Composition, Physical Properties and Drying Characteristics of Seed Oil of Momordica charantia Cultivated in Sri Lanka

Karawila (Momordica charantia), also known as bitter gourd, is widely used as a food and a medicine in Asian countries. Representative samples of the seeds of the most abundant cultivar (MC43) in Sri Lanka were collected. The kernel represented 60 ± 4.7% of the seed by dry weight basis. The oil content of the dry kernel was 40.45 ± 3.12%. The seed oil was rich in α-eleosteric acid (50.04 ± 4.80%) and three other geometrical isomers of 9,11,13-octadecatrienoic acid that constituted 6.55%. The acid value, the saponification value and the iodine value were 2.73 ± 0.876, 190.70 ± 1.82 mg/g and 115.96 ± 3.46 cg/g, respectively. The set-to-touch drying time of 3 h observed for the seed oil of MC43 was significantly less than that of linseed oil (13 h). The presence of a high amount of conjugated octadecatrienoic acids, low acid value, high saponification value, moderate iodine value and the low set-to-touch drying time are promising indicators of the potential of karawila seed oil as a good drying oil for the paint and coating industry.     

The structure of the triacylglycerols,containing punicic acid,in the seed oil ofTrichosanthes kirilowii

Triacylglycerols of the seed oil ofTrichosanthes kirilowii have been resolved by high-performance liquid chromatography (HPLC) in the silver-ion and reverse-phase modes. The fatty acids were identified by gas chromatography/mass spectrometry as the picolinyl esters. The main components arecis,cis-C18:2n-6 (38.2 mole%), C18:3_9c,11t,13c (punicic acid, 38.0 mole%), andcis-C18:1n-9 (11.8 mole%). Small amounts of C18:3_9c,11t,13t (α-eleostearic acid) and C18:3_9t,11t,13c (catalpic acid) were detected. Silver-ion HPLC exhibited excellent resolution in which fractions were resolved on the basis of the number and configuration of double-bonds. In this instance, the strength of interaction of a conjugated trienoic double-bond system with silver ions seemed to be between that of dienoic and monoenoic double bond systems. The triacylglycerols were also separated into 20 fractions by reverse-phase HPLC, and the fractionation was achieved according to the partition number in which a conjugated trienoic double bond was not equivalent to three monoenoic double bonds in a molecule with a given chainlength. The principal triacylglycerol species are (C18:2n-6) (C18:3_9c,11t,13c )₂ (28.3 mol% of total), (C18:1n-9)(C18:2n-6) (C18: 3_9c,11t,13c ) (19.0 mol%), and (C18:2n-6)₂(C18:3_9c,11t,13c ) (16.2 mol%), while simple triacylglycerols such as (C18:3_9c11t,13c )₃ and (C18:2n-6)₃ were present as minor components only (<1.0 mol%). Species esterified with conjugated trienoic acids comprise more than 96% of the total. Stereospecific analysis gave rise to insurmountable difficulties, but it is evident that there is some asymmetry in the distribution of fatty acids in the molecules.     

Temperature effects on tocopherol composition in soybeans with genetically improved oil quality

Tocopherol, a natural antioxidant, typically accounts for a small percentage of soybean (Glycine max L. Merr.) oil. Alleles that govern the expression of polyunsaturated fatty acids in soybean germplasm are influenced by temperature. However, little is known about the environmental influences on tocopherol expression. The objective of this study was to assess the influence of temperature on tocopherol composition in soybean germplasm that exhibit homozygous recessive and dominant alleles that govern the predominant ω-6 and ω-3 desaturases. The control cv. Dare and three low-18:3 genotypes (N78-2245, PI-123440, N85-2176) were grown under controlled-temperature environments during reproductive growth. Analysis of crude oil composition at various stages of seed development revealed a strong negative correlation between total tocopherol content and growth temperature. The relative strength of this correlation was greater in the germplasm that exhibited homozygous alleles governing the ω-6 desaturase than those governing the ω-3 desaturase. The decline in total tocopherol with reduced temperature was attributed predominantly to loss of γ-tocopherol. However, γ-tocopherol concentration also was directly related to 18:3 concentration in all genotypes. Thus, low-18:3 oils contained both a lower content and a lower concentration of γ-tocopherol. Although the biochemical basis for this observation is unknown, the antioxidant capacity of γ-tocopherol appeared to be directly associated with changes in oil quality that were mediated more by genetic than by environmental influences on 18:3 concentration. Another aspect of this work showed that low-18:3 soybean varieties should be expected to contain more α-tocopherol, especially when grown under normal commercial production environments. This condition should be regarded as another beneficial aspect of plant breeding approaches to the improvement of soybean oil quality.     

