Acid Degumming Research Articles

Refining process for production of refined palm-pressed fibre oil

Palm-pressed fibre oil (PPFO) is rich in natural phytonutrients such as carotenes and tocotrienols (vitamin E), which makes it worth further development to enhance its quality. Crude PPFO is currently extracted using solvents without further refining. This study aimed to refine crude PPFO using a combination of processes including degumming, bleaching, and deacidification. Various doses of hot distilled water at 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 v/v% were applied during water degumming to remove soluble and hydratable gummy materials in crude PPFO. Degumming with acids at doses ranging from 0.1 to 1.0 wt% were tested to obtain oil with low phosphorus content. Bleaching earth doses ranging from 0.1 to 1.0 wt% were used to absorb trace metals and other impurities. The bleached PPFO was subjected to deacidification to remove free fatty acid (FFA). The optimum refining conditions were using 5.0 v/v% of hot distilled water at 90 °C for 20 min for water degumming, 1.0 wt% of phosphoric acid at 90 °C for 10 min for acid degumming, 0.1 wt% of natural bleaching earth at 105 °C for 15 min during bleaching, and deacidification at 110 °C at 0.1 mtorr. The refined PPFO (RPPFO) showed a 98% reduction of phosphorus content (from 565 ppm to 13±2 ppm) and FFA removal of 97% (from 5.94% to 0.15%), while deterioration of bleachability index (DOBI) increased by 44% (from 1.99 to 2.87±0.17). In addition, RPPFO was rich in carotenoids (1208±23 ppm) and vitamin E (904±8 ppm) that can be developed into high value products. The RPPFO meets the quality specifications of refined, bleached, and deodorised palm oil (RBDPO) while maintaining the heat-sensitive phytonutrients.

Production and characterization of electrical transformer insulating fluid from blending Castor and Neem seed oils

Castor and neem seed oils were first purified separately through the process of acid degumming, neutralization, bleaching, filtering, washing and drying. The refined castor and neem seed oils was mixed thoroughly at a ratio of 40:60, 50:50 and 60:40 to make up weight of 100g each. The blended ratios were synthesized separately through epoxidation and transesterification reactions to satisfactorily remove glycerol and unsaturation and form an epoxy in the triglycerides of the mixture. The epoxidation process of the triglyceride significantly increased the viscosity whereby making the blended fluids more physically, chemically and thermally balanced. The blended oil esters produced were washed properly with distilled water and dried to purify the esters. The blended epoxy castor-neem oil methyl ester in ratio of 40:60, 50:50 and 60:40 (BEME46, BEME55 and BEME64) were characterized and the following results were obtained: the viscosities of BEME46, BEME55 and BEME64 at a lower temperature of 30°C were 9.30 cSt, 9.45 cSt and 9.48 cSt respectively, while the viscosities at a higher temperature of 70°C were 3.30 cSt, 3.32 cSt and 3.48 cSt respectively, using a glass capillary kinematic viscometer and hot water bath setup. The dielectric strength of BEME46, BEME55 and BEME64 were 30.55 kV, 30.75 kV and 32.02 kV respectively using a megger test set. The acid value or neutralization number of BEME46, BEME55 and BEME64 were 0.1683 mgKOHg-1oil, 0.1405 mgKOHg-1oil and 0.1405 mgKOHg-1oil respectively. The densities were 0.8260 gcm-1, 0.8251 gcm-1 and 0.8219 gcm-1 respectively, while the flash points were 165°C, 168°C and 160°C respectively. BEME46, BEME55 and BEME64 were compared with Transformer Mineral oil obtained from APO Transmission station. It was revealed that the blended oil esters met the transformer standard specifications.

