Hemp (Cannabis sativa L.) Varieties: Fatty Acid Profiles and Upgrading of γ‐Linolenic Acid–Containing Hemp Seed Oils

Hemp seeds (HS) constitute a rich nutrient source and contain γ‐linolenic acid (GLA, 18:3, n‐6), which is a healthy fatty acid (FA). The objectives of this research are i) to look for GLA‐rich varieties of unhusked hemp seeds (UHS) and commercial hulled hemp seeds (HHS); ii) to check the influence of different extracting systems on both oil yield and FA profiles; iii) to test a simultaneous oil extraction/GLA‐enrichment process looking to improve GLA content. Hop and European hackberry seeds (both from Cannabaceae family) are also analyzed for comparative purposes. GLA is the most discriminant FA among UHS varieties, ranging in both UHS and HHS seeds from 0.5% to 4.5% of total FA, while hop seeds are the richest GLA source from Cannabaceae (7.2% of total FA). The extraction system selected for hemp seeds processing has a clear influence on oil yields, although, the FA profiles are slightly modified. The use of n‐hexane and n‐hexane:acetone in extractions allows an improvement in oil yields at the same GLA percentage. A process comprising saponification and subsequent cooling allows the improvement of GLA percentage in both hemp and hop seeds extracts at values higher than 10% of total FA, at high yields (>70%). Practical Applications: The global HS market increases significantly year after year and the demand of hemp products is increasing rapidly. The natural GLA sources in nature are limited, and although hemp contains GLA, this reaches low percentages in the oil. Hemp is a well‐established crop with highly standardized agricultural technologies, thus, the development of any well‐designed processes feasible for application in oil extraction industries, would allow the development of new GLA‐based functional seed oils. This would boost the development of the agricultural and food industries dedicated to revaluing hemp products.     

Biodiesel production from tobacco (Nicotiana tabacum L.) seed oil with a high content of free fatty acids

The production of fatty acid methyl esters (FAME) from crude tobacco seed oil (TSO) having high free fatty acids (FFA) was investigated. Due to its high FFA, the TSO was processed in two steps: the acid-catalyzed esterification (ACE) followed by the base-catalyzed methanolysis (BCM). The first step reduced the FFA level to less than 2% in 25 min for the molar ratio of 18:1. The second step converted the product of the first step into FAME and glycerol. The maximum yield of FAME was about 91% in about 30 min. The tobacco biodiesel obtained had the fuel properties within the limits prescribed by the latest American (ASTM D 6751-02) and European (DIN EN 14214) standards, except a somewhat higher acid value than that prescribed by the latter standard (<0.5). Thus, tobacco seeds (TS), as agricultural wastes, might be a valuable renewable raw material for the biodiesel production.     

Influence of Extraction Method on Yield,Physicochemical Properties and Tocopherol Content of Manketti (<Emphasis Type="Italic">Schinziophyton rautanenii</Emphasis>) Nut Oil

The influence of extraction method on yield, physicochemical characteristics and tocopherol content of manketti nut oil extracted by four different methods has been determined. Soxhlet (SE) and supercritical fluid (SFE) extractions yielded 45.3 and 44.8%, respectively, while screw press and mechanical shaking extractions had 39.7 and 27.3%, respectively. SPE and SE extractions gave oils that had lower values of unsaponifiable matter (0.70; 0.74%) indicating lower amounts of minor components such as tocopherols (233.13; 290.68 µg/g oil), a greater extent of lipid peroxidation parameters; peroxide values (6.25; 3.01 mequiv O₂/kg), para‐anisidine values (10.22; 9.94), totox value (22.72; 15.96), flavour score (?0.25; 2.11), and high acid values (1.23; 1.03 mg KOH/g oil), respectively, compared to SFE and MSE oils. This was attributed to the high processing temperatures of SPE and SE extractions compared to SFE and MSE oils. Refractive indices (1.485–1.487), iodine values (127.97–129.07, Wijs) and density (0.908–0.914 g/cm³) were not affected by extraction method indicating that the oils generally had the same double bond content. Saponification values (182.98–192.95 mg KOH/g oil) and ester values (181.95–192.11), were not affected by extraction method except for SE oil which had lower values that were speculated to be due to co‐extraction with colour pigments.     

