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1.
Kerry Ward Rachael Scarth J. K. Daun C. T. Thorsteinson 《Journal of the American Oil Chemists' Society》1994,71(8):811-815
This study characterizes the chlorophyll pigments present in canola oil immediately after commercial extraction and following
oil storage to determine the best storage conditions for analytical samples and to examine the changes that chlorophyll derivatives
undergo during oil processing and storage. Samples of pressed, solvent-extracted, crude and degummed canola oils, obtained
from a commercial crushing plant, were stored for one month under four different conditions—in the freezer, in a refrigerator
and at room temperature both in the light and in the dark. Chlorophyll derivatives (chlorophylls, pheophytins, pyropheophytins)
were measured by high-performance liquid chromatography immediately after sampling and then on a weekly basis. The main pigments
present in commercially extracted canola oil were pheophytin a, pyropheophytin a, chlorophyll a and chlorophyll b. The “a”
derivatives comprised 81 to 100% of total chlorophyll pigments in the fresh oil samples. During degumming, the remaining chlorophylls
were converted to pheophytins and pyropheophytins. During oil storage, exposure to light at room temperature affected the
composition of chlorophyll derivatives as chlorophyll b was converted to pheophytin b and chlorophyll a was converted first
to pheophytin a, then to pyropheophytin a. 相似文献
2.
Y. Endo C. T. Thorsteinson J. K. Daun 《Journal of the American Oil Chemists' Society》1992,69(6):564-568
Chlorophyll pigments present in canola seed, meal and crude and degummed oils were analyzed by high-performance liquid chromatography
(HPLC) with a fluorescence detector. Chlorophylls a and b, low levels of pheophytin a, and occasionally traces of pheophorbide
and its methyl ester were present in canola seed. Meals and oils contained magnesium-deficient chlorophyll pigments such as
pheophorbide a, methylpheophorbide a, pheophytins a and b, and pyropheophytins a and b but not chlorophyll a or b. The amounts
of chlorophyll pigments were oil > seed >> meal. Both crude and degummed oils contained pheophytin a and pyropheophytin a
as main components, but the ratio of pyropheophytin a to pheophytin a was markedly higher in degummed oils. No pheophorbides
were detected in degummed oils. These results suggest that oil processing steps such as extraction and degumming affect the
composition of chlorophyll pigments.
Publication No. 678 Canadian Grain Commission. 相似文献
3.
Christina Anniva Despina Grigoriadou Eleni Psomiadou Maria Z. Tsimidou 《Journal of the American Oil Chemists' Society》2006,83(4):371-375
In previous studies we reported the presence of compounds with spectral characteristics similar to pheophytin α (Pheo α),
which often accompany the Pheo α peak in the chromatographic profile of virgin olive oils (VOO) at 410 nm under normal-phase
HPLC conditions. The occurrence and levels of these compounds were found to be affected by storage conditions of the oil samples.
In the present study we investigated whether the major Pheo a degradation products, identified as pyropheophytin α (coeluting
with the respective epimer) and 132-OH-pheophytin α, could be used as estimates of VOO history. The content of Pheo α and its degradation products was determined
for a great number of authentic olive oil samples of unknown history. Results are discussed in comparison with other quality
indices (e.g., antioxidant content) when necessary. High amounts of the pyro form (20–30% of total pheophytins) were related
to thermal abuse or lengthy storage. The presence of allomers indicated oxygen availability. The levels of these products,
0–20% of the total pheophytin content for 62% of the samples, seemed to be influenced by the presence of pro- and antioxidants.
When low levels of Pheo α are not accompanied by other degradation products, light exposure for a certain period of storage
can be assumed. 相似文献
4.
The production of prooxidant compounds brought about through subjecting chlorophyll a or pheophytin a to laboratory-scale
processing in the presence of canola oil or tricapryloylglycerol was investigated. The addition of chlorophyll a (60 ppm)
to canola oil prior to processing resulted in an oil of lowered stability. No large contribution to the produced instability
by any one processing step was found when pheophytin a was added (60 ppm) to canola oil prior to processing. To isolate the
effect of processing on the pigment, tricapryloylglycerol was used in the place of unsaturated canola oil as a carrier for
pheophytin a (60 ppm). A control consisted of processed tricapryloylglycerol that had no added pheophytin prior to processing.
