Malodorants hydrolysis

Fatty acids are susceptible to oxidative attack and cleavage of the fatty acid chain. As oxidation proceeds, the shorter-chain fatty acids break off and produce progressively higher levels of malodorous material. This condition is known as rancidity. Another source of rancidity in fatty foods is the enzymatic hydrolysis of the fatty acid from the glycerol. The effect of this reaction on nutritional aspects of foods is poorly understood andhttie research has been done in the area. 

Reaction (3) represents the hydrolysis of HS ion and, in a sense, explains why aqueous solutions of alkali metal hydrogen sulfides are both basic and malodorous. 

Caution. Lithium diphenylarsenide and lithium diphenylphosphide are strong bases and very corrosive, and contact of them with the skin should be avoided. Hydrolysis of both compounds is vigorous and generates the malodorous and toxic secondary arsine or phosphine. Hence these experiments should be conducted in a fume hood. The products and the intermediates are also toxic and should be handled with due care. All manipulations should be done under nitrogen. 

Fats and oils become rancid on standing, i.e., they develop disagreeable odors and tastes. Two reactions are involved in this process—hydrolysis and oxidation. Hydrolysis is important as a source of rancid odors only for certain triacylglycerols that contain C4 and C, carboxylic acids. Butter is an example—its triacylglycerols contain about 3 to 4 percent butanoic acid and about 1 to 2 percent hexanoic acid. Hydrolysis due to bacteria from the air releases these volatile and malodorous acids. Air oxidation of the double bonds of unsaturated fatty acids released by bacterial hydrolysis also contributes to rancidity. Oxidation cleaves the double bond, with each carbon of the double bond being converted to a COOH group. 

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