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1.
Oxidative stability of high-fatty acid rice bran oil at different stages of refining 总被引:2,自引:0,他引:2
The contents of natural antioxidants and the oxidative stability of rice bran oils at different refining steps were determined.
Tocopherols and oryzanols were constant in crude and degummed oils but decreased in alkali-refined, bleached and deodorized
oils. The process of degumming, alkali-refining, bleaching and deodorization removed 34% of the tocopherols and 51% of the
oryzanols. During storage of deodorized oil for 7 wk, 34% of the tocopherols and 19% of the oryzanols were lost. The maximum
weight gain, peroxide value and anisidine value were obtained from alkali-refined oil during storage. The order of oxidation
stability was crude ≥ degummed > bleached = deodorized > alkali-refined oil. 相似文献
2.
Abdalbasit Mariod Bertrand Matthäus Ismail H. Hussein 《Journal of the American Oil Chemists' Society》2011,88(5):603-609
Stripped and non-stripped oils from Sclerocarya birrea [marula oil (SCO)], Aspongopus viduatus [melon bug oil (MBO)] and Agonoscelis pubescens [sorghum bug oil (SBO)], traditionally used for nutritional applications in Sudan, were investigated for their fatty acid
and tocopherol composition, and their oxidative stability. Three stripping methods were used, phenolic compounds extraction,
silicic acid column, and aluminum oxide column. The stripping methods did not affect the fatty acid composition. Non-stripped
SCO, MBO and SBO contained oleic, palmitic, stearic and linoleic acids, which were not significantly (P < 0.05) different than stripped SCO, MBO and SBO. The stripping methods’ effect on the tocopherol composition of the studied
oils, the total amount of tocopherol in non-stripped oils decreased by extraction of phenolic compounds, mean that part of
the tocopherols was extracted with the phenolic compounds. No traces of tocopherols were found in oils stripped using silicic
and aluminum columns and the tocopherols were eliminated during the stripping processes. The stability of SCO, MBO and SBO
oils was 43, 38 and 5.1 h, respectively, this stability decreased by 22.0, 37.6 and 23.5%, respectively after extraction of
phenolic compounds. This stability decreased by 96.9, 98.2 and 90.2% respectively, when stripped using the aluminium column
and decreased by 92.6, 96.1 and 86.3% when stripped by the silicic column. It is possible to assume that the tocopherols and
phenolic compounds play a more active role in the oxidative stability of the oils than the fatty acid composition and phytosterols. 相似文献
3.
Effects of processing steps on the contents of minor compounds and oxidation of soybean oil 总被引:4,自引:0,他引:4
The processes of degumming, alkali refining, bleaching and deodorization removed 99.8% phospholipids, 90.7% iron, 100% chlorophyll,
97.3% free fatty acids and 31.8% tocopherols from crude soybean oil. The correlation coefficient between the removals of phosphorus
and iron in soybean oil during processing was r = 0.99. The relative ratios of α-, β -, γ- and δ-tocopherols in crude oil,
degummed oil, refined oil, bleached oil and deodorized soybean oil were almost constant, γ- and δ -tocopherols represented
more than 94% of tocopherols in soybean oil. The order of oxidation stability of oil is crude > deodorized > degummed > refined
> bleached oil. 相似文献
4.
The thermal degradation (weight loss) of individual FA and of catfish and menhaden oils collected from different refining
steps was investigated by thermogravimetric analysis. The heat resistance of FA was partially dependent on chain length and
degree of unsaturation. The weight loss of catfish and menhaden oils increased with increased heating temperatures, regardless
of the oil refining process. All oil samples (except crude catfish oil) were decomposed after the heating temperature reached
550°C. Based on the thermogravimetric curves, the following thermal stability sequence at different refining steps for both
catfish and menhaden oils was proposed: crude > degummed > neutralized > bleached > deodorized oils. 相似文献
5.
