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Öğe Antimicrobial activity of cold pressed citrus seeds oils, some citrus flavonoids and phenolic acids(Innovhub Ssi-Area Ssog, 2018) Guneser, B. Aydeniz; Zorba, N. N. Demirel; Yilmaz, E.This study aims at determining the antimicrobial activity of cold pressed lemon, orange, and grapefruit seed oils, and to compare their activities with some antibiotic disks, flavonoid and phenolic acid standards. These oils had inhibition zones ranging from 6.62 to 11.00 mm against fifteen tested pathogenic bacteria. Only lemon seed oils and orange seed oil showed some inhibition against Candida utilis yeast. None of the oils had measurable inhibition zone against Micrococcus luteus ATCC 4698. Although most oils showed no growth inhibition even at a 100% concentration, Escherichia coli ATCC 25922 and Salmonella Enteriditis ATCC 13076 inhibited at 100% oil concentrations. Cold pressed and solvent extracted lemon seed oils inhibited growth of Staphylococcus aureus RSKK 1009 at 2% level, and cold pressed and microwave treated-cold pressed orange seed oil inhibited growth of Klebsiella pneumonia ATCC 700603 at 16 and 50%, respectively. The antibiotic disks ampicillin, sulbactam, piperacillin, tobramycin, mezlocillin, amoxicillin and cycloheximide presented 3-4 fold larger inhibition zones (10.24 - 47.00 mm) than the oil samples. Similarly, flavonoid standards naringin, naringenin, hesperidin, neohesperidin, catechin and kaempherol; and phenolic acids gallic, syringic, tr-ferulic, rosmarinic, tr-2-hydroxycinnamic and chlorogenic acids had inhibition zones like the seed oil samples. Hence citrus seed oils pose moderate levels of antimicrobial activity and could be used as antimicrobial aids.Öğe Cold pressed versus refined winterized corn oils: quality, composition and aroma(Consejo Superior Investigaciones Cientificas-Csic, 2017) Guneser, B. Aydeniz; Yilmaz, E.; Ok, S.The aims of this study were to characterize and compare cold pressed and fully refined winterized corn oils. Free fatty acidity (FFA), peroxide (PV) and p-anisidin (p-AV) values, saponification number, total carotenoid and phenolic contents of cold pressed corn oils were higher than that of the refined winterized corn oils. Linoleic and oleic acids (approximately 53-54% and 30-31%, respectively) were detected as the major fatty acids in both oil samples. Fifteen different sterols with a majority of beta-sitosterol, campesterol, and stigmasterol were quantified in both oil samples. Although phenolic compounds were not quantified in the refined winterized oil samples, some flavonoids (hesperidin, rutin) and phenolic acids (gallic, syringic, rosmaniric and trans-ferulic) were detected in the cold pressed oil samples. This study concludes that cold pressed corn oils could be superior in terms of bioactive compounds but still need some quality improvements for sensory attributes.Öğe Comparing the effects of conventional and microwave roasting methods for bioactive composition and the sensory quality of cold-pressed orange seed oil(Springer India, 2019) Guneser, B. Aydeniz; Yilmaz, E.This study aims to report the composition of bioactives and volatile aromatic compounds, and determine the descriptive sensory properties of cold-pressed orange seed oil. The effects of oven pre-roasting and microwave pre-roasting of the seeds before cold pressing were compared. Thirteen sensory parameters were used to define the oil samples. The major bioactive components of the orange seed oils were naringin, hesperidin, and trans-ferulic acid. Flavonoids constituted the main phenolic class with 78.5% and 74.4%, followed by phenolic acids with 21.4% and 25.5% in the oven and microwave pre-roasted oil samples. The mean concentration of hesperidin and naringin varied from 903.4 to 909.6mg/kg and from 234.3 to 299.8mg/kg, respectively. The results showed for the first time in the literature that orange seed oil contains some volatile aromatic compounds and glycosylated flavanones that could have functional properties. Hence, cold-pressed orange seed oil could be suggested as the new potential health-promoting oil.Öğe Effects of microwave roasting on the yield and composition of cold pressed orange seed oils(Inst Grasa Sus Derivados, 2017) Guneser, B. Aydeniz; Yilmaz, E.The aim of this study was to valorize orange (Citrus sinensis) seeds, which are generated as waste. This study presents data about raw orange seed, the meal gained after cold pressing, and characterization data of the cold pressed seed oils. Furthermore, the effects of microwave roasting of the seds compared to regular roasting (control) were determined. The oil yield of orange seed cold pressing was around 52.93-62.99%. After cold pressing, 13.57-17.97% oil remained in the meal together with 20.68-25.61% protein. Hence, pressed meals could be valorized for different purposes. Except for turbidity, the color b* value, free acidity, the p-anisidine value and antioxidant capacity, there was no significant difference between the two oil samples for the measured physicochemical properties. Six different fatty acids were quantified and the major fatty acids were linoleic, palmitic and oleic acids. The fatty acid composition of the orange seed oil can be accepted as nutritionally balanced. Among the fifteen sterols quantified, beta-sitosterol was dominant (around 77-78%). Likewise, the a-tocopherol content of the samples was not significantly different. The thermal onset and peak temperatures, and enthalpies for crystallization and melting were also reported. This study showed that good quality orange seed oils can be produced by cold pressing, and the oils could be used in food and non-food applications.
