Effects of different drying methods on phenolic content, antioxidant capacity and general characteristics of selected dark colored Turkish fig cultivars

Abstract

Fig 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.

Survey of Phenolic Acids, Flavonoids and In Vitro Antioxidant Potency Between Fig Peels and Pulps: Chemical and Chemometric Approach

“…In addition, dark-colored peels exhibited the highest antioxidant capacity compared to the light-colored ones. These results were similar to those reported by Solomon et al [ 29 ], Pande and Akoh, Ammar et al, Konak et al [ 35 , 36 , 37 ], where several methodologies have been employed to assess the in vitro antioxidant capacity of different fig parts. It is noteworthy that such in vitro antioxidant assays are semi-quantitative and do not always represent the in vivo antioxidant capacity [ 38 ].…”

“…It combined the highest levels of flavonoids compounds and consequently showed high level of DPPH• and ABTS•+ radical scavenging capacity. This cultivar has dark-colored fruits, which is in accordance with several studies, which showed that fig skins have much higher amounts of phytochemical compounds, mainly flavonoids, which strongly contribute to the antioxidant capacity [18,29,30,35,37].…”

“…skins have much higher amounts of phytochemical compounds, mainly flavonoids, which strongly contribute to the antioxidant capacity [18,29,30,35,37].…”

Recent insight on nutritional value, active phytochemicals, and health‐enhancing characteristics of fig (Ficus craica)

“…As a result, figs from dark‐colored cultivars had an antioxidant potential of 3–4 times greater than those from light‐colored cultivars. These results were supported by numerous research findings (Faleh et al., 2012; Konak et al., 2015; Pereira et al., 2020). The sun‐drying process positively impacted antioxidant potential, enhancing the antioxidant activities of dried figs compared to fresh ones, according to the impact of drying on antioxidant capacity (Chang et al., 2016; Paramanya et al., 2023).…”

Determination of phytochemicals of Turkish fig genetic resources

“…While TP values of 'Bursa Siyahı', 'Sarı Zeybek' and 'Yeşilgüz' accessions in the study by Çalışkan et al [2012] were 118.4, 76.4 and 86.6 mg GAE 100 g -1 FW, respectively, the TP values of these accessions in our study were detected as 76.4, 58.9 and 73.4 mg of GAE 100 g -1 of FW, respectively, showing a decrease. While AOA values of 'Divrekkara' (TR1101), 'Sarılop' (TR1029) and 'Sarı Zeybek' (TR1098) accessions were 335, 178.06 and 144.04 µmol trolox 100 g -1 FW, respectively, AOA values belonging to the same accessions in the study by Konak et al [2015] were determined as 208, 70 and 99 µmol trolox 100 g -1 FW. When compared to the studies of the other researchers, TP and AOA values obtained from the same accessions vary in the range of 15 to 60 %.…”