Subramaniam Sathivel Witoon Prinyawiwatkul Ioan I. Negulescu Joan M. King 《Journal of the American Oil Chemists' Society》2008,85(3):291-296
Changes 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. 相似文献
6.
Vanessa Ribeiro Pestana Rui Carlos Zambiazi Carla R. B. Mendonça Mariangela H. Bruscatto María Jesús Lerma-García Guillermo Ramis-Ramos 《Journal of the American Oil Chemists' Society》2008,85(11):1013-1019
The quality changes and the concentrations of tocopherols and γ-oryzanol, during successive steps of rice bran oil refining
(RBO), were studied. For this purpose, samples of crude, degummed, neutralized, bleached, dewaxed and deodorized RBO were
taken from an industrial plant and analyzed. The moisture, pH, acidity, peroxide value and unsaponifiable matter, were determined.
The fatty acid composition was evaluated by GC, and the concentrations of tocopherols and γ-oryzanol were determined using
HPLC with fluorescence and UV–Vis detection, respectively. To identify γ-oryzanol components, fractions of the HPLC eluant
were collected and analyzed using mass spectrometry. Oil refining reduced the peroxide value and acidity to 1 and 3% of the
values obtained in crude RBO, respectively. The fatty acid composition were not significantly altered during refining. The
concentrations of the tocopherols in RBO followed the order α > (β + γ) > δ. The total concentration of tocopherols was 26 mg/100 g,
and remained practically unaltered during refining. Up to nine components were distinguished in γ-oryzanol. After collecting
the elution fractions, up to six components were identified by electrospray mass spectrometry. Refining reduced the total
concentration of γ-oryzanol to 2% of its initial value. 相似文献
7.
Autocatalytic esterification of free fatty acids (FFA) in rice bran oil (RBO) containing high FFA (9.5 to 35.0% w/w) was examined
at a high temperature (210°C) and under low pressure (10 mm Hg). The study was conducted to determine the effectiveness of
monoglyceride in esterifying the FFA of RBO. The study showed that monoglycerides can reduce the FFA level of degummed, dewaxed,
and bleached RBO to an acceptable level (0.5±0.10 to 3.5±0.19% w/w) depending on the FFA content of the crude oil. This allows
RBO to be alkali refined, bleached, and deodorized or simply deodorized after monoglyceride treatment to obtain a good quality
oil. The color of the refined oil is dependent upon the color of the crude oil used. 相似文献
8.
Commodity (normal) and high-oleic soybean oils extracted by extrusion-expelling (E-E) were minimally processed using water
degumming and adsorptive deacidification to produce edible oil. Degummed and deacidified oils were deodorized at 150°C for
1 h by purging with N2, CO2, or steam. They were also conventionally deodorized for quality comparisons. Generally, the oxidative stability of the properly
gas-purged commodity oils was better than that of the conventionally deodorized oils. Total tocopherols, FFA contents, and
colors of the deodorized oils were not significantly different among the treatments. Sensory analysis of the oils showed that
the toasty/nutty flavors of the gas-purged oils, especially for the degummed oils, were more intense than those of the conventionally
deodorized oils. The beany flavors of gas-purged oils were not significantly different from those of conventionally deodorized
oils, although the flavor intensities tended to be slightly higher in gas-purged oils. The overall flavor intensities of the
gas-purged oils were similar to those of conventionally deodorized oils. Therefore, E-E soybean oil has the potential to be
minimally refined to produce edible oil with good compositional and sensory qualities. 相似文献
9.
