If you have to grease a pan with shortening can just use vegetable spray?

No, you should not use vegetable spray instead of shortening to grease a pan. While both shortening and vegetable spray can be used to prevent food from sticking to a pan, they have different properties and may not be interchangeable in all cases.

Shortening is a solid fat made from vegetable oil that has been hydrogenated. It has a high melting point and is therefore solid at room temperature. Shortening is often used to grease baking pans because it can withstand the high temperatures of baking without burning or smoking. It also creates a barrier between the pan and the food, which helps to prevent sticking.

Vegetable spray, on the other hand, is a liquid oil that has been aerosolized. It is made from vegetable oil, but it does not contain any solid fats. Vegetable spray has a low melting point and is therefore liquid at room temperature. This means that it can burn or smoke at high temperatures, which makes it unsuitable for use in baking pans. Additionally, vegetable spray does not create as effective a barrier between the pan and the food as shortening, which can result in food sticking to the pan.

Therefore, it is not advisable to use vegetable spray instead of shortening to grease a pan. Shortening is the better choice for this purpose due to its high melting point and its ability to create a barrier between the pan and the food.