Production technology and characteristics of Styrian pumpkin seed oil

Cucurbita pepo subsp. pepo var. Styriaca, the so‐called Styrian oil pumpkin, is a phylogenetically young member of the Cucurbita spp. A single mutation occurred only in the 19^th century and led to dark green seeds with stunted outer hulls. This mutation facilitated the production of Styrian pumpkin seed oil that became a regional specialty oil in the south‐eastern part of Europe during the last few decades. We describe in this article the production and economic value of this edible specialty oil as well as the most important parameters relevant for its quality. Furthermore, we report on its molecular composition including fatty acids, vitamins, phytosterols, minerals, polyphenols, and those compounds that are responsible for its color, taste and flavor. Finally, information is provided on potential contaminants of Styrian pumpkin seed oil as well as its putative beneficial health effects.     

Stability of pumpkin seed oil

In Austria pumpkins are grown primarily for the production of pumpkin seeds that can be used for eating or the production of salad oil. Pumpkin seed oil is dark green and its fatty acid composition consists typically of linoleic acid and oleic acid as the dominant fatty acids. The saturated fatty acids palmitic and stearic acid occur at lower levels. The samples for this study were taken from a breeding program that intends to increase the seed and oil productivity. 15 samples with different contents of linoleic acid (40—57%) and vitamin E (100—600 μg/g) were selected. The stability of the oil was measured in a Rancimat that oxidizes the oil at 120 �C and measures the induction time that is needed for the oxidation. The correlation analysis showed that only the ratio of linoleic acid to oleic acid had a significant influence on the oxidative stability of the oil. Vitamin E did not show any correlation. When α‐tocopherol was added to the oil a strong pro‐oxidative effect was observed.     

Phytosterols and steryl esters in diverse Cucurbita,Cucumis and Citrullus seed oils

Δ⁷‐Phytosterols present in pumpkin seed oil are significant for the prevention of prostate disorders. Herbal medicines are increasingly offered as dried kernels or concentrated ethanolic extracts of Cucurbita pepo seeds. Until now, the pumpkin seeds of C. pepo have almost exclusively been used for this purpose. Only a few data concerning the sterol content of other Cucurbitoideae seeds are available. Therefore, we isolated, identified, and quantified the free and esterified phytosterols of 12 Cucurbita, 3 Cucumis, and 3 Citrullus seed oils. The total sterol content of these seeds ranged from 297 mg per 100 g oil in Cucurbita maxima ‘Turk's Turban’ to 814 mg per 100 g oil in Citrullus lanatus ‘Sugar Baby Watermelon’, equivalent to 64 to 193 mg per 100 g seeds respectively. These were mainly Δ⁷‐sterols (˜82%) with the steryl esters acounting for ˜32% of the total sterol content.     

Can chemometrics protect pumpkin seed oil buyers from false Styrian PGI labels?

A group of scientists from Loeben Universtity is proposing the use of chemometrics in the detection of authenticity of Styrian PGI pumpkin seed oil. They have shown that pumpkin seeds from Austria and foreign countries differ in the composition of various element traces. Based on that they are able to differentiate between false and authentic PGI pumpkin seed using mathematical modeling.     

A new strategy for edible vegetable oil production

Consumer preference has changed rapidly from refined oils towards virgin oils in recent years. Virgin oils are edible vegetable oils obtained by mechanical procedures, such as expelling or pressing from oil seeds, and are consumed without being refined. Such oils are considered as specialty oils, because only small and medium size mills produce them in small amounts for gourmet and health markets from very different oil seeds. To meet consumer demands, bulk production of virgin oils should be accomplished from commodity oil seeds, such as rapeseeds, at reasonable prices. For this purpose two challenges have to be solved: production of high quality oil seeds, and production of virgin oils with a higher oil yield. In this article we focus on the pre‐treatment processes of oil seeds to increase oil yield, and describe a new alternative process, ultrasound‐assisted alcoholic treatment of oil seeds.     

