Review on Recent Trends in Rice Bran Oil Processing

Contemporary Views of the Extraction, Health Benefits, and Industrial Integration of Rice Bran Oil: A Prominent Ingredient for Holistic Human Health

Globally, 50% of people consume rice (Oryza sativa), which is among the most abundant and extensively ingested cereal grains. Rice bran is a by-product of the cereal industry and is also considered a beneficial waste product of the rice processing industry. Rice bran oil (RBO) is created from rice bran (20-25 wt% in rice bran), which is the outermost layer of the rice kernel; has a lipid content of up to 25%; and is a considerable source of a plethora of bioactive components. The main components of RBO include high levels of fiber and phytochemicals, including vitamins, oryzanols, fatty acids, and phenolic compounds, which are beneficial to human health and well-being. This article summarizes the stabilization and extraction processes of rice bran oil from rice bran using different techniques (including solvent extraction, microwaving, ohmic heating, supercritical fluid extraction, and ultrasonication). Some studies have elaborated the various biological activities linked with RBO, such as antioxidant, anti-platelet, analgesic, anti-inflammatory, anti-thrombotic, anti-mutagenic, aphrodisiac, anti-depressant, anti-emetic, fibrinolytic, and cytotoxic activities. Due to the broad spectrum of biological activities and economic benefits of RBO, the current review article focuses on the extraction process of RBO, its bioactive components, and the potential health benefits of RBO. Furthermore, the limitations of existing studies are highlighted, and suggestions are provided for future applications of RBO as a functional food ingredient.

Developing Lipase Inhibitor as a Novel Approach to Address the Rice Bran Rancidity Issue─A Critical Review

Rice bran is a valuable byproduct from the food processing industry, which contains abundant protein, essential unsaturated fatty acids, and numerous bioactive compounds. However, its susceptibility to rancidity greatly restricts its wide utilization. Many strategies have been proposed to delay the rancidity of rice bran, but most of them have their respective limitations. Here, we proposed that developing rice ban lipase peptide inhibitors represents an alternative and promising prescription for impeding the rancidity of rice bran, in contrast to the conventional stabilization approaches for rice bran. For this reason, the rancidity mechanisms of rice bran and the research progress of rice bran lipases were discussed. In addition, the feasibility of utilizing in silico screening and phage display, two state-of-the-art technologies, in the design of the related peptide inhibitors was also highlighted. This knowledge is expected to provide a theoretical basis for opening a new avenue for stabilizing rice bran.

A review of different frying oils and oleogels as alternative frying media for fat-uptake reduction in deep-fat fried foods

Purpose

This review aims to examine the potential of oleogels as a frying medium to decrease oil absorption during deep-frying and enhance the nutritional and energy content of foods. By investigating the factors influencing oil incorporation during deep-frying and examining the application of oleogels in this process, we seek to provide insights into using oleogels as an alternative to traditional cooking oils.

Scope

Deep-frying, a widely used cooking method, leads to the retention of large amounts of oil in fried food, which has been associated with health concerns. To address this issue, researchers have investigated various methods to minimize oil absorption during frying. One promising approach is the use of oleogels, which are thermo-reversible, three-dimensional gel networks formed by entrapment of bulk oil with a low concentration (<10% of weight) of solid lipid materials known as oleogelators. This review will focus on the following aspects: a) an overview of deep-fried foods, b) factors influencing oil uptake and underlying mechanisms for oil absorption during deep-frying, c) the characterization and application of different frying oils and their oleogels in deep-fried foods, d) components of the oleogel system for deep-frying, and e) the health impact, oxidative stability, and sensory acceptability of using oleogels in deep-frying.

Key findings

The review highlights the potential of oleogels as a promising alternative frying medium to reduce fat absorption in deep-fried foods. Considering the factors influencing oil uptake during deep-frying, as well as exploring the properties and applications of different frying oils and their oleogels, can result in improved product qualities and heightened consumer acceptance. Moreover, oleogels offer the advantage of lower fat content in fried products, addressing health concerns associated with traditional deep-frying methods. The capacity to enhance the nutritional and energy profile of foods while preserving sensory qualities and oxidative stability positions oleogels as a promising choice for upcoming food processing applications.

