A: Six Enemies of Frying Oil:

Air: Air bubbles that are pumped into oil during filtering causes oxidation and impacts fried food flavor.

Heat: If the fryer's temperature is too high, the oil oxidation will happen rapidly.

Soap: Grease cleaning can produce an alkaline flavor and causes oil to darken.

Carbon: Bread crumbs and small pieces of food will carbonize and cause chemical reactions, resulting in oil breakdown.

Water: Water from food, steam, and residual water after cleaning will cause hydrolysis, which will cause oil to darken and smoke.

Salt: Salt exists in marinades and breading breaks will cause solubilization, Which triggers a chemical reaction that begins the breakdown and reduces the service life of the oil.

The main reactions during the use of frying oil include starch gelatinization, Maillard reaction, protein denaturation, caramelization reaction, etc. Unsaturated fatty acids are oxidized to peroxides and hydroperoxides, which continue to decompose into fatty acids, aldehydes, ketones, and other small molecules, and are finally oxidized to acids. As a result, the oil deteriorates, increasing the acid value, peroxide value, and viscosity of the frying oil, darkening the color of the oil, increasing the trans fatty acids, aggravating the foam of the oil, and affecting the smell and taste.