Acidic and enzymatic pre-treatment effects on cold-pressed pumpkin, terebinth and flaxseed oils




β-glucosidase, Cold-pressed oil, Enzymatic pre-treatment, Flaxseed, Pumpkin seed, Terebinth


Oil yield and the properties of oil can be improved with various enzymatic pre-treatments before obtaining oil from oilseeds by cold-press extraction. A commercial mixture of pectolytic enzymes was used in this study. In addition, apple seed meal as a source of β-glucosidase enzyme and citric acid were applied to oilseeds (pumpkin, terebinth and flaxseed) as pre-treatments. The results were evaluated by comparing the effects of the pre-treatments on oil yield and properties. Enzyme preparate could increase the oil yield of pumpkin seeds (~300%) and flaxseed (151%). Significant increases in the phenolic contents of terebinth (from 91.67 to 319.33 mg GAE/kg) and flaxseed oils (from 12.03 to 40.47 mg GAE/kg) were achieved by citric acid and enzymatic pre-treatments. These two pre-treatments were also effective in terms of peroxide formation and oxidative stability in terebinth oil. With the help of the pre-treatments applied to oilseeds it was possible to increase the transition of phenolics from seeds to oil for terebinth oil with increase ratios of 245% for citric acid, 248% for the enzymatic process compared to the control.


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Adlard E, Waksmundzka H, Sherma J. 2011. High performance liquid chromatography in phytochemical analysis. Chromatographia 74, 749.

Akın G, Arslan FN, Karuk ESK, Yılmaz I. 2018. Cold-pressed pumpkin seed (Cucurbita pepo L.) oils from the central Anatolia region of Turkey: Characterization of phytosterols, squalene, tocols, phenolic acids, carotenoids and fatty acid bioactive compounds. Grasas Aceites 69 (1), e232.

Andjelkovic M, Van Camp J, Trawka A, Verhé R. 2010. Phenolic compounds and some quality parameters of pumpkin seed oil. Eur. J. Lipid. Sci. Technol. 112, 208-217.

Anwar F, Zreen Z, Sultana B, Jamil A. 2013. Enzyme-aided cold pressing of flaxseed (Linum usitatissimum L.): Enhancement in yield, quality and phenolics of the oil. Grasas Aceites 64 (5), 463-471.

Arawande JO, Komolafe EA, Shakpo IO. 2011. Effect of citric acid and storage containers on the keeping quality of refined soybean oil.Pak. J. Sci. Ind. Res. Ser. A: Phys. Sci. 54 (1), 40-44.

Blois MS. 1958. Antioxidant determinations by the use of a stable free radical. Nature 181 (4617), 1199-1200.

Çalıkoğlu E, Kıralan M, Bayrak A. 2006. Uçucu yağ nedir, nasıl üretilir ve Türkiye'deki durumuna genel bir bakış. (What is essential oil, how is it produced and an overview of the situation in Turkey). Turkey 9. Food Congress; 24-26 May 2006, Bolu, 569-570.

Dalgıç L, Sermet OS, Özkan G. 2011. Farklı kavurma sıcaklıklarının menengiç yağ kalite parametreleri üzerine etkisi.Academic Food J. 9 (3), 26-36.

Dessi MA, Deiana M, Day BW, Rosa A, Banni S, Corongiu FP. 2002. Oxidative stability of polyunsaturated fatty acids: effect of squalene. Eur. J. Lipid. Sci. Technol. 104, 506-512.<506::AID-EJLT506>3.0.CO;2-1

Do YK, Kim JM, Chang SM, Hwang JH, Kim WS. 2009. Enhancement of polyphenol bio-activities by enzyme reaction. J. Mol. Catal. B Enzym. 56 (2-3), 173-178.

Emir DD, Aydeniz B, Yılmaz E. 2015. Effects of roasting and enzyme pretreatments on yield and quality of cold-pressed poppy seed oils. Turk. J. Agric. For. 39 (2), 260-271.

Ergöçen G. 2013. Purification and characterization of β-glucosidase from prunus armeniaca seeds. (β-glukozidaz enziminin kayısı (Prunus armeniaca) çekirdeklerinden saflaştırılması ve karakterizasyonu), Master thesis. Çukurova University, Institute of Science.

Ertaş E, Bekiroğlu S, Özdemir İ, Demirtaş İ. 2013. Comparison of fatty acid, sterol, and tocol compositions in skin and kernel of turpentine (Pistacia terebinthus L.) fruits. J. Am. Oil. Chem. Soc. 90 (2), 253-258.

European Union Commission Regulation EEC 2568/91 on the characteristics of olive oil and olive pomace and their analytical methods. Official European Commission. L248, 1991.

Ezeh O, Gordon MH, Niranjan K. 2016. Enhancing the recovery of tiger nut (Cyperus esculentus) oil by mechanical pressing: Moisture content, particle size, high pressure and enzymatic pre-treatment effects. Food Chem. 194, 354-361. PMid:26471565

Fruehwirth S, Steinschaden R, Woschitz L, Richter P, Schreiner M, Hoffmann B, Pignitter M. 2020. Oil-assisted extraction of polyphenols from press cake to enhance oxidative stability of flaxseed oil. Lebensm. Wiss. Technol. 110006.