Phytosterols in rice bran and their health benefits

With the continuous technological innovation in the high-value utilization of rice bran byproducts, rice bran oil retains a higher concentration of beneficial components such as a well-balanced composition of fatty acids and abundant phytosterols. This makes it a highly nutritious and healthy vegetable oil. This review provides an overview of the advancements made in separating, purifying, and processing phytosterols in rice bran oil. The review also introduces techniques for assessing the stability of rice bran oil. Moreover, the review emphasizes the nutritional value of phytosterols found in rice bran oil, highlighting their various health benefits, including their anticancer, anti-inflammatory, anti-allergic, antibacterial, cholesterol-lowering, skin-protective, anti-obesity, anti-diabetic, neuroprotective, gastroprotective, and immune-enhancing effects. Attaining a comprehensive understanding of the research progress made in phytosterols derived from rice bran oil can offer valuable guidance for the efficient utilization of rice bran.

Electrostatic field as an emergent technology in refining crude oils: a review

Vegetable oils and fatty acid esters (FAEs) are commonly used in various industrial and commercial applications. However, the presence of contaminants in these oils can severely affect their functionality and suitability. Conventional refining techniques for vegetable oils typically involve degumming, neutralization, bleaching and deodorization. Meanwhile, refining of FAEs often utilize wet or dry washing processes. These are often resource-intensive, producing substantial waste products, causing neutral oil loss, and can also result in the loss of micronutrients. To address these challenges, researchers have explored the use of nano-adsorbents and electrostatic field (E-field) technologies as alternatives in purifying industrial dielectric oils by removing polar particles and contaminants. Nano-adsorbents demonstrated increased efficiency in removing polar contamination while minimizing neutral oil loss. However, removal of these spent adsorbents can be challenging due to their nano-size, and physicochemical properties. The use of these materials combined with E-field technologies offers a novel and sustainable solution for removing spent nano-adsorbents and contaminants. This review provides an overview of current traditional and novel refining technologies for vegetable oils and FAEs, including their associated limitations. Compared to conventional methods, E-field treatment offers several advantages, making it an attractive alternative to conventional approaches in food processing and oil refining.

High-Value Compounds and Bioactivity of Rice Bran, Rice Bran Protein: A review

BACKGROUND

Rice bran and rice bran protein are important sources of minerals, energy, and vitamins. Other bioactive compounds are abundantly available to exert therapeutical activity. Health-promoting activities of high-value compounds of rice bran were significant, as observed in recent studies.

INTRODUCTION

A variety of bioactive components present in rice bran and rice bran extract are responsible to exhibit therapeutical potential like chemopreventive, cardioprotective, hepatoprotective, immunomodulatory, neuroprotective, and lipid-lowering activity. Several bioactivity representative compounds like γ-oryzanol, ferulic acid, caffeic acid, tricin, protocatechuic acid, vanillic acid, coumaric acid, phytic acid, isoferulic acid, gallic acid, γ-amino butyric acid, sinapic acid, saturated and unsaturated fatty acids, vitamin E complexes, β-sitosterol, stigmasterol, campesterol, cyanidin-3-glucoside, peonidin-3-glucoside, quercetin, rutin, kaemferol, β-carotene, lutein, vitamin B and lycopene are known to display significant health benefits. The bioactive components produced therapeutical effects by regulation of different mechanisms like increasing faecal excretion, reducing oxidative stress, reducing the level of malondialdehyde (MDA), regulation of NF-kb activation, reduction of proinflammatory cytokines production, suppression of SREBP-1, reduction in the expression of anti-apoptotic protein Bcl-2, elevated the expression of pro-apoptotic protein Bax, up-regulating P53 expression and suppressing COX-2.

