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    Bioactives, Aromatics and Sensory Properties of Cold-Pressed and Hexane-Extracted Lemon (Citrus Limon L.) Seed Oils
    (Springer, 2017) Guneser, Buket Aydeniz; Yılmaz, Emin
    The objective of this study was to provide more essential data about the bioactive, aromatic volatile composition and sensory properties of lemon seed oils to possibly establish new application areas of this unexplored new oil. Furthermore, cold pressing and hexane extraction were compared. Catechin, eriocitrin, rutin, naringin, naringenin, hesperidin, neohesperidin and kaempherol as flavonoids, and gallic, syringic, tr-ferulic, rosmaniric and tr-2-hydrocinnamic acids as phenolic acids were quantified in the oils. Naringin, gallic and syringic acids were significantly higher in the cold-pressed sample. Around 30 different aromatic volatiles were identified in both samples, and, for the majority, the concentrations were higher in the cold-pressed sample. It was observed that lemon seed oil is very aromatic, mostly characterized by citrus, herbal, terpenic, woody, and floral aroma descriptors. A panel evaluated the oils for sensory properties with 13 different definition terms (clarity, lemon peel, roasted, raw vegetable, grassy, bitter, astringent, waxy, nutty, fatty, spicy and throat-catching). The oil was defined as very bitter, astringent, spicy and throat-catching. In conclusion, lemon seed oil was found unsuitable for direct edible use, but might be preferable for its unique aroma and bioactive components for functional food, pharmaceutical and cosmetic applications.
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    Öğe
    Bitterness Reduction of Cold Pressed Grapefruit Seed Oil by Adsorbent Treatment
    (Wiley, 2018) Guneser, Buket Aydeniz; Yılmaz, Emin
    The goal of this study is to remove bitterness of cold pressed grapefruit seed oil by adsorbent treatments. The oil is treated with amberlites XAD7, IR120, and IRA400 resins, and natural zeolite, sepiolite, and montmorillonite at 3% (w/w) level. Oil physicochemical properties, oil flavonoid, phenolic acid and phytosterol compositions, oil sensory descriptive analysis, oil consumer preferences as well as properties of the adsorbents are determined. The largest surface area, pore radius, pore volume, and oleic acid adsorption capacity are observed for natural sepiolite, zeolite and XAD7 amberlite. Adsorbent treatment usually reduced oil viscosity, free acidity, and soap content. In removal of flavonoids, natural sepiolite, zeolite and XAD7 resin are the most successful. Reductions from 3.0 to 60.0% are quantified. Phytosterol composition is not changed significantly by adsorbent treatment. Quantitative sensory descriptive data shows that natural sepiolite at first, followed by natural zeolite and amberlite XAD7 reduced bitterness and throatcatching scores almost by half, but consumer preference test results shows that these reductions were not enough for consumers to accept the taste/flavor of the treated oils. Hence, bitterness removal from grapefruit seed oil still remains as a research challenge.
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    Öğe
    Valorization of Grapefruit Seeds: Cold Press Oil Production
    (Springer, 2019) Yılmaz, Emin; Guneser, Buket Aydeniz; Ok, Selcuk
    PurposeThe aims of this study were valorization of grapefruit seeds by producing oil with cold press technique and characterization of the obtained oils.MethodsControl group and enzyme treated seeds were cold pressed in laboratory scale machine, and common physicochemical properties, fatty acid, sterol, tocopherol, flavonoid, phenolic acid, pigment, volatile aromatics compositions of the oils were determined in addition to their sensory descriptive analyses.ResultsIt was shown that the oil contains linoleic acid (40%), beta-sitosterol (80%) and alpha-tocopherol (220-320mg/kg oil) as the major components. Naringin, hesperidin, neohesperidin, rutin as prominent flavonoids; tr-ferulic and gallic acids as dominant phenolic acids were quantified. Furthermore 26 different (d-limonene, furfural, 3-methylbutanal etc.) volatile aromatics were determined. The oils are shown to be bioactives and aromatics rich samples, but they have strong bitter and astringent taste.ConclusionsHence, the oil could only be used to enrich other edible oils and foods for functional purposes, and could be utilised for cosmetic, chemical, energy and other purposes. [GRAPHICS] .