Optimised Production of Biodiesel Synthesised from Waste Animal Fat

The fleshings produced during the pre-tanning process in tanneries and animal wastes generated from slaughter house are causing serious environmental concern because of improper disposal techniques. These solid wastes contain fat and proteins which can be recovered for wide variety of applications. The fats extracted from these wastes are used as feedstock for the production of biodiesel, which serves as an alternate for conventional diesel fuel because of their sustainability. The use of these animal fats ruled out the issues over the ‘Food versus Fuel’ conflict, as edible feed stocks were used in the production of biodiesel earlier. This work projects on the synthesis of biodiesel from waste animal fats by the means of methyl-based transesterification. A maximum fat recovery of 85% was achieved by the means of autoclave heat treatment method. The refining of fat was carried out by following acid degumming, where Orthophosphoric acid was mixed with the fat to remove the phospholipids as residues. Pretreatment of the extracted fat was done using glycerolysis, where the FFA % of these fats were reduced from 7% to 0.25% with a recorded efficiency of 96.4%. Alkali catalysed transesterification was carried out by investigating various operating parameters like oil/alcohol molar ratio, catalyst concentration, temperature and reaction time and optimising them. The optimised process parameters produced a maximum yield of 94% biodiesel. The fuel properties of the produced biodiesel were compared with the ordinary diesel fuel based on both ASTM D-6751 and IS 15607: 2005 standards.

Variation of density and flash point in acid degummed waste cooking oil

Recycling of waste cooking oil represents a source of convenient raw materials for industry. Within the large number of products derived from the treatment of waste cooking oil, eco-friendly lubricants grown in importance during the last years. Recycling process for such application consists usually of acid or basic degumming followed by a filtration step. The effect of the specific type of acid degumming on the density and on the flash point of the recycled oil was evaluated employing full factorial design. Two mathematical equations were derived which allow to estimate respectively the density and the flash point of the recycled oil, depending on the: (a) pH of the washing solution, (b) oil/water ratio, (c) temperature of the system, and (d) the stirring time. Practical applications Recycle of waste cooking oil presents several advantages. Mainly it is beneficial for the environment and considered as mandatory by law in several countries, and could furnish a useful low price raw material for several kind of industries. Recently, a multitude of local small scale industries have based their business on this topic and the recycling process employed often consists in a degumming step followed by filtration. This article deals with the tuning of the main parameters of the degumming step related with the density and the flash point of the final product. These parameters are important especially for lubricant synthesis.

Assessment of water degumming and acid degumming of mixed algal oil

Crude algal oil from Chlorella sp. contained high amount of phospholipids, causing lower conversion rate of transesterification and difficulty in glycerol separation. Since the crude algal oil was solid at ambient temperature that could not go to degumming process straightly, it was mixed with refined palm oil in the ratio of 30:70w/w to obtain suitable viscosity for further processing. The response surface methodology with Box-Behnken design was applied to investigate water and acid degumming processes. The studied parameters were temperature, time, and amount of degumming reagent (water or phosphoric acid). The greatest phospholipid removal reached 82.5% under the optimum condition of acid degumming with temperature 90°C, 60min and phosphoric acid 0.42wt.%. The water degumming at optimum condition (temperature 100°C, 30min and water 80wt.%) only gave 19.4% phospholipid removal. The major phospholipids in Chlorella sp. oil was considered to be the non-hydratable phospholipids.

Optimization of a soft degumming process of crude rapeseed oil—Changes in its antioxidant capacity

A modified soft degumming process of crude rapeseed oil for maximizing phospholipid removal and minimizing losses of antioxidants was proposed and optimized by response surface methodology. The effects of water volume, degumming time, and concentration ratio of sodium dodecyl sulfate to disodium ethylenediaminetetraacetate on the concentration of phospholipids and phenolics and antioxidant capacity of oils were evaluated. The soft degumming process removed phospholipids from the crude oil (94.9–98.7%) more effectively than industrial acid degumming (95.3%). Moreover, rapeseed oils revealed high phenolic content (20.0–22.1mg sinapic acid (SA)/100g) and antioxidant capacity, as determined by ferric-reducing antioxidant power (FRAP=301–328μmol Trolox equivalent (TE)/100g), 2,2-diphenyl-1-picrylhydrazyl (DPPH=528–739μmol TE/100g), and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS=1300–1505μmol TE/100g) methods.The predicted optimum water volume (11.5mL), time (19.7min), and concentration ratio of sodium dodecyl sulfate to disodium ethylenediaminetetraacetate (=1) resulted in total phospholipids=67mg/kg, phenolics=20.8mg SA/100g, FRAP=313μmol TE/100g, DPPH=617μmol TE/100g, and ABTS=1346μmol TE/100g.Replacement of industrial acid degumming by the proposed soft degumming can improve the stability of rapeseed oil with potent antioxidant capacity.