METHODOLOGY

Several research engines like PubMed, google scholar, science direct, etc. were used to collect the data on the mentioned keywords. Recent scientific works were included in this article.

CONCLUSION

In this review paper, we profiled the high-value compounds and focused on their antioxidant, anti-hyperlipidemic, antidiabetic, and anticancer activity with their possible mechanism of action.

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.

Production of rice bran oil (Oryza sativa L.) microparticles by spray drying taking advantage of the technological properties of cereal co-products

AIM

To evaluate the effects of the use of rice co-products (flour and protein) on the encapsulation process and on the stability of rice bran oil.

METHODS

The stability of the emulsions was evaluated by dynamic turbidimetry, zeta potential, and creaming index. Efficiency parameters, particle size, and densities were investigated in the particles. The study of oxidative stability was carried out by the determination of peroxides and volatiles (60 °C for 8 weeks).

RESULTS

Rice bran oil presented 1.75% ɣ-oryzanol. AG/RP (10% of rice protein): no phase separation after 24 h, higher zeta potential (- 29.09 mV ±0.67), encapsulation efficiency (73.90% ± 0.22) and real density (1.27 g/cm^-3), and smaller particle size (8.27 µm ± 0.13). Lower peroxide (AG/RF/RP) and hexanal (AG/RF) levels were associated with the use of rice flour.

CONCLUSION

The co-products improve the emulsion characteristics, particle properties and stability of the encapsulated oil.

Quality, Key Production Factors, and Consumption Volume of Niche Edible Oils Marketed in the European Union

Consumer’s awareness of the health-promoting aspects of food and their search for products with high nutritional value is driving increased interest in niche oils. Such oils are produced on a small scale due to limited access to raw material and its low oil content. The aim of this multi-criteria analysis was to position niche oils. Data for the study were collected based on a literature review regarding twenty-three niche oils available on the European Union market. Analysis of quality parameters, key production factors, waste reusability, and average annual consumption volume in 2015–2020 was performed. Based on the research, it was concluded that linseed (flaxseed) oil, hemp oil, mustard oil, raspberry seed oil, and sesame oil should be of the most interest to consumers. They are characterized by the highest content of tocopherols, sterols, polyphenols, and carotenoids, a favorable ratio of mono- and polyunsaturated fatty acids, and pro-ecological and sustainable production technology. Based on the results of the study, the need for empirical research was identified, the key to filling the knowledge gaps in the area of edible niche oils.

Polyploidization Increases the Lipid Content and Improves the Nutritional Quality of Rice

Plant polyploidization is frequently associated with changes in nutrient contents. However, the possible contribution of metabolites to this change has not been investigated by characterizing the metabolite contents of diploid and tetraploid forms of rice (Oryza sativa L.). We compared the metabolites of a group of diploid-tetraploid japonica brown rice and a group of diploid-tetraploid indica brown rice based on liquid chromatography-tandem mass spectrometry. In total, 401 metabolites were identified; of these, between the two diploid-tetraploid groups, 180 showed opposite expression trends, but 221 showed the same trends (147 higher abundance vs. 74 lower abundance). Hierarchical cluster analysis of differential metabolites between diploid and tetraploid species showed a clear grouping pattern, in which the expression abundance of lipids, amino acids and derivatives, and phenolic acids increased in tetraploids. Further analysis revealed that the lipids in tetraploid rice increased significantly, especially unsaturated fatty acids and phospholipids. This study provides further basis for understanding the changes in rice nutritional quality following polyploidization and may serve as a new theoretical reference for breeding eutrophic or functional rice varieties via polyploidization.

Synthesis of lipase-hydrogel microspheres and their application in deacidification of high-acid rice bran oil

The main challenge of rice bran oil (RBO) as a highly nutritional edible oil is the high content of free fatty acids.

