Refining Vegetable Oils: Chemical and Physical Refining

Abstract

This review presents recent technologies involved in vegetable oil refining as well as quality attributes of crude oils obtained by mechanical and solvent extraction. Usually, apart from virgin oils, crude oils cannot be consumed directly or incorporated into various food applications without technological treatments (refining). Indeed, crude oils like soybean, rapeseed, palm, corn, and sunflower oils must be purified or refined before consumption. The objective of such treatments (chemical and physical refining) is to get a better quality, a more acceptable aspect (limpidity), a lighter odor and color, longer stability, and good safety through the elimination of pollutants while minimizing oil loss during processing. However, the problem is that refining removes some essential nutrients and often generates other undesirable compounds such as 3-MCPD-esters and trans-fatty acids. These compounds directly influence the safety level of refined oil. Advantages and drawbacks of both chemical and physical refining were discussed in the light of recent literature. Physical refining has several advantages over chemical one.

Proximate Composition, Physicochemical, and Lipids Profiling and Elemental Profiling of Rapeseed (Brassica napus L.) and Sunflower (Helianthus annuus L.) Grown in Morocco

“…Vegetable oils and seeds are composed of a complex mixture of other compounds, which provided vital roles in the comfort of human life in various aspects [ 5 ], especially as sources of bioactive compounds such as natural antioxidants, vitamins, flavonoids, minerals, dietary fiber, and carbohydrates [ 6 , 7 ]. When consumed in appropriate amounts, they can reduce the risk of cancer development, as they are associated with a wide range of health benefits, such as antimutagenic effect, anti-inflammatory properties, reduction of low-density lipoprotein synthesis, and antioxidant properties [ 6 ].…”

Mineral oil hydrocarbons in minimally processed nutraceutical oils

“…At a basic level, some oils are not subjected to further processing steps after the "first press" and, thus, the resulting product is dubbed "minimally processed". On the other hand, expressed oils could be subjected to different refining process steps including degumming, neutralization, bleaching, dewaxing, winterization and steam deodorization, resulting in a highly refined finished product (Gharby, 2022). Fish oils are commonly refined through molecular distillation, a process involving heating oils at temperatures between 130 o C to 150 o C in a column under a high vacuum (Rossi et al, 2012), leading to the purification and concentration of target distillation products such as omega-3 fatty acids.…”

An Overview on the Use of Extracts from Medicinal and Aromatic Plants to Improve Nutritional Value and Oxidative Stability of Vegetable Oils

“…VOs and fats are important constituents of human consumption and are essential components of our daily diet [ 30 ]. They are classified as vegetable or animal oils and fats depending on their source.…”