García A, Brenes M, José Moyano M, Alba J, García P. Garrido A. 2001. Improvement of phenolic compound content in virgin olive oils by using enzymes during malaxation. J. Food. Eng. 48 (3), 189-194.

Gorjanović SŽ, Rabrenović BB, Novaković MM, Dimić EB, Basić ZN, Sužnjević DŽ. 2011. Cold-pressed pumpkin seed oil antioxidant activity as determined by a DC polarographic assay based on hydrogen peroxide scavenge. J. Am. Oil. Chem. Soc. 88 (12), 1875-1882.

Harborne JB. 1965. Plant polyphenols-XIV.: Characterization of flavonoid glycosides by acidic and enzymic hydrolyses. Phytochemistry 4 (1), 107-120.

Hraš AR, Hadolin M, Knez Ž, Bauman D. 2000. Comparison of antioxidative and synergistic effects of rosemary extract with α-tocopherol, ascorbyl palmitate and citric acid in sunflower oil.Food Chem.71 (2), 229-233.

Jafari M, Goli SAH, Rahimmalek M. 2012. The chemical composition of the seeds of Iranian pumpkin cultivars and physicochemical characteristics of the oil extract. Eur. J. Lipid. Sci. Technol. 114 (2), 161-167.

Karataş G. 2015. Susam tohumuna uygulanan ön işlemlerin kalite özellikleri ve yağ verimine etkisi. (Effects of pre-treatments on quality characteristics and oil yields of sesame seeds). Doctoral dissertation. Istanbul Technical University, Institute of Science.

Kavak DD, Altıok E, Bayraktar O, Ülkü S. 2010. Pistacia terebinthus extract: As a potential antioxidant, antimicrobial and possible β-glucuronidase inhibitor. J. Mol. Catal. B Enzym. 64 (3-4), 167-171.

Kaya F, Özer A. 2015. Characterization of extracted oil from seeds of terebinth (Pistacia terebinthus L.) growing wild in Turkey. Turk. J. Sci. Technol. 10 (1), 49-57.

Koubaa M, Mhemdi H, Barba FJ, Roohinejad S, Greiner R, Vorobiev E. 2016. Oilseed treatment by ultrasounds and microwaves to improve oil yield and quality: An overview. Food Res. Int. 85, 59-66. PMid:29544853

Küçükhüseyin BE. 2012. Domates, biber ve havuçta meyvelerin fitoöstrojen içeriklerinin belirlenmesi. (Identification of phytoestrogen contents of tomato, pepper and carrot). Master thesis. Ankara University, Institute of Science.

Laroze L, Soto C, Zúñiga ME. 2010. Phenolic antioxidants extraction from raspberry wastes assisted by-enzymes. Electron. J. Biotechn. 13 (6).

Latif S, Anwar F, Ashraf M. 2007. Characterization of enzyme-assisted cold pressed cotton seed oil. J. Food Lipids 14, 424-436.

Latif S, Anwar F, Hussain AI, Shahid M. 2011. Aqueous enzymatic process for oil and protein extraction from Moringa oleifera seed. Eur. J. Lipid. Sci. Technol. 11, 1012-1018.

Latif S, Anwar F. 2009. Physico-chemical studies of hemp (Cannabis sativa) seed oil using enzymeassisted cold pressing. Eur. J. Lipid. Sci. Technol. 10, 1042-1048.

Liu JJ, Gasmalla MAA, Li P, Yang R. 2016. Enzyme-assisted extraction processing from oilseeds: Principle, processing and application. Innov. Food Sci. Emerg. Technol. 35, 184-193.

Maier T, Schieber A, Kammerer DR, Carle R. 2009. Residues of grape (Vitis vinifera L.) seed oil production as a valuable source of phenolic antioxidants. Food Chem. 112 (3), 551-559.

Mazaheri Y, Torbati M, Azadmard-Damirchi S, Savage GP. 2019. Effect of roasting and microwave pre-treatments of Nigella sativa L. seeds on lipase activity and the quality of the oil.Food Chem. 274, 480-486. PMid:30372968

Medvedevskikh SV, Baranovskaya VB, Medvedevskikh MY, Krasheninina MP, Sergeeva AS. 2021. Reference measurement procedure for the determination of mass fraction of fat content in food.Accred. Quality Ass. 26, 165-175.

Murkovic M, Pfannhauser W. 2000. Stability of pumpkin seed oil. Eur. J. Lipid. Sci. Technol. 102 (10), 607-611.<607::AID-EJLT607>3.0.CO;2-E

Nakić SN, Rade D, Škevin D, Štrucelj D, Mokrovčak Ž, Bartolić M. 2006. Chemical characteristics of oils from naked and husk seeds of Cucurbita pepo L. Eur. J. Lipid. Sci. Technol. 108 (11), 936-943.

