Nurhan Uslu

Determination of Bioactive Compounds and Mineral Contents of Seedless Parts and Seeds of Grapes

In this study, phenolic compounds, minerals, total flavonoids, total phenolic contents and antioxidant activities of the seedless parts (pulp+skin) and seeds of table and wine grapes were determined. Also, the total oil, tocopherol contents and fatty acid composition of seed oils of table and wine grapes were investigated. The highest total phenolic content of the grape pulp was found in Trakya ilkeren (199.063mg/100 g), while total flavonoid and antioxidant activity of the pulp was determined at a high level in Red Globe (6.810 mg/g, 90.948%). Antioxidant activity, and the total phenolic and flavonoid contents of grape seeds varied between 86.688 and 90.974%, 421.563 and 490.625 mg GAE/100 g, and 90.595 and 145.595 mg/g respectively (p < 0.05). Generally, the main phenolic compounds of all grape pulps and seeds were gallic acid, 3,4- dihydroxybenzoic acid, (+)-catechin and 1,2-dihydroxybenzene. In addition, the oil contents of grape seeds ranged from 5.275 (Cavus) to 13.881% (Cinarli karasi) (p < 0.05). The major fatty acids of grape seed oils were linoleic, oleic and palmitic acid. The seed oil of the Trakya ilkeren variety was rich in tocopherols in comparison with the other varieties. The major minerals of both the seedless parts and the seeds were determined as K, Ca, P, S, Mg.

The effect of rosemary essential oil on physico-chemical properties of extra-virgin olive oil stored in colourful bottles

The aim of the study was to investigate the effect of both storage material colour (red, green, yellow and transparent glass bottle) and rosemary essential oil on the physico-chemical properties of extra-virgin olive oil. For this reason, free fatty acid, peroxide value, viscosity, colour and fatty acid composition of oils were measured at regular intervals. Free fatty acid and peroxide values of olive oils stored in different coloured bottles increased partly during storage. After 90 days of storage, free fatty acid values of samples changed between 0.78 and 0.89 mg KOH/g oil. By the 90th day of storage peroxide values of samples had changed from 32.75 to 79.46 meq O2/kg oil, whereas the peroxide value of the control group on the 90th day was 94.55 meq O2/kg. On the first day (0 day), ‘L*’, ‘a*’ and ‘b*’ values of control groups were determined to be 70.81, -3.69 and 38.26, respectively. During storage, these values partly increased. Linoleic acid (40.95-43.92%), oleic acid (33.04-34.99%) and palmitic ac...

Oil content and fatty acid composition of eggs cooked in drying oven, microwave and pan

In this study, the effect of heating on the oil yield and fatty acid composition of eggs cooked in drying oven, microwave oven, pan and boiled were determined, and compared. The highest oil content (15.22%) was observed for egg cooked in drying oven, while the lowest oil (5.195%) in egg cooked in pan. The cooking in microwave oven caused a decrease in oleic acid content (46.201%) and an increase in the amount of palmitic acid content (26.862%). In addition, the maximum oleic acid (65.837%) and minimum palmitic acid (14.015%) contents were observed in egg oil cooked in pan. Results showed that fatty acids were significantly affected by cooking method. This study confirms that the cooking processing influences the fatty acid composition of egg oils.