Physical‐chemical characteristics and oxidative stability of oil obtained from lyophilized raspberry seed

Fresh raspberry (Rubus idaeus), cultivar Willamette, was freeze‐dried (lyophilization). A byproduct of lyophilization is “fine dust” of raspberry consisting of finely ground raspberry fruit body and seed. The seeds were separated. The seed oil was isolated and its physical and chemical characteristics were determined. Parameters that characterize the seed and quality of the oil were examined, including fatty acid composition, oxidative stability under different storage conditions, and radical‐scavenging activity. The fatty acid composition was determined by GC/FID and the contents of the dominant fatty acids were found as: oleic 16.92%, linoleic 54.95%, and α‐linolenic acid 23.97%. The oxidative stability of the oil was poor. The induction period by Rancimat test at 100 °C was 5.2 h. The radical‐scavenging activity is similar to that of resveratrol [1,3‐benzenediol 5‐(1^E‐2‐4‐hydroxy‐phenyl‐ethyl)]. Although this product is used in the candy industry, it would be far more useful if raspberry oil of satisfactory quality could be extracted. This paper demonstrates that sifted lyophilized seeds can be used for the extraction of oils. This process allows for maximal usage of the byproducts, reduces losses and it increases the development of new products.     

Chemical Composition and Antioxidant Activity of Seeds of Various Halophytic Grasses

Increasing population has resulted in overexploitation of conventional seeds. The limited supply of water and salinization of agricultural lands are threats to crop production. This creates food insecurity and results in ever‐increasing prices of crops and edible oils. Halophytes that produce high‐quality seeds can serve as sources of oil and edible products. We analyzed the chemical composition and antioxidant activity of seeds from 5 halophytic grasses, i.e., Aeluropus lagopoides, Eragrostis ciliaris, Eragrostis pilosa, Panicum antidotale, and Sporobolus ioclados. These seeds contained crude protein (10–29%), carbohydrates (32–55%), crude fiber (4–21%), minerals (3.8–9.2%), and oil (4–11%), indicating their nutritional potential. Oils of these seeds had suitable fatty‐acid composition with 62–82% unsaturation and only 17–24% saturation. Out of this, 91–94% of the total oil constituted by linoleic, oleic, and palmitic acids. High contents of total phenols (2.8–4.2 mg gallic acid equivalent [GAE] g^?1), flavonoids (0.5–1.3 mg Quercetin equivalent [QE] g^?1), and tannins (0.3–1.3 mg catechin equivalent [CE] g^?1) supported their high antioxidant activity (1,1‐Diphenyl‐2‐picryl‐hydrazyl (DPPH) activity in terms of half maximal inhibitory concentration‐IC₅₀ 1.1–5.86 mg mL^?1; 2,2′‐azino‐bis3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS) 18.8–72.8 mmol Trolox g^?1; ferric‐reducing antioxidant power 2.0–4.4 mmol Fe⁺² g^?1). The reverse phase‐high‐pressure liquid chromatography analysis identified the presence of bioactive phenolic antioxidants (mainly gallic acid, chlorogenic acid, coumaric acid, ferulic acid, kaempferol, and quercetin). Due to these characteristic composition and salt tolerability, these plants can serve as potential sources of industrial raw materials for food, edible oil, phytochemicals, and oliochemicals.     

Sterols in pumpkin seed oil

The sterol fraction of unsaponifiable matter obtained from a Yugoslav pumpkin seed ripening was investigated by gas liquid chromatography on a glass capillary column. It contained at least 14 different sterols ten of which were identified primarily by combined gas chromatography-mass spectrometry as cholesterol, brassicasterol, campesterol, stigmasterol, 24-methylcholest-7-en-3β-ol, Δ^7,22,25-stimastatrien-3β-ol, α-spinasterol, Δ^7,25-stigmastadien-3β-ol, Δ^7,25-stigmastenol, and Δ⁷-avenasterol. It was shown that the unidentified sterols in the oil obtained from a Chinese pumpkin seed were Δ^7,25-stigmastadien-3β-ol, and Δ^7,22,25-stigmastatrien-3β-ol,. There was practically no difference in the composition of Yugoslav and Chinese pumpkin seed oil, the main characteristic of which was the presence of Δ⁷-sterols as was already stated by Sucrow.     

