Pumpkin seed oil

Pumpkin seed oil factory in Prekmurje, Slovenia
Cucurbita pepo var. styriaca
Dried seed of Cucurbita pepo var. styriaca

Pumpkin seed oil (Kernöl or Kürbiskernöl in German, bučno olje in Slovenian, bučino ulje in Croatian, tikvino ulje or bundevino ulje in Serbian, ulei de dovleac in Romanian, and tökmag-olaj in Hungarian), is a culinary specialty from what used to be part of the Austro-Hungarian Empire and is now southeastern Austria (Styria), eastern Slovenia (Styria and Prekmurje), Central Transylvania, Orăștie-Cugir region of Romania, north western Croatia (esp. Međimurje), and adjacent regions of Hungary.

The Steirisches Kürbiskernöl (styrian pumpkin seed oil) [1] and the Štajersko prekmursko bučno olje (styrian prekmurjen pumpkin oil)[2] are European Union Protected Designation of Origin (PDO) products.

The oil is an important export commodity of Austria and Slovenia. It is made by pressing roasted, hull-less pumpkin seeds, from a local variety of pumpkin, the "Styrian oil pumpkin" (Cucurbita pepo subsp. pepo var. 'styriaca',[3][4] also known as var. oleifera). It has been produced and used in Styria's southern parts at least since the 18th century. The earliest confirmed record of oil pumpkin seeds in Styria (from the estate of a farmer in Gleinstätten) dates to February 18, 1697.

The viscous oil is light to very dark green to dark red in colour depending on the thickness of the observed sample. The oil appears green in thin layers and red in thick layers, an optical phenomenon called dichromatism.[5] Pumpkin oil is one of the substances with the strongest dichromatism. Its Kreft's dichromaticity index is -44.[6] When used together with yoghurt, the oil turns bright green and is sometimes referred to as "green-gold".

Culinary uses

Pumpkin seed oil has an intense nutty taste and is rich in polyunsaturated fatty acids. Browned oil has a bitter taste. Pumpkin seed oil serves as a salad dressing when combined with honey or olive oil. The typical Styrian dressing consists of pumpkin seed oil and cider vinegar. The oil is also used for desserts, giving ordinary vanilla ice cream a nutty taste. It is considered a real delicacy in Austria and Slovenia, and a few drops are added to pumpkin soup and other local dishes. Using it as a cooking oil, however, destroys its essential fatty acids.[7][8]

Seed types and oil

Pumpkin seed oil in a clear glass vial
A drop on a white plate showing dichromatism

Other types of pumpkin seed oil are also marketed worldwide. International producers use white seeds with shells and this produces a cheaper white oil. New producers of seeds are located in China.

An analysis of the oil extracted from the seeds of each of twelve cultivars of C. maxima yielded the following ranges for the percentage of several fatty acids:[9]

n:unsat Fatty acid name Percentage range
(14:0) Myristic acid 0.09-0.27
(16:0) Palmitic acid 12.6-18.4
(16:1) Palmitoleic acid 0.12-0.52
(18:0) Stearic acid 5.1-8.5
(18:1) Oleic acid 17.0-39.5
(18:2) Linoleic acid 18.1-62.8
(18:3) Linolenic acid 0.34-0.82
(20:0) Arachidic acid 0.26-1.12
(20:1) Gadoleic acid 0-0.17
(22:0) Behenic acid 0.12-0.58

The sum of myristic and palmitic acid (cholesterogenic saturated fatty acids) content ranged from 12.8 to 18.7%. The total unsaturated acid content ranged from 73.1 to 80.5%. The very long chain fatty acid (> 18 carbon atoms) content ranged from 0.44 to 1.37%.

Localisation in the seed

The oil is localised in the small lipid droplets in the cotyledon cells.[10]

