Bleached Oil Research Articles

Determination of Melting Points, Specific Heat Capacity and Enthalpy of Catfish Visceral Oil During the Purification Process

AbstractChanges in melting points, enthalpy, and specific heat capacity of catfish visceral oil at each step of the purification process were studied. Melting points of −46.2 to 21.2 °C for crude oil, −45.9 to 11.5 °C for degummed oil, −44.3 to 11.4 °C for neutralized oil, −47.1 to 9.9 °C for bleached oil and −52.3 to 8.0 °C for deodorized oil were observed. Enthalpy (kJ/kg) was 74.1 for crude oil, 74.7 for degummed oil, 75.1 for neutralized oil, 79.3 for bleached oil, and 84.3 for deodorized oil. The specific heat capacities at 20 °C for crude, degummed, neutralized, bleached, and deodorized oils were 1.69, 1.96, 1.97, 1.91, and 1.83 kJ/kg °C, respectively.

Some Aspects of Palm Oil Bleaching with Activated Plantain Peel Ash

The present study seeks to investigate the bleaching of palm oil with activated plantain peel ash (APPA). Concentrations of β-carotene, iron, copper, lead, and phosphorus in the crude (unbleached) and bleached palm oil were evaluated. The peroxide value, anisidine value, acidity and colour of the oils were also determined. The objectives were to assess the bleaching performance of the APPA, compare the performance of APPA with that of a commercial natural earth (Pure-Flo Neutral B-80) and investigate the effects of particle size of APPA and APPA/oil ratio on the bleaching performance of APPA. The results indicated that APPA significantly decreased all the investigated characteristics apart from acidity. Results also indicated that Pure-Flo Neutral B-80 slightly performed better than APPA under the same experimental conditions.

Effect of Attapulgite Pore Size Distribution on Soybean Oil Bleaching

AbstractThe pore size distribution and specific surface area of the attapulgite was a crucial parameter for the uptake of pigments of oil. Bleaching of the soybean oil with three attapulgites with different pore size distribution, which were assigned a, b, and c, respectively was investigated. The specific surface area and the pore size distribution of the attapulgites were characterized. The Freundlich isotherm analysis was used to evaluate the sorption capacity of the three attapulgite. Sample b gave the highest surface area and sample c the lowest. Sample b exhibited a wider pore distribution (8–65 Å) whereas samples a and c had more micropores smaller than 15 Å. Sample a, in contrast to samples b and c, was characterized by some larger pores (100–170 Å). The sorption capacity followed the sequence: attapulgite sample c > attapulgite sample a > attapulgite sample b. The sorption capacity was decided by the pore size distribution. The more pores with a distribution range 8–32 Å (i.e., close to the diameter of the pigments), the more pigments removed. The attapulgite sample c, which had most pores (8–32 Å) was the best.

Assessing the bleaching capacity of some Cameroonian clays on vegetable oils

Four Cameroonian clays, constituted mainly of smectites associated to minor amounts of kaolinite and quartz, have been used to bleach palm oil, cottonseed oil and maize germ oil. Kinetic studies show that the best temperature and contact time for optimum bleaching of vegetable oil varied with the type of oil; these are: 95 °C and 2.5 h for palm oil, 85 °C and 0.25 h for cottonseed oil, and 85 °C and 0.5 h for maize germ oil. The bleaching ability of natural clays was poor when compared with that of industrial adsorbents. Acid activation of Cameroonian clays with 1N sulphuric acid solution increased tremendously their adsorptive capacity, which therefore matches those of the industrial adsorbents. Further increase of the concentration of the acid solution used for clay activation did not induce a noticeable increase in the bleaching power of the adsorbents. This was attributed to the fact that the increase in the surface area is due to the formation of silica but the surface area of H-clays remains almost constant over strong acid leaching and silica has very poor bleaching power of vegetable oils. FT-IR spectroscopy studies of the adsorbents after bleaching suggest strong interactions between the clays and adsorbent surface. Acid and iodine values of bleached oils reveal that oils are not deteriorated by clays during the bleaching process. The overall results lead to the conclusion that Cameroonian clays can be converted into potent adsorbents for bleaching vegetable oils.