Effects of light quality on the accumulation of oil in a mixed culture of Chlorella sp. and Saccharomyces cerevisiae

BACKGROUND: Chlorella strains rather than terrestrial oil crops having higher oil content and shorter generation time have been considered as promising candidates for alternative biodiesel. Since the influence of light quality on oil formation of microalgae in either monoculture or mixed culture has been shown to be either inconsistent or ambiguous, a light‐emitting diode (LED) photo‐bioreactor with different light sources and intensities was used in this study to investigate a cost‐effective lipid production process. RESULTS: The oil accumulation in a mixed culture of Chlorella sp. and Saccharomyces cerevisiae was higher than that in the monoculture under the different light sources used. Results of the influence of light quality on the mixed culture indicated that the optimal light wavelength and intensity for biomass formation was red LED light at 1000 lux, whereas the optimum for oil formation was blue LED light at 1000 lux. A novel two‐stage LED photo‐bioreactor was thus proposed and the highest P_max and productivity in this study were obtained as 261 mg L^?1 and 8.16 mg L^?1 h^?1, respectively. CONCLUSION: A novel two‐stage LED photo‐bioreactor using a mixed culture to optimize microalgal oil production was proposed and successfully demonstrated in this study. Copyright © 2011 Society of Chemical Industry     

Determination of seed oil content and fatty acid composition in sunflower through the analysis of intact seeds, husked seeds, meal and oil by near-infrared reflectance spectroscopy

A methodological study was conducted to test the potential of near-infrared reflectance spectroscopy (NIRS) to estimate the oil content and fatty acid composition of sunflower seeds. A set of 387 intact-seed samples, each from a single plant, were scanned by NIRS, and 120 of them were selected and further scanned as husked seed, meal, and oil. All samples were analyzed for oil content (nuclear magnetic resonance) and fatty acid composition (gas chromatography), and calibration equations for oil content and individual fatty acids (C_16:0, C_16:1, C_18:0, C_18:1, and C_18:2) were developed for intact seed, husked seed, meal, and oil. For intact seed, the performance of the calibration equations was evaluated through both cross- and external validation, while cross-validation was used in the rest. The results showed that NIRS is a reliable and accurate technique to estimate these traits in sunflower oil (validation r ² ranged from 0.97 to 0.99), meal (r ² from 0.92 to 0.98), and husked seeds (r ² from 0.90 to 0.97). According to these results, there is no need to grind the seeds to scan the meal; similarly accurate results are obtained by analyzing husked seeds. The analysis of intact seeds was less accurate (r ² from 0.76 to 0.85), although it is reliable enough to use for pre-screening purposes to identify variants with significantly different fatty acid compositions from standard phenotypes. Screening of intact sunflower seeds by NIRS represents a rapid, simple, and cost-effective alternative that may be of great utility for users who need to analyze a large number of samples.     

Chemical Compositions and Mineral Contents of Some Hull-Less Pumpkin Seed and Oils

The main objective of this study was to determine total oil, total phenol, antioxidant activity and mineral contents of hull‐less pumpkin seeds and also fatty acid composition of seed oils. The results indicated that total oil, total phenol content and antioxidant activity values were found between 33.04 and 46.97 %, 56.94 and 87.15 mg GAE/100 g and 0.19 and 11.75 %, respectively (p < 0.05). Linoleic, oleic, palmitic and stearic acids were the most prominent fatty acids in all genotypes. The most abundant mineral in the studied seeds, which belong to different genotypes, was potassium (2704.75–1033.63 ppm) followed by phosphorus (3569.690–9108.835 ppm) and magnesium (1275.15–3938.16 ppm) (p < 0.05). Particularly genotype‐1 was the richest seed in essential fatty acids and minerals.     

