It sounds like a creative way to solidify vegetable oil at room temperature without hydrogenation. I don't think the process itself poses any health risks, but you'd still be consuming palm oil, which contains loads of saturated fat.
A shortening is a cooking fat that is solid or semisolid at room temperature. These include butter, lard, hydrogenated margarines (transfats), and hydrogenated vegetable oils (transfats).
The only health risk to using "old" shortening, is the health risks you assume by using shortening at all. Shortening (usually vegetable shortening [hydrogenated oils/ transfats], lard or clarified butter) is usually processed so that it has a very long shelf life[years] and is no different at the end of the shelflife than at the beginning. Shortening lasts a very long time, as long as it doesn't get contaminated.
No
It depends on the recipe. Shortening becomes solid at room temperature while vegetable oil does not. So vegetable oil may be substituted for melted shortening only in recipes that do not depend on shortening becoming solid for texture when cooled.
No.
Yes
Yes, melted shortening can replace vegetable oil in zucchini bread, although shortening is not a healthy choice.
Shortening, such as Crisco, is made from vegetable oil.
Shortening is made from partially-hydrogenated or hydrogenated vegetable oils.
Vegetable oil is unsaturated. Butter is saturated. Im not sure about shortening.
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Yes