The removal of colour, carotene and acidity from crude olive oil by using sepiolite

SummaryThe capacity of sepiolite to adsorb colouring matters in olive oil was studied. The effects of adsorption time, temperature and solid:liquid ratio were selected as parameters. The effect of bleaching of olive oil was evaluated for determining the % free fatty acid (FFA), % bleachability and residual carotene by using both thermally activated sepiolite (AS) and acid‐activated sepiolite (AAS). Results reveal that thermally acid‐activated sepiolite was more efficient than thermally activated sepiolite. The adsorption equilibriums of carotene and FFA on AS and AAS were described by the Freundlich models. A higher adsorption coefficient (K) was observed for AAS (Kcarotene = 2.73 × 10−3mgg−1, KFFA = 0.98mgg−1) compared to AS (Kcarotene = 2.63 × 10−7mgg−1, KFFA = 0.21mgg−1). Moreover, the rate constants obtained for carotene and colour by using AAS (kcolor = 0.0241 min−1, kcarotene = 0.0217min−1) were higher than that of AS (kcolor = 0.01min−1, kcarotene = 0.0165min−1).

Co‐composting of Acid Waste Bentonites and their Effects on Soil Properties and Crop Biomass

Acid waste bentonite is a byproduct from vegetable oil bleaching that is acidic (pH < 3.0) and hydrophobic. These materials are currently disposed of in landfills and could potentially have a negative impact on the effective function of microbes that are intolerant of acidic conditions. A study was undertaken using three different sources of acid waste bentonites, namely soybean oil bentonite (SB), palm oil bentonite (PB), and rice bran oil bentonite (RB). These materials were co-composted with rice husk, rice husk ash, and chicken litter to eliminate their acid reactivity and hydrophobic nature. The organic carbon (OC) content, pH, exchangeable cations, and cation exchange capacity (CEC) of the acid-activated bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the water drop penetration time (WDPT) decreased from >10 800 s to 16 to 80 s after composting. Furthermore, these composted materials showed positive impacts on soil physical attributes including specific surface area, bulk density, and available water content for crop growth. Highly significant increases in maize biomass (Zea mays L.) production over two consecutive cropping cycles was observed in treatments receiving co-composted bentonite. The study clearly demonstrates the potential for converting an environmentally hazardous material into a high-quality soil conditioner using readily available agricultural byproducts. It is envisaged that the application of these composted acid waste bentonites to degraded soils will increase productivity and on-farm income, thus contributing toward food security and poverty alleviation.

Alteration of Chemical Composition and the Oxidative Stability of Bleached Pomace−Olive Oil on Activated Clays

This work is a contribution to the study of the bleaching process, which is a very important stage in the refining process of vegetable oils and used to reduce or convert undesired constituents to harmless ones from fats and oils. The virgin olive oil, taken as reference, and the pomace-olive oil were bleached in the optimal conditions using Tunisian bleaching earths (South of Tunisia) which were activated in our laboratory and compared with commercial clays. It was shown that activated Tunisian clays are characterized by a very important adsorptive capacity, comparable to that of commercial clays. Also, the physicochemical stability of bleached oils was studied. The fatty acid composition (GC), the triacylglycerol composition (HPLC), and the oxidative stability (UV spectrometry) allowed us to conclude that oils, bleached with the Tunisian activated clays, do not undergo considerable physicochemical alterations and remain corresponding to the international standards for refined oils for human consumption.

Adsorption bleaching of soyabean oil in presence of small amount of solvents

The presence of small amounts of solvents from 1.0 to 5.0% enhanced the adsorption bleaching efficiency of soyabean oil. The solvents used were ethanol, benzene and acetone. Among the solvents acetone gave the best results. The temperature maintained during the process ranged from 70-75 °C. The process is convenient and simple and can be practiced in a commercial scale. The process temperature being low, oil quality could be better retained.

