed mono- and diglycerides from rice bran oil and glycerol

A spray-dried cholesterol free salad dressing powder was developed using mixed mono- and diglycerides (MG-DG) as emulsifier. The optimum conditions for enzymatic synthesis of the MG-DG from rice bran oil (RBO) and glycerol (Gly) using Candida antarctica lipase was investigated. The synthesis was done by glycerolysis of refined RBO and Gly at molar ratios of 2:1, 2.5:1 and 3:1 (Gly to RBO) and enzyme concentrations of 2% and 5%. Highest MG and DG yield (0.54 ± 0.01 and 0.49.03 ± 0.0 mg/mL) was obtained in sample prepared using 2:1 molar ratio and 5% enzyme concentration and this sample is considered optimum. Salad dressings prepared using 0.5, 1.0, and 1.5% MG-DG concentration (of optimum MG-DG) were spray dried at inlet temperatures of 150, 160 and 170 °C to find the best conditions. Salad dressing of 0.5% MG-DG spray-dried at 170 °C had the highest powder yield (42.70%), solubility (98.04%) and stability (100%). After reconstitution, this optimum sample was compared well next to a control salad dressing prepared using commercial distilled monoglycerides. These findings demonstrate the feasibility of preparing a spray dried salad dressing powder with the synthesized MG-DG as an emulsifier.

Synthesis and characterization of novel tamarind gum and rice bran oil-based emulgels for the ocular delivery of antibiotics

In this study, we developed tamarind gum (TG) and rice bran oil (RBO)-based emulgels. The control formulation (TR0), did not contain RBO. The emulgels were named as TR1, TR2, TR3, and TR4, which contained 5% (w/w), 10% (w/w), 15% (w/w), and 20% (w/w/) of RBO, respectively. The microscopic studies showed that the emulgels were biphasic in nature. FTIR spectroscopy revealed the reduction in the hydrogen bonding with an increase in the RBO content. Impedance profiles suggested that the resistive component of the emulgels was increased as the RBO content was increased. The thermal analysis suggested that the addition of RBO reduced the water holding capacity of the emulgels. Stress relaxation studies revealed that the fluidic component was considerably higher in TG/RBO-based emulgels as compared to TR0. In vitro release study of the model drug (ciprofloxacin HCl; a hydrochloride salt of ciprofloxacin) suggested a significantly lower release from the emulgel matrices (TR1-TR4) in comparison to TR0. However, ex vivo corneal permeation of the drug increased with an increase in the RBO content. Since the emulgels were able to improve the corneal permeation of the model drug, the emulgels can be explored to deliver drugs to the internal structures of the eye.

Characterization and determination of free phytosterols and phytosterol conjugates: The potential phytochemicals to classify different rice bran oil and rice bran

Phytosterols are important beneficial compounds found in rice bran (RB) and rice bran oil (RBO). Although relationships have been confirmed between the forms of phytosterols and their bioactivities, the analysis of different forms of phytosterols in RB and RBO has been lacking. In this study, high temperature gas chromatography-mass spectrometry (HTGC-MS) was combined with the single standard to determine multi-components (SSDMC) method to determine free sterols (FSs) and steryl glycosides (SGs) in RB and RBO. High-performance liquid chromatography (HPLC) was used to determine steryl ferulates (SFs). There was clear variation in the composition of FS, SF and SG, indicating that different forms of phytosterols can discriminate between different RB and RBO. The developed method may be also useful for the detection of other compounds of interest in oils, oil seeds or cereals.

Antioxidant interaction of α-tocopherol, γ-oryzanol and phytosterol in rice bran oil

In this study, purified rice bran oil (RBO) was used as a lipid matrix model to study the individual and binary antioxidant capacity of the minor constituents (α-tocopherol, γ-oryzanol and phytosterol) added at different concentrations and ratios. The results revealed that concentration influenced on the oxidation stability and scavenging capacity, while ratio mainly affected the type of interaction or the degree of synergism or antagonism. It was important to notice that the antioxidant capacity of α-tocopherol would decrease under high concentration. Besides, the inhibition of phytosterol on α-tocopherol and the formation of hydrogen bond between γ-oryzanol and phytosterol were speculated by the interactions of these minor constituents. This work helps to select efficient combinations for stabilizing the anti-oxidation of nutrient enriched RBO or provide suggestions for moderate retain of minor constituents in RBO.

Isolation and structural elucidation of unique γ-oryzanol species in rice bran oil

Even though γ-oryzanol (OZ) such as 24-methylenecycloartanyl ferulate (24MCAFA) is abundant in purified rice bran oil, we realized that the oil contained the prospect of two additional novels of OZ species. To identify this, we isolated and analyzed their chemical structures by using HPLC-UV-MS, NMR, and IR. We revealed for the first time that the oil had also contained cyclobranyl ferulate (CBFA) and cyclosadyl ferulate (CSFA) which are likely to be exist due to the isomerism of 24MCAFA under acid condition. OZ profile including CBFA and CSFA was roughly similar between commercial rice bran oils and processed foods containing the oils, suggesting that people might have often consumed CBFA and CSFA from rice bran oils and/or processed foods. Since different OZ species are known to have different functionality, this study opens the chance to explore more the contribution of CBFA and CSFA for human health and wellness.