References

  1. "Database Of Origin & Registration (AT/PGI/0017/1460)". European Commission. Retrieved November 25, 2015.
  2. "Database Of Origin & Registration (SI/PGI/0005/0418)". European Commission. Retrieved November 25, 2015.
  3. Fürnkranz, Michael; Lukesch, Birgit; Müller, Henry; Huss, Herbert; Grube, Martin; Berg, Gabriele (2012). "Microbial Diversity Inside Pumpkins: Microhabitat-Specific Communities Display a High Antagonistic Potential Against Phytopathogens". Microbial Ecology. Springer. 63 (2): 418–428. doi:10.2307/41412429. JSTOR 41412429.
  4. Košťálová, Zuzana; Hromádková, Zdenka; Ebringerová, Anna (August 2009). "Chemical Evaluation of Seeded Fruit Biomass of Oil Pumpkin (Cucurbita pepo L. var. Styriaca)". Chemical Papers. Springer Versita for Institute of Chemistry. 63 (4): 406–413. doi:10.2478/s11696-009-0035-5.
  5. Kreft, Samo; Kreft, Marko (November 2007). "Physicochemical and Physiological Basis of Dichromatic Colour" (PDF). Naturwissenschaften. Springer Science+Business Media. 94 (11): 935–939. doi:10.1007/s00114-007-0272-9. PMID 17534588.
  6. Kreft, Samo; Kreft, Marko (2009). "Quantification of Dichromatism: A Characteristic of Color in Transparent Materials". Journal of the Optical Society of America. Optical Society of America. 26 (7): 1576–1581. doi:10.1364/JOSAA.26.001576. PMID 19568292.
  7. "The Benefits of Pumpkin Seeds". Health Learning Info. Retrieved September 17, 2013.
  8. "Healthy Cooking Oils". University of Kansas Medical Center. Retrieved September 17, 2013.
  9. Stevenson, D. G.; Eller, F. J.; Wang, L.; Jane, J.; Wang, T.; Inglett, G. E. (2007). "Oil and Tocopherol Content and Composition of Pumpkin Seed Oil in 12 Cultivars". Journal of Agricultural and Food Chemistry. 55: 4005–4013. doi:10.1021/jf0706979. PMID 17439238. Note: The data are found in Table 3 on page 4010
  10. Kreft, M., Zorec, R., Janeš, D., Kreft, S. (2009). Histolocalisation of the oil and pigments in the pumpkin seed. Annals of Applied Biology, 154:413–418
  • Dreikorn, K.; Berges, R.; Pientka, L.; Jonas, U. (September 2002). "Phytotherapy of Benign Prostatic Hyperplasia. Current Evidence-based Evaluation". Urologe A. (in German). 41 (5): 447–451. ISSN 0340-2592. PMID 12426861. Only a few randomized clinical trials that meet standard criteria of evidence-based medicine but with relatively short follow-up times and some meta-analyses mainly regarding Serenoa repens and Pygeum africanum as well as more recent studies on pumpkin seeds have shown clinical effects and good tolerability. 
  • Vahlensieck, Jr., W. (18 April 2002). "With alpha blockers, finasteride and nettle root against benign prostatic hyperplasia. Which patients are helped by conservative therapy?". MMW - Fortschritte der Medizin (in German). 144 (16): 33–66. PMID 12043098.  Summary: Established medications for the treatment of BPH in current use are alpha-blockers, finasteride, and the phytotherapeutic agents pumpkin seed (Cucurbitae semen), nettle root (Urticae radix), the phytosterols contained in Hypoxis rooperi, rye pollen and the fruits of saw palmetto (Sabalis serrulati fructus)
  • Dreikorn, K. (April 2002). "The role of phytotherapy in treating lower urinary tract symptoms and benign prostatic hyperplasia". World Journal of Urology. 19 (6): 426–435. doi:10.1007/s00345-002-0247-6. ISSN 1433-8726. PMID 12022711.  Summary: A number of short-term randomised trials and some meta-analyses in the recent literature suggest clinical efficacy and good tolerability for some preparations, mainly extracts from Serenoa repens and also Pygeum africanum, products with high concentrations of beta-sitosterol, and pumpkin seeds.
  • Bracher, F. (January 1997). "Phytotherapy of Benign Prostatic Hyperplasia". Urologe A. (in German). 36 (1): 10–17. PMID 9123676. In this article, the most widely used phytopharmaceutical agents, such as saw palmetto berry extracts, Radix urticae extracts, pumpkin seeds, pollen extracts and different phytosterols, are described. Based on these results, the use of phytopharmaceutical agents for the treatment of mild to moderate symptomatic BPH seems to be well justified. 
  • Carbin, B. E.; Larsson, B.; Lindahl, O. (December 1990). "Treatment of benign prostatic hyperplasia with phytosterols". British Journal of Urology. 66 (6): 639–641. doi:10.1111/j.1464-410x.1990.tb07199.x. PMID 1702340. In a randomised, double-blind study, the preparation Curbicin, obtained from pumpkin seeds and dwarf palm plants (Cucurbita pepo l. and Sabal serrulata), was compared with a placebo in the treatment of symptoms caused by prostatic hyperplasia; 53 patients took part in the study, which was carried out over a 3-month period. Urinary flow, micturition time, residual urine, frequency of micturition and a subjective assessment of the effect of treatment were all significantly improved in the treatment group. 
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