Characterization of nanoporous materials prepared from montmorillonite clay and its application to the decolorization of mare's milk oil

Nanoporous materials have been prepared by leaching the purified montmorillonite clay with sulfuric acid (H2SO4) solution with varying concentrations (0.5–2 M) at 80°C for 0.5–4 h. Acid leaching causes partial amorphisation of the clay with depletion of MgO, Al2O3, CaO and Fe2O3 components mostly from interlayer and octahedral sites. This increases the specific surface area by more than 3 times, i.e. from 49.1 to 157 m2/g. The pore-size distribution curves calculated from the adsorption isotherms of the leached montmorillonite show that most of the pores are in the mesoporous region with their diameter ranging 3–4 nm. This material turns out to be appropriate for bleaching of the mare's milk oil. The chemical and structural changes of the acid-leached montmorillonite are discussed in terms of the decolorization capacity.

Optimisation of Bleaching Conditions for Soybean Oil Using Response Surface Methodology

The refining process applied to soybean oil (SBO) in order to obtain the desirable purity characteristics as edible oil, produces chemical changes by partially removing desirable components such as tocopherols. In this study, the effect of temperature (76.4-143.6°C), contact time (6.4-73.6min) and clay amount (0.16-1.84% w/w) on tocopherol content and quality of SBO were evaluated. Neutralised soybean oil was subjected to bleaching using different clay amounts (Tonsil Optimum 320 FF), stirring (250rpm), and partial vacuum (60mmHg). A response surface methodology (RSM) was used to find the parameters that produce bleached oil with minimum peroxide value (PV), maximum tocopherol retention (TOCR) and light colour. The optimal bleaching conditions for SBO were: temperature, 96°C; time, 23min; clay amount, 1.4% w/w oil. Under these conditions, a bleached soybean oil with 0.1meq/kg of PV, 91.74% of TOCR, and colour 1.53 Lovibond red value units was obtained.

Determination of Al(III) activation conditions for white bentonite used for cottonseed oil bleaching by robust design

AbstractThe optimum Al(III) activation conditions for white bentonite (Ordu, Turkey), used as a bleaching agent for cottonseed oil, were investigated. AlCl3–clay suspension was hydrolyzed in situ using NaOH to investigate possible pillars. Five controllable factors that mainly affect the activation process were specified as initial AlCl3 concentration (F1), OH−/Al3+ molar ratio (F2), NaOH volumetric flow‐rate (F3), cation‐exchange temperature (F4) and thermal treatment temperature (F5). Each factor was examined at four levels by using a robust (Taguchi) design to determine optimum activation conditions. The response variable of each experimental run was taken as bleaching efficiency, which is defined in terms of absorbance at 420 nm. The effect of desired levels of factors to the system response was compared using the signal‐to‐noise (S/N) ratio. An importance factor (IF) was suggested in order to compare the affectability of each factor to the response variable by using the integrated area under the S/N ratio curves. The most important factor affecting bleaching efficiency was F5, followed in sequence by F2 &gt; F1 &gt; F4 &gt; F3. The availability of AlO species after activation in the clay crystal structure was determined by FTIR analysis. The optimum levels of each factor for Al3+ activation of clay were F1 5 meq g−1 clay, F2 2.0, F3 1200 mL h−1, F4 25 °C and F5 700 °C. Copyright © 2005 Society of Chemical Industry

