Amaranth seed (Amaranthus hypochondriacus cv. K432) was processed to obtain oil, reported to be a promising source of squalene. The amaranth seed was ground using
a stone mill, then separated into oil-rich embryonic tissue (or “bran”) and starchy perisperm. Amaranth bran was much more
stable than rice bran when free fatty acid (FFA) content and peroxide value were monitored. Milling at a gap of 0.755 mm did
not result in excessive damage to the starch in the perisperm fraction and yielded a bran fraction that contained more than
three-fourths of the oil and a starchy fraction consisting of more than two-thirds of the seed weight. The bran particles
were too fine for effective bench-scale extraction of the oil. Consequently the bran was extruded into collects prior to extraction.
Two extrusion settings were evaluated regarding the rate of moisture injection, while the bran feed rates were constant. There
was no significant difference in appearance or size between the two dried collets. Collets were extracted with hexane using
an Armfield Extraction/Desolventizing Unit (Model FT 29, Armfield, Ltd., Hampshire, England). Oil recovery averaged 97.7 and
80.0%, respectively. Oil was extracted at high yield from the bran when the bran was extruded into collets. Oil can be obtained
as a coproduct of amaranth starch by milling and separating the fractions of amaranth seed. Milling, extrusion, and extraction
did not decrease significantly the squalene content in amaranth oil, but increased FFA content and peroxide value and changed
tocopherol content of the oil. 相似文献
Model oil systems containing physically refined rice bran oil to which oryzanol was added were examined to determine the effects
of oryzanol concentration on FFA values. When oryzanol was added to the model oils at a 0.5% level and FFA was determined,
increases in FFA value were 0.28% as determined with phenolphthalein, 0.58% with thymolphthalein, and 0.07% with alkali blue
6B. Oils containing added oryzanol at 0.5–1.5% showed a proportionate increase in FFA values with an average increase of 0.413%
per gram of oryzanol. A direct titration of purified oryzanol showed an acidity of 42.5% expressed as FFA. In spectroscopic
studies, the phenolic group in the ferulic acid moiety of oryzanol was titrated by sodium hydroxide. Based on these data,
indicator correction factors for oryzanol's acidity and a formula for calculating real FFA content of vegetable oils containing
oryzanol were developed. 相似文献
Extraction and in situ esterification of rice bran oil with ethanol were investigated by studying the effects of rice bran oil FFA content and water
content of ethanol. Ethyl ester formation in the ethanol phase increased as FFA content increased. Neutral oil solubility
in this phase fell considerably, resulting in a high ethyl ester content. The decrease of the water content in ethanol led
to an increase in neutral oil solubility in ethanol and promoted the equilibrium of reaction to ethyl-ester formation, resulting
in lower FFA content of the product. The main factor that affected yield and monoester content when using high-acidity bran
and various monohydroxy alcohols was the solubility of neutral oil in alcohol. The highest monoester content was obtained
with methanol. 相似文献
Rice bran with FFA levels above 0.1% cannot be used as a food ingredient due to oxidative off-flavor formation. However, extracting
high FFA oil from bran by in situ methanolic esterification of rice bran oil to produce methyl ester biodiesel produces greater yields relative to low-FFA
rice bran oil. Therefore, high-FFA bran could be exploited for biodiesel production. This study describes an FTIR spectroscopic
method to measure rice bran FFA rapidly. Commercial rice bran was incubated at 37°C and 70% humidity for a 13-d incubation
period. Diffuse reflectance IR Fourier transform spectra of the bran were obtained and the percentage of FFA was determined
by extraction and acid/base titration throughout this period. Partial least squares (PLS) regression and a calibration/validation
analysis were done using the IR spectral regions 4000-400 cm−1 and 1731-1631 cm−1. The diffuse reflectance IR Fourier transform spectra indicated an increasing FFA carbonyl response at the expense of the
ester peak during incubation, and the regression coefficients obtained by PLS analysis also demonstrated that these functional
groups and the carboxyl ion were important in predicting FFA levels. FFA rice bran changes also could be observed qualitatively
by visual examination of the spectra. Calibration models obtained using the spectral regions 4000-400 cm−1 and 1731-1631 cm−1 produced correlation coefficients R and root mean square error (RMSE) of cross-validation of R=0.99, RMSE=1.78, and R=0.92, RMSE=4.67, respectively. Validation model statistics using the 4000-400 cm−1 and 1731-1631 cm−1 ranges were R=0.96, RMSE=3.64, and R=0.88, RMSE=5.80, respectively. 相似文献
