Rancidity
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Rancidification pathways[edit]
Three pathways for rancidification are recognized.[3]
Hydrolytic rancidity[edit]
Hydrolytic rancidity occurs when water splits fatty acid chains away from the glycerol backbone in triglycerides (fats). The chemical term is ester hydrolysis. Usually this hydrolysis process goes unnoticed, since most fatty acids are odorless and tasteless. A particular problem arises with butter, which contains triglycerides with a high content of butyric acid derivatives and acetic acids.
Oxidative rancidity[edit]
Oxidative rancidity is associated with the degradation by oxygen in the air. Via a free radical process, the double bonds of an unsaturated fatty acid can undergo cleavage, releasing volatilealdehydes and ketones. This process can be suppressed by the exclusion of oxygen or by the addition of antioxidants. Oxidation primarily occurs with unsaturated fats.
Microbial rancidity[edit]
Microbial rancidity refers to a process in which microorganisms, such as bacteria, use their enzymes such as lipases to break down fat. This pathway can be prevented by sterilization.
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Reducing rancidification[edit]
The free radical pathway for the first phase of the oxidative rancidification of fats.
Antioxidants are often added to fat-containing foods to delay the onset or slow the development of rancidity due to oxidation. Natural antioxidants include polyphenols (for instance flavonoids), ascorbic acid (vitamin C) and tocopherols (vitamin E). Synthetic antioxidants include butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), TBHQ, propyl gallate and ethoxyquin. The natural antioxidants tend to be short-lived[citation needed], so synthetic antioxidants are used when a longer shelf-life is preferred. The effectiveness of water-soluble antioxidants is limited in preventing direct oxidation within fats, but is valuable in intercepting free
Rancidification pathways[edit]
Three pathways for rancidification are recognized.[3]
Hydrolytic rancidity[edit]
Hydrolytic rancidity occurs when water splits fatty acid chains away from the glycerol backbone in triglycerides (fats). The chemical term is ester hydrolysis. Usually this hydrolysis process goes unnoticed, since most fatty acids are odorless and tasteless. A particular problem arises with butter, which contains triglycerides with a high content of butyric acid derivatives and acetic acids.
Oxidative rancidity[edit]
Oxidative rancidity is associated with the degradation by oxygen in the air. Via a free radical process, the double bonds of an unsaturated fatty acid can undergo cleavage, releasing volatilealdehydes and ketones. This process can be suppressed by the exclusion of oxygen or by the addition of antioxidants. Oxidation primarily occurs with unsaturated fats.
Microbial rancidity[edit]
Microbial rancidity refers to a process in which microorganisms, such as bacteria, use their enzymes such as lipases to break down fat. This pathway can be prevented by sterilization.
-------------------------------------------------
Reducing rancidification[edit]
The free radical pathway for the first phase of the oxidative rancidification of fats.
Antioxidants are often added to fat-containing foods to delay the onset or slow the development of rancidity due to oxidation. Natural antioxidants include polyphenols (for instance flavonoids), ascorbic acid (vitamin C) and tocopherols (vitamin E). Synthetic antioxidants include butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), TBHQ, propyl gallate and ethoxyquin. The natural antioxidants tend to be short-lived[citation needed], so synthetic antioxidants are used when a longer shelf-life is preferred. The effectiveness of water-soluble antioxidants is limited in preventing direct oxidation within fats, but is valuable in intercepting free