Biochemical Engineering Journal 42 (2008) 148–152 Contents lists available at ScienceDirect Biochemical Engineering Journal journal homepage: www.elsevier.com/locate/bej Antimicrobial activity of celery fruit isolates and SFE process modeling Duˇ san Miˇ si´ c a , Irena Zizovic b,∗ , Marko Stameni´ c b , Ruˇ zica Aˇ sanin a , Mihailo Risti ´ c c , Slobodan D. Petrovi´ c b,d , Dejan Skala b a Faculty of Veterinary Medicine, University of Belgrade, BulevarOslobodjenja 18, 11000 Belgrade, Serbia b Faculty of Technology and Metallurg, University of Belgrade, Karnegijeva 4, 11020 Belgrade, Serbia c Institute for Medicinal Plant Research “Dr Josif Panˇ ci´ c”, Tadeuˇ sa Koˇ s´ cuˇ ska 1, 11000 Belgrade, Serbia d Hemofarm Group, Vrˇ sac, Serbia article info Article history: Received 17 January 2008 Received in revised form 9 June 2008 Accepted 15 June 2008 Keywords: Supercrirical fluid extraction Antimicrobial activity Celery (Apium graveolens) Modeling Mass transfer Food engineering abstract The antimicrobial activity of celery fruit essential oil obtained by supercritical fluid extraction with carbon dioxide and by hydrodistillation was investigated against Staphylococcus aureus, Listeria monocytogenes and Listeria ivanovii strains, isolated from victuals of animal origin and from clinical specimens. The super- critical extract was moderately or much more effective than the essential oil obtained by hydrodistillation against almost all the investigated strains, except in the case of one Listeria strain originating in minced meat, where the MIC values were identical. For two S. aureus strains originating in minced meat, supercriti- cal extract had very strong antimicrobial activity, with MIC values of ≤40 g/ml. The chemical composition of the supercritical extract as well as of the oil obtained by hydrodistillation of dried fruits was analyzed. Qualitative and quantitative analyses were performed using GC/FID and GC/MS. The supercritical extract was greatly superior to the oil obtained by hydrodistillation in terms of the concentration and quantity of the isolated bioactive compounds: sedanenolide, sedanolide and 3-n-butylphthalide. The yields of the supercritical extraction and hydrodistillation were 2.74 and 1.63wt.%, respectively. The process of super- critical fluid extraction was modeled using a model on the secretory structure scale. The modeling results showed good agreement with the experimental data. © 2008 Elsevier B.V. All rights reserved. 1. Introduction One of the most important trends in the food industry today is the application of natural food additives. The application of food additives produced by synthetic chemical processes has been severely limited. Also, the inclusion of synthetic additives in some food products has been completely banned. On the other hand, many naturally occurring compounds found in plants have been shown to possess antimicrobial functions and serve as a source of antimicrobial agents against foodborne pathogens [1,2]. The antimicrobial activity of essential oils has long been recognized [3–5]. Therefore, essential oils which often contain major aromatic and flavoring components of herbs may have great potential use as food flavors and preservatives [6]. Celery fruit (seed) extracts are extensively used as flavoring ingredients in many food products, including meat products, soups, frozen dairy desserts, candies, baked goods, gelatins, puddings, condiments and relishes, snack foods, alcoholic and non-alcoholic ∗ Corresponding author. Tel.: +381 11 3303 795; fax: +381 11 3370 473. E-mail address: zizovic@tmf.bg.ac.yu (I. Zizovic). beverages and others [7]. Celery fruit is also used for treat- ing bronchitis and asthma, as well as liver and spleen diseases [8]. Sedanolide is considered to be one of the main flavor com- pounds [9,10] responsible for the characteristic aroma of celery. In addition to sedanolide, several other phthalides, such as sedaneno- lide and 3-n-butylphthalide, are present in high concentrations [7,11]. Sedanolide and 3-n-butylphthalide were reported as tumor- inhibitory compounds in the forestomach of female A/J mice by inducing the glutathione S-transferase (GST) enzyme activity [12]. The chemical composition of celery fruit essential oil has been thoroughly investigated. According to literature data [11,13] on the comparative chemical composition of celery fruit essential oil obtained by supercritical fluid extraction (SFE) (sedanolide 28.84%, sedanenolide 22.39% and 3-n-butylphthalide 5.49%) and hydrodistillation (sedanolide 2.50%, sedanenolide 9.89% and 3-n- butylphthalide 2.68%), it can be concluded that SFE gives extracts with higher concentrations of the main active compounds than hydrodistillation. According to the data available from the literature [14], hydrodistilled celery fruit oil was strongly inhibitory against Yersinia enterocolitica, Geotrichum candidum and Rhodotorula, mod- erately inhibitory against Listeria monocytogenes and Staphylococcus 1369-703X/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.bej.2008.06.008