Effects of enzymatic free fatty acid reduction process on the composition and phytochemicals of rice bran oil

The effects of enzymatic free fatty acid reduction process (EFFARP) on the composition and phytochemicals of dewaxed and degummed rice bran oil (DDRBO) were investigated and compared with the effects observed using internal acyl acceptors. The acid value of DDRBO was effectively decreased from 16.99 mg KOH/g to approximately 0.36 mg KOH/g by EFFARP. EFFARP significantly decreased the moisture content and peroxide value of DDRBO and increased the induction period. The Sn-2 fatty acid comoposition of DDRBO after EFFARP was very reaching the total fatty acid composition. EFFARP significantly increased the triacylglycerol content compared to the control, while the oryzanol content was not obviously affected. The contents of free sterol, and total tocopherol and tocotrienol were increased slightly by EFFARP compared to the control. When conducted under vacuum with added nitrogen, EFFARP shows great application potential in the edible oil industry.

Extraction of γ-oryzanol from rice bran using diverse edible oils: enhancement in oxidative stability of oils

Diverse edible oils including perilla, corn, soybean, canola, sunflower, olive, and grape seed oils were mixed with heat-stabilized rice bran to extract γ-oryzanol from the rice bran. The oxidative stabilities of the oils with or without extraction were compared by analyzing the headspace oxygen content, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV). Grape seed oil extracted significantly high γ-oryzanol content while canola oil extracted lowest γ-oryzanol content (p < 0.05). All the solvent oils except corn oil possessed enhanced oxidative stability at 100 °C after extracting γ-oryzanol from stabilized rice bran, based on the results of the headspace oxygen depletion and CDA methods. However, all the recovered oils had high p-AV than vegetable oils. Especially, perilla oil had an exceptionally high p-AV, which may be due to its high linolenic acid content.

Microencapsulation of rice bran oil using pea protein and maltodextrin mixtures as wall material

In this work, the encapsulation of rice bran oil extracted using supercritical CO2 has been studied. In the first stage, the emulsification process by high pressure homogenization was studied and optimized. The effect of the working pressure (60-150 MPa), the composition of the carrier (mixtures of pea protein isolate (PPI) and maltodextrin (MD), from 50 to 90% of PPI) and the carrier to oil ratio (2-4) on the emulsion droplet size (EDS) was studied. To minimize the EDS, moderate pressures (114 MPa), a carrier composed mainly by PPI (64%) and carrier to oil ratios around 3.2 were required. The emulsion obtained in the optimal conditions (EDS = 189 ± 3nm) was dried using different technologies (spray-drying, PGSS-drying and freeze drying). The supercritical CO2 based drying process (PGSS) provided spherical particles that resulted in the smallest average size (but broader distribution) and lower encapsulation efficiency (53 ± 2%).

Studies on eggless mayonnaise from rice bran and sesame oils

Mayonnaise was prepared by replacing refined sunflower oil with physically refined rice bran oil (RBO), filtered sesame oil (SO) and blends of both RBO:SO. Emulsions were formulated using xanthan gum as a replacer for egg. The effect of replacing xanthan gum on varying oil blends (RBO:SO) on the physicochemical properties such as texture (consistency), stability, viscosity, and bioactives (oryzanol and sesamol content) were also studied. Significant differences were observed in the fat content of the emulsions prepared. Xanthan gum based mayonnaise's had 63-65% fat, whereas control sample with egg had 78% fat. The spreadability ranged between 1.2 and 1.6 N and stability of these spreads was found to be better than that of control. Mayonnaise with the desired colour, optimum spreadability and excellent emulsion stability could be prepared using RBO, and blends of RBO:SO. Significant differences were seen in the instrumental consistency and rheological studies among the mayonnaises prepared. The present study focusses on the preparation of a healthy mayonnaise using rice bran and sesame oil and their blends which have beneficial health effects due to the presence of oryzanol and sesamol.

Rice bran oil ameliorates hepatic insulin resistance by improving insulin signaling in fructose fed-rats

Background

Insulin resistance is an inadequate metabolic response of the peripheral tissue to circulating insulin. It plays an important pathophysiological role in type 2 diabetes mellitus. The purpose of the study was to investigate the molecular effects of rice bran oil (RBO) on the gene expression of insulin receptor (IR), insulin receptor substrate-1 (IRS-1), glucose transporters-4 and 5 (GLUT-4 and 5) in insulin-resistant rats induced by high fructose diet (HFD).

Methods

Rats were divided into six groups (10 rats each) as follows: Groups 1 and 2: rats received a standard diet with corn oil or RBO (as the sole source of fat), respectively. Group 3: animals fed on HFD, which was furtherly divided into 2 sub-groups: rats fed HFD either for one (HFD1) or for 2 months (HFD2). Group 4, rats fed HFD containing RBO for 1 month (HFD1 + RBO), while rats in group 5 fed HFD for 30 days then RBO was added to the diet for another 30 days (HFD2 + RBO). Serum levels of glucose and insulin, as well as hepatic gene expression of insulin receptors and glucose transporters were determined. Livers were isolated for histopathological study.

