Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article The Use of Organic Sun-Dried Fruits for Delivery of Phenolic Compounds(İzzet KARA, 2022) Dervişoğlu, Gökhan; Yemenicioğlu, AhmetThe aim of this study is to characterize and increase the total soluble (water soluble + alcohol soluble) phenolic (SPCT) and flavonoid content (SFCT) and total soluble free radical scavenging based antioxidant capacity (SACT) of major sun-dried fruits such as raisins, figs, prunes and apricots. Due to their high insoluble dietary fiber content, the bound antioxidant capacity formed 61 to 67% of the overall antioxidant capacity (water soluble + alcohol soluble + bound) of sun-dried fruits. The SPCT, SFCT and SACT of sun-dried fruits changed between 1675 and 3860 μg catechin/g (d.w.), 161 and 495 μg catechin/g (d.w.) and 13 and 28.5 μmol Trolox/kg (d.w.), respectively. The incorporation of green tea polyphenols into sun-dried raisins, figs and apricots by controlled rehydration conducted in green tea extracts increased their SPCT, SFCT and SACT 1.5 to 1.8 fold, 1.3 to 1.6 fold, and 1.5 to 2.6 fold, respectively. The method applied caused limited increases in SPCT (1.1 fold) and SFCT (1.2 fold) of prunes, but it increased SACT of these fruits 1.6 fold. This study showed the possibility of using sun-dried fruits not only as source of dietary fiber, but also for delivery of phenolic compounds. The methods used in this study for delivery of green tea phenolic compounds to selected organic sun-dried fruits could be an alternative method to increase intake of these invaluable antioxidant compounds and increase functionality of sun-dried fruits which are already accepted as good source of dietary fiber.Conference Object Citation - Scopus: 11Effects of Different Drying Methods on Phenolic Content, Antioxidant Capacity and General Characteristics of Selected Dark Colored Turkish Fig Cultivars(International Society for Horticultural Science, 2017) Konak, R.; Köseoğlu, İ.; Yemenicioğlu, Ahmetig fruit is a good source of minerals and crude fibers. The dark-colored fig cultivars rich in anthocyanins are also known with their high polyphenol content. However, although there are many different dark-colored fig cultivars grown in Turkey, the dried fig industry has traditionally been concentrated on drying of several yellow-colored fig cultivars. The aim of this study is to determine the effects of sundrying and oven-drying on some general characteristics, phenolic content and antioxidant capacity of 2 dark-colored (black) and 2 light-colored (yellow) fig cultivars selected from genetic collection of Turkish Fig Research Institute. The figs were obtained by harvesting at the semi-dry stage at 40-50% moisture content and applying sun-drying or oven-drying to reach final moisture content between 20 and 26%. The sun-drying was conducted on mats for 2-3 days under the sun while the oven-drying was applied for 12 h at 60°C and at the air velocity of 0,5 m s-1. The result of the study clearly showed almost 1,5-2 fold higher total phenolic content and ABTS free radical scavenging based antioxidant capacity of fresh dark-colored figs than fresh light-colored ones. The drying had almost no negative effects on the total phenolic content of both dark- and light-colored figs. The drying also did not have a negative effect on antioxidant capacity of light-colored figs, but it caused a limited reduction (between 20 and 30%) in antioxidant capacity of dark-colored figs due to the well-known heat labile nature of their color compounds anthocyanins. The use of sun-drying or oven-drying did not have a considerably different effect on final phenolic contents and antioxidant capacities of dried figs. This study clearly showed that it is possible to obtain phenolic rich dried figs by use of dark colored fig cultivars such as TR1101 and TR1102.Article Citation - WoS: 115Citation - Scopus: 135Antioxidant Activity and Phenolic Content of Fresh and Dry Nuts With or Without the Seed Coat(Academic Press Inc., 2009) Arcan, İskender; Yemenicioğlu, AhmetTotal antioxidant activities based on ABTS free radical scavenging activity and phenolic content of fresh or dry hazelnuts, walnuts and pistachios assayed with their seed coats changed between 3063 and 11,076 μmol trolox equivalents/100 g d.w. and 256 and 755 mg gallic acid equivalents/100 g d.w., respectively. The walnuts used in this study showed the highest antioxidant activity, followed by pistachios and hazelnuts. The removal of seed coat reduced the total antioxidant activity of hazelnuts, walnuts and pistachios almost 36, 90 and 55%, respectively. The total antioxidant activities of investigated fresh and dry nuts are not considerably different. However, phenolic content and antioxidant activity in hydrophilic and ethanolic fractions obtained by successive extraction of nuts showed some variation. The antioxidant activity in 1-serving portion of fresh or dry walnuts is equivalent to that in almost 2-serving portions of black tea, and 1.2-1.7-serving portions of green and Earl Grey tea. One-serving portions of dry hazelnuts and fresh or dry pistachios contained antioxidant activity equivalent to that in 0.7-1-serving portions of black tea. The antioxidant activity measurements correlated with phenolic content (r2 = 0.70). This study showed the potential of using fresh or dry nuts to develop functional foods with high antioxidant activity.