The effect of roasting on the chemical composition and oxidative stability of pumpkin oil

This study is concerned with the effect of the process of roasting of naked pumpkin seeds prior to their pressing on the chemical composition and oxidative stability of the extracted oil. Ground seeds were roasted at temperatures of 90, 110, and 130°C for 30 and 60 min, according to the traditional technology of production of roasted pumpkin oil. Depending on the roasting conditions of the seeds, this treatment resulted in a significant increase of the contents of phospholipids (from 0.005 to 0.463%), total phenolic compounds (from 4.63 to 19.60 mg/kg), and total tocopherols (from 265.79 to 350.98 mg/kg) in oil. Higher contents of these minor components enhanced the oxidative stability of the oil, i.e., increased the induction period (from 4.50 to 12.93 h). However, at the same time, the applied thermal treatment generated an increase in the primary and secondary oxidation products, resulting in higher Totox values that could lower the quality of the oil.     

Nondestructive NMR determination of oil composition in transformed canola seeds

Magic-angle spinning (MAS) ¹³C nuclear magnetic resonance (NMR) spectroscopy is a convenient method for nondestructive, quantitative characterization of seed oil composition. We describe results for intact hybrid and transformed canola seeds. The MAS ¹³C NMR technique complements and agrees with gas chromatography results. The spectral resolution approaches that of neat, liquid oils. MAS ¹³C NMR data allow quantitative analysis of major oil components, including saturates and oleic, linoleic, and linolenic acyl chains. ¹³C NMR directly and quantitatively elucidates, triglyceride regiochemistry and acyl chain cis-trans isomers that cannot be quickly detected by other methods. MAS ¹³C NMR can serve as the primary method for development of near-infrared seed oil calibrations. These NMR methods are nondestructive and attractive for plant-breeding programs or other studies (e.g., functional genomics) where loss of seed viability is inconvenient.     

Oxidative stability of Echium plantagineum seed oil bodies

Echium plantagineum seed contains a highly polyunsaturated oil (approximately 14% linoleic acid, 10% γ‐linolenic acid, 33% α‐linolenic acid and 14% stearidonic acid); almost half of the fatty acids are omega‐3 fatty acids, so there is an interest in the possible health benefits of this oil, which, once extracted, is prone to oxidation. For the first time in reported literature, oil bodies (OBs), the organelles that store the oil in mature seed, were recovered from E. plantagineum seeds. The oxidative stability of these organelles ex vivo, dispersed in an aqueous continuous phase, was tested against processed E. plantagineum oil emulsions stabilised with either SDS or Tween 20. For both primary and secondary oxidation products the OBs were the most stable form of dispersed oil, and the dispersed systems were all more stable than bulk E. plantagineum oil after incubating at 40°C for 7 days. The possible reasons for the enhanced chemical stability of E. plantagineum OBs are explored in this paper. Practical applications: OBs, the natural store of oil in oilseeds, can be recovered from seeds intact and are relatively stable to oxidation ex vivo. Echium seed OBs, enriched in physiologically active omega‐3 fatty acids, therefore offer an attractive alternative to traditional oil extraction methods and overcome the need to encapsulate the omega‐3 rich oil.     

Characterization of a 13-lipoxygenase from virgin olive oil and oil bodies of olive endosperms