Identification of Acylglycerols Containing Dihydroxy Fatty Acids in Castor Oil by Mass Spectrometry

Ricinoleate, a monohydroxy fatty acid, in castor oil has many industrial uses. Dihydroxy fatty acids can also be used in industry. The C₁₈ HPLC fractions of castor oil were analyzed by electrospray ionization mass spectrometry of lithium adducts to identify the acylglycerols containing dihydroxy fatty acids and the dihydroxy fatty acids. Four diacylglycerols identified were diOH18:1-diOH18:1, diOH18:2-OH18:1, diOH18:1-OH18:1 and diOH18:0-OH18:1. Eight triacylglycerols identified were diOH18:1-diOH18:1-diOH18:1, diOH18:1-diOH18:1-diOH18:0, diOH18:2-diOH18:1-OH18:1, diOH18:1-diOH18:1-OH18:1, diOH18:1-diOH18:0-OH18:1, diOH18:2-OH18:1-OH18:1, diOH18:1-OH18:1-OH18:1 and diOH18:0-OH18:1-OH18:1. The locations of fatty acids on the glycerol backbone were not determined. The structures of these three newly identified dihydroxy fatty acids were proposed as 11,12-dihydroxy-9-octadecenoic acid, 11,12-dihydroxy-9,13-octadecadienoic acid and 11,12-dihydroxyoctadecanoic acid. These individual acylglycerols were at the levels of about 0.5% or less in castor oil and can be isolated from castor oil or overproduced in a transgenic oil seed plant for future industrial uses.     

Partial purification of <Emphasis Type="Italic">Nigella sativa</Emphasis> L. Seed lipase and its application in transesterification reactions

Nigella sativa L. seed lipase isolated from defatted seeds was partially purified and used as catalyst in transesterification reactions. Purification of an ammonium sulfate-precipitated sample (at 35% saturation, Nigella PL) by DEAE ion-exchange chromatography increased the specific activity from 13.9 to 156.7 U/mg protein. Nigella PL and Nigella CPL (the partially purified enzyme sample obtained by DEAE ion-exchange chromatography) catalyzed the transesterification of vinyl acetate with octanol, with racemic sulcatol (6-methyl-5-hepten-2-ol), and with racemic trans-sobrerol (trans-p-menth-6-ene-2,8-diol) in different organic solvents. Both activity and enantioselectivity of the enzyme samples used for these biotransformations were affected by the nature of the organic solvent.     

Cis-trans isomerization of octadecatrienoic acids during heating. Study of pinolenic (cis-5,cis-9,cis-12 18∶3) acid geometrical isomers in heated pine seed oil

To understand the heat-inducedcis-trans isomerization of ethylenic bonds in octadecatrienoic acids, pine seed oil, which contains the unusual nonmethylene-interrupted pinolenic (cis-5,cis-9,cis-12 18∶3) acid as a major component, was heated under vacuum at 240°C for 6 h together with linseed and borage oils. As a results, a small percentage of pinolenic acid undergoescis-trans isomerization. The main isomer that accumulates is thetrans-5,cis-9,trans-12 18∶3 acid. Minor amounts of the three mono-trans isomers are also present. Identification of isomers was realized by combining gas-liquid chromatography on a CP Sil 88 capillary column, argentation thin-layer chromatography and comparing the equivalent chainlengths of artifacts to those of isomers present in NO₂-isomerized pine seed oil. Hydrazine reduction was used to demonstrate that there was no positional shift of double bonds. Heat-induced geometrical isomerization of pinolenic acid differs from that of α- and γ-linolenic acids in at least two aspects. The reaction rate is slower (about one-fourth), and mono-trans isomers are formed in low amounts.     

Nondestructive estimation of fatty acid composition in seeds of Brassica napus L. by near-infrared spectroscopy

The feasibility of near-infrared (NIR) spectroscopy for the nondestructive determination of fatty acid composition in rapeseed was examined. NIR spectra were measured on extracted oil, intact rapeseed kernels, and an intact signle rapeseed with an InfraAlyzer 500 in a syrup cup or a single-grain cup. NIR spectra were scanned from 1100 to 2500 nm at 2-nm intervals. As the percentage of linoleic acid increased, the spectral values in the region 1696–1724 nm, where linoleic acid has its absorption band, became always stronger downward in second-derivative NIR spectra. As the percentage of erucic acid increased the spectral value at 1728 nm, where erucic acid has its absorption band, became always a little bit stronger downward in the second-derivative NIR spectra. On the basis of their NIR spectral patterns, linoleic acid and erucic acid could be successfully determined in both intact seed kernels and in a single seed of rape without damaging them.     

