Large amounts of strawberries are frozen to be sold to the consumer as such to be used for the manufacture of jams and jellies or for use in the bakery trade. Few strawberries for retail are sliced, mixed with sugar. Some strawberries are frozen individually on wire mesh and packaged in carton and overwrapped and placed in shipping cases for holding in frozen storage.
Strawberries used for the manufacture of other foods are usually frozen whole, in wooden barrels, mixed with sugar. A proportion of fruit to sugar of 3:1 or 2:1 may be used. The barrels of fruit are placed in cold rooms at 10 degree F or below. In order to mix the sugar with the fruit, the barrels are rocked during filling and rolled periodically during the several days required for freezing. The frozen fruit is sometimes stored at 10 degree F. Strawberry and sugar mixtures may also be packed in slip cover cans holding 30 lb of product.
In the manufacture of strawberry jam, water is added to the defrosted fruit mixture, as well as more sugar. The amount of sugar depending on how much sugar was added to the frozen product. About 0.25% - 0.3% of dispersed pectin is added, and the product is heated in open kettles to a soluble solids content of 65%. The pH is then adjusted to 3.3 with citric acid solution and the preserve is packaged in glass jars and vacuum capped. The sealed jars are then heated to a temperature of about 160 degree F, then cooled. In manufacturing strawberry jelly, about 0.3 – 0.35 % dispersed pectin is used, and the pH is regulated to 3.0 – 3.2.Strawberries Used for manufacturing of Other Foods