Separation and purification of fatty acids by membrane technology: a critical review

Fatty acids (FAs) are a very important group of raw materials for chemical industry, and the technology of separating or purifying the FAs from the reaction product mixture has always been the hotspot of research. Membrane processes for separation of FAs are being increasingly reported. Compared with conventional FAs separation methods, membrane separation has the advantages of low energy consumption, system compactness, high separation efficiency, easy scale-up, high available surface area per unit volume and low working temperatures, thereby attracting considerable attention of many researchers. In this regards, this paper critically reviewed the developments of methods for FAs separation and purification, and the future prospects of coupling membrane technology with hydrolysis for enhanced production of FAs.

Revealing the thermal oxidation stability and its mechanism of rice bran oil

Although the stability of rice bran oil (RBO) has been showed on several studies, the factors which make it capable on maintaining its stability under thermal oxidation has not been sure yet. We hypothesized that its fatty acid composition [high composition of oleic acid (OA), lower composition of linoleic acid (LA) and α-linolenic acid (LnA)] and/or its antioxidant agents [γ-oryzanol (OZ)] and vitamin E [tocopherol (Toc), tocotrienol (T3)] might be the biggest factor. To prove the hypothesis, we thermally oxidized RBO under 40 °C for 17 days to mimic the harsh daily storage condition, and compared it with soybean oil (SO) and rapeseed oil (RPO) then monitoring their primary oxidation products [triacylglycerol hydroperoxide (TGOOH)] from easily oxidized fatty acid contained in triacylglycerol (TG) and the amount loss of antioxidant agents. As a result, RBO showed the lowest TGOOH/TG ratio, followed by RPO and SO. The superior stability RPO compared SO might occur due to because of the influence of the fatty acid profile (higher OA and lower LA). For RBO’s case, besides its fatty acid profile, the existence of OZ and the synergistic effect of OZ and vitamin E might have a greater contribution in maintaining its stability under thermal oxidation.

Genetic and genomic approaches to address rapid rancidity of rice bran

Rice bran is an invaluable by-product of paddy processing industry. It is rich in minerals, protein, lipids, and crude fiber. In addition, it also possesses compounds with anti-oxidant, anti-allergic, anti-diabetic, and anti-cancer properties. It forms a basis for the extraction of rice bran oil and preparation of various functional foods with health benefits and potential to prevent chronic health issues. Nevertheless, the rapid deterioration of bran upon storage acts as a major limitation in exploiting the full potential of rice bran. In this review, we have discussed three strategies to address rapid rancidity of rice bran and enhance its shelf life and storability vis-a-vis emphasizing the importance of rice bran in terms of its nutritional composition. One strategy is through exploitation of the null mutations in the genes governing lipases and lipoxygenases leading to nonfunctional enzymes (enzyme deficient approach), another strategy is through reducing the PUFA content that is more prone to oxidation (substrate deficient approach) and a third strategy is through enhancing the antioxidant content that effectively terminate the lipid peroxidation by donating the hydrogen atom.

Natural products for controlling hyperlipidemia: review

Hyperlipidemia is an abnormality of lipid metabolism, characterized by an elevation of total cholesterol, triglyceride, and low density lipoprotein-cholesterol, and/or a decreasing of high density lipoprotein cholesterol in circulating levels. Hyperlipidemia has been ranked as one of the greatest risk factors contributing to prevalence and severity of coronary heart diseases. Hyperlipidemia-associated lipid disorders are considered the cause of atherosclerotic cardiovascular disease. There has been a growing interest in natural products and their role in the maintenance and improvement of health and wellness. The cholesterol-lowering effect of dietary plants has been well studied and various natural products were shown to be helpful in lowering plasma cholesterol levels and encouraging safety profile. The main focus of this review is to describe what we know to date of natural products, along with their lipid-lowering mechanisms, which are either through inhibition of cholesterol absorption, inhibition of cholesterol synthesis or antioxidant mechanisms.

