INTRODUCTION
Sour cherry (Prunus cerasus L.) is a stone fruit belonging to the Rosaceae family (Önem, 2017). The homeland of the sour cherry is probably a region lying between the Caspian Sea and the mountains of Northern Anatolia. It is also reported that wild sour cherries are found on Mount Olympus in Macedonia, in the mountainous parts of Italy and in central France (Önal, 2002). The top five sour cherry-producing countries are Turkey, USA, Russia, Iran, and Ukraine (Kappel et al., 2012).
Sour cherry is one of the most attractive fruits in terms of nutritional value and sensory properties. It is characterized by its intense red color and sour–sweet flavor and contains many bioactive compounds beneficial to health. Organic acids that affect sour taste stimulate the secretion of digestive enzymes, vitamins, and minerals and are responsible for the smooth course of chemical reactions in the body (Nowicka et al., 2015). The potential health benefits of sour cherries have made them economically valuable. According to researchers in literature, sour cherries have been reported to be good for many diseases such as cardiovascular diseases, cancer, sleep disorders, and obesity (Kappel et al., 2012; Önem, 2017). This situation was attributed to the beneficial health effects of phyto-compounds found in fruits. Sour cherry contains higher amounts of phyto-compounds, especially phenolic substances, compared to many other fruits (Ferretti et al., 2010).
In sour cherries, the most common subgroups of polyphenols are procyanidins and anthocyanins, but colorless and pale yellow polyphenols are also found in significant amounts and have distinct biological activities. Polyphenols identified in sour cherry juices include anthocyanins as well as (−)-epicatechin (flavanol), neochlorogenic, chlorogenic, and 3-coumaroylquinic acids (hydroxycinnamic acids), as well as quercetin and kaempferol glycosides (flavonols) (Levaj et al., 2010). It also contains high levels of β-carotene and small amounts of lutein and zeaxanthin. It is also a good source of vitamins C, B, A, E, K and minerals such as Ca, P, K, Mg (Ma & Lin, 2010; Önem, 2017; Rao & Rao, 2007). Sour cherries are generally not consumed fresh due to their high acidity and low content of simple sugars. This is the main reason for their industrial processing into juice, jam, frozen, or dried fruits (Blando & Oomah, 2019). It is thought...