Results

HFD induced insulin resistance with a reduction in the hepatic level of insulin receptor and glucose transporters at both protein and molecular levels. Addition of RBO improved the insulin sensitivity and up-regulated the expression of the tested genes.

Conclusion

HFD impaired the insulin sensitivity of the hepatocytes by down-regulating the insulin receptor genes. Addition of RBO alleviated all the hazardous effects.

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 Å that 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.

Investigation of stability, consistency, and oil oxidation of emulsion filled gel prepared by inulin and rice bran oil using ultrasonic radiation

Inulin, rice bran oil and rosemary essential oil were used to produce high quality emulsion filled gel (EFG) using ultrasonic radiation. Response surface methodology was used to investigate the effects of oil content, inulin content and power of ultrasound on the stability and consistency of prepared EFG. The process conditions were optimized by conducting experiments at five different levels. Second order polynomial response surface equations were developed indicating the effect of variables on EFG stability and consistency. The oil content of 18%; inulin content of 44.6%; and power of ultrasound of 256 W were found to be the optimum conditions to achieve the best EFG stability and consistency. Microstructure and rheological properties of prepared EFG were investigated. Oil oxidation as a result of using ultrasonic radiation was also investigated. The increase of oxidation products and the decrease of total phenolic compounds as well as radical scavenging activity of antioxidant compounds showed the damaging effect of ultrasound on the oil quality of EFG.

Nutritionally enriched 1,3-diacylglycerol-rich oil: Low calorie fat with hypolipidemic effects in rats

An enzymatic process was developed for the preparation of a nutritionally enriched 1,3-diacylglycerol(DAG)-rich oil from a blend of refined sunflower and rice bran oils. The process involves hydrolysis of vegetable oil blend using Candida cylindracea followed by esterification with glycerol using Lipozyme RM1M. The resultant DAG-rich oil contains 84% of DAG (66% of 1,3-DAG, 18% of 1,2-DAG) and 16% of triacylglycerol (TAG) along with micro nutrients like γ-oryzanol, tocotrienols, tocopherols and phytosterols. Nutritional studies of the DAG-rich oil were conducted in Wistar rats and compared with sunflower oil (SFO). The calorific value of the DAG-rich oil was estimated to be 6.45 Kcals/g as against 9.25 Kcals/g for SFO. The serum and liver cholesterol and TAG levels in rats fed with 1,3-DAG-rich oil were found to be significantly reduced as compared to rats fed diet containing SFO. We conclude that 1,3-DAG-rich oil is a low calorie fat and exhibits hypolipidemic effects.

Effect of rice bran oil spread on the physical, sensory and fatty acid profile of cake

Studies were carried out to replace hydrogenated fat (HF) with rice bran oil (RBO) and two varieties of rice bran oil spread RBOS1 and RBOS2 in the preparation of cake. Physico-chemical properties, sensory properties, scanning electronic microscopic (SEM) study and fatty acid estimation with reference to trans fatty acids of cake made with control and experimental samples were studied. The best acceptable cake among the four i.e., RBOS2 cake was selected for consumer evaluation along with control (HF) cake. Results revealed that there was no significant difference in overall acceptability of cake made with HF and RBOS2. The internal structure and pore structure of RBOS2 cake was finer and smoother than the control cake as per SEM imaging. The pores within the core varied in diameter between 13.9 and 29.6 µm in control cake and between 16.9 and 58.6 µm in RBOS2 cake at 500 × magnification indicating good textural properties compared to HF cake. The fatty acids analysis results showed that the amount of total trans fatty acids (TFA) was 15.46% in HF cake, 3.56% in RBO cake, 4.54% in RBOS1 cake, and 3.78% in RBOS2 cake. The major trans fatty acids observed in all samples were elaidic acid (C18:1 trans-9) and Linolelidic acid (C18:2, trans-6). Elaidic acid was the highest in HF cake (6.64%) and the least in RBO cake (2.62%). Linolelidic acid was the highest in HF cake (8.48%) and the least in RBOS2 cake (0.91%). Trans Vaccenic acid was detected only in HF cake (0.34%). TFA content assumes significance in terms of its ill effects on the health of consumers, only if fat content is also high. Hence, consumption of the HF products might prove to be harmful, if consumed in large amounts and at higher frequencies. Therefore RBOS can be promoted as healthy fat for production of baked products.

