Zereshk (barberry) is the dried fruit of a thorny shrub called Berberis vulgaris, also known as European barberry or simply barberry, and is cultivated for its fruit primarily in Iran. The shrub, native to central and southern Europe, northwest Africa and western Asia, grows to about 9 feet tall and produces bright yellow flowers that bloom in late spring. The fruit is a small oblong bright red berry, 7 to 10 millimeter long and 3 to 5 millimeter wide, that ripens in late summer or autumn. The fruit is edible but sharply acidic. Except for its fruits and seeds, the plant is mildly poisonous. Its most potent agent is berberine, which is known to have a number of therapeutical effects.
The ripe barberries have high content of Vitamin C and are used in cooking for their pleasantly acidic taste and fruity aroma. The berries have been traditionally used as an ingredient in making jam. The berries are high in pectin which makes the jam congeal as it cools after having been boiled. A widely available Russian candy called Барбарис (Barberis) is made using extract from the berries. In southwestern Asia, especially Iran, the berries are used for cooking, as well as for jam-making. In Iran, dried barberries are commonly used as a currant in rice dishes like zereshk polo and shirin polo or as garnish for polo (plain rice). It is also used in kuku sabzi (herbs frittata). In India, pickled barberries are served with curries or used like raisins in desserts.
Medicinal use of barberry dates back more than 2,500 years. It has been used in Indian folk medicine to treat diarrhea, reduce fever, improve appetite, relieve upset stomach, and promote vigor as well as a sense of wellbeing. Today, it is widely used for medicinal purposes in Iran, including for biliary disorders (such as gallbladder disease) and heartburn.
Barberry is used to ease inflammation and infection of the urinary (bladder and urinary tract infections), gastrointestinal, and respiratory tracts (sore throat, nasal congestion, sinusitis, bronchitis) as well as candida (yeast) infections of the skin. Barberry extract may also improve symptoms of certain skin conditions including psoriasis, but more research is needed to confirm these findings.
Store zereshk in the refrigerator in an airtight container if using within weeks of purchase. For long term storage, zereshk is best stored in airtight container or ziplock bag in the freezer to maintain its bright red color and freshness. The red color of zereshk darkens with age as it oxidizes.