Influences of Low Temperature Storage on the Qualities of "Sordum" Plum

Food Chemical Studies on Plum Friuts (Part VII)

Abstract

"Sordum" plums were stored at 3°C for 30 days, (at 20°C) for 15 days, and at 20°C after 3°C storage, respectively. During storage at 20°C, the hardness and the weight of them rapidly decreased, whereas red pigments in the peel and pulp steeply developed. The increase of the amounts of free-amino nitrogen, total surgars and polyphenols was also observed in the juice. The plums detriorated in 7 to 10 days. Hydrochloric acid-soluble pectin which is a major component of pectin in plums at harvest decreased rapidly in proportion to the increase of watersoluble pectin during storage at 20°C. These changes were little observed during storage at 3°C except softening and weight loss. Changes of the qualities of the plums stored at 20°C after 3°C were remarkable. Free-amino acids in the juice had a tendency to increase at the beginning and the middle of the storage and to decrease at the end. Plorine and alanine readily increased at 20°C, and alanine content became 8 times higher than the value at harvest.