The subsequent addition of pigment-treated processed tricapryloylglycerol to linseed oil (1:1, w/w) caused a decrease in the
stability of the latter, when compared with the control. No differences were observed between the prooxidant tricapryloylglycerol
and the control tricapryloylglycerol by methods involving ultraviolet spectroscopy and thin-layer or gas chromatography. 相似文献
5.
Anwar A. Hamama Harbans L. Bhardwaj 《Journal of the American Oil Chemists' Society》2011,88(3):361-366
In this study, the contents of total and individual phytosterols in sprouts made from seeds of seven canola (Brassica
napus L.) lines (Acropolis, Banjo, Jetton, KS-7740, KSM3-1-124, Mussette and Virginia), grown at three locations in Virginia (Orange,
Petersburg and Suffolk), were determined. Canola sprouts contained, on an average, 36.3 g sterols in 100 g of unsaponifiable
matter (UNSAP), 10.7 mg sterols in 1 g of oil and 2.4 mg sterols in 1 g of dry sprouts. The contents of individual phytosterols
(μg per g of oil) in canola sprouts were 1,162 brassicasterol, 3,799 campesterol, 34 stigmasterol, 5,359 β-sitosterol, 201
Δ5-avenasterol and 97 Δ7-stigmastenol. Canola lines had significant effects on the contents of oil, brassicasterol and campesterol. Locations had
significant effects on the oil, UNSAP, total sterols, brassicasterol, stigmasterol and β-sitosterol. The oil content in canola
sprouts was positively correlated with total sterols and Δ5-avenasterol, whereas oil content was negatively correlated with brassicasterol content. In general, the contents of campesterol
and β-sitosterol increased with an increase in total sterol content. The concentrations of sterols were in the following decreasing
order: β-sitosterol > campesterol > brassicasterol > Δ5-avenasterol > Δ7-stigmastenol > stigmasterol. These results indicate that canola sprouts may have the potential as a natural source of dietary
sterols and might be desirable for human nutrition. 相似文献
6.
Four different microemulsions differing in their core lipid component (triolein, canola oil, squalene, or seal oil) and containing
1,3-dihydroxypropan-2-one 1,3-diiopanoate (DPIP), a potential radioimaging probe, were prepared by means of ultrasonication.
The DPIP microemulsions were incubated with acetylated human low density lipoprotein (AcLDL) and the amount of DPIP transferred
into AcLDL was examined. The amount of DPIP in the microemulsions expressed as DPIP/oil (w/w) was dependent on the core lipid
component of the microemulsion in the order of seal oil (0.19±0.04, mean ±standard deviation) > squalene (0.15±0.02) > canola
oil (0.12±0.02) > triolein (0.07±0.004). With the exception of canola oil, all microemulsions were effective in enhancing
the transfer of DPIP into Acl DI in comparison with commonly used methods, i.e, direct diffusion and detergent solubilization.
DPIP in seal oil resulted in the highest amount of DPIP transferred into AcLDL [309.16±34.82 vs. 203.19±64.51 using squalene
and 151.31±28.54 using triolein (DPIP molecules per AcLDL particle)]. For the first time, oil from harp seals, was studied
as a major core lipid component of formulating pharmaceutical microemulsions. DPIP in seal oil resulted in the highest transfer
of DPIP into AcLDL which is likely due to the highest DPIP concentration found in this microemulsion as well as the high fluidity
of seal oil. 相似文献
7.
Uday S. Annapure Rekha S. Singhal Pushpa R. Kulkarni 《European Journal of Lipid Science and Technology》1999,101(6):217-221
Reduction of oil content in deep fat fried foods would be welcome by both the food manufacturers and the consumers. Among the many approaches that have been evaluated for this purpose, use of hydrocolloid additives is believed to be most promising. Work in this area is restricted mostly to cellulose derivatives. The mechanism of action of these derivatives is attributed to formation of an oil resistant barrier film, an alteration in surface hydrophobicity of the product being fried, and the thermal gelation. However, most hydrocolloids would alter the surface hydrophobicity, and many of them have the ability to form films. Furthermore, the presence of other food constituents can alter all these properties. Hence, hydrocolloids at 0.25— 2.00 % (on the basis of chickpea flour) were screened for their ability to reduce oil uptake in sev, a model deep fat fried product prepared from chickpea flour. Results obtained indicate that the ability to reduce oil uptake in this product decreases in the following order: gum arabic > carrageenan > gum karaya > guar gum > carboxymethylcellulose > hydroxypropylmethyl cellulose. Hydrocolloids such as xanthan, gum ghatti, gum tragacanth, and locust bean gum were found to be ineffective (<10 % reduction in the oil content) for this purpose. 相似文献
8.