Linseed oil, also known as flaxseed oil, is obtained from the dried, ripened seeds of the flax plant (Linum usitatissimum). The oil is obtained by pressing, sometimes followed by solvent extraction supported by a refining process. Linseed oil is an edible oil that is in demand as a nutritional supplement, as a source of α‐linolenic acid an n‐3 fatty acid. The aim of this work was to investigate: (1) the influence of the corn crisp extrusion process on the degradation of fatty acids in linseed oil (LO) and some preparations obtained from the linseed oil such as ethyl ester (EE) and free fatty acids (FFA) added to the corn in order to increase the nutritional value of the crisps, (2) influence of the oil and two fatty preparations obtained from it on the quality of corn crisps, (3) interaction of the lipid fraction with starch. The extrusion process did not degrade the fatty acids significantly. Expansion ratio obtained in the corn crisp extrusion process decreased from 620 % down to 153 %, the size of pores/thickness of the starch–protein walls forming the structure of the extruded product decreased from 10 μm down to 4 μm, the hardness of the crisps increased from 20 to 75 N, and number of lipid–starch complexes increased with rising polarity of the lipid fraction. FFA were complexed mostly by starch (about 90 %), to a lesser degree by EE (about 60 %) and to the least extent by triacylglycerols (about 10 %). The studies performed under industrial conditions using the single screw extruder for the production of corn crisps with the application of standard parameters of the extrusion process indicated that the addition of a mass of 5 % of the various lipids (triacylglycerols of linseed oil, ethyl esters and fatty acids obtained from linseed oil) to corn grits prior to the extrusion process significantly affect the quality of corn crisps. 相似文献
In situ esterifications of high-acidity rice bran oil with methanol and ethanol and with sulfuric acid as catalyst were investigated.
In the esterification with methanol, all free fatty acids (FFA) dissolved in methanol were interesterified within 15 min,
and it was possible to obtain nearly pure methyl esters. The amount of methyl esters obtained from a given rice bran was dependent
on the FFA content of the rice bran oil. In the esterification with ethanol, it was not possible to obtain pure esters as
in methanol esterification, because the solubilities of oil components in ethanol were much higher than those in methanol. 相似文献
The influence of specific factors on in situ methanolic esterification of rice bran oil (RBO) using sulfuric acid catalyst was investigated. using high-FFA rice bran
was found to be the most effective means to increase methyl ester yields. The ester content of the extract increased about
67% when the FFA content of oil was increased from 16.6 to 84.5%. Increasing the reaction time beyond 30 min did not affect
yields. Increasing the temperature from 20 to 65°C elevated the FAME yield by about 30%, but increasing the amount of acid
catalyst above 5 mL did not enhance yield, and increasing the methanol dose from 200 to 250 mL had a negligible effect. 相似文献
Summary and Conclusions The oil, contained in bran from regularly milled rice, when stored at prevailing atmospheric temperature, humidity, and natural
moisture content is subject to rapid hydrolysis which increases the free fatty acid content of the oil to a point where it
cannot be economically refined.
Data have been presented showing the effects of a) temperature, b) drying at temperatures of 70°, 85°, 100°, and 110°C. for
various periods of time up to 5 hours, c) different relative humidities before and after drying, and d) added moisture on
the rate of formation of free fatty acids during storage in bran from both regular and “Converted” rice.
Decreasing the storage temperature tends to retard the formation of free fatty acids. In the case of regular rice bran deterioration
during storage occurred at a fairly rapid rate even at 3°C. whereas bran from “Converted” rice was fairly stable when stored
at this temperature.
The investigation of the effect of heating or drying and the effect of different relative humidities on the storage of rice
bran have shown that bran from both regular and “Converted” rice can be stored for periods of at least four months without
excessive increase in the content of free fatty acids, provided the bran is dried sufficiently and is maintained at a low
moisture content. An increase in the moisture content of predried bran causes a rapid increase in the free fatty acid content
of the oil in the bran.
Investigations of the effect of chemical inhibitors and of inert atmosphere on the rate of free fatty acid formation of regular
rice bran indicated that these were ineffective in preventing deterioration.
Presented at the 40th Annual Meeting of the American Oil Chemists’ Society, New Orleans, La., May 10–12, 1949; Report of a
Study Made Under the Research and Marketing Act of 1946.
One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S.
