Supercritical carbon dioxide extraction and deacidification of rice bran oil

Bioactives from Crude Rice Bran Oils Extracted Using Green Technology

Crude rice bran oils from different rice cultivars and extraction methods bear different contents of nutraceuticals. The health benefits of lowering cholesterol activity of rice bran oil being confirmed by many reports are partly attributed to non-nutrient nutraceuticals, especially γ-oryzanol, phytosterols, and policosanols. As the world has been facing the global warming crisis, green extraction technology is gaining attention from many sectors. The current study aims to compare the nutraceutical composition with respect to γ-oryzanol, phytosterol, and policosanol content as well as the antioxidant properties of crude rice bran oils extracted from white and red rice bran using three green technologies, comparing with conventional hexane extraction. The data show that the traditional solvent extraction gave the highest oil yield percentage (26%), but it was not significantly different from subcritical liquefied dimethyl ether extraction (24.6%). Subcritical liquefied dimethyl ether extraction gave higher oil yield than supercritical CO2 extraction (15.5–16.2%). The crude rice bran oil extracted using subcritical liquefied dimethyl ether extraction produced the highest total phenolic contents and antioxidant activities. The highest γ-oryzanol content of the crude rice bran oil was found in oil extracted by conventional cold press (1370.43 mg/100 g). The γ-oryzanol content of the oil obtained via subcritical liquefied dimethyl ether extraction was high (1213.64 mg/100 g) compared with supercritical CO2 extraction. The red rice bran yielded the crude rice bran oil with the highest total phytosterol content compared with the white bran, and the oil from red rice bran extracted with subcritical liquefied dimethyl ether generated the highest total phytosterol content (1784.17 mg/100 g). The highest policosanol content (274.40 mg/100 g) was also found in oil obtained via subcritical liquefied dimethyl ether extraction.

Cleaner lipid processing: Supercritical carbon dioxide (Sc-CO2) and short path distillation

Today, regulations and consumer awareness demand production technologies with minimum impact on the environment and maximum utilization of available resources. In the field of lipids, two well-known technologies for avoiding the use of organic solvents and chemicals stand out: supercritical (Sc) fluids and short path distillation (SPD). To date, both technologies involve high operating costs that have limited their application to selected high value-added products which are high temperature sensitive. However, improvements in process control and materials make further implementation of these techniques possible. In this chapter, an integrative review has been carried out with the aim of compiling the literature on the application of these technologies to lipid extraction, micronization and fractionation of liquid mixtures. Special attention has been paid to the separation of compounds by both technologies: deacidification, partial purification of acylglycerol compounds, isolation of unsaponifiable compounds and separation of toxic and polluting compounds.

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.

Integration of physicochemical, molecular dynamics, and in vitro evaluation of electrosprayed γ-oryzanol-loaded gliadin nanoparticles

Electrospraying is a technique to improve the application and stability of bioactive compounds in food. Here, electrospraying was applied to fabricate gliadin particles incorporated γ-oryzanol. The round particles were obtained, with an average diameter of 481.56 ± 283.74 nm, from scanning electron microscopy. Simulations demonstrated how γ-oryzanol-loaded gliadin particles were unfolded in acetic acid and culminated in their globular shape under an electric field. The results also revealed that γ-oryzanol was present in gliadin particles. Moreover, there was a successful formation of particles with a homogeneous distribution and an enhanced thermostabilization of γ-oryzanol. In food simulants, γ-oryzanol demonstrated an initial burst release, followed by a subsequent, slower release that occurred gradually. Finally, MTT assays showed concentration- and time-dependent inhibitions of γ-oryzanol-loaded gliadin particles on HT-29 cells, with IC₅₀ values of 0.47 and 0.40 mg/mL for 24 and 48 h, respectively. This study described a protocol for developing γ-oryzanol-loaded gliadin particles with enhanced stability, valuable release-behavior, and decreased HT-29 proliferation.

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.

Gut Microbiota and Metabolome Response of Decaisnea insignis Seed Oil on Metabolism Disorder Induced by Excess Alcohol Consumption

This study investigated the modulatory effects of Decaisnea insignis seed oil (DISO), which was rich in palmitoleic acid (55.25%), palmitic acid (12.25%), and oleic acid (28.74%), on alcohol-induced metabolism disorder in mice. Fifty mice were orally administered with 38% alcohol (0.4 mL/day) and without or with DISO (3, 6, and 12 g/kg) for consecutive 12 weeks. DISO inhibited the alcohol-induced weight loss and liver function abnormality (p < 0.01) and shifted the profiles of cecal microbiome: elevating the abundance of Lactobacillus, Ruminoccoceae_UCG_004 (p < 0.05) and decreasing abundance of Parabacteroides (p < 0.05). This treatment also regulated metabolome response of amino acid and lipid metabolism in cecal content: upregulating 5-hydroxyindole-3-acetic acid (p < 0.05), 6-hydroxynicotinic acid, 5-methoxytryptamine, nicotinamide, and nicotinic acid (p < 0.1) and downregulating androsterone, tryptophan, and indole-3-acetamide (p < 0.05). DISO protected against alcoholic liver injury and gut microbiota dysbiosis by enriching the relative abundance of Lactobacillus, which was positively associated with the improvement of intestinal permeability and tryptophan metabolism.

