Texture and Crystallization Control in Raisins

Upon protracted storage of raisins a crystalline material can develop on their surface, especially at higher moisture levels. A method of controlling this formation was developed, which consisted of subjecting the raisins to a mild heat‐treatment. This heat‐treatment procedure also had a tenderizing effect on raisins, making them noticably softer. Other factors were studied that affected raisin texture during storage with bran‐flakes. Raisin desiccation rate was found to be affected by storage temperature, pressure and coatings. Paraffin coating had the most pronounced effect. Protein coatings of solubilized soy protein or egg albumen followed by heat‐denaturation also significantly reduced moisture loss from raisins stored with bran flakes.