Why Refining vegetable oil is crucial
With its high polyunsaturated fatty acid content, bland flavour, good storage stability and low viscosity, refined sunflower oil has emerged as one of the most popular cooking oils in India. In modern society, consumers cannot use crude oil directly without proper processing due to the unacceptable colour and odour. Quality and stability of vegetables oil products depend on seed quality, seed treatment prior to extraction, extraction method and processing conditions.
Crude sunflower oil is obtained from partially dehulled seeds by mechanical pressing followed by extraction and refining. Refining removes impurities some of which are naturally present in seeds, formed during harvesting or during extraction of crude oil.
What are the impurities?
Vegetable oil undergoes degradation almost immediately after the seed is crushed. The oil shows primary oxidation and may develop a darker color or higher free fatty acids and sometimes, unpleasant flavor.
- Gums, phosphatides and mucilaginous substances act as emulsifier increasing loss of oil. Oil decomposes at high temperature and leads to a darker color of the final refined oil.
- Free fatty acids increase foaming, reduce smoke point and diminish keeping properties of the oil.
- Compounds such as phosphatides, free fatty acids, odiferous volatiles, colorant, waxes and metal compounds in oil negatively affect taste, smell, appearance and storage stability of the refined oil.
Refined means impurities removed, better flavour and high nutrients
Efficient refining processes remove these impurities from the oil or reduce them to a level where their deleterious effects on oil stability are minimum and made suitable for human consumption while retaining desired components (tocopherols, phenols, sterols) and with the minimum losses of oil. These oil refining processes also yield a stable product with a bland or pleasant taste ideal for cooking requirements for high and low heat cooking.