Satu Pekkarinen Anu Hopia Marina Heinonen 《European Journal of Lipid Science and Technology》1998,100(3):69-74
The effect of various processing conditions on the composition and the oxidative stability of mechanically pressed (90–95°C) rapeseed oil was investigated. The five different rapeseed oils included crude (nondegummed), superdegummed, steam stripped (at 140°C for 4h, nondegummed), physically refined (degummed, bleached and deodorized at 240°C), and cold pressed (40°C) oils. Oils were autoxidized in the dark at 60°C and under light at 25°C. Oxidation was followed by measuring changes in the peroxide values (PV) and the consumption of tocopherol and carotenoid was measured. In the dark the oils reached PVs of 10 meq/kg in the order: cold pressed > superdegummed > steam stripped ≅ crude > refined. However, under light conditions the order changed as follows: cold pressed > crude ≅ steam stripped > superdegummed > refined. Processing had no effect on fatty acid composition nor α-tocopherol content of the oils. Superdegumming and steam stripping decreased the carotenoid content of the oils while cold pressing and refining reduced also chlorophyll, γ-tocopherol and phosphorus content of the oils. 相似文献
10.
The crude oil extracted from soy flakes with supercritical carbon dioxide (SCCO2) was characterized for color, free fatty acid, phosphorus, neutral oil loss, unsaponifiable matter, tocopherol and iron content
and compared to a commercial hexane-extracted sample of crude degummed oil. Characterization and processing studies indicate
that SCCO2 extraction yields a product comparable to a hexane-extracted degummed oil. However, hexane-extracted degummed soybean oils
exhibit better oxidative stability because phosphatides, which are natural antioxidants, are essentially absent in SCCO2-extracted oils.
Presented at AOCS Meeting, Toronto, May, 1982. 相似文献
11.
Kanok Yooritphun Supathra Lilitchan Kornkanok Aryusuk Kanit Krisnangkura 《Journal of the American Oil Chemists' Society》2017,94(2):301-308
Alkaline neutralization is a classical method for removal of free fatty acids (FFA) in crude oil. It is generally accompanied by neutral oil loss. Thus, reduction of refining losses associated with alkaline neutralization is very desirable. Refined, bleached and deodorized (RBD) palm oils with different FFA contents were used as oil models in this study. FFA in the oil models were neutralized with sodium hydroxide in polyhydric alcohols as neutralization media. Glycerol, propylene glycol and ethylene glycol in water were effective neutralization media. FFA in the oil models were totally removed in one step of neutralization, while percentages of refining losses were different. The losses were increased in the order of water > propylene glycol > ethylene glycol > glycerol used as neutralization media. Also, a higher concentration of polyhydric alcohol in the neutralizing media significantly reduced the percentage of refining loss (p < 0.05). Glycerol (90% in water) was the most effective neutralization media (p < 0.05). When neutralization was carried out on crude palm oil (containing 7.53% FFA), refining loss was reduced from 36.1% (in water) to 20.0% (in 90% glycerol in water). 相似文献
12.
G. R. List C. D. Evans K. Warner R. E. Beal W. F. Kwolek L. T. Black K. J. Moulton 《Journal of the American Oil Chemists' Society》1977,54(1):8-14
Various processing steps were explored in an at-tempt to improve the quality of oil from field- and storage-damaged soybeans.
A crude soybean oil (5.7% free fatty acid) commercially extracted from damaged soybeans was degummed in the laboratory with
different reagents: water, phosphoric acid, and acetic anhydride. Two alkali strengths, each at 0.1 and 0.5% excess, were
used to refine each degummed oil. After vacuum bleaching (0.5% activated earth) and deodorization (210 C, 3 hr), these oils
were un-acceptable as salad oils. A flavor score of 6.0 or higher characterizes a satisfactory oil. Scores of water and phosphoric
acid degummed oils ranged from 4.5 to 5.1, while acetic anhydride degummed oils aver-aged 5.6. Flavor evaluations of (phosphoric
acid de-gummed) single- and double-refined oils (210 C deodorization) showed that the latter were signifi-cantly better. Flavor
scores increased from 5.0 to about 6.0. To study the effects of deodorization tem-perature, the crude commercial oil was alkali-refined,
water-washed and bleached with 0.5% activated earth, but the degumming step was omitted. Flavor evalua-tion of oil deodorized
at 210, 230, and 260 C showed that each temperature increment raised flavor scores significantly. Further evaluations of specially
proc-essed oils (water, phosphoric acid, and acetic anhy-dride degummed oils given single and double refinings and deodorized
at 260 C) showed that deodorization temperature is the most important factor affecting the initial quality of oil from damaged
beans. Flavor evaluations showed that hydrogenation and hydro-genation-winterization treatments produced oils of high initial
quality, but with poorer keeping proper-ties than oils from normal beans. No evidence was found implicating nonhydratable
phosphatides in the oil flavor problem. Iron had a deleterious effect in oils not treated with citric acid during deodorization.
