Browsing by Author "Artik, Nevzat"

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Changes in Pigment Profile and Surface Colour of Fig (Ficus Carica L.) During Drying
(Wiley, 2012) Yemis, Oktay; Bakkalbasi, Emre; Artik, Nevzat
In this study, anthocyanins in three fresh fig varieties (Ficus carica L.) cultivated in Turkey were characterised and quantified by HPLC/DAD and HPLC/MS. In addition, the carotenoid composition of Sarilop and Sarizeybek, yellow fig varieties, was determined, and then the ripening- and drying-related changes in carotenoids and surface colour of figs were monitored during conventional sun-drying. Four different anthocyanins, cyanidin-3-glucoside, cyanidin-3,5-diglucoside, cyanidin-3-rutinoside (major anthocyanin) and pelargonidin-3-glucoside, were identified in samples. Lutein, zeaxanthin, beta-cryptoxanthin and beta-carotene were carotenoids in yellow fig varieties. Approximately 80% of carotenoid compounds in yellow fig varieties degraded at the end of drying (i.e. seventh day). L (lightness), a (redness and greenness) and b (yellowness and blueness) colour parameters were measured by Hunter Lab system. Great changes in carotenoid composition and surface colour were observed at ripening stage on tree. A significant reduction in L and b values that refers to browning in figs was made in the first 3 days of drying process.
Changes in the Phenolic Content and Free Radical-Scavenging Activity of Vacuum Packed Walnut Kernels During Storage
(Karger, 2013) Bakkalbasi, Emre; Yilmaz, Ozay Mentes; Yemis, Oktay; Artik, Nevzat
In this study, the effects of storage temperature, O-2 permeability of packaging materials and variety on phenolic content and free radical-scavenging activity of vacuum-packaged walnut kernels were studied over a 12 months storage period. Methyl gallate (23.70 - 93.75 mg/kg), ellagic acid (137.95 - 569.22 mg/kg), and an ellagic acid pentoside (270.59 - 637.17 mg ellagic acid equivalent/kg) were identified in walnut varieties. While a slight decrease in the amount of ellagic acid was observed during 12 months storage, decreases in the amount of ellagic acid pentoside, total phenolic content and free radical-scavenging activity were severe. The present study concluded that it is possible to protect the phenolic content and antiradical activity of walnut kernels by packaging in Polyamide/Polyethylene laminate pouches having an oxygen permeability lower than 63.40 +/- 0.40 (mL/m(2)/24h at 23 degrees C) under vacuum at 20 degrees C up to twelve months.
Effects of Packaging Materials, Storage Conditions and Variety on Oxidative Stability of Shelled Walnuts
(Elsevier Science Bv, 2012) Bakkalbasi, Emre; Yilmaz, Ozay Mentes; Javidipour, Issa; Artik, Nevzat
The effects effects of storage temperature, oxygen permeability of packaging material and variety on oxidative stability of vacuum-packaged walnut kernels were studied over a 12 months storage period. The oxidation experiments applied to two popular walnut varieties (Yalova-1 and Yalova-3) grown in Turkey. The peroxide values and hexanal contents of walnut samples significantly increased (p < 0.01) during storage at 30 degrees C. The highest hexanal content (4464.5-6406.9 mu g/kg) were observed in Yalova-3 variety stored at 30 degrees C for 12 months in Polyamide/Polyethylene film pouches (oxygen permeability: 63.4 +/- 0.4 mL/m(2)/24 h (23 degrees C)) with 90 mu m total thickness. The effect of storage temperature and variety on lipid oxidation was found to be higher than the effect of oxygen permeability of the packaging material. It was concluded that for vacuum-packed walnut kernels in PA/PE film pouches having 63.4 +/- 0.4 mL/m(2)/24 h (23 degrees C) oxygen permeability, 20 degrees C is sufficient to protect against oxidation for 12 months. (C) 2011 Elsevier Ltd. All rights reserved.
Tocopherol Contents of Walnut Varieties Grown in Turkey and the Effect of Storage on Tocopherol Content
(Wiley, 2014) Bakkalbasi, Emre; Yilmaz, Ozay Mentes; Poyrazoglu, Ender Sinan; Artik, Nevzat
Tocopherol contents of seven popular walnut varieties grown in Turkey were determined. The effects of storage temperature, oxygen permeability of packaging material and walnut variety on the tocopherol content of vacuum-packed walnut kernels were also examined during the 12 months of storage. alpha-, gamma- and delta-tocopherol were identified and quantified in walnut varieties. alpha-, gamma-, delta- and total tocopherol contents of walnuts ranged from 9.69 to 14.13, 298.75 to 470.02, 10.06 to 25.98 and 321.27 to 505.28 mg/kg walnut, respectively. The decrease in the amount of these compounds during the 12 months of storage was severe in packaging material having high oxygen permeability (63.40 +/- 0.40 mL/m(2)/24 h [23C]) and at 30C. The present study concluded that it is possible to protect the tocopherol content of walnut kernels by packaging in polyamide/polyethylene laminate pouches having an oxygen permeability lower than 63.40 +/- 0.40 mL/m(2)/24 h (23C) under vacuum at 10C up to 12 months.