Effect of storage on the fatty acids of dried ryegrass

Abstract

1. The compositions of the fatty acids in ryegrass were determined in fresh samples, and in samples dried at room temperature for 26 h, at 50° and for 18 h or at 100° for 12 h. The drying of grass resulted in a small increase in palmitic acid and a decrease in linolenic acid in the total fatty acids.2. Samples of grass dried at 50° and 100° were stored at three relative humidities (rh < 3%, 47% and 80%) for 13 months.3. There were marked changes in the samples stored at 80% rh, with an onset of mould growth and a loss of dry matter. The samples stored at lower humidities had no mould.4. There were two types of change in the fatty acids during storage. The deterioration brought about and mould was accompanied by a decrease in the concentration of linolenic acid and an increase in the concentrations of oleic and linoleic acids. The other type of change observed at the lower humidities resulted in a decrease in the content of linolenic and an increase in the content of palmitic, and did not affect the amounts of oleic and linoleic cells.5. There was little difference between the changes that occurred in the composition of the total fatty acids of the grass dried at 50° and of that dried at 100°. The changes that were at all significant appeared to occur less rapidly, particularly in the early months of storage, in the grass dried at the higher temperature for the shorter time.