All About Oil
WHAT IS A SMOKING POINT OF OIL?
The smoking point as the name suggest can very simply be termed, is the temperature at which the oil begins to smoke. Every cooking fat has a smoke point, this defines the temperature at which the oil stops shimmering and breaks down the fat. This smoke point varies with regards to the components, the level of refinement and the nature of the oil. The higher the level of refinement, the higher is the smoking point of oil. The process of heating the oil produces more fatty acids which is why it is always been advised not to use the same oil for deep frying more the twice as the smoking point gets reduced with every use.
WHY IS A HIGH SMOKING POINT OIL IS PREFERRED FOR DEEP FRYING?
Deep fried food always tastes the best, but choosing the right oil for deep frying preserves the flavour of the food and it all starts with proper deep frying with a high smoke point oil. What does proper deep frying mean? For example lets us take that you need to deep fry a food at 350-375 degree Fahrenheit. What happens when you drop your food in the oil at this temperature. The food gets submerged in the oil and immediately seals the surface so that the fat cannot get inside the food, thereby the food’s natural moisture is preserved and also the food gets cooked from inside out. So this can happen only when the oil used for deep frying has a high smoke point. If the oil’s smoking point is low, it might allow the oil to seep inside the food, and it also makes the frying process longer. So choosing the oil with high smoke point can even make your food healthy, as it does not make your food greasy. Peanut oil or groundnut oil infact can be termed as the best oil for deep frying as it does not absorb the natural flavour of food cooked in oil and thereby retains the uniqueness of each and every food deep fried in groundnut oil.
WHAT IS COLD PRESSED OIL?
Cold pressed oils are produced naturally at room temperature not exceeding 120 degree Fahrenheit without any preconditioning of the oil seeds. The oilseeds are not precooked or roasted and does not involve in any solvent extraction or refining process which can take off the natural antioxidants, vitamins and flavour from the oil. The heat generated during the cold pressing process is mostly because of the friction and it does not damage the natural properties of the oil. Since the oil is generated naturally at room temperature the acid value is also low, so there is no need to refine the oil produced. The cold pressed oils are distinctive with all the natural flavours sealed up, retaining the original taste. It should also be noted that the cold pressed oil does not foam during the process of deep frying and it also has a nice colour and aroma. Cold pressed oils are cholesterol free and they do not carry any harmful solvent residues. Most importantly cold pressed oils does not undergo any refining or deodorizing process. They contain the natural antioxidants, with all the natural flavour and odour retained at the end process.
WHY IS CHEKKU/GHANI OIL EXPENSIVE?
Traditionally Chekku/Ghani involves bullock turning the wooden/stone crusher to extract oil. There are different types of Ghanis available all over India. And in southern India, these stone Ghani/chekku usually with a capacity of 35 to 40 kg requires two bullocks and two operators to complete one cycle of oil extraction process. It should be noted that oil extracted through Ghani yields almost 5 percent less oil than the modern extraction process, because of the insufficient pressure. In recent times the oil extracted through chekku has gained its popularity and demand back but still people struggle with a question of chekku oil being expensive compared to the refined oils in the market. Looking back , in the beginning of the twentieth century there were almost 5 lakh Ghanis involved in the process of oil extraction all over India, which yielded around 8 lakh tons of oil through Ghanis. But now the oil extracted through the traditional Ghani process is less than 4 percent, the very reason being the low production capacity of Ghani. When a traditional Ghani has a capacity of 50 kg per day, the modern method can produce twice more than that, which ultimately makes the running cost high and the yield is much less when compared with the modern industrial solvent extraction method. The bullocks used in the Ghani has to be trained and fed properly for effective production. All these factors added on with the benefits of natural unrefined healthy oil from the chekku in the current scenario makes it a bit more expensive.
HOW IS RICE BRAN OIL EXTRACTED?