Degumming and Neutralization of Rice Bran Oil

AbstractThe present study aimed to perform degumming and neutralization steps of crude oil from rice bran. The degumming was studied through a central composite rotational design where the study variables were the amount of water added and temperature and the response variable was phosphorus content. In the neutralization study, a complete experimental design was used, with the study variables being temperature and amount of NaOH solution added, while the response variables were acidity and γ‐oryzanol content. The best working region for degumming was in the condition of 5% water and a temperature of 58C, under this condition the oil showed a phosphorus contentof 4.10 mg/100 g. In the neutralization step, the best condition was 60C and an addition of 20% excess soda, where an acidity of 0.41% oleic acid and γ‐oryzanol content of 1.10% was obtained.Practical ApplicationsWater degumming proves to be advantageous compared to acid degumming, commonly carried out in oil refining industries since the phospholipids obtained in this step can be dried to yield lecithin without the need of purification. The lecithin obtained from the degumming process has commercial value, especially for its emulsifying action and can be used in food industries, in products such as ice cream, milk powder and chocolates. In its composition, rice bran oil has the γ‐oryzanol compound, a natural antioxidant that is extracted during the refining process of rice bran oil, especially during the neutralization step.The refining difficulties presented by the rice bran oil reflect the high cost of the final product compared to other oils. Thus, the study of the degumming step for the use of lecithin is justified, since the lecithin obtained from water degumming can be used as a byproduct of the oil industry, generating profit. The study of neutralization to preserve the maximum γ‐oryzanol content in the rice bran oil is justified by the benefits that this can bring to the health of consumers, such as lower total plasma cholesterol and increased HDL cholesterol levels. Furthermore, the maintenance of this compound improves oil quality, since the γ‐oryzanol increases the oxidative stability of the oil occasioned for factors such as the amount of water, oxygen, process and storage temperature and time.

Enzymatic Wheat Germ Oil Degumming

<abstract> Wheat germ oil (WGO) contains significantly higher amounts of phospholipids than commodity oils. The high phospholipid content in WGO adversely affects its appearance and gives it a very dark and cloudy appearance. Previous studies have demonstrated that water and acid degumming, which are commonly used for commodity oils, are not effective for WGO. This study examined the efficiency of enzymatic degumming for removing phospholipids from hexane extracted and mechanically pressed crude WGO. Two enzymes, Lecitase Ultra and Lysomax, were examined. Process variables (water:oil ratio, reaction time, and temperature) were evaluated for high oil yield and low residual phospholipid content in degummed WGO. Degumming with Lecitase Ultra was more effective than Lysomax. Both enzymes, Lecitase Ultra (219 mg kg^-1 residual phosphorus in the oil) and Lysomax (294 mg kg^-1 residual phosphorus), were more effective than water and acid degumming. The oil yields under the conditions that resulted in the highest phospholipid removal (84% to 88% removal) were about 88.7% and 89.6% for Lecitase Ultra and Lysomax, respectively. Significant amounts of tocopherols were lost during enzymatic degumming.

Acid and Enzymatic Degumming of Wheat Germ Oil

The objective of this study was to evaluate the efficiency of acid and enzymatic degumming for crude wheat germ oil refining. Both hexane extracted and mechanically pressed oils were examined in the study. The effects of five variables on acid degumming efficiency were examined: temperature, time (mixing type: 60 min stirring versus 2 min homogenization), water:oil ratio, acid type (phosphoric and citric acids), and acid concentration. Phosphoric acid was more effective than citric acid for removing phospholipids from crude wheat germ oil. Phosphoric acid degumming at 70°C, 2 min homogenization, phosphoric acid concentration of 0.05%, and water:oil ratio of 7.5% resulted in the lowest (989 mg kg -1 ) residual phosphorus content in the oil. The oil yield under these degumming conditions was 93.5%. About 76% of the total tocopherols were lost during phosphoric degumming of hexane extracted oil. Tocopherol loss was much lower (19%) for mechanically pressed oil degummed under the same conditions as hexane extracted oil. A commercial phospholipase (GumZyme) was also evaluated for WGO degumming. The lowest phosphorus level achieved in the enzymatically degummed oil was 573 mg kg -1 . Enzymatic degumming was more effective than acid degumming in removing phospholipids from wheat germ oil.