Dietary gamma oryzanol plays a significant role in the anti-inflammatory activity of rice bran oil by decreasing pro-inflammatory mediators secreted by peritoneal macrophages of rats

Ricebran oil (RBO) is promoted as heart friendly oil because of its ability to maintain serum lipids at desirable levels. Inflammation also plays an important role on cardiovascular health. The role of minor constituents present in unsaponifiable fraction (UF) of RBO on inflammatory markers is not well understood. To evaluate this, we have taken RBO with UF (RBO-N), RBO stripped of UF (RBO-MCR) and RBO-MCR supplemented with UF from RBO (UFRBO) or Gamma-Oryzanol (γ-ORY) were added in AIN-93 diets which was then fed to Wistar rats for a period of 60 days. Groundnut oil with UF (GNO-N), UF removed GNO (GNO-MCR) and GNO-MCR supplemented with UF from RBO or γ-ORY was also used for comparison. The peritoneal macrophages from the rats were activated and pro-inflammatory mediators such as Reactive Oxygen Species (ROS), eicosanoids, cytokines, hydrolytic enzymes of lysosomal origin were monitored. The results indicated that UF of RBO and γ-ORY supplemented in the dietary oils play a significant role in reducing the secretion of pro-inflammatory mediators by macrophages. Hence γ-ORY in RBO significantly contributed to the anti-inflammatory properties of RBO.

RNAi-mediated down-regulation of the expression of OsFAD2-1: effect on lipid accumulation and expression of lipid biosynthetic genes in the rice grain

BACKGROUND

The bran from polished rice grains can be used to produce rice bran oil (RBO). High oleic (HO) RBO has been generated previously through RNAi down-regulation of OsFAD2-1. HO-RBO has higher oxidative stability and could be directly used in the food industry without hydrogenation, and is hence free of trans fatty acids. However, relative to a classic oilseed, lipid metabolism in the rice grain is poorly studied and the genetic alteration in the novel HO genotype remains unexplored.

RESULTS

Here, we have undertaken further analysis of role of OsFAD2-1 in the developing rice grain. The use of Illumina-based NGS transcriptomics analysis of developing rice grain reveals that knockdown of Os-FAD2-1 gene expression was accompanied by the down regulation of the expression of a number of key genes in the lipid biosynthesis pathway in the HO rice line. A slightly higher level of oil accumulation was also observed in the HO-RBO.

CONCLUSION

Prominent among the down regulated genes were those that coded for FatA, LACS, SAD2, SAD5, caleosin and steroleosin. It may be possible to further increase the oleic acid content in rice oil by altering the expression of the lipid biosynthetic genes that are affected in the HO line.

Simultaneous quantification of vitamin E, γ-oryzanols and xanthophylls from rice bran essences extracted by supercritical CO2

Since the nutrition value of rice is diminished during rice processing, technology that can preserve and sustain functional compounds is necessary. In this study, supercritical carbon dioxide (SC-CO2) extraction was optimized for operational conditions (time, temperature, pressure and modifier) to extract vitamin E, γ-oryzanols and xanthophylls from rice bran. The simultaneous quantification of the compounds was developed using high-performance liquid chromatography with diode array and fluorescence detectors. Central composite design and respond surface methodology were applied to achieve optimum extraction conditions. The optimized conditions were 60min, 43°C, 5420psi with 10% ethanol as a modifier. Pigmented rice bran extracts contained greater amounts of functional phytochemicals than non-pigmented rice bran extracts (0.68, 1410, and non-detectable μg/g compared with 16.65, 2480, and 0.10μg/g of vitamin E, γ-oryzanols and xanthophylls in pigmented and non-pigmented ones, respectively). SC-CO2 extraction with modifier would be promising for preparation of phytochemical essences for therapeutic purpose.

Effects of dietary supplementation with rice bran oil on the growth performance, blood parameters, and immune response of broiler chickens

Background

The objective of this experiment was to investigate the effects of dietary supplementation of rice bran oil (RBO) on growth performance, blood parameter, and immune response in broiler chickens.

Methods

A total of 240 1-d-old ROSS 308 male broilers were randomly allotted to 4 dietary treatments with six replicated pens consisting of ten chicks. The basal diet was formulated to be adequate in energy and nutrients. Three additional diets were prepared by adding 5, 10 or 20 g/kg of RBO to the basal diet. The experimental diets were fed on an ad libitum basis to the birds during 35 d.

Results

Results indicated that increasing inclusion level of RBO in diets improved BW gain (linear and quadratic, P < 0.01), improve feed conversion ratio (linear, P < 0.05) of birds during 0 to 35 d. There was no effect of inclusion level of RBO in diets on feed intake of birds. There was no effect of inclusion level of RBO in diets on erythrocytes of birds. However, heterophil, lymphocyte, and monocytes increased (linear and quadratic, P < 0.01) with inclusion level of RBO in diets increased. Feeding the diets containing increasing amount of RBO to birds increased (linear, P < 0.01) the concentrations of total cholesterol. Increasing inclusion level of RBO in diets increased concentrations of IgG (linear, P < 0.01). There was no effect of inclusion level of RBO in diets on concentrations of IgM.

Conclusions

These results suggest that dietary RBO may be used functional ingredient to improve growth performance, total cholesterol in serum, and immune response of birds.

