HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ANALYSIS OF PEANUT PHOSPHOLIPIDS .2. EFFECT OF POSTHARVEST STRESS ON PHOSPHOLIPID-COMPOSITION

Peanuts are harvested in late September, and sometimes the harvest sea son can extend through most of October. When weather patterns delay ha rvest, the result may cause an immature crop, curing problems, rain da mage, and freeze damage. All of the above stress situations can affect oil quality and flavor of the peanuts by altering phospholipid compos ition. Such changes are related to refining problems as well as flavor problems. A new high-performance liquid chromatography (HPLC) method was used for the analysis of phospholipids from postharvest stressed p eanuts. The concentrations of phosphatidic acid (PA), phosphatidyletha nolamine (PE), and phosphatidylcholine (PC) were higher in immature se ed when compared to mature seed. A slight increase in concentration wa s observed for phosphaltidylglycerol (PC), and a decrease in phosphati dylinositol occurred in immature peanuts. All phospholipids increased in concentration except PG when peanuts were cured at a high temperatu re (40 degrees C). When peanut seeds were frozen at -16 degrees C (bef ore curing), a significant increase in concentration was observed for PA and PG, whereas the concentrations of PC and PE decreased to very l ow levels when compared to the control. Where concentration permitted, molecular species were separated on a reverse-phase column by HPLC.