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.     

<Emphasis Type="Italic">Annona squamosa</Emphasis> and <Emphasis Type="Italic">Catunaregam nilotica</Emphasis> Seeds,the Effect of the Extraction Method on the Oil Composition

Annona squamosa and Catunaregam nilotica seeds and oils were characterized for their approximate analysis and physico-chemical properties. The oil and protein contents were 26.8, 17.5 and 40.0, 22.2%, in A. squamosa and C. nilotica seeds, respectively. The oils were extracted using cold extraction (CE) and Soxhlet extraction (SE) methods. Fatty acids and tocopherols were determined by GC–MS and HPLC, respectively. Generally the physico-chemical properties and fatty acids were not significantly (P ≤ 0.05) affected by the extraction methods. The major fatty acids of A. squamosa oil extracted by CE and SE were oleic 49.2 and 50.5%, linoleic 22.3 and 22.7%, palmitic 15.6 and 15.2%, and stearic 10.6 and 9.3%, respectively. While the major fatty acids in C. nilotica oil extracted by CE and SE were oleic 10.5, and 10.4%, linoleic 63.1 and 63.4%, palmitic 9.7 and 9.8% and stearic 5.1 and 5.4%, respectively. The tocopherol content of CE and SE extracted oils from A. squamosa amounted to 16.6 and 15.5 and from C. nilotica amounted to 110.5 and 107.7 mg/100 g oil, respectively, with delta-tocopherol as the predominant tocopherol in A. squamosa oil, and beta-tocopherol in C. nilotica oil. The total amount of amino acids was found to be 7.266 and 14.202 g/100 g protein, in seeds of A. squamosa and C. nilotica, respectively.     

Nondestructive Estimation of Fat Constituents of Sesame (Sesamum indicum L.) Seeds by Near‐Infrared Reflectance Spectroscopy

A rapid and efficient method for oil constituent estimation in intact sesame seeds was developed through near‐infrared reflectance spectroscopy (NIRS) and was used to evaluate a sesame germplasm collection conserved in China. A total of 342 samples were scanned by reflectance NIR in a range of 950–1650 nm, and the reference values for oil content and fatty acid (FA) profiles were measured by Soxhlet and gas chromatograph methods. Useful chemometric models were developed using partial least squares regression with full cross‐validation. The equations had low standard errors of cross‐validation, and high coefficient of determination of cross‐validation (R_c²) values (>0.8) except for stearic acid (0.794). In external validation, r² values of oil and FA composition equations ranged from 0.815 (arachidonic acid) to 0.877 (linoleic acid). The relative predictive determinant (RPD_v) values for all equations were more than 2.0. The whole‐seed NIR spectroscopy equations for oil content and FA profiles can be used for sesame seed quality rapid evaluation. The background information of the 4399 germplasm resources and accessions with high linoleic acid content identified in this study should be useful for developing new sesame cultivars with desirable FA compositions in future breeding programs.     

Analyzing seed weight,fatty acid composition,oil, and protein contents in <Emphasis Type="Italic">Vernonia galamensis</Emphasis> germplasm by near-infrared reflectance spectroscopy

Vernonia galamensis is a potential new industrial oilseed crop from the Asteraceae family. The interest in this species is due to the presence of a high vernolic acid content of its seed oil, which is useful in the oleochemical industry for paints and coatings. The development of a rapid, precise, robust, nondestructive, and economical method to evaluate quality components is of major interest to growers, processors, and breeders. NIR reflectance spectroscopy (NIRS) is routinely used for the prediction of quality traits in many crops. This study was conducted to establish a rapid analytical method for determining the quality of intact seeds of V. galamensis. A total of 114 Vernonia accessions were scanned to determine seed weight, FA composition, oil, and protein contents using NIRS. Conventional chemical analysis for FA composition, total oil, and protein contents were performed by GC, Soxhlet extraction, and the Dumas combustion method, respectively. Calibration equations were developed and tested through cross-validation. The coefficient of determination in cross-validation for FA ranged from 0.47 (linoleic acid) to 0.55 (vernolic acid), and for oil, protein, and seed weight from 0.71 (oil) to 0.86 (seed protein). It was concluded that NIRS calibration equations developed for seed weight and seed quality traits can be satisfactorily used as early screening methods in V. galamensis breeding programs.     

