Physicochemical properties of sesame oil

Sesame oil is soluble in alcohol and can be dissolved in ether, chloroform, petroleum benzene, but sesame oil is not soluble in water. After sesame oil was purified and met the quality standards of trade, sesame oil showed light yellow color, is odorless, has a savory taste and showed no symptoms of cloud at a temperature of 0 degree Celcius.
Sesame oil is used for cooking oil and for various industrial purposes. Sesame oil contains antioxidants (sesamin, and sesamolin) so sesame oil can be stored more than one year without being deteriorated (rancid). Potato chips fried in sesame oil could be stored up to three months, while potato chips fried in corn oil could only stored up to three weeks. Sesame oil contains a low saturated fatty acid, so that sesame oil provide many benefits both on health and the potential to maintain fitness.

Sesame oil contains oleic acid 35.50 to 37.5%, linoleic acid 35-50%, less than 1% linolenic acid and saturated fatty acids palmitic 11.07%. Basically, sesame oil contains high unsaponifiable matters in the form of sterols, but levels of non-oil materials is relatively low. The typical character of sesame oil is contain approximately 0.3 to 0.5% sesamoline and also contain sesamin about 0.5 to 0.1%. Sesamol in sesame oil produced from the hydrolysis of sesamoline and is an antioxidant. Phosphatides compounds present in small amount of about 0.1 percent in sesame oil, whereas the amount of tocopherol in sesame oil was less than 0.06%.
High-grade crude sesame oil can be used as a salad oil without winterization (winterization) process. Sesame oil is used extensively in the pharmaceutical industry, as in the manufacture of ammonia liniment because the physical properties of sesame oil are not easily separated . Sesame oil is synergistic with phrethrum. These were the unique characteristics of sesame oil. Sesame oil has a positive optical rotation value.
Physicochemical properties of sesame oil can be summarized as follows. Density of sesame oil at a temperature of 25 Celcius degree is 0.916 to 0.921. Refractive index of sesame oil at a temperature of 25 Celcius degree is 1.4763. Iodine value of sesame oil is 103-112. Saponification value of sesame oil is 188-193. Reichert-meiss value of sesame oil is 1.2. Hehner value of sesame oil is 95.6 to 95.9. Freezing point of sesame oil is 21 – 24 Celcius degree. Melting point of sesame oil is 21 to 31.5 Celcius degree.

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Sesame oil processing

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Sesame oil processing

Sesame plants are included in the Sesamum genus. Number of species of this genus is quite a lot, but only 18 species had been identified among others. They are Sesamum alatum, Sesamum angolense, Sesamum angustifolium, Sesamum indicum, Sesamum laciniatun, Sesamum latifolium, Sesamum occidentale, Sesamum protatum, and Sesamum radiatum. Many species cultivated in Indonesia are the Sesamum indicum.
Sesame varieties is very diverse in the world. Sesame varieties are generally divided into two types, the long-lived one and usually with a fork stem, and the type of short stem with no fork. There are two kinds of sesame known in the international market, which is black and white.

Characteristics of sesame in Indonesia are generally long-lived, i.e. 120-140 days, ramose dense, and producing low quantity yield, aproximately 350 kg / ha. Sesame seeds is the material bearing vegetable oil with low saturated fatty acid content that can be consumed directly, in the form of flour or oil. In addition, sesame seeds needed for the raw material of industries such as pharmaceuticals, cosmetics, and pesticides industry. Sesame oil, used traditionally to prevent some diseases. Due to the roles of sesame seed and oil, sesame seed demand will increase in the future. Consumption of sesame oil is mainly in Japan, EU, Korea, the United States and Egypt. All of those countries are developed countries.
Sesame seed contains 50-53% vegetable oil, 20% protein, 7-8% rough fiber, 15% residue-free nitrogen, and 4.5-6.5% ash. Sesame oil is rich in unsaturated fatty acid, especially oleat acid (C18: 1) and linoleat acid (C18:2, Omega-6), and 8-10% saturated fatty acid. Sesame oil is also rich in Vitamin E. Sesame cake, produced after the oil extracted is used as a source of protein in cattle feed in Indonesia.
Sesame cake as a side product of oil extraction can also be processed to be cabuk. Cabuk is an Indonesian traditional food produced from fermentation of sesame cake. Cabuk is usually processed with garlic, onion, chili, tomatoes, and salt, into a delicious side dish. Cabuk contains protein aproximately 36-39.8%. Cabuk also can be processed to be a sauce, just like soya sauce. Firstly, cabuk is saved in a closed container for a month to allow optimum fermentation. Then, fermentation product is boiled until viscous, filtered, and flavored to be a delicious sesame sauce.

Sesame oil production
a. Cold Press
Cold press oil is produced at temperature of 450C or less. Cooling during extraction is necessary to improve the quality of oil. Virgin sesame oil is produced naturally, without chemicals, and additional material, and also by minimizing heat treatment during the process. Sesame oil with best quality obtained by using cold press, and then filtering. Virgin sesame oil produced from cold press contains higher natural antioxidant compound, such as tocopherol and carotene, than toasted sesame oil.
b. Toasted
In order to produce more delicious flavor in sesame oil, processors usually toast sesame seeds at temperature of 60-800C (5-15 minutes) before press it to extract its oil. High temperatures increase the yield, but it cause a decrease in oil taste, slightly bitter. Controlling toasting is important since excessive time of toasting will burnt sesame seeds so that the oil will lost their pores to come out from sesame seed. Then, sesame seed is ground by using sharp knive in a grinder machine, to facilitate the oil to be extracted by mechanical press. In this mechanical press, sesame oil will be separated from sesame cake and pass through filter pores . To produce 1 liter of oil requires 3 kg of sesame seeds. Finally, sesame oil is clarified in centrifuge machine.
c. Hot press
Hot press oil cheaper. In this method, oil yield will increase along with increasing temperature of process. Sesame cake produced from first mechanical press can be processed again to produce more oil at a high temperature (1000C). Crushing sesame seed into small particles also increase the yield. The smell of hot-pressed sesame oil is delicious.

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