Proportions of C18∶1n−7 and C18∶1n−9 fatty acids in canola seedcoat surface and internal lipids

Lipids of canola seedcoats (Brassica napus L. andB. rapa L.) were prepared by surface washing and by complete extraction of seed coats with toluene. The major fatty acyl-containing triacylglycerols, wax esters and free fatty acids were separated by thin-layer chromatography prior to transesterification and analysis by gas-liquid chromatography. The proportion of C18∶1n−7 to C18∶1n−9 was higher in the extracted lipids than in the surface-washed lipids for all three classes.     

Effects of Lead on the Morphology and Structure of the Nucleolus in the Root Tip Meristematic Cells of Allium cepa L.

To study the toxic mechanisms of lead (Pb) in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1–10 μM) there were persistent nucleoli in some cells during mitosis, and at high concentration (100 μM) many of the nucleolar organizing regions were localized on sticky chromosomes in metaphase and anaphase cells. Pb induced the release of particles containing argyrophilic proteins to be released from the nucleus into the cytoplasm. These proteins contained nucleophosmin and nucleolin. Pb also caused the extrusion of fibrillarin from the nucleus into the cytoplasm. Western blotting demonstrated the increased expression of these three major nucleolar proteins under Pb stress.     

NIR reflectance spectroscopic analysis of the FA composition in sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) seeds

The feasibility of using NIR reflectance spectroscopy to estimate the FA composition of sesame seed (Sesamum indicum L.) samples from the National Institute of Crop Science of Japan and from Myanmar was examined. Multiple linear-regression analyses of NIR sepctral data and chemical data for whole seeds were carried out to develop calibration equations for predicting the proportion of each of the four major FA in sesame seeds from the total FA composition. The SE of prediction (SEP) was 0.616% for palmitic acid, 0.348% for stearic acid, 1.051% for oleic acid, and 0.826% for linoleic acid. This NIR method provides a simple, rapid, and nondestructive means of estimating the FA composition of sesame seeds for breeding selection, regardless of the color of the sesame seed coats. However, the proportions of palmitic and stearic acids could not be reliably measured because their SEP were almost as great as the SD of their concentrations in the set of prediction samples. The relationship between NIR spectral patterns and the FA composition of sesame seeds also was examined. The correlation coefficient calculated for the standardized second-derivative NIR spectral readings at 1708 nm and the percentages of linoleic acid was −0.830. A rough estimate of the proportion of linoleic acid in the total FA composition of sesame seeds could be obtained even with single sesame seeds, except for those with a black coat, based on NIR spectral pattern analysis using the wavelength assignments of linoleic acid.     

Fatty acids of the seeds from pine species of the Ponderosa-Banksiana and Halepensis sections. The peculiar taxonomic position of Pinus pinaster

The fatty acid compositions of pine seed oils were determined from 11 species of the Banksiana subsection and three species of the Ponderosa subsection. All were collected in North America (United States, Mexico, and Cuba). These analyses also included the seed oils from the unique European species of the Ponderosa-Banksiana section (Banksiana subsection), Pinus pinaster, and from three pine species of the Halepensis section, which are related to the Banksiana subsection. Emphasis was placed on their Δ5-olefinic acid content and profile. Principal-component analysis of fatty acid compositions showed that all North American species constituted a fairly homogeneous group. However, P. jeffreyi was slightly eccentric, and P. pinaster, a west-Mediterranean species, was completely isolated from the North American group. Other species from the Banksiana and Ponderosa subsections could not be distinguished on the basis of their seed oil fatty acid compositions. With respect to Δ5-olefinic acids, the North American species (except for P. jeffreyi) had 5,9-18:2, 5,9,12-18:3, 5,11-20:2, and 5,11,14-20:3 acid concentrations in the ranges 1.9 to 3.2, 17.7 to 22.9, 0.2 to 0.4, and 2.0 to 3.5%, respectively (sum, 22.7–28.5%). Levels of corresponding acids in P. pinaster were 0.9, 7.9, 0.9, and 7.0%, respectively (sum, 16.7%). Other differences were observed for linoleic acid (42.6 to 48.6% vs. 52.2%) and α-linolenic acid (0.3 to 0.6% vs. 1.4%). Pinus pinaster was close to species of the Halepensis section (5,9-18:2, 0.5 to 1.0%; 5,9,12-18:3, 3.1 to 4.4%; 5,11-20:2, 0.4 to 0.5%; 5,11,14-20:3, 3.6 to 5.4%; sum, 8.6–11.1%), which were clearly separated from the Ponderosa-Banksiana section. Among all pines analyzed, P. pinaster presented the highest level of sciadonic (5,11,14-20:3) acid, a component that has three ethylenic bonds in common with arachidonic and eicosapentaenoic acids.