FRUIT JUICES are non alcoholic beverages which have been prepared from sound, ripe, and flavorsome fruits. They are valued as energy foods because of their sugar content which ranges according to the fruit from 2 to 16 percent. They supply such minerals as iron, calcium, and phosphates and sulfates of potassium and sodium. They also contain carotene and those elements of the Vitamin B complex known as thiamin and riboflavin. In the case of tomato and citrus fruit juices they are one of the finest sources of the antiscorbutic Vitamin C and of hesperidin or Vitamin P. The oxidation in the body of the fruit acids (citric, tartaric, and malic) assists in maintaining the blood's acid-base balance.
The principal machines used in Ihe preparation of fruit juices are hydraulic and filter presses which extract the juices from the fruits and a homogenization machine which so reduces the size of the suspended solid particles that it retards their setlling on the bottom of the container. A deaerating machine is employed to expel oxygen and other gases, thus conserving the full flavor of the juices and the potency of their vitamin content. The microorganisms which might cause spoilage of fruit juices are most frequently destroyed by the application of heal. This process of preservalion employs both the holding-pasteurization and the flash-pasteurization methods. In the holding method heat is applied to Ihe juices for several hours at a relalively low lemperalure (135 °F.) or for half an hour at a higher temperature (150 °F.). In the flash method the juices are heated for one to three minutes at temperatures ranging from 170 ° to 190 °F. This method is preferred because it destroys the pectic enzymes which sometimes make the juice cloudy in appearance. It is also an excellent means of maintaining the nalural flavor of the juice because it does nol impart a "cooked" taste.