ENHANCING OF THE PERFORMANCE EFFICIENCY OF OILS BLEACHING EARTH

Various percentages of citric acid [0.05, 0.1, 0.15 and 0.2%] were blended with the oil (w/v) before the bleaching of either soybean oil (SOO) or sunflower oil (SUO) to rise the performance efficiency of bleaching earth. Afterwards, activated bleaching earth was added to these oils for bleaching them at 1% level. Also, the same clay was used at 2% level for bleaching the above mentioned oils without us-ing citric acid as a reference. The study revealed that better result for raising the bleaching efficiency of SOO was obtained with 0.15% citric acid. Whilst, 0.1% cit-ric acid gave the best result pertaining the bleaching efficiency of SUO. Also, the data showed high reductions in the values of peroxide number, soap, conjugated dienes and trienes for the bleached oils with the increasing percent content of citric acid. While, the acidity values of the bleached oils (SOO and SUO) slightly in-creased with increasing citric acid percentages. On the other hand, using of citric ac-id at the ratios of 0.15 and 0.2% gave almost the same values in the bleaching effi-ciency of SOO. While, using of citric acid at the ratios of 0.1 and 0.15% gave nearly the same results of bleaching efficiency of SUO. Also, the data indicated that using of citric acid caused somewhat no changes in the fatty acid composition or their oxi-dative stabilities in the bleached oils. Therefore, it can be concluded that the reduc-tion in the color of sunflower and / or soybean oils up to a levels of 33.3 and 36.7% is attainable by using either 0.1 or 0.15% citric acid prior to the bleaching step to de-crease the imported content from bleaching earth to Egypt

Statistical modelling of acid activation on cotton oil bleaching by Turkish bentonite

The aim of the study was to determine the highest bleaching capacity and derive a model for acid activation of a Turkish bentonite using a full factorial design. The selected factors were contact time, solid to liquid ratio, acid concentration and moisture of bentonite. A first-order model is obtained by using 2 4 full factorial design. Auxiliary experiments for the second-order model were conducted according to an orthogonal central composite design. An experimental test carried out using a factorial design 2 4 indicated that contact time, solid to liquid ratio and moisture of bentonite have a positive effect, whereas acid concentration has a negative effect. Furthermore, the highest bleaching capacity was found to be 74.2%.

Al‐Pillared clay for cottonseed oil bleaching: An optimization study

AbstractIn this study, Al‐pillared white bentonite (Ordu‐Unye, Turkey) was used for cottonseed oil bleaching. Pillaring process parameters were optimized in terms of bleaching efficiency as the bleaching capacity of cottonseed oil. The initial cation concentration, hydrolyzing agent ratio, and thermal treatment temperature were chosen as major process parameters. Pillared clays were characterized by FTIR and differential thermal analysis. The bleaching efficiency of bentonite increased from 11.8 to 17.5% by acid activation and to 33.5% by further Al pillaring. The optimal pillaring process conditions for cottonseed bleaching were an initial concentration of AICl3, of 0.5 M, a OH−/Al3+ molar ratio of 0.3, and a thermal treatment temperature of 700°C.

Reuse of discarded deactivated bleaching earth in the bleaching of oils

Discarded bleaching earth was used after its reactivation for the bleaching of sunflower, soybean and corn oils. The efficiency of reactivated bleaching earth was compared to the efficiency of virgin activated bleaching earth. Acid reactivated earth (pH 2.5-3) had a slightly higher content in silicone than virgin activated or neutralized reactivated earths. The best results in the color of sunflower and corn oils were obtained when neutralized earth (pH 6–7) was used at 1 and 2 % levels. Acid reactivated earth used at 2 % achieved a higher reduction in soybean oil color than virgin earth (pH 3) at the same dosage. Both reactivated earths reduced peroxide value, iron, conjugated dienes and soap, while they increased acidity and conjugated trienes. Furthermore, these reactivated earths determined higher decrements in the oil induction period than virgin earth. Reactivated earth could be used for 5 cycles for the bleaching of soybean or corn oils and for more than 6 cycles for sunflower oil.

Carbon–mineral adsorbents prepared by pyrolysis of waste materials in the presence of tetrachloromethane

Natural bentonite spent in the process of plant oil bleaching was used as an initial material for preparation of carbon–mineral adsorbents. The spent bleaching earth was treated using four procedures: T (thermal treatment); H (hydrothermal treatment); C (thermal treatment with addition of CCl 4 vapor); M (modification of porous structure). Raw bentonite, RB (raw bleaching earth), and carbon materials prepared using plant oil were compared. The physicochemical characteristics of the adsorbents were determined using different methods: nitrogen adsorption/desorption, XRD, TEM, and MS-TPD. Carbon–mineral adsorbents contain from 5.23 to 19.92% C (w/w) and carbon adsorbents include from 84.2 to 91.18% C (w/w). Parallel processes of organic substance carbonization, porous structure modification, sublimation or evaporation of metal chlorides, and removal of hydrogen chloride take place during pyrolysis of waste mineral materials in the CCl 4 atmosphere.