Neđeral S, Škevin D, Kraljić K, Obranović M, Papeša S, Bataljaku A. 2012. Chemical composition and oxidative stability of roasted and cold pressed pumpkin seed oils. J. Am. Oil. Chem. Soc. 89 (9), 1763-1770.

Rahman MJ, Costa de Camargo A, Shahidi F. 2018. Phenolic profiles and antioxidant activity of defatted camelina and sophia seeds. Food Chem. 240, 917-925. PMid:28946362

Ranalli A, Malfatti A, Lucera L, Contento S, Sotiriou E. 2005. Effects of processing techniques on the natural colourings and the other functional constituents in virgin olive oil. Food Res. Int. 38, 873-878.

Sainvitu P, Nott K, Richard G, Blecker C, Jérôme C, Wathelet JP, Paquot M, Deleu M. 2012. Structure, properties and obtention routes of flaxseed lignan secoisolariciresinol: a review. Biotechnol. Agron. Soc. Environ. 16(1), 115-124.

Sevindik O, Selli S. 2016. Üzüm çekirdek yağı eldesinde kullanılan Ekstraksiyon yöntemleri. (The extraction methods of grape seed oil). Gida/The J. Food 42 (1), 95-103.

Siger A, Józefiak M. 2016. The effects of roasting and seed moisture on the phenolic compound levels in cold-pressed and hot-pressed rapeseed oil. Eur. J. Lipid. Sci. Technol. 118 (12), 1952-1958.

Singleton VL, Orthofer R, Lamuela-Raventós RM. 1999. Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent. Meth. Enzymol., 152-178.

Sirilun S, Chaiyasut C, Pengkumsri N, Peerajan S, Chaiyasut K, Suwannalert P, Sivamaruthi B. 2016. Screening and characterization of beta-glucosidase production by Saccharomyces cerevisiae. J. Appl. Pharm. Sci. 6 (5), 029-035.

Soto C, Concha J, Zuniga ME. 2008. Antioxidant content of oil and defatted meal obtained from borage seeds by an enzymatic-aided cold pressing process. Process Biochem. 43 (6), 696-699.

Şeran EB. 2011. Yağlı tohumlara uygulanan ultrasonik destekli ön işlem ile soğuk pres yağlarında verim ve kalitenin artırılması. (Increasing yield and quality in cold press oil with ultrasonic assisted pre-treatment applied to oilseeds). Master thesis. Istanbul Technical University, Institute of Science.

Tanska M, Roszkowska B, Skrajda M, Dabrowski G. 2016. Commercial cold pressed flaxseed oils quality and oxidative stability at the beginning and the end of their shelf life. J. Oleo Sci. 65 (2), 111-121. PMid:26782307

Tong AM, Lu WY, Xu JH, Lin GQ. 2004. Use of apple seed meal as a new source of β-glucosidase for enzymatic glucosylation of 4-substituted benzyl alcohols and tyrosol in monophasic aqueous-dioxane medium. Bioorganic Med. Chem. Lett. 14 (9), 2095-2097. PMid:15080986

Tsao R. 2010. Chemistry and biochemistry of dietary polyphenols. Nutrients 2 (12), 1231-1246. PMid:22254006 PMCid:PMC3257627

Tuberoso CIG, Kowalczyk A, Sarritzu E, Cabras P. 2007. Determination of antioxidant compounds and antioxidant activity in commercial oilseeds for food use. Food Chem. 103 (4), 1494-1501.

Vujasinovic V, Djilas S, Dimic E, Romanic R, Takaci A. 2010. Shelf life of cold-pressed pumpkin (Cucurbita pepo L.) seed oil obtained with a screw press. J. Am. Oil. Chem. Soc. 87 (12), 1497-1505.

Watson R, Ross R. 2014. Polyphenols in plants: isolation, purification and extract preparation. Amsterdam: Elsevier, Academic Press.

Wiesenborn D, Kangas N, Tostenson K, Hall C, Chang K. 2005. Sensory and oxidative quality of screw-pressed flaxseed oil. J. Am. Oil. Chem. Soc. 82 (12), 887-892.

Yıldız EG. 2013. Pistacia terebinthus (menengiç) meyve ekstrelerinin ve menengiç kahvesinin total fenolik ve flavonoit madde kompozisyonlarının ve antioksidan etkilerinin karşılaştırılması. PhD Thesis, Erciyes University, Faculty of Pharmacy, p. 56.

Yu HL, Xu JH, Lu WY, Lin GQ. 2007. Identification, purification and characterization of β-glucosidase from apple seed as a novel catalyst for synthesis of O-glucosides. Enzyme. Microb. Technol. 40 (2), 354-361.

Zolman J. 1993. Experimental design and statistical inference. Biostatistics Oxford University Press, Inc., New York.



How to Cite

Özkılıç S, Arslan D. Acidic and enzymatic pre-treatment effects on cold-pressed pumpkin, terebinth and flaxseed oils. grasasaceites [Internet]. 2022Jun.13 [cited 2022Oct.6];73(2):e462. Available from:




Funding data

Necmettin Erbakan Üniversitesi
Grant numbers BAP-171319003