Effect of Conjugated Linoleic Acid and Fatty Acid Positional Distribution on Physicochemical Properties of Structured Lipids

Specific structured lipids (SSL), previously produced by enzymatic acidolysis of coconut oil with different levels of conjugated linoleic acid (CLA) as fatty acid (FA), using a sn-1, 3 specific immobilized lipase, were used to prepare randomized structured lipids (RSL). A fraction of each SSL was subjected to chemical interesterification with sodium methoxide catalyst in order to modify the FA positional distribution and produce the corresponding RSL. Both families of structured lipids (SL) containing CLA were physicochemically characterized. Then, analysis of variance (ANOVA) was performed to evaluate the effects of CLA content (10, 20, 30 and 40%) and FA positional distribution (specific and randomized) on physicochemical properties of SL. Free fatty acids (FFA), peroxide value (PV) and p-anisidine value (p-AV) were not significantly affected by either CLA content or distribution. As expected, the iodine value (IV) and saponification value (SV) were influenced by CLA content but not by FA positional distribution, while oxidative stability index (OSI) was affected by both factors. Dropping point (DP), cloud point (CP) and solid fat content (SFC) decreased with the increase of CLA, while viscosity increased with the level of CLA. The FA positional distribution affected practically all the evaluated physical properties of SL, except CP and DP.     

Gurum Seeds: A Potential Source of Edible Oil

Cucurbitaceae family seeds are mostly discarded as agro-industrial wastes. Gurum (Citrullus lanatus var. colocynthoide) is an underutilized wild cucurbit plant, closely related to desert watermelon, which is grown abundantly in some African countries. Gurum seeds can play a significant role in health and nutrition due to their high oil content. This review describes the nutritional composition of gurum seeds and their oil profile. Gurum seeds are a good source of oil (27–35.5%), fiber (26–31%), crude protein (15–18%), and carbohydrates (14–17%). Gurum seeds oil is extracted by supercritical CO₂ (SFE), screw press, and solvent extraction techniques. The gurum seeds oil is composed of unsaturated fatty acids with a high proportion of linoleic acid (C18:2) and oleic acid (C18:1). Gurum seeds oil contains various bioactive compounds, such as tocopherols, phytosterols, and polyphenols. It is reported that solvent extraction gives a higher yield than the screw press and SFE, but the SFE is preferred due to safety issues. More studies are required for producing better quality gurum seeds oil by using novel extraction techniques that can increase oil yield.     

Genetic diversity for lipid content and fatty acid profile in rice bran

Rice (Oryza sativa L.) bran contains valuable nutritional constituents, which include lipids with health benefits. A germplasm collection consisting of 204 genetically diverse rice accessions was grown under field conditions and evaluated for total oil content and fatty acid (FA) composition. Genotype effects were highly statistically significant for lipid content and FA profile (P<0.001). Environment (year) significantly affected oil content (P<0.05), as well as stearic, oleic, linoleic, and linolenic acids (all with P<0.01 or lower), but not palmitic acid. The oil content in rice bran varied relatively strongly, ranging from 17.3 to 27.4% (w/w). The major FA in bran oil were palmitic, oleic, and linoleic acids, which were in the ranges of 13.9–22.1, 35.9–49.2, and 27.3–41.0%, respectively. The ratio of saturated to unsaturated FA (S/U ratio) was highly related to the palmitic acid content (r ²=0.97). Japonica lines were characterized by a low palmitic acid content and S/U ratio, whereas Indica lines showed a high palmitic acid content and a high S/U ratio. The variation found suggests it is possible to select for both oil content and FA profile in rice bran.     

