Changes in Sugar and Starch Content in Garden Peas (Pisum sativum L.) during Storage at Various Temperatures

Abstract

Changes in sugar and starch content in garden peas (Pisum sativum L., 'Kishu-usui') at storage temperatures of 1, 5, 10, 15 and 20°C were studied. HPLC was used to determine the sucrose, raffinose, and stachyose levels. At storage temperatures at or above 10°C, sucrose levels steeply declined in keeping with the increased temperatures. In contrast, at temperatures of 1°C and 5°C, sucrose levels increased during the 1st half of the storage period and decreased thereafter. Raffinose and stachyose increased at all of the temperatures studied, with stachyose expressing a higher increase. At temperatures of 10, 15 and 20°C, stachyose became the predominant sugar after the middle of the storage period. At temperatures ≥ 10°C, starch content increased quickly within a few days after the beginning of storage. At the 5°C temperature, the content increased from the 10th day of storage, but at the 1°C temperature, if increased from the 15th day. The lower the storage temperature, the higher the starch increments became. Judging from the above, the changes in saccharide levels of the stored garden peas were similar to those observed in normal development, leading to the conclusion that the process of maturation was not halted by storage. Even if the temperature of storage was at 1°C, it appeared to be difficult to maintain the quality of garden peas 'Kishu-usui' over a long period of time.