Presented at AOCS Meeting, Philadelphia, September 1974. 相似文献
13.
Abdalbasit Mariod Bertrand Matthäus K. Eichner Ismail H. Hussein 《Journal of the American Oil Chemists' Society》2006,83(6):529-538
The behavior of crude Sclerocarya birrea kernel oil (SCO) and Sorghum bug (Agonoscelis pubescens) oil (SBO) during deep-frying of par-fried potatoes was studied with regard to chemical, physical, and sensory parameters,
such as content of FFA, tocopherols, polar compounds, oligomer TG, volatile compounds, oxidative stability, and total oxidation
(TOTOX) value. Palm olein was used for comparison. Whereas potatoes fried in SCO that had been used for 24 h of deep-frying
at 175°C were still suitable for human consumption, potatoes prepared in SBO that had been used for 6 to 12 h were not, considering
the sensory evaluation. In looking at the chemical and physical parameters, SBO exceeded the limits, after no later than 18
h of use, for the amount of polar compounds, oligomer TG, and FFA recommended by the German Society of Fat Sciences (DGF)
as criteria for the rejection of used frying oils. In contrast to SBO, SCO oil did not exceed the limits for the content of
polar compounds and oligomer TG during the frying experiment. Only the amount of FFA was exceeded; this was because the amount
of FFA at the beginning of the experiment was higher than for refined oils. The results showed that both oils were suitable
for deep-frying of potatoes, but remarkable differences in the time during which both oils produced palatable products were
found. 相似文献
14.
Bijay Krishna De Jignesh Dahyabhai Patel 《European Journal of Lipid Science and Technology》2011,113(9):1161-1167
The applicability of calcium hydroxide (lime) in the neutralization of rice bran oil (RBO) was investigated. Crude RBO samples of three different free fatty acids (FFAs) (3.5–8.4 wt%) were degummed, dewaxed, bleached, and neutralized with lime and deodorized. The oils obtained thus were characterized by determining the color, peroxide value (PV), content of unsaponifiable matter (UM), and FFA. Conventionally practiced caustic soda neutralization (at 80–90°C) of FFA has in the present investigation been replaced by a high temperature (150–210°C) low pressure (2–4 mm Hg) reaction with lime. It was observed that neutralization with Ca(OH)2 at high temperature (210°C) and under low pressure (2–4 mm Hg pressure) may substantially reduce the FFA content (0.8 wt%, after 2 h). The deodorized oil was found to be of acceptable color, PV, and content of UM and FFA. Neutralization of oil was also carried out by using NaHCO3 and Na2CO3, nonconventional alkalies for neutralization, and the results were compared with NaOH and Ca(OH)2. Overall recovery of oil in Ca(OH)2 refining process (88.5 ± 0.6 wt%, for Sample 1 containing 8.4%‐wt FFA) was found to be more than other competitive processes studied. 相似文献
15.
Michael H. Gordon Ibrahim Abdul Rahman 《Journal of the American Oil Chemists' Society》1991,68(8):574-576
The effect of various processing procedures on the composition and oxidative stability of coconut oil has been studied. The
crude oil is relatively stable but major reductions in oxidative stability occur during the bleaching of oil degummed with
phosphoric acid; during alkali refining; during the deodorization of oil degummed with citric acid and bleached; and during
the deodorization of oil processed with a combined phosphoric acid degumming and bleaching operation. The reasons for the
loss of oxidative stability during processing are discussed with reference to changes in the composition of the oil. Residual
traces of citric acid or phosphoric acid play an important role in stabilizing processed oils. The tocopherol content is also
important, although no additional stabilization of the oil occurs on adding levels of tocopherol above those present naturally
in the crude oil. A combined phosphoric acid degumming and bleaching process leads to smaller losses of tocopherols than sequential
treatments. 相似文献
16.