Fatty Acid Composition and Oil Yield in Fruits of Five <Emphasis Type="Italic">Arecaceae</Emphasis> Species Grown in Cuba

The present study targeted the whole-fruit oil yield and fatty acid composition from five of the most abundant Arecaceae species grown in Cuba. The oil yields (% dry weight), determined by the Soxhlet extraction technique with hexane, were 25.5, 5.3, 6.9, 5.4, and 6.4% for Roystonea regia, Colpothrinax wrightii, Sabal maritima, Sabal palmetto and Thrinax radiata, respectively. The free fatty acid (FFA) content varied from 2.7 to 6.8%. Fatty acid (FA) profiles of the oils indicated that lauric acid (13.7–44.4%), myristic acid (9.4–22.4%) and palmitic acid (9.2–17.1%) as major saturated FA; whereas oleic acid (9.6–42.7%) and linoleic acid (9.3–17.0%) as major unsaturated FA. R. regia fruit seemed the most promising among Arecaceae grown in Cuba because of its high oil yield and low oil FFA content.     

Chemical composition and physicochemical and hydrogenation characteristics of high-palmitic acid solin (low-linolenic acid flaxseed) oil

The physicochemical characteristics and FA compositions were determined for refined-bleached-deodorized (RBD) high-palmitic acid solin (HPS) oil, RBD solin oil, and degummed linseed oil. The predominant FA in HPS oil were palmitic (16.6%), palmitoleic (1.4%), stearic (2.5%), oleic (11.3%), linoleic (63.7%), and linolenic (3.4%). HPS oil was substantially higher in palmitic acid than either solin oil or linseed oil, and similar to solin oil in linolenic acid content. HPS, solin, and linseed oils exhibited similar sterol and tocopherol profiles. The physicochemical characteristics of the three oils (iodine value, saponification value, m.p., density, specific gravity, viscosity, PV, FFA content, color) reflected their FA profiles and degree of refinement. During hydrogenation of HPS oil, the proportion of saturated FA (palmitic and stearic) increased, and that of unsaturated FA (oleic, linoleic, and linolenic) decreased as the iodine value declined. This resulted in an inverse linear relationship between m.p. and iodine value. Hydrogenation also generated trans FA. The proportion of trans FA was inversely related to iodine value in partially hydrogenated samples. Fully hydrogenated HPS oil (i.e., HPS stearine, iodine value <5) was devoid of trans FA.     

Effect of rosehip extraction process on oil and defatted meal physicochemical properties

The physicochemical properties of oil from Rosa affinis rubiginosa seeds were analyzed after extraction by (i) organic solvent, (ii) cold pressing, and (iii) cold pressing assisted by enzymatic pretreatment using a mixture of the Novo-Nordisk A/S products Cellubrix (cellulase and hemicellulase activities) and Olivex (pectinase, cellulase, and hemicellulase activities). There were no significant differences in oil quality parameters, such as iodine value, refractive index, saponification value, unsaponifiable matter, and FA profile, when applying any of the three extraction processes. Although significant variations were observed in FFA content (acid value) and PV of the oil obtained by both of the cold-pressing oil extraction processes, these results were lower than the maximum value established from the Codex Alimentarius Commission. All-trans-retinoic acid content improved by 700% in rosehip oil obtained through cold pressing, with and without enzymatic pretreatment, in comparison with organic solvent extraction. This result is quite important for cosmetic oil because all-trans-retinoic acid is the main bioactive component responsible for the regenerative properties of this oil.     

Hybrid <Emphasis Type="Italic">Hibiscus</Emphasis> seed oil compositions

The seeds of cultivated Hibiscus spp. were extracted with supercritical carbon dioxide, and the resulting extracts were analyzed to identify the major TG components as the corresponding FAME. The seed oils were composed predominantly of oleic and linoleic FA (69.6–83.4%) with lesser amounts of palmitic acid (14.8–27.0%). Minor amounts of C14, C18, and C20 saturated FA were also detected. The oil content of the seeds was determined to be between 11.8 and 22.1 wt% for hybrid varieties and between 8.9 and 29.5 wt% for the native species from which the hybrid varieties were developed. The protein content of the defatted seed meal averaged 20% for the hybrid varieties. The composition of the extracted hibiscus seed oils suggests potential edible applications.     

