Discuss the type of fat that a consumer would want to purchase to ...

[chandani]

Discuss the type of fat that a consumer would want to purchase to make a shortened cake and why. Include the crystallinity of the fat.
 
  What will be an ideal response?

Question 2

Distinguish between oxidative and hydrolytic rancidity.
 
  What will be an ideal response?

[brbarasa]

Answer to Question 1

The consumer would want to choose a hydrogenated shortening. The crystals in hydrogenated shortening are of the beta prime (') form. These are very fine and fairly stable. They produce a fine texture. The consumer would want to store the fat in a cool location. If hydrogenated shortening is stored at a warm temperature, the ' crystals will melt gradually and then recrystallize into the intermediate crystal form. These are coarser and give a grainy appearance to fat. They are not recommended for use. Also the consumer would not want to use lard. Lard contains beta () crystals and is often interesterified before being marketed. It would not cream well. Butter or margarine would be too soft to cream well.

Answer to Question 2

Both are forms of spoilage in fats. Oxidative rancidity occurs in polyunsaturated oils where oxygen adds at double bonds. This is a self-perpetuating reaction where free radicals, peroxides, and hydroperoxides are formed. Hydrolytic rancidity occurs in meat and dairy products where the triglyceride is lipolyzed to yield glycerol and free fatty acids. Both cause poor odor and taste.