A cost‐effective acid degumming process produces high‐quality Jatropha oil in tropical monsoon climates

Degumming is an essential step to remove the gum from crude vegetable oil in order to produce high‐quality vegetable oil with minimum impurity for various applications, such as food or feedstock for production of biodiesel fuel (BDF). In the tropical monsoon region, degummed Jatropha oil is low‐quality and the loss on degumming is serious because the removal of the gum is a difficult task. Herein, a facile and economic process for efficient removal of the gum from crude Jatropha oil was developed with consideration for the tropical monsoon climate in Southeast Asian Nations, in which phosphoric acid (PA) was used as a degumming agent. When crude Jatropha oil was agitated with 0.025 wt% of PA and 2 vol% of water at 60°C for 30 min, followed by aging at 30°C for 60–120 min and filtering through the Teflon‐coated filter, the PA‐degummed Jatropha oil with ultra‐low contents of phosphorus (P), alkali metals and alkaline earth metals was entirely good as oil feedstock for production of high‐quality BDF based on the international fuel standards (i.e., EN 14214:2012). Moreover, the degummed Jatropha oil trapped in the unwanted gum was easily recovered by the sieving technique.Practical applications: For the first time, the degumming of crude Jatropha oil in the tropical monsoon climate is thoroughly studied. To form the gum completely, the amounts of PA and water are kept at 0.025 wt% and 2 vol% of crude Jatropha oil, respectively, and the agitation temperature is kept at 60°C. The gum is removed through the Teflon‐coated filter after aging at 30°C for 60–120 min, which is similar to the monthly mean temperatures ranging between 26 and 31°C in Thailand. The advantages of this process are that it is simple and cost effective, since expensive instruments for separation and purification are not used, such as high‐speed centrifuge or special membrane. Most of the degummed oil trapped in the unwanted gum can be easily recovered through a stainless steel sieve. Accordingly, this process is currently operating on a pilot plant scale in Thailand.A facile and economic process was developed for efficient removals of phospholipids, alkali metals, and alkaline earth metals from crude and non‐edible Jatropha oil in the tropical monsoon climate, resulting in high‐quality Jatropha oil as an entirely good feedstock for production of high‐quality biodiesel fuel.

Modifying Plant Oils for Use as Fuel in Rural Contexts Tanzania: Techno-Economic Analysis

Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.

Degumming of rice bran oil

Rice bran oil (RBO) is an excellent cooking and salad oil due to its high smoke point and delicate flavor. The nutritional qualities and health effects of RBO are also established. The content of phospholipids in crude RBO is a major problem during processing of the oil in various food applications. It has been reported that water degumming process is suitable for the removal of hydrat- able phospholipids (HPL). Nonhydratable phospholipids (NHPL) can be removed only during acid degumming or enzymatic degumming processes. Rapid equilibrium extraction has been found suitable for reducing the phos- pholipid content of RBO. Many researchers have found the efficiency of water, acid, and enzymatic degumming of RBO. New techniques of degumming for RBO have also been established using ultrafiltration and nanofiltration membranes. The presented techniques are individually significant based on phospholipids efficiency. Hence, the present paper reviews the prevailing techniques of RBO degumming.

Comparison of acid degumming and enzymatic degumming process for Silybum marianum seed oil

In this study the effects of processing conditions of acid degumming and enzymatic degumming on the removal of phospholipids from Silybum marianum seed oil were investigated and the degumming efficiency was compared based on the phospholipid content. An orthogonal array experimental design was performed to optimise the process of citric acid degumming. Based on range analysis and analysis of variance, the optimal processing conditions were determined to be a citric acid dosage of 3 g kg(-1) , a degumming temperature of 70 °C, a water addition of 40 mL kg(-1) and a degumming time of 30 min. Under these conditions the phospholipid content of degummed S. marianum seed oil was reduced from 273.0 to 128.1 mg kg(-1) . In the case of enzymatic degumming, the effects of enzyme reaction time and enzyme dosage were investigated using single-factor experiments. The optimal processing conditions were found to be an enzyme reaction time of 6 h and an enzyme dosage of 100 mg kg(-1) oil. Under these conditions the phospholipid content of degummed S. marianum seed oil was reduced to 17.95 mg kg(-1) . The results indicated that enzymatic degumming is more effective than acid degumming.