Molecular Mechanisms for the Modulation of Selected Inflammatory Markers by Dietary Rice Bran Oil in Rats Fed Partially Hydrogenated Vegetable Fat

Industrially produced partially hydrogenated vegetable fat (PHVF) contains trans fatty acids (TFA) mostly comprising elaidic acid (EA, 18:1∆9t). Though, the harmful effects of TFA on health have been repeatedly publicized, the fat containing TFA have been continued to be used as a cooking medium in many regions of the world. The adverse effects of PHVF on oxidative stress and inflammatory markers and the possible ameliorative action of rice bran oil (RBO) on these markers were evaluated. Weaning rats were fed a AIN-93 purified diet supplemented with the following lipids: groundnut oil (GNO, 10 wt%), PHVF (10 wt%), RBO (10 wt%), PHVF blended with RBO at 2.5, 5.0 and 7.5 wt% levels. The final concentration of the lipids in the diet was maintained at 10 wt%. Rats were fed these diets for 60 days. They were sacrificed and analyzed for oxidative stress and inflammatory markers. The rats fed PHVF showed lower levels of lipid peroxidation and hepatic antioxidant enzymes. The rats fed PHVF-containing diets showed enhanced levels of interleukin-1β, C-reactive proteins and also showed enhanced levels of paw inflammation when injected with carrageenan as compared to rats given GNO, RBO or PHVF blended with incremental amounts of RBO. The macrophages from rats fed diet containing PHVF showed up-regulation in the expressions of cytosolic phospholipase A2 (cPLA2), nuclear factor-κB p65, toll like receptor (TLR)-2, TLR-4 and down-regulation in the expressions of peroxisome proliferator activated receptor gamma (PPAR)γ, adiponectin receptor (AdipoR)-1 and AdipoR-2 when compared to rats fed diet containing GNO, RBO and PHVF blended with RBO. It was concluded that dietary PHVF enhance pro-inflammatory markers which can be reduced by judiciously blending PHVF with RBO.

Development of designer chicken shred with response surface methodology and evaluation of its quality characteristics

Meat is considered to be an excellent source of protein, essential minerals, trace elements and vitamins but negative concerns regarding meat consumption and its impact on human health have promoted research into development of novel functional meat products. In the present study Rice bran oil (RBO), and Flaxseed oil (FSO) were used for attaining an ideal lipid profile in the product. The experiment was designed to optimise the RBO and FSO concentration for development of product with ideal lipid profile and maximum acceptability by the application of central composite rotatable design of Response surface methodology (RSM). Levels of RBO and FSO were taken as independent variables and overall acceptability (OAA), n-6 and n-3 fatty acids as responses. Quadratic fit model was found to be suitable for optimising the product. Sample with RBO (20.51 ml) and FSO (2.57 ml) yielded an OAA score of 8.25, 29.54 % of n-6 and 7.70 % of n-3 having n-6/n-3 ratio as 3.8:1. Optimised product was analysed for physico-chemical, sensory and microbial profile during storage at 4 ± 1 °C for 30 days. Increase in the lipid oxidative parameters was observed during storage but it was not significant (p < 0.05). Studies revealed great potential of developing functional poultry products with improved nutritional quality and good shelf stability by incorporating RBO and FSO.

Safety assessment of rice bran oil in a chicken embryo model

OBJECTIVE

Rice Bran Oil (RBO) is extracted from the outer layer of rice. Little information is available regarding its safety. The present study was conducted to assess its safety in chicken embryo model.

MATERIALS AND METHODS

RBO was injected on day 4 of incubation of chickens. The tissues and serum samples were collected. Oxidative stress parameters in the liver, kidney and brain and biochemical parameters of serum were measured. The deformities were also investigated.

RESULTS

The changes in the liver enzymes activity were not statistically significant. There was significant decrease and increase in lipid peroxidation and glutathione level, respectively. It is suggested that RBO is a natural antioxidant source. Low-density lipoprotein cholesterol (LDL) also decreased. No abnormal findings were observed in the chickens.

CONCLUSION

No toxic effect was observed following RBO administration in chicken embryos. This study showed that RBO is not a safety concern.

Rice bran oil and canola oil improve blood lipids compared to sunflower oil in women with type 2 diabetes: A randomized, single-blind, controlled trial

BACKGROUND

Hypolipidemic effects of vegetable oils have been demonstrated in a number of studies, but there is no study, which compares the effects of canola oil (CO) and rice bran oil (RBO) on diabetic patient. We aimed to compare the effects of CO and RBO consumption on blood lipids in women with type 2 diabetes.

METHODS

Seventy-five postmenopausal women with type 2 diabetes participated in this single-center, randomized, controlled, parallel-group trial in Shiraz, Iran. Participants were randomly allocated to three groups including a control group (balance diet + 30 g/d sunflower oil) and two intervention groups (balance diet + 30 g/day CO or RBO). At baseline and after 8 weeks, serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured.

RESULTS

At 8 weeks, mean of serum levels of TG (mg/dL), TC (mg/dL), and LDL-C (mg/dL) significantly decreased in the CO group (-23.66, P < .001; -11.92, P < .001; and -6.33, P = .013, respectively) and RBO group (-38.62, P < .001; -17.25, P < .001; and -8.90, P = .002, respectively) compared with the controls (7.01, 4.06, and 2.90, respectively). Also, in comparison with CO group, the changes of TG, LDL-C, and non-HDL-C levels were significantly more in the RBO group (P = .007, P = .012, and P = .011, respectively). Levels of serum HDL-C remained unchanged in all groups at the end of study.