K. Sosulski F. W. Sosulski E. Coxworth 《Journal of the American Oil Chemists' Society》1988,65(3):357-361
Hydrolysis of three canola cultivars with carbohydrase reduced oil extraction time and increased oil yield. The optimum pretreatment
before hexane extraction of oil was flaking, autoclaving, adjustment to 30% seed moisture including 0.12% enzyme concentration
(g enzyme protein/100 g flakes), and incubation for 12 hr at 50 C, followed by drying to 4% moisture. Hexane extraction was
enhanced by grinding the flakes. The relative order of enzyme efficiency in enhancement of oil extraction was mixed activity
enzyme >β-glucanase>pectinase>hemicellulase>cellulase.
Presented at the AOCS Annual Meeting in Honolulu, HI in May 1986. 相似文献
9.
Ratnayake WM Plouffe L Hollywood R L'Abbé MR Hidiroglou N Sarwar G Mueller R 《Lipids》2000,35(4):409-420
In recent studies, the life span of stroke-prone spontaneously hypertensive (SHRSP) rats was altered by a variety of dietary
fats. It was relatively shorter in rats fed canola oil as the sole source of fat. The present study was performed to find
out whether the fatty acid profile and the high content of sulfur compounds in canola oil could modulate the life span of
SHRSP rats. SHRSP rats (47 d old, n=23/group) were matched by body weight and systolic blood pressure and fed semipurified diets containing 10% canola oil, high-palmitic
canola oil, low-sulfur canola oil, soybean oil, high-oleic safflower oil, a fat blend that mimicked the fatty acid composition
of canola oil, or a fat blend high in saturated fatty acids. A 1% sodium chloride solution was used as drinking water to induce
hypertension. After consuming the diets for 37 d, five rats from each dietary group were killed for collection of blood and
tissue samples for biochemical analysis. The 18 remaining animals from each group were used for determining their life span.
The mean survival time of SHRSP rats fed canola oil (87.4±4.0 d) was not significantly different (P>0.05) from those fed low-sulfur canola oil (89.7±8.5 d), suggesting that content of sulfur in canola oil has no effect on
the life span of SHRSP rats. The SHRSP rats fed the noncanola oil-based diets lived longer (mean survival time difference
was 6–13 d, P<0.05) than those fed canola and low-sulfur canola oils. No marked differences in the survival times were observed among the
noncanola oil-based groups. The fatty acid composition of the dietary oils and of red blood cells and liver of SHRSP rats
killed after 37 d of treatment showed no relationship with the survival times. These results suggest that the fatty acid profile
of vegetable oils plays no important role on the life span of SHRSP rat. However, phytosterols in the dietary oils and in
liver and brain were inversely correlated with the mean survival times, indicating that the differential effects of vegetable
oils might be ascribed, at least partly, to their different phytosterol contents. 相似文献
10.
Flaxseed, echium, and canola oils contain α-linolenic acid (18∶3n−3, ALA) in a range of concentrations. To examine their effect
on elevating cardiac levels of long-chain n−3 FA, diets based on these n−3-containing vegetable oils were fed to rats for
4 wk. Sunflower oil, which contains little ALA, was a comparator. Despite canola oil having the lowest ALA content of the
three n−3-containing vegetable oils, it was the most potent for elevating DHA (22∶6n−3) levels in rat hearts and plasma. However,
the relative potencies of the dietary oils for elevation of EPA (20∶5n−3) in heart and plasma followed the same rank order
as their ALA content, i.e., flaxseed>echium>canola>sunflower oil. This paradox may be explained by lower ALA intake leading
to decreased competition for Δ6 desaturase activity between ALA and the 24∶5n−3 FA precursor to DHA formation. 相似文献
11.