Department of Agriculture. 相似文献
The extraction of rice bran oil using the conventional organic solvent‐based Soxhlet method involves hazardous chemicals, whereas supercritical fluid extraction is a costly high‐temperature operating system. The subcritical carbon dioxide Soxhlet (SCDS) system, which operates at a low temperature, was evaluated for the extraction of rice bran oil in this study. In addition, rice bran that had been subjected to steam or hot‐air stabilization were compared with unstabilized rice bran (control). The yields; contents of tocopherols, tocotrienols and oryzanol; fatty acid profiles; and the oxidative stabilities of the extracted rice bran oils were analyzed. The yields using hexane and SCDS extraction were approximately 22 and 13–14.5 %, respectively. However, oil extracted using the SCDS system contained approximately 10 times more oryzanol and tocol compounds and had lower free fatty acid levels and peroxide values compared with hexane‐extracted oil. Overall, SCDS extraction of steamed rice bran represents a promising method to produce premium‐quality rice bran oil. 相似文献
The aim of this study was to find out how the refining process affects the susceptibility of rice bran oil to oxygen of air at high temperature. Samples of crude and refined rice bran oil were heated at 180 °C for 8 h with and without stirring in laboratory‐scale experiments. After every 30 min, samples were taken for analysis. The influence of stirring on rice bran oil heat stability was related to the loss of tocopherols and sterols, and to the thermooxidative state of the samples, which was evaluated according to polymer formation and changes occurring in fatty acid composition and triacylglycerol (TAG) structure. The results demonstrated a significant loss of natural antioxidants during the heating process with stirring, accompanied by a decrease in the levels of linoleic acid (18:2) and TAG (LLO, LLP and OLO) which resulted in a substantial increase of polymer TAG. The unsaturated fatty acids in the sn‐2 and sn‐1,3 positions were differently affected during the heating process. 相似文献
The effects of minor components in crude rice bran oil (RBO) including free fatty acids (FFA), rice bran wax (RBW), γ-oryzanol,
and long-chain fatty alcohols (LCFA), on alkali refining losses were determined. Refined palm oil (PO), soybean oil (SBO)
and sunflower oil (SFO) were used as oil models to which minor component present in RBO were added. Refining losses of all
model oils were linearly related to the amount of FFA incorporated. At 6.8% FFA, the refining losses of all the model oils
were between 13.16 and 13.42%. When <1.0% of LCFA, RBW and γ-oryzanol were added to the model oils (with 6.8% FFA), the refining
losses were approximately the same, however, with higher amounts of LCFA greatly increased refining losses. At 3% LCFA, the
refining losses of all the model oils were as high as 69.43–78.75%, whereas the losses of oils containing 3% RBW and γ-oryzanol
were 33.46–45.01% and 17.82–20.45%, respectively. 相似文献
The inactivation of rice bran lipase was studied in vitro and in vivo using metal ions in methanol or HCl. Lipase was extracted from rice bran in 0.1 M potassium phosphate buffer, pH 7.0 and purified by ammonium sulphate fractionation. The 25–55% ammonium sulphate fraction was subjected to DEAE-cellulose ion exchange chromatography and the fraction (F6) eluted at Ve/Vo of 14.37 was purified about 333-fold. In-vitro studies on F6 lipase showed that Fe3+ and Ni2+ completely inhibited the lipase activity at 5 × 10?5 M concentration, while Zn2+ and Cu2+ did so at 2.5 × 10?4 M. The results on in-vivo inactivation of rice bran lipase showed that Fe3+ and Ni2+ at 200 μg g?1 significantly checked the release of free fatty acids (FFA) from rice bran for 6 days of storage when compared with using concentrated HCl (2%, v/w) only. The triglyceride content of oil was also maximum with Fe3+ and Ni2+ treatment at 200 μg g?1. The present results suggest that Fe3+ and Ni2+ could be effectively used to arrest the release of FFA in rice bran and thus contribute to improving the edible quality of rice bran oil. 相似文献
Zein‐based plastic sheets and films were formed by extrusion through a slit‐die or blowing head. Zein was plasticized with oleic acid and formed into a wet moldable mass (resin) to feed the extruders. Both single‐ and twin‐screw extruded sheets showed higher elongation at break, lower tensile strength, and lower Young's Modulus than non‐extruded samples. Stress‐strain plots for extruded samples showed evidence of plastic behavior. Observed necking of samples under tensile stress was also taken as evidence of plastic behavior. Small differences in tensile strength and elongation at break between single‐ and twin‐screw extruded samples were attributed to the effect of small voids observed by SEM in single‐screw extruded samples. Blown film extrusion was affected by feed moisture content and barrel temperatures. Optimal moisture content was determined at 14–15% while temperature at the three extruder zones was maintained at 20–25, 20–25, and 35 °C, respectively. Temperature at the blowing head was 45 °C. Film samples blown after either single‐ or twin‐screw extrusion showed similar tensile properties to those of slit die extruded samples.