Minor Constituents in Canola Oil Processed by Traditional and Minimal Refining Methods

AbstractThe minimal refining method described in the present study made it possible to neutralize crude canola oil with Ca(OH)2, MgO, and Na2SiO3 as alternatives to NaOH. After citric acid degumming, about 98 % of the phosphorous content was removed from crude oil. The free fatty acid content after minimal neutralization with Ca(OH)2 decreased from 0.50 to 0.03 %. Other quality parameters, such as peroxide value, anisidine value, and chlorophyll content, after traditional and minimal neutralization were within industrial acceptable levels. The use of Trisyl silica and Magnesol R60 made it feasible to remove the hot‐water washing step and decreased the amount of residual soap to &lt;10 mg/kg oil. There were no significant changes in chemical characteristics of canola oil after using wet and dry bleaching methods. During traditional neutralization, the total tocopherol loss was 19.6 %, while minimal refining with Ca(OH)2, MgO, and Na2SiO3 resulted in 7.0, 2.6, and 0.9 % reductions in total tocopherols. Traditional refining removed 23.6 % of total free sterols, while after minimal refining free sterols content did not change. Both traditional and minimal refining resulted in almost complete removal of polyphenols from canola oil. Total phytosterols and tocopherols in two cold‐pressed canola oils were 774 and 836 mg/100 g, and 366 and 354 mg/kg, respectively. The minimal refining method described in the present study was a new practical approach to remove undesirable components from crude canola oil meeting commercial refining standards while preserving more healthy minor components.

Sinapis alba seed as a prospective biodiesel source

Seed processing and oil pre-treatment were optimised to improve the yield and quality of biodiesel obtained from Sinapis alba. By using solvent extraction or mechanical pressing followed by solvent extraction, an oil extraction yield greater than 41 wt.% and a de-oiled cake with less than 2 wt.% of oil could be obtained. The oil characterisation showed that erucic acid was the most predominant fatty acid in the oil composition (>50 wt.%). A high phosphorous content (>36 mg/kg) and acid value (>1.5 mg KOH/g) were obtained. To obtain a biodiesel with a high methyl ester content, it was necessary to carry out an oil refining process (acid degumming and chemical de-acidification) followed by a standard transesterification with methanol and sodium methoxide as a catalyst. Finally, the quality of the purified biodiesel was tested according to the EN 14214 and ASTM D6751 standards. The results of this work revealed the possibility of using the oil from Sinapis alba seeds as a suitable source for biodiesel.

Distribution of Cyclolinopeptides in Flaxseed Fractions and Products

Hydrophobic cyclic peptides, termed cyclolinopeptides, found in flaxseed are known for their immunosuppressive activity. This study is the first report of the occurrence of cyclolinopeptides in flaxseed fractions and products produced by aqueous processing and cold pressing. The distribution of cyclolinopeptides in flaxseed was determined after processing of flaxseed by various industrial and laboratory processes. Extracts of the water-soluble mucilage did not contain cyclolinopeptides. The cotyledon had the highest concentration of cyclolinopeptides, whereas seed coat had lower levels. An oil body fraction separated from seed after homogenization in water, followed by centrifugation, had the highest concentration of cyclolinopeptides of the fractions produced by this method. Further washing of the oil body fraction led to a loss of cyclolinopeptides. When oilseed was extruded using an expeller press, cyclolinopeptides were found in greater concentrations in crude oil and the solid sediment present in the oil fraction than in meal or the unprocessed seed. The concentration of cyclolinopeptides in crude flaxseed oil immediately after pressing was much higher than that observed in flaxseed oils purchased from a retail outlet. The effect of oil refining treatments on the removal of cyclolinopeptides was also tested. Acid degumming using aqueous H(3)PO(4) removed cyclolinopeptides from crude flaxseed oil. Alkali refining was less effective as this treatment failed to remove all peptides equally. This work illustrates ways that cyclolinopeptides may be extracted from flaxseed oil that could be developed for large-scale industrial extraction. The ability to extract cyclolinopeptides on a larger scale would allow faster exploitation of commercial applications of these molecules and provide the flaxseed industry with value-added coproducts.

