Lipids and Fixed Oils
Start with the big picture
Fixed oils consist mainly of glycerol esterified with long-chain fatty acids and are saponifiable, unlike volatile essential oils. Their extraction and refining affect composition and quality, while the degree of unsaturation helps classify oils as drying, semidrying, or nondrying. Pharmaceutical applications include nutrient use and lipophilic drug delivery; examples such as castor, olive, and linseed oils illustrate differing properties and uses. Stability is influenced by hydrolytic and oxidative rancidity, and can be supported by antioxidants and suitable storage. Quality assessment draws on analytical constants—including acid, saponification, iodine, and peroxide values—along with identity tests and evaluation of unsaponifiable matter. Industrial modification can produce soaps or more solid fats.
What you'll learn
- Describe the chemical structure and defining properties of fixed oils.
- Distinguish fixed oils from volatile essential oils.
- Relate unsaturation and iodine value to oil classification and drying behavior.
- Compare major causes of rancidity and approaches to maintaining stability.
- Identify analytical constants and tests used in fixed-oil quality assessment.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