Some Strategies for Utilization of Rice Bran Functional Lipids and Phytochemicals

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

Assessment of changes in the content of anthocyanins, phenolic acids, and antioxidant property of Saccharomyces cerevisiae mediated fermented black rice bran

Studies on phytochemical properties and bioactivities of rice bran revealed the wealth of natural complex antioxidant compounds. The composition and the properties of the rice bran get altered after fermentation by several microbes. This study was designed to optimize the black rice bran fermentation conditions for the total anthocyanin (ACN) content, total antioxidant properties, and relative activity of β-glucosidase (BGS) by Saccharomyces cerevisiae. The Box–Behnken design and response surface methodology was employed to achieve the maximum response in fermentation. The kinetic analysis of HPLC based phytochemical determination and bioconversion of ACN, and in vitro antioxidant assays were performed during fermentation. The optimum pH, temperature and NaCl concentration to achieve maximum ACN content, antioxidant capacity, and BGS activity were pH 4.0, 40 °C, and 0.5%, respectively. Bioconversion of cyanidin-3-glucoside and peonidin-3-glucoside to cyanidin and peonidin was recorded at a significant level, respectively. The maximum activity of BGS on rice bran was noticed at 24 h of fermentation. The results suggested that phytochemical content was not changed significantly, whereas the antioxidant properties of rice bran were slightly enhanced after 24 h of fermentation. Additional detailed in vivo evaluation is required to explain the impact of submerged fermentation on the bioactivity of rice bran.

Simplified Physical Upgrading of High-Acid Adlay Bran Ethanol Extracts by Supercritical CO2

Deacidification is one of the key steps in oil-refining processes. This study reported a simple approach for upgrading high-acid adlay bran oil by supercritical carbon dioxide (SC-CO2) extraction. The high-acid adlay bran oil was obtained by three-stage countercurrent ethanol extraction of adlay bran, with high free fatty acids (34 % FFAs). The FFA content in adlay bran oil reduced to 10.6 % by SC-CO2extraction under optimized conditions. Interestingly, the SC-CO2deacidification process also markedly reduced oil color value from 11.5 (Red) to 0.3 (Red) and acetone-insoluble matters in the oil from 1.56 % to 0.17 %. The results indicated solvent extraction combined with SC-CO2deacidification method could be a feasible approach to significantly upgrade high-acid adlay bran oil and simplify refining process of adlay bran oil.

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.

Assessment of the quality of bran and bran oil produced from some Egyptian rice varieties

BACKGROUND

Rice (Oryza sativa L.) is one of the leading food crops of the world, the staple food of over half the world's population. The bran, which is an important byproduct obtained during rice milling, constitutes about 1/10 of the weight of the rice grain. Rice bran is the outer brown layer including the rice germ that is removed during the milling process of brown grain. This milling byproduct is reported to be high in natural vitamins and minerals, particularly vitamin E.

OBJECTIVES

The present study was conducted to determine the chemical composition of bran and bran oil of 13 different rice varieties commonly produced in Egypt, to study the utilization of rice bran in bread production, and to assess the quality and acceptance of the rice bran edible oil produced.

METHODS

Rice bran was produced from 13 Egyptian varieties of recently harvested rice as well as from paddy rice stored for 1 year. The extracted bran was immediately stabilized then subjected to chemical analysis (such as moisture content, protein, fat, carbohydrates, fiber, and ash) as well as trace and heavy metals determination (P, K, Na, Ca, Fe, Zn, Cu, and Mg). Bread was produced by adding Giza172 rice bran at three different concentrations to wheat flour then subjected to chemical analysis, caloric content, and organoleptic examination. Bran oil was extracted from the different varieties of rice bran (recently harvested and stored) then subjected to chemical and organoleptic examinations as well as vitamin E and oryzanol determination.

RESULTS

The percentage of rice bran of newly harvested Egyptian rice was 11.68% and was 10.97% in stored rice. The analysis showed mean values of 5.91 and 5.53% for moisture, 14.60 and 14.40% for crude protein, 14.83 and 15.20% for fat, 44.77 and 45.40% for carbohydrates, 6.55 and 7.06% for crude fiber, and 8.87 and 8.50% for ash for newly harvested and stored rice bran, respectively. Bread containing 15% rice bran showed the highest score percentages for organoleptic quality compared with the control (100% wheat flour). Rice bran oil showed higher scores of taste, smell, appearance, and texture than corn oil and sunflower oil.

CONCLUSION

Rice bran contains high nutritional components as well as phytochemicals such as vitamin E (i.e. tocopherols and tocotrienols) and the γ-oryzanol fraction that have positive effects on human health. Storage of paddy rice before milling resulted in significant effect on all studied rice bran characters and rice bran oil characters under the present investigation except crude protein and carbohydrates characters.

RECOMMENDATIONS

Substitution of wheat flour with rice bran by 15% in bread production to fortify the bread with vitamin E and to reduce the amount of imported flour is recommended.

Supercritical fluid extraction: Recent advances and applications

Among the different extraction techniques used at analytical and preparative scale, supercritical fluid extraction (SFE) is one of the most used. This review covers the most recent developments of SFE in different fields, such as food science, natural products, by-product recovery, pharmaceutical and environmental sciences, during the period 2007-2009. The revision is focused on the most recent advances and applications in the different areas; among them, it is remarkable the strong impact of SFE to extract high value compounds from food and natural products but also its increasing importance in areas such as heavy metals recovery, enantiomeric resolution or drug delivery systems.