Dérick Rousseau Karine Forestière Arthur R. Hill Alejandro G. Marangoni 《Journal of the American Oil Chemists' Society》1996,73(8):963-972
Chemical interesterification of butterfat-canola oil blends, ranging from 100% butterfat to 100% canola oil in 10% increments,
decreased solid fat content (SFC) of all blends in a nonlinear fashion in the temperature range of 5 to 40°C except for butterfat
and the 90∶10 butterfat/canola oil blend, whose SFC increased between 20 and 40°C. The sharp melting associated with butterfat
at 15–20°C disappeared upon interesterification. Heats of fusion for butterfat to the 60∶40 butterfat/canola oil blend decreased
from 75 to 60 J/g. Blends with >50% canola oil displayed a much sharper drop in enthalpy. Heats of fusion were 30–50% lower
on average for interesterified blends than for their noninteresterified counterparts. Both noninteresterified and interesterified
blends deviated substantially from ideal solubility, with greater deviation as the proportion of canola oil increased. The
change in the entropy of melting was consistently higher for noninteresterified blends than for interesterified blends. Chemical
interesterification generated statistically significant differences for all triacylglycerol carbon species (C) from C30 to C56′ except for C42′ and in SFC at most temperatures for all blends. 相似文献
12.
The present study examined the antioxidant activity of black tea theaflavins and catechin derivatives in canola oil. Oxidation
was conducted at 95°C by monitoring the oxygen consumption and decreases in the linoleic and α-linolenic acids of canola oil.
All were tested at a concentration of 0.5 mM. Catechins, including (−)-epicatechin, (−)-epicatechin gallate, (−)-epigallocatechin,
and (−)-epigallocatechin gallate (EGCG), were more effective than theaflavins, namely, theaflavin-1, theaflavin-3-gallate,
theaflavin-3′-gallate, and theaflavin-3,3′-digallate (TF3), against the lipid oxidation of canola oil. Among the four theaflavins, TF3 was the most effective, whereas among the four catechins, FGCG was the most potent. Under the same conditions, all theaflavins
and catechins were more powerful than BHT as an antioxidant in heated canola.oil. Little or no difference in antioxidant activity
was observed between each catechin and epimer pair. Methylation of the 3′-OH led to a significant loss of antioxidant activity
of the catechins. 相似文献
13.
R. C. Strayer J. A. Blake W. K. Craig 《Journal of the American Oil Chemists' Society》1983,60(8):1587-1592
A cooperative project using the facilities of the POS Pilot Plant Corporation, the Saskatchewan Research Council and the Agricultural
Engineering Department, University of Saskatchewan, and funded by Agriculture Canada, was initiated in 1980 to investigate
the feasibility of using canola and high erucic rapeseed oil as a replacement/extender to diesel fuel in direct-injection
diesel engines. Work carried out included the documented production and refining of canola and R500 (high erucic) vegetable
oils, preparation of methyl ester and of blends of all these fuels with methanol and ethanol. These fuels were evaluated by
ASTM and improvised tests to determine their usefulness as diesel fuel. Engine tests involved a 2-cylinder Petter diesel and
a 6-cylinder John Deere turbocharged diesel. Results were similar for both engines in short-term performance tests, and indicated
that: (a) maximal power was essentially the same when burning canola oil as when burning diesel fuel; (b) specific fuel consumption
was ca. 6% higher when burning canola oil, but because canola oil has a heating value 14% less than diesel fuel, the thermal
efficiency is somewhat higher when operating on canola oil; (c) there were no starting problems down to 10 C; (d) there were
fewer particulates in the exhaust when burning canola oil; and (e) there was generally less combustion noise when burning
canola oil. The high viscosity of canola oil (ca. 35 times that of disel fuel at 20 C) poses a major problem in using the
oil at low temperature. Blending with diesel fuel and the creation of a methyl ester from the canola oil both proved effective
in reducing viscosity, but neither lowered the pour point apprecibly. Efforts on reduction of pour points and further work
on blends and on heating the fuel are described. 相似文献
14.