Fatty Acid Composition of Seeds From Wild and Cultivated Ginseng (Panax ginseng Meyer): Occurrence of a High Level of Petroselinic Acid

The lipid content and fatty acid (FA) composition of seeds from the Asian ginseng Panax ginseng growing naturally in taiga forests of the Russian Far East and seeds from cultivated ginseng were studied in this work. The total lipid content of seeds from both wild and cultivated plants was 9–12 % of fresh weight. FA were analyzed as isopropyl esters on a polar capillary column BD‐225, which allows good separation of petroselinic and oleic acids. The structure of FAs was confirmed using GC–MS of fatty acid methyl ester (FAME) and 4,4‐dimethyloxazoline derivatives. In all the seed samples, the major FA was petroselinic acid 18:1(n‐12) which comprised more than 60 %; the contents of oleic and linoleic acids were lower (15–17 and 15–16 %, respectively). Earlier, a higher level (>80 %) of oleic acid had been reported for ginseng seeds. This discrepancy can be explained by an insufficient separation of these acids on standard columns used for GC of FAME. In general, seeds of wild and cultivated ginseng are very similar in lipid content and FA composition.     

Concentration of linoleic acid from cottonseed oil by starch complexation

The extraction of linoleic acid from fatty acids(FA) of the cottonseed oil using starch–FA complexes was developed for the first time. We showed that starch can form inclusion complexes of different strengths with FA and that the different strengths stem from the differences in chain length, degree of unsaturation, and position of double bonds of FA. The optimal separation conditions were determined as follows: The inclusion temperature is 69 °C, the inclusion time is 30 min, the starch/FA mass ratio is 10:1, and the ratio of the volume of methanol–water solution and the mass of FA is 18:1. Compared to urea inclusion complexation, starch complexation has milder reaction temperature and shorter reaction time. Under these conditions, linoleic acid can be concentrated from 38.9% to 70.04% by one-off extraction. Moreover, the experimental results demonstrate the almost perfect reusability of starch. These results show that starch complexation is a promising method that can be used to obtain highly concentrated linoleic acid from cottonseed oil.     

Changes in FA composition and antioxidative activity of pigment extracts from Korean red pepper powder (Capsicum annuum L.) Due to processing conditions

The FA compositions by parts of Korean red pepper (Capsicum annuum L.) were analyzed, and the changes in FA composition and antioxidative activity in pigment extracts due to processing were investigated. The main FA in the pericarp and seeds were palmitic, oleic, and linoleic acids. Linoleic acid in the seeds was 73.9% of the total FA, or about 1.7 times as much as in the pericarp. Linolenic acid was scarcely present in the seeds. The percentages of unsaturated FA in the pericarp and seeds were 73.3 and 83.2, respectively. The ratios among FA varied according to the processing conditions, but the FA compositions themselves remained approximately the same. The antioxidative activity of pigment extracts in the photooxidation of linoleic acid was measured by monitoring oxygen consumption and conjugated diene formation. Changes in drying methods resulted in significant differences in antioxidative activity, but changes in storage conditions had little effect. Conjugated diene formation and oxygen consumption were positively correlated. An improved drying method could allow the antioxidative activity of red pepper pigments to be conserved.     

