Anason Tohumundan Süperkritik Karbondioksit Ekstraksiyonuyla Anason Esansiyel Yağı Eldesinde Tepki-yüzey Yönteminden Yararlanılarak Optimum Koşulların Belirlenmesi

Abstract

Gıda Mühendisi F. Nevin Başoğlu Anahtar Kelimeler: Anason, esansiyel yağ, trans-anetol, süperkritik ekstraksiyon, tepki- yüzey yöntemi, merkezi-bileşik deney tasarımı, GC-MS (gaz kromatografısi-mass spektroskopisi). Anason, pastacılık, alkollü içkiler ve şekerlemeler başta olmak üzere gıda, kozmetik, eczacılıkta kullanılmaktadır. Ancak anasona hoş keskin kokuyu veren ana bileşen olan trans-anetol maddesi çeşitli elde etme işlemleri sırasında okside olarak bozulmakta, bu arada hoşa gitmeyen birçok koku maddesi oluşmaktadır. Oluşan bu oksidasyon ürünleri esans yağının karakterini bozarak kalitesini düşürmektedir. Bu nedenden dolayı yapılan bu tez çalışmasında dünyada bu konudaki en son tekniklerden biri olan süperkritik ekstraksiyon tekniği kullanılarak, üstün kalitede anason esans yağı üretilmeye ve üretimde kalitenin en yüksek (trans-anetol içeriğinin en yüksek) olacağı optimum işleme koşullan belirlenmeye çalışılmıştır. Süperkritik ekstraksiyonla anason esansiyel yağ kalitesi üzerine, basınç, sıcaklık ve ekstraksiyon süresinin etkisi Tepki- Yüzey Yöntemi (Response Surface Methodology) ile tanımlanmıştır. Bu yöntemde 2. Dereceden 3 Değişken ve 5 Kademeli Merkezil Bileşik Deney Tasarımından yararlanılmıştır. Süperkritik ekstraksiyonda elde edilen esansiyel yağlar GC-MS 'de analiz edilerek içerdiği bileşenler birer tepki (response) olarak değerlendirilmiş ve her çalışma koşulunun etkisi GC bileşenlerindeki değişikliklerle belirlenmeye çalışılmıştır. Elde edilen sonuçların SPSS istatistik programıyla varyans analizleri yapılmış olup, belirlenen regresyon katsayılarına dayanarak optimum koşulların belirleyen bir model formül oluşturulmuştur. Tepki-yüzey grafikleri MATHEMATICA-2 programında çizilmiştir. Tepki yüzey grafiklerinde de görüldüğü gibi optimizasyon sadece trans- anetol maksimize edilmiştir. Tepki-yüzey yöntemi sonucunda belirlenen optimum üretim koşulları; 102 bar basınç; 42.6 °C sıcaklık ve 1 17. 1 dakika ekstraksiyon süresidir.

Food Engineer F.Nevin Basoglu Key Words: Anise seeds, essential oil, supercritical fluid extraction, response-surface methodology, experimental design, GC-MS (gas chromatography-mass spectroscopy). Anise seeds are traditionally used in production of pastries, alcoholic drinks and some confectionery ices. 7rara-anethol which is characterized by a fine, fresh, and sharp odor is the main and dominating component of anise essential oil. However, heatformed during traditional extraction processes, partially decomposes its structure and leads to the oxidation of trans-anethol, which results in the formation of numerous undesirable compounds. These by-products are mainly cw-anethol, methyl-chavicol, beta- bisabolene, gama-himachalene and anise aldehyde. Supercritical fluid extraction (SFE) technique has a better capability of extraction of solutes that those of conventional solvent extraction and distillation methods. This fairly new separation technique utilizes supercritical fluides (fluides above their critical points) to extract the desired material from another phase. SFE separation with CO2 has a lot of advantages; it has low viscosity and large diffusion coefficient; it is non-toxic, non-flammable, of low cost and readily available. For this reason, this study aims the production of anise essential oil using Supercritical CO2 extraction method which is of higher quality and yields higher trans-anothol content. Experimental Design was choosen to optimize the extraction process for best utilization of source and time. Various types of designs have been applied in supercritical extraction studies. Rotatable designs are more advantagous than orthogonal designs, since they provide an insight in determining the direction to what experiment İs next. Therefore, a "three variable, five level central composite design" was used for the optimization of anise essential oil production by SFE. "Response Surface Methodology" is a collection of mathematical and statistical techniques that are useful for modeling and analysis in applications where a response (dependent variable) of interest is influenced by several variables and the objective is to optimize it, whenever the system is too complex to propose a deterministic mathematical model. There are total 23 points as 8 cube points, 6 star points and 9 central points in the 2nd order central composite experimental design with 3 factor 5 level. These points are given in Table 1 with their coded values and in Table 2 with their real values. Table 3 summarizes the real values used for coded values. Table 1. Experimental points in the 2nd order central composite design with 3 factor 5 level (with coded values) The composition of each of the 23 essential oils obtained by SFE using above conditions were analyzed by Hewlett Packard 5971 A quadropole gas chromatography- mass spectroscopy (GC-MS). Working conditions of GC-MS were as the following: Column: Innowax, 60m-x 0.25u,m x 0.25mm stainless steel capillary column. Column temperature: programmed to increase +5°C/min from 70°C to 200°C; Injector temperature: 250°C ; Split ratio: 50:1, Injection volume: 0.1 u.1. Carrier gas and flow: Helium, 1 ml/min Electron impact 70eV Total ion monitoring :35-550 amu Transfer line temperature: 280°C Ion source temperature: 180°C XI Table 2. Experimental run points in the 2nd order central composite design (3 factor and Gas chromatographic results of compositional analyses obtained with anise essential oil samples are summarized in Table 4. 7ra?w-anethol was observed to be the main component of anise essential oil.. Later, these findings were subjected to ANOVA using SPSS program software; the results of statistical analyses are summarized in Table 5. The polynomial model of trans-anethol had the biggest regression coefficient. XII The optimization model developed specially for t-anethol is expressed in the equation as follows; y(*-anethoI) = 87.394- 1.398*x3 + 2.005*xi*x2 + 1.168*xi*x3 - 1.227 (x3)2 Using response surface methodology, the optimal conditions for producing anise essential oil with SFE for the selected parameters were found to be as follows; Pressure: 102 bar, Temperature: 42.6 °C, Time: 11 7.1 minutes. XIII e >s.£> <ü O 3 S Oh OO (D tn i»