Blown extrusion of zein film with single‐screw extruder. 相似文献
Crude rice bran oil containing 16.5% free fatty acids (FFA) was deacidified by extracting with methanol. At the optimal ratio
of 1.8:1 methanol/oil by weight, the concentration of FFA in the crude rice bran oil was reduced to 3.7%. A second extraction
at 1:1 ratio reduced FFA in the oil to 0.33%. The FFA in the methanol extract was recovered by nanofiltration using commercial
membranes. The DS-5 membrane from Osmonics/Desal and the BW-30 membrane from Dow/Film Tec gave average FFA rejection of 93–96%
and an average flux of 41 L/m2·h (LMH) to concentrate the FFA from 4.69% to 20%. The permeate, containing 0.4–0.7% FFA, can be nanofiltered again to recover
more FFA with flux of 67–75 LMH. Design estimates indicate a two-stage membrane system can recover 97.8% of the FFA and can
result in a final retentate stream with 20% FFA or more and a permeate stream with negligible FFA (0.13%) that can be recycled
for FFA extraction. The capital cost of the membrane plant would be about $48/kg oil processed/h and annual operating cost
would be about $15/ton FFA recovered. The process has several advantages in that it does not require alkali for neutralization,
no soapstock nor wastewater is produced, and effluent discharges are minimized. 相似文献
By varying the extracting conditions, it may be possible to produce high-quality, low-phosphorus and low-free fatty acid (FFA)
oil extracted from water or mechanically damaged soybeans. The variability in phospholipids and FFA was studied in oil extracted
by an alternative process from undamaged, damaged and aged soybeans subjected to various changes. Forrest and Hutcheson cultivars
were used, and extractions were from finely ground flour rather than from flakes. Freezing caused the maximum increase in
FFA and phosphorus levels compared to other levels in damaged or undamaged soybeans, but the levels were reasonable compared
to flake extraction. Phosphorus and FFA increased when storage temperatures went from 25 to 45°C, extraction temperatures
from 25 to 50°C and moisture of the flour from 6 to 10%. However, the storage time of soybeans with initially high moisture
(20%) did not have a marked influence on FFA and phosphorus levels. Immediately after grinding moisture of the flour elevated
or lowered the phosphorus level to a great extent, although it had little influence on the FFA level. Phosphatidic acid and
phosphatidylcholine were identified as the main phospholipids present when total phosphorus was low in extracted oil. The
time taken for the flour to dry to 6% moisture (after grinding and before it was extracted) was critical. The alternative
extraction process moderated the expected increase in FFA and phospholipids as the result of soybean damage. 相似文献
The kinetics of γ‐oryzanol degradation in antioxidant‐stripped rice bran oil were investigated at 180°C for 50 h. Ferric chloride was added to the oil at different concentrations (0, 2.5, 5.0, and 7.5 mg/kg‐oil) to determine the degradation reaction rate of γ‐oryzanol and the extent of lipid oxidation (peroxide value and p‐anisidine value). It was found that the losses of γ‐oryzanol and its four components (cycloartenyl ferulate, 24‐methylene cycloartanyl ferulate, campesteryl ferulate, and β‐sitosteryl ferulate) could be described by a first‐order kinetics model. The degradation rate constant, k, linearly increased (p < 0.05) with the ferric chloride concentration, and increased about 1.5 times when 7.5 mg/kg‐oil ferric chloride was added. Ferric chloride addition also accelerated the lipid oxidation of rice bran oil significantly (p < 0.05). Practical applications: This paper describes the kinetic analysis of the degradation of γ‐oryzanol, a major phytochemical in rice bran oil, at its frying temperature. The results indicated that iron in the form of ferric chloride accelerated both the degradation of γ‐oryzanol and lipid oxidation. 相似文献
In the present work, a new strain Pseudomonas indica MTCC 3714 was studied for the production of biosurfactants using various rice‐bran oil industry residues viz. rice‐bran, de‐oiled rice‐bran, fatty acids and waxes. Among all the carbon sources, a maximum reduction in surface tension (26.4 mN/m) was observed when the media were supplemented with rice‐bran and the biosurfactant was recovered using the ultrasonication technique as one of the steps in the extraction process. Biosurfactants were obtained in yields of about 9.6 g/L using rice‐bran as the carbon source. The structure of the biosurfactants as characterized by FT‐IR, NMR (1H and 13C) and LC–MS analysis revealed that the majority of the biosurfactants were di‐rhamnolipids. The biosurfactants produced were able to emulsify various hydrocarbons and showed excellent potential in microbial enhanced oil recovery, as it was able to recover kerosene up to 70 % in a sandpack test. 相似文献