All over the world, people have started diversifying oilseed cultivation to better match modern day’s health, nutritional and taste requirements. Although oil is popularly derived from oilseeds like groundnut, soybean, sunflower, rapeseed mustered, castor, cotton seed, etc., various tree fruits (like coconut, palm, olive, etc.) are also reliable sources for oils; in fact, fruit sources provide higher yielding. Oil, derived from such vegetable sources, is called vegetable oil. However, every vegetable oil may not necessarily be suitable for human consumption and thus they are used industrially. Moreover, commercial value of certain edible oils is better for industrial usage, for example castor oil.
Apart from vegetable oil, there are many petroleum based oils which are non-edible. Such petroleum oils are extensively used for various industrial applications like fuels. Rapid depletion of petroleum oil reserve along with the steep increase in energy demand throughout the world paved the way for finding out alternative sources for wide industrial requirements. As a result of extensive researches, now-a-days it is possible to utilize certain vegetable oils as bio-diesel and others. However, large scale commercialization is still pending owing to its high cost and low rate of supply. Therefore, all vegetable and petroleum oils can be broadly classified into another two groups—edible oil and non-edible oil.
As the name suggests, edible oils are beneficial for human consumption and are popularly used for such purpose. They have high nutritional value and less industrial demand. Such oils also require less processing to make it safe and hygienic for health. Majority of vegetable oils come under edible oil; however not all. There are few vegetable oils and all petroleum oils which are not suitable for eating and have industrial demand. Such oils are grouped under the umbrella of non-edible oils. Even animal fats also come under this group. Various differences between edible oil and non-edible oil are given below in table format.
Table: Differences between edible oil and non-edible oil
| Edible Oil | Non-Edible Oil |
|---|---|
| These are based on vegetable sources (oilseed grains and plant fruits). | These can be vegetable oils, petroleum oils or animal fat. |
| Edible oils are mainly used for direct human consumption as food intake. | Non-edible oils have industrial usages such as fuel and biofuel, or in producing soap, detergent, paint, etc. |
| Edible oils contain various nutritional elements and thus are healthy and hygienic. | Non-edible oils may not necessarily be healthy and hygienic. |
| Extraction of edible oil usually does not require any chemical processing. | Different chemical processing are desired to make this oil suitable for a particular application. |
| These are more expansive due to tight requirement cleanliness and also limited supply. | They have comparatively lower price and are economic for industrial large scale applications. |
Sources: Edible oils are directly extracted from oilseed grains, nuts and tree fruits. Thus their sources are predominantly organic; for example seeds of groundnut, soybean, sunflower, rapeseed, linseed, safflower, peanut, etc. Oil extracted from tree fruits or seeds like palm oil, coconut oil, olive oil, etc. are also edible. All vegetable oils are not edible; some vegetable oils have low demand as food source. There are more than 50 crops whose oil is primarily used for industrial purposes, some popular examples are rubber, neem, tobacco, castor, drumstick, almond, avocado, tomato, bean, date, rice, milkweed, sal, salmon, kusum, jojoba, etc. Apart from these non-edible vegetable oils, petroleum based oils and animal fat are predominantly used for non-edible purposes. So non-edible oils consist of non-edible vegetable oils, petroleum oils, and animal fats and therefore, it can be organic or inorganic. However, there exist no clear boundary between culinary use and industrial use, so certain oils can be used for both purposes based on market demand and production.
Applications: Edible oils are consumed, directly or indirectly, as food ingredients. They are mainly used for cooking including sautéing, frying and baking. They can also be consumed directly (like flavouring) without any culinary processing; however, in limited amount. Non-edible oils are not used as food intake, rather they are utilized in various forms for several industrial applications. Few major consumers of such oils are transport industries, candle, soap, synthetic detergent, resin, ink, wax, dye, paint and varnish factories. Non-edible vegetable oils, which are also known as second generation feedstock, can be used for sustainable production of biodiesel and thus have emerged as promising substitute for rapidly depleting petroleum oil reserves. Apart from fuel, they can also be used for the production of lubricant, coolant, engine oil, grease, etc. Some of them also have pesticidal, medicinal and cosmetic usages.
Nutritional value: Edible oils must be rich in nutrition; ideally such oils should be digestible, rich in caloric value and free from unsaturated fat. Most edible oils are actually healthy fat and don’t contain any toxic component like lectin that can pose a risk on human health. Oils help absorbing fat soluble vitamins (A, D, E, and K) and also provide other benefits. Non-edible oils are either not safe for human consumption as food or not rich in nutrition.
Processing requirement: Usually edible oils do not require any chemical processing for its extraction from oilseeds, nuts or fruits. Cold or hot pressing are considered as sufficient for extraction. First pressed oil are of high quality in terms of nutrition and purity and the same has extra value towards culinary usage. However, animal fat must be processed in various physical and chemical methods before its consumption. Non-edible organic or inorganic oil usually requires several chemical treatments to make it suitable for specific purpose.
Oil cost: Edible oil extraction process must be hygienic with highest level of purity. Any deviation may cause altercation with toxic elements or bacterial infection that can make the oil unsafe for human consumption. Tight quality control requirement along with higher demands and limited production made edible oil costlier. Non-edible vegetable oil plants can be grown in marginal lands having low fertility. They can be grown in arid zones (regions with low rainfall) with minimum requirement of irrigation facility. Apart from oil, such plants also generate by-products that have sufficient commercial value. So non-edible vegetable oils are cheaper as compared to edible one. Other forms of non-edible oils are also cheaper but their resources are limited and are influenced by geo-political factors.
A through comparison among edible oil and non-edible oil is presented in this article. The author also suggests you to go through the following references for better understanding of the topic.
- Atabani et al. (2013); Non-edible vegetable oils: A critical evaluation of oil extraction, fatty acid compositions, biodiesel production, characteristics, engine performance and emissions production; Renewable and Sustainable Energy Reviews; Vol.18; pp. 211-245.
- Oilseeds: Properties, Processing, Products and Procedures by G. Nagaraj (2009, NIPA).
