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Öğe Changes in volatile compounds of black cumin (Nigella Sativa L.) seed oil during thermal oxidation(Taylor & Francis Inc, 2014) Kiralan, MustafaThis study examined the oxidation stability and volatile compounds in samples of black cumin seed oil at 60 and 100 degrees C. Oxidative changes of black cumin oils followed by periodic determination of its conjugated dienes and trienes during accelerated conditions (60 and 100 degrees C). Black cumin oil showed high resistance to oxidation during thermal oxidation (60 and 100 degrees C). In addition to oxidative stability, volatile compounds in the oil were determined by headspace solid phase microextraction with gas chromatography-mass spectrometry analysis technique. The major componenent of the oil was p-cymene (44.77%) followed by thymoquinone (28.62%). Some volatile compounds were lost rapidly during thermal oxidation at the end of storage. Levels of thymoquinone, 4-terpineol, -longipinene, carvacrol, and isolongifolene reduced slowly and remained more stable during storage at two temperatures (60 and 100 degrees C).Öğe Comparison of oxidation stability of virgin olive oils from different locations of Turkey(Akademiai Kiado Rt, 2014) Karakuş, M.; Bayrak, Ali; Çalıkoğlu, Eda; Kiralan, MustafaTen kinds of virgin olive oil of two major cultivars (Ayvalik and Memecik) produced in several areas of Turkey (Bayindir, Edremit, Ortaklar, Burhaniye, Ezine, Tire, Havran, Ayvalik, Altinoluk, and Kucukkuyu) were analysed. The quality characteristics, fatty acid composition, total phenol, and o-diphenol content of the samples were determined. Oxidative stability and free radical scavenging activity were determined using Rancimat test, Schaal oven test, and DPPH method. It was found that while Memecik oil from Ortaklar demonstrated the strongest oxidative stability, Ayvalik oil from Ezine had the lowest oxidative stability among the samples. Fatty acid composition and especially oleic acid/linoleic acid ratio was previously defined as a parameter that can help distinguish cultivars from one another; however, this study proved that total phenol, especially o-diphenol content of the oil, has the strongest effect on oxidative stability compared to other factors including fatty acid composition.Öğe DETERMINATION AND CLASSIFICATION OF VOLATILE COMPOUNDS OF PASTIRMA USING SOLID PHASE MICROEXTRACTION/GAS CHROMATOGRAPHY/MASS SPECTROMETRY(Slovak Univ Agriculture Nitra, 2013) Demirok, Eda; Kiralan, Mustafa; Carbonell-Barrachina, Angel A.Pastirma, a traditional dry cured Turkish meat product, has a great number of specific aroma compounds, which occur as a result of lipid oxidation, protein degradation and formulation of cemen paste. These compounds give characteristic flavor to pastirma and the main objective of this study was to determine the nature of these compounds. Fifty-eight volatile compounds, grouped into nine chemical classes were identified using solid phase microextraction technique (SPME) coupled to gas chromatography/mass spectrometry (GC-MS). Aldehydes, mostly lipid oxidation products, were determined as the major chemical group, representing 17.54-78.02% of total volatile compounds. The major volatile aldehyde was hexanal (2.36-55.41%), followed by 2-methyl-2-butenal (0.97-14.69%) and then heptanal (0.29-4.77%). Sulfur compounds possibly derived from spices or formed by proteolysis of sulfur-containing amino acids, were the second most abundant group, with concentrations ranging between 6.04 and 50.60%. Other important volatile compounds of pastirma were aliphatic hydrocarbons, aromatic ketones, hydrocarbons, esters, alcohols, acids, terpenes, and furans.Öğe Effect of conventional and microwave heating on the oxidative stability of oil from a wild Turkish hazelnut cultivar (Corylus colurna)(Innovhub Ssi-Area Ssog, 2020) Kiralan, Mustafa; Sarica, Ercan; Ozaydin, Aysegul; Ozkan, Gulcan; Eren, Omer; Ramadan, Mohamed FawzyThe effects of microwave (5, 10, 15, and 20 min at 600 W) and conventional heating (60 degrees C) on the quality and stability of oil extracted from a wild Turkish hazelnut (Corylus colurna) cultivar was performed and compared. Oxidative stability of oil samples was measured by measuring peroxide value (PV) and UV absorption characteristics (K-232 and K-270). Degradation of total phenolics, tocopherols, and fatty acids was also examined 270 during heating experiments. The increase in PV and conjugated dienes (K-232) of conventional-heated oils was higher than that of microwave-heated oils. alpha-Tocopherol is consumed fast during both conventional and microwave heating treatments. Microwave and conventional heating resulted in the degradation of phenolics content in the heated oils.