Price elasticity of demand is the change in the quantity demanded for a unit increase in the price. For regular products the price elasticity of demand is negative which indicates that the quantity demanded decreases as the price is increased.
As the magnitude of the price elasticity of demand increases there is a larger impact on the demand for the same increase in the price. This is the case where the product is not a necessity or for which many substitutes are available. In the opposite scenario, the magnitude of price elasticity of demand is smaller.
The quantity of corn oil demanded would decrease by a large extent for a unit increase in the price if the substitutes for corn oil are easily available and are relatively inexpensive. This would also decrease the revenue earned by sellers of corn oil.
On the other hand, if it is difficult to substitute corn oil with another product or the substitute remains more expensive when compared to corn oil, the decrease in demand for a unit increase in price is small. The impact on the revenues of sellers would also be small.