CONCLUSIONS

Substitution of RBO or CO for sunflower oil could attenuate lipid disorders in type 2 diabetes women. Moreover, RBO could improve lipid profile more efficiently than CO.

Nootropic and anti-stress effects of rice bran oil in male rats

Rice bran oil (RBO) is an important product of rice bran. It is considered to be one of the most important nutritious oil due to its favorable fatty acid composition and unique composition of naturally occurring biologically active antioxidant compounds. This study was designed to monitor the effects of oral intake of RBO on stress response in rats. RBO was extracted using hexane. Rats were divided into Control and test (RBO-treated). RBO-treated rats were given 0.2 ml/day RBO for 6 weeks. Food intake and body weight changes were monitored weekly. After 6 weeks open field activity and Morris Water Maze (MWM) test were performed. Results showed that weekly cumulative food intake but not body weight were lower in RBO-treated rats during 1st to 5th week of treatment, which were normalized at the end of treatment. Exploratory activity of RBO-treated rats in an open field was increased. Spatial memory in Morris water maze was enhanced in RBO-treated than control rats. An episode of 2 h restraint stress decreased the 24 h food intake of both control and RBO-treated animals. Behavioral deficits were lower in RBO-treated rats. Exposure of 2 h restraint stress increased brain serotonin (5-hydroxytryptamine: 5-HT) metabolism. These increases were lower in RBO-treated restrained than their respective control animals. Serotonergic neurotransmitter mechanism is implicated in stress. The findings of the study show beneficial effects of RBO in learning and memory functions. Moreover, the study also highlights the attenuating effect of RBO on stress induced behavioral and neurochemical effects in rats.

Nanoencapsulation of rice bran oil increases its protective effects against UVB radiation-induced skin injury in mice

Excessive UV-B radiation by sunlight produces inflammatory and oxidative damage of skin, which can lead to sunburn, photoaging, and cancer. This study evaluated whether nanoencapsulation improves the protective effects of rice bran oil against UVB radiation-induced skin damage in mice. Lipid-core nanocapsules containing rice bran oil were prepared, and had mean size around 200 nm, negative zeta potential (∼-9 mV), and low polydispersity index (<0.20). In order to allow application on the skin, a hydrogel containing the nanoencapsulated rice bran oil was prepared. This formulation was able to prevent ear edema induced by UVB irradiation by 60 ± 9%, when compared with a hydrogel containing LNC prepared with a mixture of medium chain triglycerides instead of rice bran oil. Protein carbonylation levels (biomarker of oxidative stress) and NF-κB nuclear translocation (biomarker of pro-inflammatory and carcinogenesis response) were reduced (81% and 87%, respectively) in animals treated with the hydrogel containing the nanoencapsulated rice bran oil. These in vivo results demonstrate the beneficial effects of nanoencapsulation to improve the protective properties of rice bran oil on skin damage caused by UVB exposure.

Formation, antioxidant property and oxidative stability of cold pressed rice bran oil emulsion

Cold pressed rice bran oil (CPRBO) is used in foods, cosmetics, and pharmaceuticals due to its desirable health and functional attributes. The purpose of this work was to study the formation, antioxidant property and oxidative stability of oil-in-water emulsion of CPRBO. The influence of oil (10-40 % CPRBO) and surfactant (1-5 % glyceryl monostearate (GMS)) concentration on the properties of emulsions were studied. The lightness (L*) and yellowness (b*) of CPRBO emulsions decreased as GMS concentration increased, which was attributed to a decrease in droplet size after homogenization. The CPRBO emulsion was stable during storage at room temperature for 30 days. Increasing the oil concentration in the CPRBO emulsions increased their antioxidant activity, which can be attributed to the corresponding increase in phytochemical content. However, GMS concentration had little impact on the antioxidant activity of CPRBO emulsions. The storage of CPRBO emulsion at room temperature showed that lipid oxidation markers gradually increased after 30 days of storage, which was correlated to a decrease in gamma oryzanol content and antioxidant activity. These results have important implications for the utilization of rice bran oil (RBO) as a function ingredient in food, cosmetic, and pharmaceutical products.

Retention of natural antioxidants of blends of groundnut and sunflower oils with minor oils during storage and frying

Unrefined groundnut oil (GNO) and refined sunflower oil (SFO) were blended with four minor oils including laboratory refined red palmolein (RRPO), physically refined rice bran oil (RBO), unrefined sesame oil (SESO), and unrefined coconut oil (CNO) containing natural antioxidants viz., β-carotene, tocopherols, oryzanol and lignans. The five blends prepared were GNO + RRPO (80:20), GNO + RBO (80:20), GNO + SESO (80:20), SFO + RRPO (50:50) and SFO + CNO (60:40). Prepared blends contained saturated fatty acids (SFA) (16.7-53.3 %); monounsaturated fatty acids (MUFA) (16.0-45.5 %) and polyunsaturated fatty acids (PUFA) (29.2-37.8 %). GNO blends viz., GNO + RRPO, GNO + RBO and GNO + SESO contained β-carotene (10.7 mg/100 g), oryzanol (0.12 g/100 g) and lignans (0.35 g/100 g) respectively as natural antioxidants. SFO was enriched with β-carotene (28.7 mg/100 g) and medium chain fatty acids (34.2 %) by blending with RRPO and CNO respectively. The oil blends (200 ml) were packed and stored at 38 °C/90 % relative humidity (RH) and 27 °C/65 % RH and samples were withdrawn at fixed intervals for analysis. Freshly prepared blends were also investigated for their frying performance. During storage, GNO + RBO blend showed highest oxidative stability probably due to the presence of oryzanol in the order GNO + RBO > GNO + SESO > GNO + RRPO. During frying, the peroxide value of GNO blends with RBO (rich in oryzanol) and SESO (rich in lignans) was less while the free fatty acid value was less in SFO blends with RRPO and CNO. Hence, blending of natural antioxidants rich minor oils (RRPO, RBO and SESO) with the major vegetable oils (GNO and SFO) may preserve them by lowering their rate of oxidation during storage and frying.

