Food Oils and Fats: Chemistry and Technology - Course Notes

The NPTEL course on Food Oils and Fats: Chemistry and Technology delivered by Prof Hari Niwas Mishra of IIT Kharagpur is of 12-weeks with 60 lectures of 30 minutes each. It covers the following topics -

1. Course Overview and Introduction
2. Food Lipids - Nature & Occurrences
3. Edible Oils - Chemistry & Properties
4. Expelling of Oils from Plant Sources
5. Solvent Extraction of Edible Oils
6. Edible Oils Refining & Deodourization
7. Modifications of Oils and Fats
8. Recovery of Fats from Animal Sources
9. Commercial Cooking & Frying Oils
10. Speciality Oils and Fats Products
11. By-product Utilisation & Valorisation of Oil Processing Industry Waste 
12. QA/QC, Laws, Regulations and Policies

Suggested Readings:

• Bailey's Industrial Oil and Fat Products - Fereidoon Shahidi
• Edible Oils: Extraction, Processing and Applications - Smain Chemat
• Fats and Oils: Formulating and Processing for Application - Richard D. Obrien
• Food Chemistry - Srinivasan Damodaran, Kirk L. Parkin. Owen R. Fennema
• Food Oils and Fats: Technology, Utilisation and Nutrition - Harry Lawson
• Oils and Fats in the Food Industry - Frank D. Gunstone
• Vegetable Oils in Food Technology: Composition, Properties and Uses -Frank D. Gunstone
• Practical Handbook of Soybean Processing and Utilization - David R. Erickson
• Rice Bran and Rice Bran Oil: Chemistry. Processing and Utilisation - Ling Zhi Cheong, Xuebing Xu
• Specialty Oils and Fats in Food and Nutrition: Properties, Processing and Applications - Geoff Talbot

Interesting facts and insights about Oils and fats from the course -

The recommended dietary guidelines by WHO/FAO suggest that 15 to 30 percent of the total energy should come from fat, with less than 10 percent from saturated fat, 6 to 10 percent from polyunsaturated fatty acids (including five to eight percent from Omega-6 and one to two percent from Omega-3) and less than one percent from trans fat. We should consume less than 300 milligrams of cholesterol per day.

Oils and fats are extracted from seeds or recovered from other parts of plants and animals. They are a mixture of mixed triglycerides and may contain phospholipids, sterols, free fatty acids, antioxidants, etc.

Health benefits:

• Vitamin absorption - Vitamins such as vitamins A, D, E, and K are fat-soluble, & need to be consumed with dietary fats in order to be properly absorbed by the body.
• Source of essential fatty acids such as Omega-3 and Omega-6. which the body can not produce on its own. These fatty acids are important for brain health, immune function, and cardiovascular health.
• Heart health - Consuming moderate amounts of monounsaturated (MUFA) and polyunsaturated (PUFA) fats, such as those found in olive oil and fish, may help improve cholesterol levels and reduce the risk of heart disease.
• Anti-inflammatory effects - Olive and coconut oil contain compounds that have been shown to have anti-inflammatory effects in the body, which may help reduce the risk of chronic diseases such as arthritis and certain cancers.
• Skin health - Oils such as coconut and avocado oil, may help improve skin health and appearance due to their moisturizing and antioxidant properties.

1 gm of fat provides 9 calories.

Vegetable oils are naturally cholesterol

Around one-third of the total oil consumed in India is palm oil.

Imports are higher than total domestic production. India imports more than 70% of its edible oil requirements which makes it vulnerable to price fluctuations and supply disruptions in the global market.

India is the 4th largest oilseeds producer in the world.

New extraction methods such as cold-pressed and expeller-pressed are becoming more popular, which allow for the production of high-quality oils without the use of harsh chemicals.

Currently about half the people in the world rely on palm oil as part of their diets and it is the dominant oil used in food in Africa and Asia.

Oil palm produces about 35% of all vegetable oil on less than 10% of the land allocated to oil crops.

The productivity per hectare of palm oil is high. However, oil palm development has a significant negative impact on global biodiversity. The expansion of palm oil plantations often involves clearing natural forests and other habitats, which can lead to the loss of biodiversity and wildlife habitat.

Plant-based oils:

• Oilseeds - Sunflower, Soyabean, Sesame, Rapeseed, Cottonseed, Flax seed, Linseed, Canola, 
• Nuts - Almond, Walnut, Groundnut/Peanut, Cocoa butter
• Cereal oils - Rice bran, Corn, Wheat germ, Maize
• Fruit oils - Olive, Palm, Coconut
• Spice oils - Cinnamon (from bark)

Olive oil contains polyphenols, which are powerful antioxidants that can help reduce the risk of heart disease.

Safflower oil is a rich source of linoleic acid.

Flaxseed oil is a rich source of alpha-linolenic acid (ALA) which is an omega-3 fatty acid that can be converted to the more active forms of omega-3s, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Oilseeds are -

• Rich in polyunsaturated fatty acids (PUFA), including omega-3 and omega-6 fatty acids
• Anti-inflammatory
• Stable at high temperature
• Economical
• May contain harmful compounds (e.g. Erucic acid in rapeseed oil)

Cereal oils

• Have a high smoke point, which means they can be used for high-temperature cooking methods like frying and baking.
• Relatively long shelf life due to high antioxidant content. 
• Can be stored for longer periods of time without going rancid or spoiling.

Almond oil is an excellent source of unsaturated fatty acids and phytosterols. It contains more vitamin E as compared to other nut oils and features excellent

moisturizing properties.

Vegetable oils are usually produced from plant seeds, nuts or fruits (e.g., rapeseed, sunflower, olive, etc.), simply by pressing and/or solvent extraction.

Major components of Vegetable oils -

• Triglycerides (95-98%)
• Glycerolipids 
• Monoglycerides
• Diglycerides
• Phospholipids
• Non-glycerolipids including 
• Sterols
• Tocopherols/tocotrienols (Vitamin E)
• Free Fatty Acids (FFA) 
• Vitamins
• Triterpenoids - Squalene
• Carotenoids/Pigments
• Proteins & peptides
• Phenolic compounds - Extra virgin olive oil has high phenolic content
• Water

Common fatty acids present in Vegetable Oils -

• Saturated
• Lauric
• Myristic
• Palmitic
• Stearic
• Monounsaturated
• Oleic
• Petroselinic
• Erucic
• Polyunsaturated 
• Linoleic
• Linolenic (a)
• Linolenic (g)
• Polyunsatumted 
• Eleostearic
• Calendic
• Oxygenated
• Ricinoleic
• Vernolic