Öğe Effect of cultivation area and climatic conditions on volatiles of virgin olive oil(Wiley-Blackwell, 2012) Kiralan, Mustafa; Özkan, Gülcan; Köylüoğlu, Fatma; Uğurlu, Hatice Aşık; Bayrak, AliTo elucidate the influence of the cultivation area and climatic conditions on volatiles of virgin olive oil from Gemlik cultivar, an investigation was carried out. Five Turkish geographical zones (Balikesir, Aydin, Manisa, Antalya and Hatay) were chosen. From these areas, fruits were collected at the same maturity stage and processed using a small experimental olive oil mill, applying identical processing conditions for all olive samples. Headspace solid-phase microextraction (HS-SPME) technique coupled to GC/MS was used for volatile analysis. Twenty-seven compounds were identified and characterised, representing 96.4098.74% of the total GC area. The major volatile representing about 50% was the (E)-2-hexenal. This compound was found in higher concentrations on olive oils from Antalya than from Hatay area. Hexanal was the second most abundant volatile compound and varied between 13.89 and 28.96%. Comparing the olive growing areas Hatay and Antalya, the hexanal concentration was about 29 and 14%, respectively. Generally, a significant difference in the composition of volatile compounds between the oils from the same olive cultivar and from different geographic regions was recorded. The results suggest that climatic factors, latitude and longitude affect the formation of volatiles.Öğe The effect of different harvest stages on chemical composition a antioxidant capacity of essential oil from Artemisia annua L.(2015) Coşge, Belgin Şenkal; Kiralan, Mustafa; Yaman, CennetÇiçeklenme öncesi (ÇÖ), % 50 çiçeklenme (% 50 Ç), tam çiçeklenme (TÇ) ve çiçeklenme sonrası (ÇS) dönemlerinde hasatedilen Artemisia annua L. (Asteraceae)dan su distilasyonu yöntemiyle elde edilen uçucu yağların kimyasal kompozisyonuGC ve GC/MS kullanılarak belirlenmiştir. Uçucu yağ içerikleri ÇÖ, % 50 Ç, TÇ ve ÇS dönemlerinde sırasıyla % 0.8, %0.96, % 1.22 ve % 1.38 bulunmuştur. Toplamda 20 bileşenin tespiti yapılmış olup, artemisia ketone (% 28.30-% 37.15),camphor (% 18.00-% 23.30) ve 1,8-cineole (% 9.00-% 10.39) ana bileşenler olarak belirlenmiştir. Üç ana bileşene aiten yüksek değerlere tam çiçeklenme döneminde hasat edilen bitkilerin uçucu yağlarında kaydedilmiştir. Ayrıca, DPPHyöntemiyle test edilen uçucu yağların serbest radikal yakalama aktivitesi TÇ?% 50 Ç?ÇS?ÇÖ sırasında bulunmuştur.Öğe The effect of different harvest stages on chemical composition and antioxidant capacity of essential oil from Artemisia annua L(Ankara University, 2015) Coşge Şenkal, Belgin; Kiralan, Mustafa; Yaman, CennetChemical composition of the essential oils obtained by hydro-distillation from Artemisia annua L. (Asteraceae) harvested before flowering (BF), 50% of flowering (50%F), full flowering (FF), and after flowering (AF) stages were determined using GC and GC/MS analysis. The essential oil contents were 0.8%, 0.96%, 1.22% and 1.38% in BF, 50% F, FF and AF, respectively. In total, 20 compounds were identified, with artemisia ketone (28.30%-37.15%), camphor (18.00%- 23.30%), and 1,8-cineole (9.00%-10.39%) as main components. The highest amounts of the three main components were recorded in the essential oils of the plants harvested in the FF stage. Also, the free radicals scavenging activity of the essential oils, tested by using DPPH method, were found to be in order of FF>50% F>AF>BF. © 2014, Ankara University. All rights reserved.Öğe The effect of different manures and synthetic fertilizer on biochemical and antimicrobial properties of mentha piperita?L(Wiley, 2014) Özbucak, Tuğba Bayrak; Ertürk, Ömer; Yıldız, Oktay; Bayrak, Ali; Kara, Meryem; Sahin, Huseyin; Kiralan, MustafaThe study was designed to examine the effects of different manures (fish, pigeon and cow) and synthetic fertilizer (nitrogen) on some biochemical activities of Mentha piperita L. (mint, peppermint). Seventeen different phenolic constituents and 19 essential oils were determined in M. piperita samples. While caffeic, gallic, ferulic, protocatechuic, syringic, o-coumaric acids and rutin were detected as common phenolics; carvone, limonene and 1.8-cineol were identified as major essential oil components in all mints. Total phenolic compounds, ferric reducing antioxidant power and cupric (III) reducing capacity (CUPRAC) tests were used to evaluate antioxidant capacities of the mints. The highest total phenolic compound (4.8 mg gallic acid equivalents/100 g) and antioxidant capacity (971 mM Fe(II)/mg; 823 mM Trolox /100 g) were observed in mints fertilized with pigeon manure. Mint samples also had different antimicrobial activities against the studied microorganisms (eight bacteria and two fungi), especially Escherichia coli and Listeria monocytogenes.