Lipase catalyzed interesterification of rice bran oil with hydrogenated cottonseed oil to produce trans free fat

Lipase catalyzed interesterification of rice bran oil (RBO) with hydrogenated cottonseed oil (HCSO) was carried out for producing a low trans free fat. The interesterification reaction was performed by varying parameters such as weight proportions of RBO and HCSO, reaction temperatures, time period and lipase concentration. Both non specific and specific lipases namely Novozym 435 and Lipozyme TL IM were employed for this study. Based on the data generated, the optimum reaction conditions were found to be: weight proportion of RBO and HCSO, 80:20; lipase concentration, 5 % (w/w) of substrates; reaction temperature, 60 °C; reaction time, 4 h for Lipozyme TL IM and 5 h for Novozym 435. The degree of interesterification, calculated based on the results of solid fat characteristics was used for comparing the catalytic activity of Novozym 435 and Lipozyme TL IM. It was observed that the degree of interesterification (DI) reached a near 100 % at the 4th hour for reaction employing Lipozyme TL IM with a rate constant of 0.191 h(-1) while Novozym 435 catalyzed reaction reached a near 100 % degree of interesterification at the 5th hour with a rate constant of 0.187 h(-1), suggesting that Lipozyme TL IM has a faster catalytic activity.

In vitro antioxidant assay of medium chain fatty acid rich rice bran oil in comparison to native rice bran oil

The study aimed to evaluate the in vitro antioxidant activity of medium chain fatty acid (MCFA) rich-rice bran oils in comparison with native rice bran oil. Different in vitro methods were used to evaluate the free radical scavenging activity, metal chelation activity, reducing acitivity, ABTS radical scavenging activity, thiobarbituric acid (TBA) value and so on at different concentrations of the oils such as 10-100 μg/mL. Inhibition of lipid peroxidation was evaluated measuring thiobarbituric acid responsive substance (TBARS) and conjugated diene formation. All the oils showed potent antioxidant activity at 100 μg/mL concentration. TBARS formation and conjugated diene formation was lower with MCFA rich oils i.e. the inhibition of lipid peroxidation was more in MCFA rich oils than original rice bran oil. Caprylic acid rich rice bran oil showed maximum antioxidant activity in comparison to capric- and lauric acid rich rice bran oils. Overall the MCFA rich rice bran oils showed to be more potent antioxidant than rice bran oil due to their lower unsaturated fatty acid content.

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 of γ-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-densitometric and TLC-image analysis methods provided 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.

One-step production of biodiesel from rice bran oil catalyzed by chlorosulfonic acid modified zirconia via simultaneous esterification and transesterification

Due to the high content (25-50%) of free fatty acid (FFA), crude rice bran oil usually requires a two steps conversion or one step conversion with very harsh condition for simultaneous esterification and transesterification. In this study, chlorosulfonic acid modified zirconia (HClSO3-ZrO2) with strong acidity and durability is prepared and it shows excellent catalytic activity toward simultaneous esterification and transesterification. Under a relative low reaction temperature of 120 °C, HClSO3-ZrO2 catalyzes a complete conversion of simulated crude rice bran oil (refined oil with 40 wt% FFA) into biodiesel and the conversion yield keep at above 92% for at least three cycles. Further investigation on the tolerance towards FFA and water reveals that it maintains high activity even with the presence of 40 wt% FFA and 3 wt% water. It shows that HClSO3-ZrO2 is a robust and durable catalyst which shows high potential to be commercial catalyst for biodiesel production from low grade feedstock.

Simultaneous HPLC quantification of five major triterpene alcohol and sterol ferulates in rice bran oil using a single reference standard

A high performance liquid chromatography (HPLC) method was developed for simultaneous quantification of five major triterpene alcohol and sterol ferulates in rice bran oils (RBO) with a single internal standard, cycloartenyl ferulate. The five compounds are cycloartenyl ferulate (1), 24-methylene cycloartanyl ferulate (2), campesteryl ferulate (3), sitosteryl ferulate (4) and stigmastanyl ferulate (5). All five compounds had good linear concentration-measurement relationships (r(2) ≥ 0.9995) and possessed similar relative response factors. The relative deviation of this method was less than 2.5% for intra- and inter-day assays, and the average recovery varied from 95.1% to 99.4%. The new method was validated by comparing the amount of 24-methylene cycloartanyl ferulate (2) in 17 RBO samples obtained with this method and that with an external standard method. This method was also successfully applied to determine five major triterpene alcohol and sterol ferulates in 17 batches of RBO samples. The results demonstrated that the present method could be utilised for quality control of RBO since some of the reference standards are not commercially available.

