Raisins are dried grapes/currants. However, unlike fresh grapes, they indeed are rich and concentrated natural sources of energy, vitamins, electrolytes, and minerals. In addition, they are packed with several health benefiting poly phenolics anti-oxidants, dietary fiber, and other phyto-nutrients.
In general, fresh grapes either seedless or seed types of the Vinifera species, such as Thompson Seedless (Sultana), Sugarone, Calmeria, Corinth... etc., are subjected to sundry or in mechanical drying techniques. In some cases, the whole bunch of grapes may be allowed to dry in the vine itself (vine-dried). The moisture content should not exceed 16% of dry weight. Thoroughly dried raisins are further stemmed, cap-stemmed, sorted, and cleaned in order to obtain right quality, dried berries. At the commercial level, the berries are processed and graded further before sold in the markets.