Effects of Degumming and Bleaching on 3‐MCPD Esters Formation During Physical Refining

AbstractCrude palm oil (CPO) was physically refined in a 200‐kg batch pilot refining plant. A study of the possible role of degumming and bleaching steps in the refining process for a possible critical role in the formation of 3‐chloropropane‐1,2‐diol (3‐MCPD) esters was evaluated. For the degumming step, different percentages of phosphoric acid (0.02–0.1%) as well as water degumming (2.0%) were carried out. Six different types of bleaching clays, mainly natural and acid activated clays were used for bleaching process at a fixed dose of 1.0%. Deodorization of the bleached oils was performed at 260 °C for 90 min. Analyses showed that 3‐MCPD esters were not detected in the CPO. Phosphoric acid degumming (0.1%) in combination with acid activated clays produced the highest levels (3.89 ppm) of 3‐MCPD esters in the refined (RBD) oil. The esters were at the lowest levels (0.25 ppm) when the oil was water degummed and bleached with natural bleaching clays. However, the refined oil qualities were slightly compromised. Good correlation of 0.9759 and 0.9351 was obtained when concentration of the esters was plotted against acidity of the bleaching earths for the respective acid and water degumming processes. The findings revealed the contribution of acidic conditions on the higher formation of 3‐MCPD esters. In order to lower the esters formation, it is important to reduce acid dosage based on the crude oil qualities or to find alternatives to acid degumming process. Neutralization of the acidity prior to deodorization was effective in reducing the formation of 3‐MCPD esters.

The Application of Peracetic Acid and Sodium Percarbonate in Green Production Processing of Ramie

The drawbacks of traditional chemical degumming for raw ramie are long process line, huge energy consumption, with large environment pollution, and low efficiency. Therefore, an attempt has been made to carry out degumming of ramie with an eco-friendly chemical namely, peracetic acid and sodium percarbonate in this communication. Compared with the traditional chemical degumming process, the oxidation degumming process with the characteristics of environment-friendly production technology is short process, less pollution, low energy consumption and high production efficiency and so on. Meanwhile, the hydrolysis products of peracetic acid and sodium percarbonate do a little harm to the environment. Tenacity, fineness, and breaking elongation of degummed samples were determined by standard methods. The results were confirmed through COD, pH, colority, SEM, tensile properties etc. The performance of peracetic acid degumming and sodium percarbonate degumming were also compared with conventional chemical degummed fiber. In addition, the COD, pH value, colority of degumming solution is greatly reduced using oxidation degumming process, environmental pollution and sewage treatment costs are significantly reduced.

Optimization of Physical Refining to Produce Rice Bran Oil with Light Color and High Oryzanol Content

AbstractCrude rice bran oil (RBO) is rich in valuable minor components such as tocotrienols, phytosterols and γ‐oryzanol. These compounds are well preserved during physical refining, but in current industrial practice, RBO is mostly refined chemically because this results in a lighter color. However this process removes most of the γ‐oryzanol. The challenge is to develop a refining process which combines a high γ‐oryzanol retention with the commercially desired light color. A modified physical refining process was developed, consisting of an acid degumming, prebleaching, dewaxing, physical removal of free fatty acids using packed column technology, a modified washing step, conventional bleaching and deodorization. A RBO with acceptable oryzanol retention of 39% had a Lovibond red color value (measured with a 5.25‐inch cell) of 2.8, approaching very close the color of a chemically refined RBO (red = 2). At the process step where high (94%) retention of γ‐oryzanol was achieved, a somewhat darker Lovibond red value of 5.2 was obtained.

Refino de óleo de farelo de arroz (Oryza sativa L.) em condições brandas para preservação do γ-orizanol

γ-orizanol is an antioxidant present in rice bran oil, but absent in other vegetable oils, which were attributed to antioxidant and hypocholesterolemic effects. The content of γ-orizanol in crude rice bran oil varies between 1-2%, but during neutralization in chemical refining this substance is transferred to soapstock. The aim of this research is to study an alternative technique of physical refining in light conditions with the purpose of preserving γ-orizanol. Inativacted and extrused rice bran obtained by the production of parboilizated rice was used to extract crude rice bran oil (Oryza sativa) by the expeller method. The process of refining consisted of: acid degumming (with 85% H3PO4), centrifugation, clarification, deodorization, and winterization. Chemical analyses were carried out by the characterization of refined oil according to the AOCS methods. Results showed that the physical refining process was able to preserve 97% of γ-orizanol, and its presence improved the oxidative stability of the oil comparing with the commercial rice bran oil (by 33% 13.3 hours to 110 oC).