Rice Bran Oil is extracted from the inner husk, as well as the germ of rice. The initial processing occurs at the rice mill. As soon as the bran and germ are removed from the kernel, stabilization process starts up in the equipment. A combination of heat, water and pressure are used to deactivate the enzymes that cause rancidity in the rice bran. The stabilized rice bran is dried and packed for further treatment. In the next stage, the stabilized rice bran is further treated with water and enzymes. This method helps in separating the insoluble fiber fraction and aqueous dispersible fraction. The fully stabilized rice bran is sent to the extraction area where the oil is extracted, which in general yields two products, a high quality crude rice bran oil and defatted rice bran. Crude rice bran oil is further processed by refining, which removes the majority of free fatty acids and provides oil with minimal processing. However for edible use, this refined oil is sent forward to an absorptive vacuum bleaching step, which removes natural pigments and impurities. Edible oil bleaching typically leaves minor flavor and odor compounds that must be removed by steam distillation before packaging.
HOW IS OIL REFINED?
Refining is carried out to meet customers demand like flavor, odour, clear appearance, light colour, stability to oxidation and suitability for frying. There are two methods followed in the process of refining. One is alkaline refining and the other one physical refining. Alkaline refining starts with the degumming process where the hydrated phosphatides can be separated. There are two types of gums present, hydratable and non-hydratable. Hydratable gums are removed during degumming steps. The next step is neutralization process. Any free fatty acids, phospholipids, waxes in the extracted oil promote fat oxidation and lead to undesirable colors and oders in the final products. These impurities are removed by treating the oil with caustic soda (sodium hydroxide) or soda ash (sodium carbonate). After neutralization the refined oils are lighter in colour, less viscous, and more susceptible to oxidation. The next process is bleaching, it is the removal of off colored materials in the oil. The heated oil is treated with various bleaching agents like fuller’s earth, activated carbon, or activated clays. Many components, including chlorophyll and carotenoid pigments, are absorbed by this process and removed by filtration. The final step is the deodorization. Volatile components like aldehydes and ketones are present in small quantities but their presence imparts strong, sometimes objectionable odour to the oil. These substances are volatile in nature and removed by deodorisation step. In physical refining, the fatty acids are removed by a steam distillation process similar to deodorization. The low volatility of fatty acids requires higher temperatures in physical refining than those required for only deodorization
IS GHEE HEALTHY?
Ghee has enormous health benefits and its very good for both mind and spirit. Ghee is a clarified butter, which means that it is butter that has been simmered into a concentrate and the residue has been removed. Ghee can last for months, or even years, without refrigeration. Ghee has a high smoke point which means it doesn’t break down into free radicals like many other oil and its ideal for cooking and deep frying. The best part is ghee doesn’t spoil easily and has a longer shelf life. Ghee is rich in oil soluble vitamins like vitamins A and E. Ghee is rich in butyric acid, a short chain fatty acid that nourishes the cells of the intestine. This butyric acid is rich in monounsaturated fatty acid which can reduce inflammatory conditions and aids in digestion. Ghee stimulates the secretion of gastric acid, thus aiding in the digestive process. Omega-3s are healthy forms of fat that can be found in ghee, in addition to other fatty acids like conjugated linoleic acid and butyric acid, both of which have positive health benefits in the body. The power of vitamin A present in ghee, provides a powerful anti-cancer substance that could help to reduce oxidative stress throughout the body. The significant levels of vitamin A in ghee make it ideal for protecting eye health. Carotenoids are antioxidants that specialize in neutralizing the free radicals, thereby preventing macular degeneration and the development of cataracts.
WHAT IS SOLVENT EXTRACTION OF OIL?
Solvent extraction of vegetable oils, which recovers more oil than the expeller method, is found to be economically attractive where large quantities of seed can be processed (at least 200 tons per day for continuous-feed process). There are solvent extraction plants with capacities of up to 4,000 tons per day. Solvent extraction is a basically a chemical oil extraction method to process oil out from vegetables, oilseeds and nuts by solvent, and Hexane is the most preferred choice. Industrial oil processing for the edible oil generally involves the solvent extraction step which may or may not be preceded by pressing. Such solvent based extraction processes can achieve yield of 95% when compared to 60 to 70% oil yield by mechanical expeller pressing method. It is relatively efficient and reliable, and this is one reason why solvent extraction is the primary means of separating large tonnages of oil from protein meal. The solvent extraction method recovers almost all the oils and leaves behind only 0.5% to 0.7% residual oil in the raw material. In the case of mechanical pressing the residual oil left in the oil cake may be from 6%to 10%.