Effect of Phospholipase A1-Catalyzed Degumming on Oryzanol, Tocopherols, and Tocotrienols of Dewaxed Rice Bran Oil

The effect of phospholipase A1-catalyzed degumming on the phosphorus content, the retention rate of oryzanol, and total tocopherols and tocotrienols of dewaxed rice bran oil was investigated with comparison to water degumming and citric acid degumming. The fatty acid composition of dewaxed rice bran oil was also studied by gas chromatography. The phosphorus content of dewaxed rice bran oil after phospholipase A1-catalyzed degumming could be decreased from 332.5 mg·kg−1 to 9.3 mg·kg−1 with the citric acid dosage of 0.10%, high shearing rate of 23000 rpm, chelation time of 60 min, NaOH dosage of 1.5 mole equivalent to the amount of citric acid, reaction temperature of 50°C, and total water dosage of 2.5%, while the phosphorus content of dewaxed rice bran oil after water and acid degumming was 120.5 mg·kg−1 and 66.4 mg·kg−1, respectively. The retention rate of oryzanol and total tocopherols and tocotrienols was 97.58% and 96.81% for phospholipase A1-catalyzed degumming, 91.44% and 85.98% for water degumming, and 92.85% and 87.75% for acid degumming. There was no obvious change in fatty acid composition. The results indicated that phospholipase A1-catalyzed degumming was an effective method since it could decrease the phosphorus content to the required level and provide high retention rate of oryzanol and total content of tocopherols and tocotrienols without obvious change of fatty acid composition.

Micronutrient productivity: a comprehensive parameter for biofortification in rice (Oryza sativa L.) grain

BACKGROUND

Enhancing the micronutrient content of staple crops such as rice will improve human nutrition and address the problem of hidden hunger globally. Rice grains consumed after polishing lack adequate amounts of micronutrients. The present study aims to reveal the effects of polishing on micronutrient content and to identify superior genotype(s) to improve yield and micronutrient content after polishing.

RESULTS

AM65 exhibited the highest zinc content, and AM180 had the highest iron content, even after polishing. There was little or no difference between the genotypes for zinc content in bran, indicating a possible threshold for micronutrient accumulation in the aleurone layer. A comprehensive selection criterion called 'micronutrient productivity' was used to select for both yield and micronutrient parameters. AM65 and ARB6 showed high zinc and iron productivity indices. OsZIP4b and OsZIP6c markers showed an association with iron content on an agarose gel. Sequencing of markers revealed that OsYSL15 and OsZIP6c were associated with grain zinc content and OsZIP3b, OsMTP1a, and OsYSL4b with grain iron content. These markers can be used for selecting superior accessions.

CONCLUSION

AM65 was loaded with micronutrients and manifested a positive correlation with the grain yield, and it is undoubtedly 'super elite'. Bran does not drain the grain but rather acts as gateway for micronutrient transportation to the endosperm. Micronutrient productivity is a comprehensive parameter for the biofortification of grain. © 2018 Society of Chemical Industry.

Rice bran nutraceutics: A comprehensive review

Agro-industry yields ample quantity of several byproducts with considerable importance. These byproducts are mostly under-utilized, often used as animal feed or rejected as waste; hence their true potential is not harnessed. The use of such superfluous resources is of not only economic significance but also a form of commercial recycling. Rice bran is an important byproduct of rice milling industry with a global potential of 29.3 million tons annually. It is gaining great attention of the researchers due to its nutrient-rich composition, easy availability, low cost, high antioxidant potential, and promising effects against several metabolic ailments. Bioactive components of rice bran, mainly γ-oryzanol, have been reported to possess antioxidant, anti-inflammatory, hypocholesterolemic, anti-diabetic, and anti-cancer activities. Rice bran oil contains appreciable quantities of bioactive components and has attained the status of "Heart oil" due to its cardiac-friendly chemical profile. Nutraceutics have successfully been extracted from rice bran using several extraction techniques such as solvent extraction, supercritical fluid extraction, microwave-, and ultrasonic-assisted extraction. Current paper is an attempt to highlight bioactive moieties of rice bran along with their extraction technologies and health benefits.