Öğe Effect of harvest time on physicochemical quality parameters, oxidation stability, and volatile compounds of extra virgin olive oil(Akademiai Kiado Rt, 2014) Çevik, Şerife; Özkan, Gülcan; Kiralan, Mustafa; Bayrak, AliThe aim of this study was to determine the changes in some physicochemical properties of olives (fruit weight, water content and oil content) and olive oils (total chlorophyll, carotenoid, pheophytin a, peroxide value and free acidity), and in the chemical properties (fatty acids, tocopherols, phenolics, oxidation stability and volatile profiles) of oils during ripening. Ripening indices (RI) of olive samples were 1.93 (unripe), 4.28 (ripe) and 5.89 (overripe). Most of the mentioned features changed with ripening. During ripening there was a sharp decrease in total chlorophyll, carotenoid and pheophytin a contents. An increase in oleic and linoleic acids and a decrease in palmitic acid were found in the fatty acid composition. Olive oils showed strong relations among oxidation stability, tocopherol content, total phenols content, and antiradical actvity of phenol extracts and these parameters decreased with maturation. Nevertheless, higher amounts of trans-2-hexenal were found in the oil from ripe olives than from unripe and overripe olives. On the other hand, the highest concentration of hexanal was found in the oil from overripe olives. In general, significant differences were observed in fruit weight, pigments, free acidity, fatty acid, tocopherol, and total phenolics contents, radical scavenger activity, oxidation stability, phenolic profile and volatile profile between the olive oils from the Gemlik cultivar at different stages of maturation.Öğe Individual and combined use of rosemary and origanum in soybean oil as natural antioxidants(Taylor & Francis Inc, 2013) Aysel, Mehtap Bircan; Bayrak, Ali; Kiralan, Mustafa; Özbucak, TuğbaDried rosemary and origanum were added to soybean oil, individually and in combination, to determine their effect on the oxidation stability of soybean oil. Samples were stored at two different temperatures (60 degrees C and room temperature) and oxidation was determined by peroxide value and conjugated diene value. The treated soybean oil samples showed evidence of antioxidant activity at 60 degrees C and at room temperature. Furthermore, it was observed that the herbs stored under room temperature had a higher activity compared to those stored at 60 degrees C.Öğe Introducing a traditional dairy product Kes: Chemical, microbiological, and sensorial properties and fatty acid composition(Wfl Publ, 2009) Cakir, Ibrahim; Coskun, Hayri; Akoglu, Ilker T.; Isleyen, M. Fatih; Kiralan, Mustafa; Bayrak, AliIn this study, it was aimed to determine the chemical, biochemical, microbiological and sensorial characteristics and fatty acid composition of Kes, traditionally produced in Bolu province in Turkey. The information on production of 'Kes' was collected from Bolu province in Turkey. Moreover, 20 samples were taken from the local bazaars in different periods in Bolu. These samples were taken to the laboratory, and the intended analyses were carried out. Also sensorial characteristics were described. In traditional way, first the cream of the milk is separated, and then it is processed for the yogurt. The yogurt is transferred in a cloth sack and allowed draining for one night. After that the content of the sack is dry salted and processed to obtain a cubic shape, which is called 'Kes', then dried under room temperature, or yogurt is churned and the whey (in Turkish, Ayran) is heated until content of the whey is precipitated. Then the precipitate is drained well and salted. After that some part of the salted precipitate is taken, shaped as cubic or conic and dried under room conditions. In the Key samples, mean dry matter was 61.59%, ash 13.66%, protein 32.42%, fat 6.30%, salt 13.26%, acidity 0.22% and pH 3.81. The mean ripening degree was 5.76% and lipolysis value 3.62 ADV (acid degree value) for Kes samples. Microbiological analysis showed that the mean number of total aerobic bacteria was 4.50 log cfu/g, molds and yeasts 3.99 log cfu/g, Lactobacillus spp. 3.80 log cfu/g and Streptococcus spp. 3.41 log cfu/g. The Kes samples contained neither coliform bacteria nor E. coli. Water activity (a(w)) of the Kes samples was 0.74 as mean of total samples. The color and appearance of Kes samples was dull-white, the structure was hard, and smell was acidic. The taste of the Kes samples was salty and acidic. The shapes of the samples were cubic, rectangular, triangle and conic. The predominant free fatty acids in the Kes samples were palmitic (C16:0) and oleic (C18:1) acids, followed by stearic (C18:0) and myristic (C14:0) acids.