PROCESS INTENSIFICATION OF MEMBRANE SYSTEM FOR CRUDE PALM OIL PRETREATMENT

ABSTRACT In the study conventional refining, microfiltration and ultrafiltration processes have been used experimentally to pretreat crude palm oil (CPO) samples with the aim of moving from the usual huge refinery plant to a more process integrated membrane module at ultrascale size that will even perform better than the former. Reduction of phosphorus for the membrane‐permeate of 43.4% was higher than that of bleached oil of 34.4%. When ceramic membranes with pore diameters of 0.45 µm and 0.2 µm were used in microfiltration, it was found that membrane with pore size of 0.45 µm was able to reject 14% of phosphorus, while ceramic membrane with pore size of 0.2 µm showed better phosphorus rejection of 56.8%. Upon applying ceramic membrane with pore sizes of 20 nm and 50 nm, 78.1% and 60% of phosphorus were rejected, respectively. Attributed to the superior performance of the membrane with 20 nm pore size over other membranes and conventional refining method on phosphorus content, a simulation study thus made, showed that the average slurry volume after about 22‐min runs for membrane with pore sizes of 0.45 µm, 0.2 µm, 50 nm and 20 nm, and the average slurry volumes are 0.05, 0.09, 0.13 and 0.18 m 3 , respectively. The percentage decrease between membrane pore size of 0.45 µm and 0.2 µm; 0.45 µm and 50 nm; and 0.45 µm and 20 nm are 73, 49 and 24%, respectively. The ultrafiltration achieved order of process miniaturization of about 10 2 −10 3 , which is in accordance with literature. This is a considerable size reduction in the process size, which reflects the magnitude of slurry volume that can be produced within a given time and meets every standard for process intensification through simulated process miniaturization.

The efficiency of the generation of photochemically active triplet states in oils containing various amounts of natural pigments

Absorption, fluorescence emission and excitation spectra as well as time resolved photothermal signals of oils, obtained by pressing the following types of seeds: evening primrose seeds, rapeseeds, borage seeds and viper's bugloss seeds, were measured. It was found that the oils differed in the compositions of fatty acids, acid values, peroxide values and contents of pigments. The oils contained not only various tocopherols and sterols but also different amounts of chlorophylls and carotenoid pigments. The chemical bleaching procedure used causes a decrease in the pigment content and changes acid values in the bleached oils in comparison with natural (unbleached) oils. The bleached oils exhibit predominantly fluorescence of fatty acids and products of their degradation. In natural oils, a high pigment and low fatty acid emission is observed, because of the excitation energy transfer from these acids to pigments that takes place. The ratios of fast thermal deactivations of natural oils to those of the bleached ones were different for various oils. This suggests that also the change in the efficiencies of triplet state generation due to bleaching differed for these oils. On the basis of the results presented it is possible to predict the influence of the oils' bleaching procedure on their stability during storage.

Irradiation bleaching of palm oil, palmolein, and palm stearin

Irradiation bleaching of palm oil, palmolein, and palm stearin

Kinetic studies on bleaching of edible oil using charred sawdust as a new adsorbent

A new and low cost acid hydrolyzed charred sawdust as an adsorbent has been used for the purification of edible oils. The maximum colouring matter adsorbed Γ p m (mg/m 2) for different oils on sawdust has been calculated. The change in free energy −Δ G×10 −1 (kJ/ mol) due to adsorption of colouring matter from the bulk to the interface of the sawdust has been calculated. From our result it has been found that the maximum adsorption has been comparable to the change in free energy. The thermodynamic parameters such as the activation energy, enthalpy, and entropy are presented. The negative value of Δ S indicates less disorder i.e. the crude oil contains more colourant and impurities before bleaching process and these are decreased during adsorption process because disorder is directly proportional with entropy.