Improvement of oil quality through oil processing

Introduction:

Refining is done to improve oil quality and make it suitable for consumption. Crude oil has many impurities. i.e., fatty acids, gummy substances, sterols, hydrocarbon, tocopherols, and phosphatides This is the traditional method of refining used for a long. Its main objective is to saponify Free Fatty Acids by using an alkali which results in soap formation. Chemical refining can be applied to refine almost all crude oils. FFA and other undesirable materials like non-glycerides are also removed through this process thus enhancing the shelf stability of oils and improving their quality.

Free fatty acids are eliminated in a physical refining deodorizer without being neutralized in a preceding processing step, according to a concise explanation of physical refining. It also emphasizes the superior quality of physically refined vegetable oils. (Speight, 2020). Physical refining eliminates just a few contaminants from the oil (mainly phosphatides, also known as phospholipids or gums).

Chemical Refining is used for removing free fatty acid. This can be done by neutralizing with caustic soda. Further Settling and centrifugal separators are used to remove sodium soap resulting in soap stock formation. Further, these neutral oils are bleached and deodorized according to the requirements. Frying depends upon the quality of the oil. Selection of good and stable quality. In refining heating temperature of the oil is 107 to 188 Fahrenheit. Count on us to guarantee that your edible oils have the best flavor, fragrance, stability, appearance, and nutritional value while also increasing product quality, safety, and yield.

Chemical Refining:

Introduction:

This is the traditional method of refining used for a long. Its main objective is to saponify Free Fatty Acids by using an alkali which results in soap formation. Chemical refining can be applied to refine almost all crude oils. FFA and other undesirable materials like non-glycerides are also removed through this process thus enhancing the shelf stability of oils and improving their quality.

Refining is done to improve oil quality and make it suitable for consumption. Crude oil has many impurities. i.e., fatty acids, gummy substances, sterols, hydrocarbon, tocopherols, and phosphatides. Chemical Refining is used for removing free fatty acid. This can be done by neutralizing with caustic soda. Further Settling and centrifugal separators are used to remove sodium soap resulting in soap stock formation. Further, these neutral oils are bleached and deodorized according to the requirements. Frying depends upon the quality of the oil. Selection of good and stable quality. In refining heating temperature of the oil is 107 to 188 Fahrenheit.

·       These impurities mainly consist of:

• ·       Oxidized products
• ·       Phospholipids (gums)
• ·       Color pigments (gossypol) in cottonseed
• ·       Metal ions (iron, copper)

Chemical Refining Steps:

• ·       Degumming
• ·       Neutralization
• ·       Bleaching
• ·       Winterization
• ·       Deodorization

Degumming (Optional):

This step can be done both in physical and chemical degumming. But optional in chemical refining as other chemicals are already used that can effectively refine the oil thus this step is optional. But degumming is necessary for physical degumming.  

Neutralization:

Neutralization can reduce many impurities and thus improve final oil quality. i.e. Free Fatty acids, phosphatides, carbohydrates, traces of metals, residual proteins, oxidation products, and other pigments. In this process, oil is treated with an alkali usually a caustic soda that converts FFAs into Soap stock and neutralizes them. More soap stock means less oil yield. Impurities separate and come on the surface then are removed. Then washing of oil to remove the soap contents. The sludge that is obtained in the bottom consists of solid material mixed with water. This stock is sold to soap manufacturers for soap formation.

This can be further used for both food and feed purpose. Hydrated gums for food and food. Soap Stock in inedible industries. This refining is compulsory in oils having more pigments and high acidity contents. Further, this will improve the oil color by reacting with the other polar compounds present in the oil. i.e., Gossypol, sesamol etc. Gossypol in cottonseed and sesamol in sesame seeds respectively. Free Fatty Acids' contents depend on the concentration of caustic soda. The more FFAs the more the soda is used to neutralize it and purify the oil.

Miscella refining:

This method is used to neutralize the cottonseed oil. This technique will effectively remove the gossypol contents in oil. Using a solvent and oil refining process in miscella refining. Miscella is pre-concentrated will adding press oil or in hexane evaporation step. This temperature is set below the boiling point of n-hexane and a solvent like caustic soda is added to it. Mixing is done in a reaction mixture. Soap Stock is further separated from it. Because of the explosion risks of hexane, this is performed in explosion-proof centrifuges.

Overall By-products of chemical refining:

These are two major by-products that are produced from chemical refining i.e. soap stock and hydrated gums.

Soap stock:

This is a source of fatty acid. Traditionally this by-product was discarded but now many soap manufacturing and other inedible industries are utilizing it. Acid oil is produced from soap stock consisting of a fatty portion of soap stock and with 1 to 2% of the moisture contents. The impurities that are removed in the neutralization process are further used in acid oil making for acidulation. This is used in feed as a high-energy nutrient. Proving 9 calories per gram than the protein of 4 calories per grams. The process should be performed as soon as possible otherwise will separate the oil and water phases and have corrosive nature.

Lecithin:

This is called hydrated gums or lecithin obtained from water degumming.  Commercially it is widely used in industries for emulsifiers and other purposes. This is made from a mixture of phospholipids.  It's a good extraction souse in soybean oil. Because it has phospholipids in high amounts. Stream and 2% water is added and centrifuged it in order to make the lecithin in hydrated form. The hydrated gums are dried to moisture below 1%. This is done to reduce damage of the oil color. Cooling is done. Then further ingredients are added according to requirements.  It is usually treated with a chemical called H2O before and after drying to remove the color pigments. Further, it has different uses.