Triacylglycerols of Apiaceae seed oils: Composition and regiodistribution of fatty acids

Oils from the seeds of caraway (Carum carvi), carrot (Daucus carota), celery (Apium graveolens) and parsley (Petroselinum crispum), all from the Apiaceae family, were analyzed by gas chromatography for their triacylglycerol (TAG) composition and fatty acid (FA) distribution between the sn‐1(3) and sn‐2 positions of TAG. Twenty‐two TAG species were quantified. Glyceryl tripetroselinate was the major TAG species in seed oils of carrot, celery and parsley, with levels ranging from 38.7 to 55.3%. In caraway seed oil, dipetroselinoyllinoleoylglycerol was the major TAG species at 21.2%, while the glyceryl tripetroselinate content was 11.4%. Other TAG species were linoleoyloleoylpetroselinoylglycerol and dipetroselinoyloleoylglycerol. Predominantly, TAG were triunsaturated (72.2–84.0%) with diunsaturates at 14.4–25.9%, and small amounts of monounsaturated TAG. Results for regiospecific analysis showed a non‐random FA distribution in Apiaceae for palmitic, petroselinic, linoleic and oleic acids. Petroselinic acid was predominantly located at the sn‐1(3) position in carrot, celery and parsley seed oils, while it was mainly at the sn‐2 position in caraway seed oil. The distribution of linoleic acid was opposite to that of petroselinic acid. Oleic acid was mostly located at the sn‐2 position, except for caraway, where it was evenly distributed between the sn‐1(3) and sn‐2 positions. Both the saturated FA, palmitic and stearic acid, were located mainly at the sn‐1(3) position. The presence of a high level of tripetroselinin in parsley seed oil (55.3%) makes it a potential source for the production of petroselinic acid.     

Improved Estimation of Oil,Linoleic and Oleic Acid and Seed Hull Fractions in Safflower by NIRS

Near-infrared reflectance spectroscopy (NIRS) of intact seeds allows the non-destructive estimation of seed quality parameters which is highly desirable in plant breeding. Together with yield, oil content and quality, a main aim in safflower (Carthamus tinctorius L.) breeding is the selection of genotypes with a low percentage of empty seeds even under cooler climates. We developed NIRS calibrations for seed oil content, oleic and linoleic acid content, the seed hull fraction and the percentage of empty seeds using seed meal and intact seeds. For the different calibrations 108–534 samples from a safflower breeding program with lines adapted to German conditions, were analyzed with reference analyses (Soxhlet, gas chromatography), and scanned by NIRS as intact seeds and seed meal. Calibration equations were developed and tested through cross validation. The coefficient of determination of the calibration (R ²) for intact seeds ranged from 0.91(oil content), 0.90 (seed hull fraction), 0.84 (empty seeds), 0.73 (linoleic acid) to 0.68 (oleic acid). The coefficient of determination of the cross validation was higher for seed meal than for intact seeds except for the parameter seed hull fraction. The results show that NIRS calibrations are applicable in safflower breeding programs for a fast screening.     

Characterization and supercritical carbon dioxide extraction of walnut oil

Walnut (Juglans regia L.) oil was extracted with compressed carbon dioxide (CO₂) in the temperature range of 308 to 321 K and in the pressure range of 18 to 23.4 MPa. The influence of particle size was also studied at a superficial velocity of 0.068 cm/s, within a tubular extractor of 0.2 L capacity (cross-sectional area of 16.4 cm²). FFA, sterol, TAG, and tocopherol compositions were not different from those of oil obtained with n-hexane. The main FA was linoleic acid (56.5%), followed by oleic acid (21.2%) and linolenic acid (13.2%). The main TAG was LLL (linoleic, linoleic, linoleic) (24.4%), followed by OLL (oleic, linoleic, linoleic) (19.6%) and LLLn (linoleic, linoleic, linolenic) (18.4%). The main component of sterols was β-sitosterol (85.16%), followed by campesterol (5.06%). The amount of cholesterol was low (0.31 and 0.16% for oils extracted by n-hexane and supercritical fluid extraction, respectively. The CO₂-extracted oil presented a larger amount of tocopherols (405.7 μg/g oil) when compared with 303.2 μg/g oil obtained with n-hexane. Oxidative stability determined by PV and the Rancimat method revealed that walnut oil was readily oxidized. Oil extracted by supercritical CO₂ was clearer than that extracted by n-hexane, showing some refining. A central composite, nonfactorial design was used to optimize the extraction conditions using the software Statistica, Version 5. The best results were found at 22 MPa, 308 K, and particle diameter (Dp) −0.1 mm.