Content of low molecular weight carbohydrates in vining peas (Pisum sativum) related to harvest time, size and brine grade

Knowledge of how the content of low molecular weight carbohydrates (LMWC), including the raffinose family oligosaccharides (RFO; raffinose, stachyose and verbascose), changes in unripe peas (Pisum sativum) around harvest time, is today limited. An early and a late maturing cultivar of peas were harvested with 24 h of each other on seven different occasions, of which three were chosen for this study. The pea samples were divided into three groups by size and brine grading, and then analysed with regard to the content of low molecular weight carbohydrates. The content of raffinose and stachyose increased in all groups during a period of 5 days. Peas that sank (sinkers) in the brine grading test had a higher content of raffinose and stachyose and a lower content of sucrose than floating peas, indicating that sinkers have reached a greater degree of maturation. The content of verbascose remained the same or decreased during the study period. In conclusion, the date of harvesting green peas for freezing affects the contents of RFO.