Öğe Oxidative and antiradical stabilities of two important virgin olive oils from Ayvalık and Memecik olive cultivars in Turkey(Taylor & Francis Inc, 2013) Kiralan, Mustafa; Bayrak, AliMemecik and Ayvalik olive cultivars were harvested from Mugla province of Turkey and processed into oil using a three phase decanter. The oils of these cultivars were subjected to free fatty acid, peroxide value, ultra violet absorption, and fatty acid composition analysis. The results showed that all obtained values were very similar and within the limits of the International Olive Oil Council regulation for virgin olive oil. The oxidative stability in samples was assessed in terms of primary and secondary oxidation products using peroxide values and induction times, respectively. Total phenol and o-diphenol contents were determined by spectrophotometric assays. The antiradical capacity of phenolic fraction was determined by 1,1-diphenyl-2picrylhydrazyl method. These analyses showed that oxidative resistance, antiradical capacity, and the content of phenols and o-diphenols were higher for Memecik oil than Ayvalik oil.Öğe Physicochemical properties and stability of black cumin (Nigella sativa) seed oil as affected by different extraction methods(Elsevier, 2014) Kiralan, Mustafa; Özkan, Gülcan; Bayrak, Ali; Ramadan, Mohamed FawzyBlack cumin (Nigella sativa) oil (BCO) was recovered using different extraction techniques including solvent free system (cold-pressing) and solvent extracted systems (Soxhlet and microwave assisted). Oils were analyzed for the composition of fatty acids and bioactive compounds (sterols, tocopherols, chlorophyll, carotenoid and phenolics profile) and for some physicochemical properties [free fatty acid, peroxide value (PV), refractive index, and ultraviolet (UV) absorption at K-232 and K-270]. Antiradical power (AP) of oils was also evaluated, wherein cold-pressed oil had stronger AP than solvent extracted oils. Phenolic profiles analyzed by HPLC revealed that thymoquinone was the main phenolic compound wherein high levels of benzoic and p-hydroxy benzoic acids were found in cold pressed-BCO. Oxidative stability (OS) of oils was evaluated during accelerated oxidation conditions (oven test at 60 degrees C and Rancimat test at 110 degrees C). The greatest induction period was 19.6h for Soxhlet-extracted BCO, and the lowest induction period was 3.48 h for cold-pressed BCO. PV of cold-pressed BCO reached 85.3 meq O-2/kg oil, while PV of the other extracted oils were under 27.0 meq O-2/kg oil at the end of storage period. (C) 2014 Elsevier B.V. All rights reserved.Öğe Quality characteristics, lipid oxidation parameters and 3-monochloropropane-1,2-diol (3-MCPD) content of Doner kebab during the cooking process(M H Schaper Gmbh Co Kg, 2020) Gulen, Sevinc; Turan, Semra; Kiralan, Mustafa; Ramadan, Mohamed FawzyDoner (doner) kebab (DK) is a traditional fast food in Turkey and several countries in the world. In the present study, the changes in lipid fraction due to thermal treatment applied during chicken DK production were investigated. To determine the oxidation levels of the lipid fraction extracted from DK samples during cooking, color (L*, a*, b*, C*, h*), conjugated diene (CD), K-232, K-270, peroxide value (PV), thiobarbituric acid value (TBA), free fatty acids (FFAs) content and polymer triglyceride content were determined. In addition, free and ester-bound 3-monochloropropane-1,2-diol (3-MCPD) levels were determined. The maximum center and surface temperatures of DK during cooking were 10.6 degrees C and 80.3 degrees C, respectively. During cooking, L* values of DK samples were increased while a* values decreased. As the moisture content of DK samples decreased with cooking, the lipids amounts increased. The FFAs contents of the lipids extracted from the cooked DK samples were 1.33-2.06%; peroxide values 2.0-3.2 meq O-2/kg; K-232 values 2.39-4.33; K-270 values 0.64-1.71; TBA values 0.74-2.24 mg MA/kg; and polymer triglyceride contents were 0.024-0.031 g/100 g. As the amount of ester 3-MCPD increased with the cooking process, free 3-MCPD levels decreased. Since the cooking was carried out at low temperatures, the amounts of free and ester-bound 3-MCPD and lipid oxidation products were low.Öğe Volatiles in an endemic Allium specie: Allium tuncelianum by headspace solid phase microextraction(Taylor & Francis Ltd, 2013) Kiralan, Mustafa; Rahimi, Amir; Arslan, Neşet; Bayrak, AliThe volatile components of an endemic garlic, Allium tuncelianum were extracted using solid-phase microextraction and analyzed by Gas chromatography and Mass Spectrometry (GC-MS). A total of 14 volatile components were identified in red and green garlic. Most of the identified compounds were sulphur compounds. The main sulphur compound was diallyl disulfide and its content in red and green garlic was 72.52 % and 67.33 %, respectively. In analysis of volatile compounds, importance of differences in content of red and green garlic were found in methyl allyl disulfide content.