Olive oil is one of the oldest known vegetable oils, and it is almost unique in that it can be consumed without any refining treatment. One of its most important quality problems is oxidative rancidity due to the oxygenation of polyenoic fatty acids and formation of compounds that derive from these fatty acid hydroperoxides. Beside autoxidation, lipoxygenases (LOXs) were suggested to be involved in this process. Here we show, that approximately 1.6% of all linoleic acid (LA) molecules within olive oil samples had been converted into LOX-derived (13S,9Z,11E)-13-hydroperoxy-9,11-octadecadienoic acid (13-HPODE) as determined by ¹H NMR- and HPLC analysis. LOX activity tests indicated the occurrence of an active 13-LOX exhibiting a pH optimum between pH 5.5 and 6.0. Furthermore, this enzyme preferentially metabolized free fatty acids. In order to elucidate the origin of this LOX, we analyzed olive endosperms for LOX forms. Chromatography of total protein extracts of the tissue showed LOX activity almost exclusively associated with a high molecular mass fraction. Light microscopic inspection, as well as the calculated phosphate, neutral lipid, and protein content of this fraction, suggested that this fraction may contain oil bodies and that LOX activity was associated with their membrane. This LOX activity had a pH optimum of 6.0. Activity assays at various temperatures indicated a significant catalytic efficiency of the enzyme up to 55°C. HPLC analysis of LA oxygenation products within the lipid fraction and of activity tests of isolated oil bodies showed that the LOX present in mature olive endosperm oil bodies was, as the enzyme from olive oil, a linoleate 13-LOX preferentially active on free LA. We suggest, that this oil body LOX from olive endosperm, is the one detected originally in olive oil and may survive at least in part olive oil production.     

Cuphea a rich source of medium chain triglycerides: Fatty acid composition and oil diversity in Cuphea procumbens

The phenological characteristics, oil content, and fatty acid composition of 34 selections of Cuphea procumbens have been studied. The mean seed yield per plant was 9.7 ± 0.43 g. Maximum seed yield (16.7 g) was noticed in NBC‐27, while the average number of fruits per plant was 124.9 ± 10.7. The oil content in the seeds ranged from 16.7—28.7%, maximum being in NBC‐34. The fatty acid composition revealed the presence of capric acid (C10:0) in all the selections of C. procumbens as the major constituent of the oil ranging from 87.7—94.6%. C. procumbens showed its novelty as an alternative source of capric acid and may be utilized as a renewable resource in the production of plasticizers and lubricants which wholly depend on petrochemical import. Researches are in progress in order to obtain tolerant cultivars against wild plant characteristics and some delayed seed shattering plants have been identified.     

Microbial conversion of sterol‐containing soybean oil production waste

Soybean extract residue (scum), a waste of soybean oil production, was examined as a raw material for C₁₇‐ketosteroid production. As a model process, its bioconversion to 9α‐hydroxyandrost‐4‐ene‐3,17‐dione (9‐OH‐AD) by Mycobacterium sp VKM Ac‐1817D was studied. The content of transformable sterols (sitosterol, stigmasterol and campesterol) in scum was estimated at ～14%. The bioconversion of scum to 9‐OH‐AD was characterized by a long lag‐period (300–350 h) followed by 9‐OH‐AD accumulation. The microbial or chemical elimination of fatty non‐identified components resulted in sterol‐enriched scum preparations. Effective conversion of these preparations by Mycobacterium sp was demonstrated: 9‐OH‐AD molar yield ～65% was reached at 60 h from the scum preparation containing 10 g dm^?3 transformable sterols. The process productivity was comparable with that for high quality‐sitosterol of wood origin (tall‐oil sitosterol). Copyright © 2004 Society of Chemical Industry     

Biodegradation of quinoline in crude oil

Removal of quinoline, which is typical of nitrogen‐containing compounds in crude oil, was achieved by a biodegradation reaction by Comamonas sp TKV3‐2‐1. The aerobic strain, Comamonas sp TKV3‐2‐1, which can grow utilizing quinoline as the sources of both carbon and nitrogen, degraded quinoline to 2‐hydroxyquinoline, finally to water‐soluble substances. The degradation reaction of 2‐hydroxyquinoline was revealed to be regarded as a rate‐limiting step controlling the overall reaction of biodenitrogenation process of quinoline in crude oil. The degradation rate of 2‐hydroxyquinoline in a stirred fermenter had a maximum of 211 mg 2‐hydroxyquinoline g‐cell^?1 h^?1 when the portion of crude oil in the reaction mixture, the cell concentration and the rotational speed of agitation impeller were 83.3%(v/v), 28.5 gdm^?3 and 11.7 s^?1, respectively. After the reaction was completed, the crude oil and the cell suspension could be separated efficiently by centrifuging. The possibility of constructing a bioprocess for removing quinoline in crude oil under storage is also discussed. © 2001 Society of Chemical Industry     