Titipong Issariyakul Mangesh G. Kulkarni Lekha C. Meher Ajay K. Dalai Narendra N. Bakhshi 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2008,140(1-3):77-85
Used cooking oil (UCO) was mixed with canola oil at various ratios in order to make use of used cooking oil for production of biodiesel and also lower the cost of biodiesel production. Methyl and ethyl esters were prepared by means of KOH-catalyzed transesterification from the mixtures of both the oils. Water content, acid value and viscosity of most esters met ASTM standard except for ethyl esters prepared from used cooking oil. Canola oil content of at least 60% in the used cooking oil/canola oil feedstock is required in order to produce ethyl ester satisfying ASTM specifications. Although ethanolysis was proved to be more challenging, ethyl esters showed reduced crystallization temperature (−45.0 to −54.4 °C) as compared to methyl esters (−35.3 to −43.0 °C). A somewhat better low-temperature property of ester was observed at higher used cooking oil to canola oil ratio in spite of similar fatty acid compositions of both oils. 相似文献
15.
This study was conducted to determine effects of genotypes and growing environment on phytosterols, triterpene alcohols, and
phospholipids (PL) in lupin (Lupinus albus L.) oil from seven genotypes grown in Maine and Virginia. The unsaponifiable lipid (UNSAP) and phospholipid (PL) fractions
ranged from 2.1 to 2.8% and from 2.6 to 2.8% of oil, respectively. UNSAP in lupin oil contained 19.9 to 28.7% sterols and
17.3 to 22.0% triterpene alcohols. Growing location significantly affected contents of total PL, PS, phosphatidylglycerol,
β-sitosterol, campesterol, and β-amyrin. Genotypic effects were significant for stigmasterol. PC (32.6 to 46.3% of PL), PE
(21.6 to 32% of PL), and PS (11.2 to 17.9% of PL) were the major PL in lupin oil. The concentration of PL classes in lupin
oil were in the following descending order: PC>PE>PS>PI>phosphatidic acid > lysophosphatidylcholine > phosphatidylglycerol
> diphosphatidylglycerol. In descending order of abundance, the sterols present in lupin oil were: β-sitosterol > campesterol
> stigmasterol > Δ5-avenasterol > Δ7-stigmastenol Lupeol was the most prominent triterpene alcohol in lupin seed oil. In general, growing environment had a much
greater influence on lupin oil characteristics than the genotypes. 相似文献
16.
Amanda D’Cruz Mangesh G. Kulkarni Lekha Charan Meher Ajay K. Dalai 《Journal of the American Oil Chemists' Society》2007,84(10):937-943
A series of alkali metal (Li, Na, K) promoted alkali earth oxides (CaO, BaO, MgO), as well as K2CO3 supported on alumina (Al2O3), were prepared and used as catalysts for transesterification of canola oil with methanol. Four catalysts such as K2CO3/Al2O3 and alkali metal (Li, Na, K) promoted BaO were effective for transesterification with >85 wt% of methyl esters. ICP-MS analysis
revealed that leaching of barium in ester phase was too high (~1,000 ppm) when BaO based catalysts were used. As barium is
highly toxic, these catalysts were not used further for transesterification of canola oil. Optimization of reaction conditions
such as molar ratio of alcohol to oil (6:1–12:1), reaction temperature (40–60 °C) and catalyst loading (1–3 wt%) was performed
for most efficient and environmentally friendly K2CO3/Al2O3 catalyst to maximize ester yield using response surface methodology (RSM). The RSM suggested that a molar ratio of alcohol
to oil 11.48:1, a reaction temperature of 60 °C, and catalyst loading 3.16 wt% were optimum for the production of ester from
canola oil. The predicted value of ester yield was 96.3 wt% in 2 h, which was in agreement with the experimental results within
1.28%. 相似文献
17.
There is little information available about phytosterols in canola (Brassica napa L.) oil and the effects of genotype and growing locations from Virginia and the mid-Atlantic region of the United States,
a potential area for the establishment of domestic production to provide edible oil. Our objectives were to characterize the
phytosterols, phospholipids, unsaponifiable matter, and FA in oil from Virginia-grown canola. Among 11 canola genotypes grown
at two locations during 1995–1996 significant variations existed for oil content and FA profiles, but not for contents of
phospholipids, unsaponifiable matter, total phytosterols, campesterol, stigmasterol, and β-sitosterol, Total phytosterol content
in the oil of Virginia-grown canola varied from 0.7 to 0.9% with a mean of 0.8%. This concentration compared favorably with
oil from Canadian canola, which typically contains 0.5 to 1.1% total phytosterols. The mean contents of brassicasterol, campesterol,
stigmasterol, β-sitosterol, Δ5-avenasterol, and Δ7-stigmatenol as percentages of total phytosterols in Virginia-grown canola were: 9.7, 32.0, 0.6, 49.3, 4.99, and 3.5%, respectively.
