Plum fruits contain 75 to 87% water and 13 to 25% dry matter. The taste of the fruit depends on the ratio of sugars to organic acids. The plum fruit has more glucose and less fructose. Malic and citric acid are prevalent acids. The total amount of organic acids, expressed as malic acid, ranges from 0.39 to 2.28%. In ripe plums, the pH value ranges from 3.3 to 3.6. The fleshy part of the fruit contains up to 0.69% pectin. The chemical composition of the fruit contains nitrogen components, from 0.6% to 0.8% (amino acids, amides, ammonium compounds and nitrogenous bases), and mineral components with only 0.5%. Potassium (54.59%) and phosphorus (17.7%) are prevalent minerals.
The most important vitamins in plums are provitamin A, vitamins B and C. Chlorophylls, carotenoids and anthocyanins are the most significant plum pigments. Anthocyanins stored in plum epidermis vacuoles are especially important. Anthocyanins are important anti-oxidants and as such, they protect the human body from cardiovascular diseases, cancer and other degenerative diseases of aging.
Plum processing by freezing is a recent method. After the fruit is cut in halves, manually or by machine, it is instantly frozen in tunnel freezers and this way the fruit retains all of its nutritious properties.