WHAT IS HYDROGENATED FAT / TRANS-FAT?
Hydrogenated fat is generally where unsaturated fat is converted into saturated fat by infusing hydrogen into it. To take a deeper look, Hydrogenated oil, or trans-fat, is made by bubbling hydrogen through oil at a very high temperature. This turns the liquid oil into solid fat, creating chemical bonds which have similar structure to plastic. These hydrogenated fats are economically cheaper and have a longer shelf life when compared to natural saturated fats. Though these hydrogenated fats claim themselves to be cholesterol free, a closer look at them contains plenty of artery clogging saturated fat. Hydrogenated fats contain trans fatty acids which are bad for the arteries and raise the cholesterol levels in the blood. If you look up at the ingredients list in cookies, biscuits and other processed food products, you would find a very harmless-looking ingredient, hydrogenated oil or partially hydrogenated oil. Hydrogenated oil, also called trans-fat or vanaspati or dalda (the monopoly the company maintained), is added to food primarily because they have a long shelf life and don’t melt easily. Vanaspati ghee as we proudly use, isn’t ghee at all. No hydrogenated fat can be healthy at any point. Trans-fats do not have any nutritional value, and are worse than saturated oils and is a toxic fat.
WHAT ARE THE TYPES OF TRANS FATS?
There are two broad types of trans fats found in foods: naturally-occurring and artificial trans fats. Naturally-occurring trans fats are produced in the gut of some animals and foods made from these animals (e.g., milk and meat products) may contain small quantities of these fats. Artificial trans fats (or trans fatty acids) are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid. The primary dietary source for trans fats in processed food is “partially hydrogenated oils.” Look for them on the ingredient list on food packages. Trans fats are not safe for human consumption as found out by several scientific studies.
WHY DO FAST FOODS CHAINS, FOOD INDUSTRY AND HOTELS USE TRANS FATS?
Trans fats are easy to use, inexpensive to produce and last a long time. Trans fats give foods a desirable taste and texture. Many restaurants and fast-food outlets use trans fats to deep-fry foods because oils with trans fats can be used many times in commercial fryers. Several countries have reduced or restricted the use of trans fats in food service establishments.
HOW DO TRANS FATS AFFECT MY HEALTH?
Trans fats raise your bad (LDL) cholesterol levels and lower your good (HDL) cholesterol levels. Eating trans fats increases your risk of developing heart disease and stroke. It’s also associated with a higher risk of developing type 2 diabetes.
WHY DID TRANS FATS BECOME SO POPULAR IF THEY HAVE SUCH BAD HEALTH EFFECTS?
Before 1990, very little was known about how trans fat can harm your health. In the 1990s, research began identifying the adverse health effects of trans fats. Based on these findings, there is now awareness on ill effects of trans fats.
WHICH FOODS CONTAIN TRANS FATS?
Trans fats can be found in many foods – including fried foods like Vada, chips, baked goods including cakes, biscuits, frozen pizza, cookies, biriyani, dosa etc., You can determine the amount of trans fats in a particular packaged food by looking at the Nutrition Facts panel. However, products can be listed as “0 grams of trans fats” if they contain 0 grams to less than 0.5 grams of trans fat per serving. You can also spot trans fats by reading ingredient lists and looking for the ingredients referred to as “partially hydrogenated oils.”
HOW CAN I CONTROL FAT CONSUMPTION?
Here are some ways to achieve that
- Eat a dietary pattern that emphasizes fruits, vegetables, whole grains, low-fat dairy products, poultry, fish and nuts. Also limit red meat and sugary foods and beverages.
- Use naturally occurring, unhydrogenated vegetable oils such as sesame, groundnut, safflower, sunflower or olive oil most often.
- Look for processed foods made with unhydrogenated oil rather than partially hydrogenated or hydrogenated vegetable oils or saturated fat.
- Avoid fried foods and food from fast food chain stores
- Limit commercially fried foods and baked goods made with shortening or partially hydrogenated vegetable oils. Not only are these foods very high in fat, but that fat is also likely to be trans fat.