Growing location did not affect phytosterols in Virginia-grown canola oil but had significant effects on contents of phospholipids,
and saturated (myristic, stearic, and arachidic) and unsaturated (palmitoleic, linoleic, linolenic, eicosenoic, and erucic)
FA. 相似文献
18.
N. A. M. Eskin M. Vaisey-Genser S. Durance-Todd R. Przybylski 《Journal of the American Oil Chemists' Society》1989,66(8):1081-1084
The effect of heating on the oxidation of low (1.6%) linolenic acid canola oil (C18∶3) at frying temperature (185 ±5°C) under
nitrogen and air was examined and then compared to a laboratory deodorized (9.0%, C18∶3) and a commercially deodorized (8.5%,
C18∶3) canola oil sample. A significantly lower development of oxidation was evident for the low C18:3 canola oil, based on
the measurement of peroxide value (PV), thiobarbituric acid (TBA), free fatty acids (FFA), dienals and carbonyls. The greater
stability of the low C18:3 canola oil was also reflected by a corresponding improvement in heated room odor intensity scores.
Heating under nitrogen (rather than air) not only improved the odors but limited the oxidation in all oils. While the low
C18:3 canola oil heated under nitrogen was acceptable in 94% of odor judgments the same oil heated in air was acceptable in
only 44%. This suggests that even low levels of C18:3 may contribute to the development of the heated room odor phenomenon. 相似文献
19.
M. F. King L. C. Boyd B. W. Sheldon 《Journal of the American Oil Chemists' Society》1992,69(6):545-551
The antioxidant properties of phospholipids (PL) in a refined salmon oil model system were measured by determining changes
in the 2-thiobarbituric acid number and decreases in the ratio of docosahexaenoic acid (DHA)/palmitic acid (22:6/16:0) of
a fish oil system incubated at 180°C for up to 3 h. The more phosphatidylcholine (PC) added to the oil system, the higher
the oxidative stability obtained. The order of effectiveness of commercial phospholipids in inhibiting oxidation and the loss
of polyunsaturated fatty acids was as follows: sphingomyelin (SPH)=lysophosphatidylcholine (LPC)=phosphatidylcholine (PC)=phosphatidylethanolamine
(PE)>phosphatidylserine (PS)>phosphatidylinositol (PI)>phosphatidylglycerol (PG)>control salmon oil. Nitrogen containing PL,
including PE, PC, LPC and SPH, were equally effective in exerting greater antioxidant properties than PS, PG and PI. The inverse
relationship observed between the oxidation index (C22:6/C16:0) and color intensity for treatments following 2 h of heating
suggests that Maillard-type reaction products may have contributed to the oxidative stability of PL-supplemented fish oils. 相似文献
20.
Kerry Ward Rachael Scarth J. K. Daun C. T. Thorsteinson 《Journal of the American Oil Chemists' Society》1994,71(12):1327-1331
This study characterizes the chlorophyll pigments in ripeningBrassica napus seed. Seed samples, collected weekly as the crop ripened, were analyzed by high-performance liquid chromatography to characterize
chlorophyll pigment composition. Chlorophyll A, chlorophyll B, pheophytin A and pheophytin B were the predominant pigments,
while pheophorbide A, methylpheophorbide A and pyropheophytin A were minor components. No differences in pigment composition
were observed between the three cultivars tested or between early and late seeding dates. There were differences in pigment
composition between the two years of the study, which may result either from seed aging during storage or from environmental
influences. Pigment composition was dependent on seed maturity, with physiologically mature green seeds containing both chlorophylls
and pheophytins, but fully mature seeds containing only chlorophylls. Pheophytins and the minor components appeared transiently,
presumably formed from the chlorophylls and subsequently degraded. The ratio of chlorophyll A/B increased during seed ripening,
with fully mature canola seed having a chlorophyll A/B ratio twice that of physiologically mature green seed. The “B” derivatives
degraded faster than the “A” derivatives, suggesting enzymatic reactions. The initial steps in the chlorophyll breakdown pathway
in canola seed appear to be:
相似文献