G. R. List J. W. King J. H. Johnson K. Warner T. L. Mounts 《Journal of the American Oil Chemists' Society》1993,70(5):473-476
A hexane-extracted crude soybean oil was degummed in a reactor by counter-currently contacting the oil with supercritical
CO2 at 55 MPa at 70°C. The phosphorus content of the crude oil was reduced from 620 ppm to less than 5 ppm. Degummed feedstocks
were fed (without further processing,i.e., bleaching) directly to a batch physical refining step consisting of simultaneous deacidification/deodorization (1 h @ 260°C
and 1–3 mm Hg) with and without 100 ppm citric acid. Flavor and oxidative stability of the oils was evaluated on freshly deodorized
oils both after accelerated storage at 60°C and after exposure to fluorescent light at 7500 lux. Supercritical CO2-processed oils were compared with a commercially refined/bleached soybean oil that was deodorized under the same conditions.
Flavor evaluations made on noncitrated oils showed that uncomplexed iron lowered initial flavor scores of both the unaged
commercial control and the CO2-processed oils. Oils treated with .01% (100 ppm) citric acid had an initial flavor score about 1 unit higher and were more
stable in accelerated storage tests than their uncitrated counterparts. Supercritical CO2-processed oil had equivalent flavor scores, both initially and after 60°C aging and light exposure as compared to the control
soybean oil. Results showed that bleaching with absorbent clays may be eliminated by the supercritical CO2 counter-current processing step because considerable heat bleaching was observed during deacidification/deodorization. Colors
of salad oils produced under above conditions typically ran 3Y 0.7R. 相似文献
17.
Friedrich Schne Jan Fritsche Jürgen Bargholz Matthias Leiterer Gerhard Jahreis Bertrand Matthus 《European Journal of Lipid Science and Technology》1998,100(12):539-545
Changes of rapeseed and linseed oil during processing During processing of crude oil in a large oil mill, three samples each of rapeseed and linseed were investigated at each processing stage, i.e. press oil, solvent-extracted oil, mixed oil, and degummed/caustic refined oil. In the case of rapeseed also bleached and desodorized oils (230°C; 3.0 mbar for 2 h) were investigated. Rapeseed and linseed oil showing the typical major fatty acids contained less than 1% trans-isomeric fatty acids (trans fatty acids = TFA). Linseed oil had a similar TFA-concentration as rapeseed oil, and the concentrations did not change during the processing stages up to degummed/caustic refined oil, and were also unchanged in the bleached rapeseed oil. Desodorization of rapeseed oil, however, trebled the TFA concentration to 0.58%. The detected tocopherol patterns were typical of rapeseed and linseed oils. There was no difference between mixed oil and degummed/caustic refined oil in the total concentration of tocopherols. Neither had bleaching any effect. Rapeseed oil desodorization diminished total tocopherol concentration by 12% from 740 mg/kg to 650 mg/kg. Due to degumming/caustic refining the phosphorus concentration of both oils decreased to less than a tenth compared to mixed oil. Other elements determined in degummed/caustic refined rapeseed oil were not detectable (manganese < 0.02 mg/kg, iron < 0.4 mg/kg, copper < 0.02 mg/kg, lead < 10 μg/kg) or only as traces zink 0.1 mg/kg, cadmium 2 μg/kg). In linseed oil, which initially showed a higher trace compounds concentration, a significant decrease was found by degumming/caustic refining. Iron could not be detected. There were traces of zinc, manganese, copper, lead, and cadmium. There was no difference between the acid values of rapeseed and linseed crude oil. Acid value decreased drastically already during the degumming/caustic refining stage. The crude linseed oils had a higher peroxide value, anisidine value and diene value than the corresponding crude rapeseed oils. With peroxide values of ≤ 0.1 mEq O2/kg found in almost all investigated rapeseed oils, no effect of refining could be detected. The anisidine value showed an increase after bleaching. Desodorization trebled the diene value. 相似文献
18.