Jatropha oil and karanja oil as carbon sources for production of sophorolipids

Biosurfactants like sophorolipids (SL) are mild and environmentally friendly surfactants to be used in cosmetics and health care products. In addition to surfactant properties, SL also possess antimicrobial and skin healing properties. SL are produced by microbial fermentation using refined vegetable oils with glucose as a carbon source. This affects the economics of the production of SL. In the present work, non‐traditional oils like jatropha oil, karanja oil, and neem oil were used as newer feedstock for fermentative production of SL using Starmerella bombicola (ATCC 22214). In the fermentation, jatropha oil and karanja oil gave 6.0 and 7.6 g/L of SL (mainly lactonic form), respectively. HPLC, liquid chromatography–mass spectrometer, and ¹H NMR of crude SL obtained from fermentation broth showed lactonic form of two major SL. Oleic acid and linoleic acid were preferentially consumed over other fatty acids by the organism. Neem oil gave lower yield, i.e., 2.63 g/L of SL (mainly acidic form). Practical applications: Jatropha oil and karanja oil are one of the non‐traditional oils grown wildly in India that have large potential that is still to be explored. These oils contain non‐glycerides components that exclude their use as edible oil. These oils can be used as substrate for SL that can find novel applications like in soil remediation, skin care production, antimicrobial agents, low foaming detergents, and food additives. The current study has provided proof of concept work that has indicated the potential of these oils to be used as substrate for SL. It has opened new avenues and there is further scope to improve the yield by validating the process parameters like aeration rate, residual substrate recycle and pH control.     

Bleaching augments lipid peroxidation products in pistachio oil and its cytotoxicity

Pistachio consumption is associated with reductions in serum cholesterol and oxidative stress due to their constituents of unsaturated fats, phytosterols, fiber, and antioxidants. Bleaching has been applied to whiten nut shells for antifungal and cosmetic purposes. However, the impact of bleaching on nutritional quality and safety of pistachios remains to be examined. In this study, we investigated whether bleaching would increase malondialdehyde (MDA) or 7‐keto‐sitosterol and decrease phytosterols in pistachio oil, as well as cause cytotoxicity of modeled Hepa1c1c7 cells. Bleaching increased MDA by more than 32% from 0.23 µg/g in raw oil, with the largest increase noted with the bleach containing H₂O₂ and Fe²⁺ (P ≤ 0.05). Bleached pistachio oil had larger than 12.6% decrease in β‐sitosterol and total phytosterols as compared to the raw oil (P ≤ 0.05). Bleaching with Fe²⁺ significantly increase 7‐keto‐sitosterol compared to bleaching alone. Hepatic cell viability was decreased the most by the oil of the pistachios treated with bleach containing Fe²⁺ (P ≤ 0.05), and lactate dehydrogenase activity in medium was elevated by >18‐folds (P ≤ 0.05). Compared to natural pistachios, the bleaching treatment had detrimental effects on nutritional quality and expected health benefits of pistachios by increasing lipid peroxidation, decreasing phytosterol content, and causing cytotoxicity. Practical applications: Bleaching has been applied to whiten the nut shell for antifungal and cosmetic purposes. However, the results of this study indicate that bleaching treatment has a detrimental impact on nutritional quality and expected health benefits of pistachios. Particularly, treatment with a bleach formula with hydrogen peroxide and transit metals increases formation of lipid peroxidation products and decreases phytosterol content. The resulting pistachio oil causes cell toxicity. Thus, bleaching practice for whitening pistachios is strongly discouraged.