Thermal oxidation of rice bran oil during oven test and microwave heating

The purpose of the present study was to evaluate the oxidative stability of physically refined rice bran oil (RBO) under oven heating at 63 °C and microwave heating conditions by absorptivity. Oil samples with tertiary-butylhydroquinone (TBHQ) (100 ppm and 200 ppm), citric acid (CA), butylhydroxyanisole/butylhydroxytoluene (BHA/BHT) and in other combination, BHA/BHT+CA were submitted to oven test for 6 days, and the linear coefficient of correlation between peroxide value and absorptivity at 232 nm was determined. The gradual increase in peroxide value and absorptivity at 232 nm was observed in all the RBO samples, control and antioxidant added. RBO samples added with tertiary-butylhydroquinone (TBHQ) had shown the least peroxide value and absorptivity as 6.10 and 5.8 respectively, when added at a concentration of 200 ppm whereas; the control RBO samples had shown the maximum values. The peroxide values obtained from the correlations during the oven test were found closely correlated with the peroxide values obtained during the microwave oven heating experimentally. The effect of microwave heating on the oryzanol content and p-anisidine value was also observed and the correlation to the oven test was established. The oryzanol content and p-anisidine values obtained after oven heating when correlated to the microwave heating data showed the oryzanol content 13,371, 13,267 and 13,188 ppm after 1 day, 4 days and 5 days respectively which were closely correlated with the experimental value.

Hypolipidemic effect of oryzanol concentrate and low temperature extracted crude rice bran oil in experimental male wistar rats

Blends of refined groundnut oil (GNO) and oryzanol concentrate having 3, 5, and 10% oryzanol in the blend, and a rice bran oil (RBO) which had retained all the nutrients such as oryzanol, tocopherols and tocotrienols and the unsaponifiable matter components of crude oil (GWF RBO) were prepared. Weanling rats were fed with diet containing the oil blends/rice bran oil at 10% level for 60 days and then dissected. The lipid profiles in serum, liver were investigated and the cholesterol levels were marginally reduced (7-16% in serum, 10-14.5% in liver) in rats fed oryzanol containing diet. RBO, GWF RBO containing diets showed a reduction of serum cholesterol by 14%, 15% respectively when compared to those fed with GNO. Serum and liver lipid analysis also showed significant change in TG concentration in rats fed blended oils containing oryzanol compared to the rats given GNO. Histology of liver and kidneys did not show changes. These studies indicated that oryzanol has an effect in lowering serum and liver cholesterol and shows antiatherogenic properties when incorporated into groundnut oil.

Physico-chemical changes in rice bran oil during heating at frying temperature

Rice bran oil was subjected to static heating at 180 + 2°C in a domestic fryer for 8 h in this process 150 ml of the heated oil samples were drawn, at intervals of every 2 h, to study the changes in the physico-chemical characteristics. Results indicated that the peroxide value and free fatty acid content increased gradually from 0.2 to 2.9 Meq.O2/kg of oil and 0.25 to 0.63% respectively. The oil became darker as given by the colour value (5R + Y) 63 Lovibond units. Tocopherol content was found to decrease from 48 mg/100gram to 5 mg/100gram at the end of 8 h of heating whereas, oryzanol was fairly stable (1.59 to 1.40%). The p-anisidine value and Total polar compound (TPC) increased from 5.04 to 18.30 and 1.0 to1.8% respectively, showing the formation of secondary oxidation products. Rice bran oil is a non-Newtonian fluids having shear thinning behavior. Heating was found to cause an increase in the flow behavior index. Fatty acid composition did not show significant changes except for the linoleic acid content which decreased from 29.4 to 27.1%.

Rice bran oil an alternate bakery shortening

Studies were carried out to replace bakery shortening with refined rice bran oil in bread preparation. Physico-chemical properties of bakery shortening and rice bran oil were studied. Rice bran oil was found to have a higher content of essential fatty acid linoleic acid (34.98%) as compared to that of bakery shortening (5.14%). Chemical composition of wheat flour used was also evaluation. Bread samples were prepared by replacing bakery shortening with rice bran oil at 0, 25, 50, 75 and 100% levels. Breads were examined for bread making quality i.e. loaf weight, loaf height, loaf volume and specific volume and organoleptic quality i.e. appearance, crust colour, crumb colour, aroma, texture, taste and overall acceptability on a 9 point hedonic scale. Statistical analysis regarding bread making quality and organoleptic quality of bread revealed that bread making and organoleptic quality of breads prepared after replacing bakery shortening with rice bran oil at 50% level varied significantly from that of control. Statistically significant variations were observed in the texture of breads prepared with shortening from that prepared after replacing bakery shortening with rice bran oil at 50% level.