Yasushi Endo Hiromi Endo Kenshiro Fujimoto Takashi Kaneda 《Journal of the American Oil Chemists' Society》1991,68(10):769-771
Edible refined, bleached and deodorized (RBD) soybean oil was fractionated by silicic acid column chromatography to identify
minor components responsible for flavor reversion. Minor components from oil eluted with diethyl ether/n-hexane (1:1) were
compared with those from corn and canola oils. All vegetable oils contain free fatty acids, diglycerides and sterols as major
ingredients in this fraction. However, unusual triglycerides consisting of 10-oxo-8-octadecenoic acid and 10-and 9-hydroxy
octadecanoic acids were detected in RBD and crude soybean oils. 相似文献
19.
C. E. Swift Sara P. Fore F. G. Dollear 《Journal of the American Oil Chemists' Society》1950,27(1):14-16
- The extraction, processing, characteristics, and stability properties of nine batches of hexane-extracted rice bran oil were investigated. The oils were refined, bleached, and deodorized and their color and stability determined. Samples of the bleached oils were hydrogenated to approximately shortening consistency, deodorized, and the stability of the hydrogenated products determined.
- Pilot plant extractions of five batches of rice bran yielded crude oils equivalent to 91% of the hexane-soluble portions of the bran.
- The nine crude oils whose content of free fatty acids ranged from 2.0 to 6.3% were refined by the cup method with losses ranging from 12.0 to 23.5% although the neutral oil content of six crude rice bran oils ranged from 89.9 to 92.6%.
- The Lovibond color of the nine refined oils ranged from 35 yellow and 4.5 red to 70 yellow and 9.5 red, and the color of the bleached oils ranged from 15 yellow and 1.5 red to 35 yellow and 3.2 red.
- Steam-refining, employed in conjunction with alkali-refining, proved effective as a means of reducing the losses in refining rice bran oil.
- The nine batches of refined, bleached, and deodorized rice bran oils had iodine values ranging from 101.3 to 105.7 and stabilities averaging 24 hours.
- Nine bleached oils hydrogenated to approximate shortening consistency had iodine values averaging approximately 66 and stabilities averaging 370 hours.
- Refined, bleached, and deodorized rice bran oil is bland but has some tendency toward flavor reversion.
- The most outstanding characteristics of rice bran oil is its exceptional stability after hydrogenation.
20.
T. K. Mag 《Journal of the American Oil Chemists' Society》1973,50(7):251-254
The treatment of crude edible oils with sodium hydroxide solutions is the standard refining procedure in the industry. Refining
with NaOH removes free fatty acids, some phosphatides, proteinaceous matter and some colored material. Up to now experience
has shown that most oils cannot be deodorized satisfactorily unless they have been caustic-refined. In the past, when most
crude oils contained several per cent of free fatty acids, caustic-refining offered itself as a particularly suitable means
of preparation for further processing. In recent years the free fatty acid content of crude oils has been, in most cases,
only a fraction of 1%, which could very readily be removed in the process of deodorization. A prerequisite for this would
be to remove by some other means those substances that interfere with satisfactory deodorizing. It has been found that the
process of bleaching can be used for this purpose if the oil is pretreated with 0.1–0.5% phosphoric acid and bleached at 325–350
F. The amount of bleaching clay required depends on the type of oil and its quality, but with many oils up to 2% clay is satisfactory.
The amount of phosphoric acid necessary also depends on the type of oil.
One of nine papers presented in the symposium “Processing of Edible Oils,” AOCS Meeting, Ottawa, September 1972. 相似文献