The relationship between lipid phytochemicals, obesity and its related chronic diseases

This review focuses on phytochemicals in oils, and summarizes the mechanisms of the anti-obesity effects of these compounds in in vitro studies, animal models, and human trials.

Supercritical CO2 Extraction of Rice Bran Oil -the Technology, Manufacture, and Applications

Rice bran is a good source of nutrients that have large amounts of phytochemicals and antioxidants. Conventional rice bran oil production requires many processes that may deteriorate and degrade these valuable substances. Supercritical CO₂ extraction is a green alternative method for producing rice bran oil. This work reviews production of rice bran oil by supercritical carbon dioxide (SC-CO₂) extraction. In addition, the usefulness and advantages of SC-CO₂ extracted rice bran oil for edible oil and health purpose is also described.

Simplified Enzymatic Upgrading of High-Acid Rice Bran Oil Using Ethanol as a Novel Acyl Acceptor

One of the major challenges in the upgrading of high-acid rice bran oil (RBO) is to efficiently reduce the amount of free fatty acids. Here we report a novel method for upgrading high-acid RBO using ethanol as a novel acyl acceptor in combination with a highly selective lipase from Malassezia globosa (SMG1-F278N). This process enabled an unprecedented deacidification efficiency of up to 99.80% in a short time (6 h); the immobilized SMG1-F278N used in deacidification exhibited excellent operational stability and could be used for at least 10 consecutive batches without detectable loss in activity. Scale-up was performed under optimized conditions to verify the applicability of this process, and low-acid (0.08%) RBO with a high level of γ-oryzanol (27.8 g/kg) and γ-oryzanol accumulation fold (1.5) was obtained after molecular distillation at lower temperature (120 °C). Overall, we report a simplified and efficient procedure for the production of edible RBO from high-acid RBO.

Microalgae-based unsaponifiable matter as source of natural antioxidants and metal chelators to enhance the value of wet Tetraselmis chuii biomass

The present work aimed to determine the antioxidant, metal chelating and neuroprotective potential of the unsaponifiable matter (UM) of Tetraselmis chuii to be applied to a biorefinery setting. The UM obtained via saponification from crude lipids extracted from microalgal wet biomass showed a radical scavenging activity (RSA) towards the DPPH radical of 90.7±1.3% and 57.1±1.2% at a concentration of 10 and 5 mg/mL, respectively. The UM fraction also displayed metal chelating capacity at a concentration of 5 mg/mL: 58.5±1.4% and 50.9±4.0% for copper and iron, respectively. The chemical characterization of the UM revealed significant levels of total phenolics (TPC, 13.61 mg GAE/g) and carotenoids (2.45 mg/g of β-carotene, lutein and violaxanthin). Overall, the separation of the UM containing high value metabolites might significantly upgrade the total wet biomass value in a biorefinery, allowing the exploitation of a stream with relevant antioxidant and metal chelating activities.

Functional and physiological properties of total, soluble, and insoluble dietary fibres derived from defatted rice bran

Enzymatic- gravimetric method was used to obtain three fractions of dietary from defatted rice bran. The functional and physiological properties such as viscosity, cation exchange capacity (CEC), and glucose dialysis retardation index (GDRI), cholesterol and bile salt adsorption capacity of the resultant fractions were evaluated. Insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) when compared showed that SDF exhibited significantly (p < 0.05) higher viscosity (2.35 mPa.s), greater GDRI value (17.65 %) at 60 min and significantly lowered concentration of cholesterol at pH 7 (29.90 %, p < 0.05). However IDF showed the highest CEC and its adsorption capacity of bile salt was higher than SDF (18.20 % vs. 13.76 %; p < 0.05), while CEC and cholesterol absorption capacity of TDF were similar to SDF. These properties indicate that rice bran soluble, insoluble and total fibres are functional ingredients which can be added to various food products and dietetic, low-calorie high-fiber foods to enhance their nutraceutical properties and health benefits.