Abstract
There are a diversity and variability of oil producing plants and different extraction methods. These vegetable and essential oils are substances stored and released by plants from their fruits, leaves, flowers, bark and stem, being complete of plant origin that provides some benefits. In the plant these oils are also known as antioxidant substances, which have the function of natural protection. It is known that the extraction method has a strong influence on its quality and composition due to its variability and environmental conditions, besides possible adulteration. Oils that are rich in polyunsaturated fatty acids are the most relevant to the cosmetic industry but are most sensitive to oxidation. The oxidation of these oils generates what is known as rancidity, with the presence of smaller and undesirable molecules, thus reducing the quality of the oil beyond its nutritional value, making them harmful to human health. Stocking conditions, such as exposure to sunlight and heat, are major phenomena that accelerate the degradation of these oils. Infrared spectrometry with Fourier transform (FTIR) is a tool with potential to evaluate the degradation effect of vegetable oils. Infrared spectra of Almond (Prunus dulcis), Andiroba (Carapa guianensis aubl.), Copaíba (Copaifera langsdorffi) and Rosehip (Rosa aff. Rubiginosa) oils before and after exposure to sun light for 90 days were analyzed, with objective of evaluating the effect of the degradation on the composition of the oil, which were acquired in local commerce of the city Porto Velho. The spectra trends show the occurrence of oxidation, with the reduction of unsaturation, in addition to the fractionation of carbon chains and appearance of functional groups such as aldehyde and alcohol.
Highlights
Vegetable oils are natural substances and insoluble in water, obtained from oleaginous species, and according to Farias et al [1], consist of triacylglycerides, which are esters formed between glycerol and three fatty acids
The self-oxidation process of these vegetable oils can be started with the removal of an allylic hydrogen from the compound, that is, a fatty acid, under conditions favored by light and temperature, generating an allyl radical
The Fourier transform infrared spectrometry (FTIR) spectra for vegetable oils under oxidative conditions of exposure to sunlight, over of 90 days are shown in Figures 1-4, and their respective Tables 2-5, with information extracted from the FTIR spectra
Summary
Vegetable oils are natural substances and insoluble in water, obtained from oleaginous species, and according to Farias et al [1], consist of triacylglycerides, which are esters formed between glycerol and three fatty acids. In addition to having fatty acids and glycerides in their composition, vegetable oils are made up of some substances such as steroids, tocopherols, phenols, flavonoids, volatile compounds, vitamins, pigments, etc., as described by Herman and Esteves, apud Pereira [2]. Among the fatty acids that form the tri-esters of lipids in vegetable oils, unsaturated fatty acids stand out, as they have important functions in the human body. As described by Rampazzo [5], oils and fats are of relevant importance in the body, as caloric sources, of essential fatty acids, in addition to transporters of fat-soluble vitamins, nutrients and antioxidants. According to Rampazzo [5], unlike saturated and monounsaturated fatty acids that can be synthesized by the body and obtained in the diet, some polyunsaturated fatty acids, known as essential fatty acids, having as examples, the important omegas (ω-3 and ω-6), cannot be synthesized by the body, and must be obtained through the consumption of foods rich in the respective acids, observing that there are few sources rich in essential fatty acids, the most common being in the diet, the fish
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
