Deodorization coconut oil

Deodorization is the last step in chemical refining. Volatile odoriferous substances, including low-molecular-weight fatty acids, are removed by stripping with steam under reduced pressure. The final product is generically called RBD (refined, bleached, and deodorized) coconut oil. 

The deodorized coconut oil flows down to the drop tank and holding chamber of the distilling column. Residence time in the deodorizer ranges from 1.5 h to 2 h. The oil from the column is withdrawn by a hermetically sealed and heat-resistant pump and conveyed to the economizer, which preheats the incoming deodorizer feedstock. The oil is cooled down to 50°C, at which temperature citric acid is added. Citric acid enhances the stability of oil by immobilizing iron and copper, which are pro-oxidants. (Note The deodorization step is omitted in the production of Cochin oil.)... 

Raw coconut oil (or virgin coconut oil) is colorless at or above 30°C and it is white when in its solid form, being an unctuous mass. Coconut oil melts at 25°Cand becomes solid below this temperature. The typical smell of coconut oil is that of coconuts (if not refined, bleached and deodorized). Coconut oil is insoluble in water at room temperature (APCC 2006 Gunstone 2011). 

RBD refers refined, bleached and deodorized coconut oil. The process for coconut oil obtaining consists in raw material preparation, extraction of oil and purification. Extracted crude oil is treated with alkali to remove free fatty acids. In the subsequent stage oil is treated with steam under vacuum to remove odors and flavors. In the last stage oil is filtered through carbon to decolorize yellow or dark colors. RBD coconut oil is edible oil and can be used in food and cosmetic applications. 

In one study (Dayrit et al., 2008), phosphorus-31 nuclear magnetic resonance spectroscopy ( P NMR) was used to differentiate virgin coconut oil from refined, bleached, deodorized coconut oil. MGs, DGs, sterols and FFAs in virgin coconut oil and refined coconut oil were converted into dioxaphospholane derivatives and analyzed by NMR. 

P NMR is a useful method for the analysis of constituents in coconut oil and gives a valuable way of distinguishing virgin coconut oil from refined, bleached, deodorized coconut oil. 

Villarino, B. J., Dy L. M., Lizada M. C. C., (2007). Descriptive Sensory Evaluation of Virgin Coeonut Oil and Refined, Bleached and Deodorized Coconut Oil. LWT Food Science and Technology 40, 193-199. 

Coconut Oil (Unhydrogenated) occurs as a viscous, white to light yellow-tan liquid. It is obtained from the kernel of the fruit of the coconut palm Cocos nucifera (Fam. Palmae). The crude oil obtained by mechanically pressing dried coconut meat (copra) is refined, bleached, and deodorized to substantially remove free fatty acids, phospholipids, color, odor and flavor components, and other non-oil materials. Compared with many natural fats, Coconut Oil (Unhydrogenated) has an abrupt melting range, changing from a rather firm, plastic solid at about 21° or below to a liquid at about 21°. 

The two main classes of soaps are toilet soap and industrial soap. Toilet soap is usually made from mixtures of tallow and coconut in the ratios 80-90 10-20. The bar soap includes regular and super fatted toilet soaps, deodorant and antimicrobial soaps, floating soaps, and hard water soaps. The super fatted soaps are also made from a mixture of tallow and coconut oil in ratios 50-60 40-50. All soaps practically contain 10 to 30 percent water and also contain perfume that serves to... 

A lower grade product called Cochin oil is coconut oil that is chemically refined and bleached but not deodorized. 

More than 90% of the fatty acids of coconut oU are saturated. This accounts for its low iodine value ranging from 7 to 12. The saturated character of the oil imparts a strong resistance to oxidative rancidity. Assessment of the oil by active oxygen method (AOM) yielded results between 30 h and 250 h (24). Although oxidative stability is reduced in RBD oils, due to losses in the natural antioxidants of crude coconut oils, the addition of citric acid at the end of deodorization as the oil is cooled to 100°C was effective in regaining considerable oxidative stability in the oil (25). 

Approximately 0.5% of crude coconut oil is not saponified by caustic treatment. The unsaponifiable matter consists mainly of tocopherols, sterols, squalene, color pigments, and carbohydrates. The odor and taste of coconut oil is largely due to 5- and y-lactones, which are present in trace quantities (24). Among the unsaponifi-ables, tocopherol contributes to the oxidative stability of crude coconut oil. A typical sample of crude coconut oil contained 55 ppm total tocopherols of which 40.7 ppm is cx-tocopherol (25). Most of the unsaponifiables are removed in the process of refining, bleaching, and deodorizing of crude coconut oil. 

From the milling of copra for the extraction of crude coconut oil through the refining steps and final storage in tanks, the oil is in continuous contact with iron and possibly copper-containing alloys, both of which are prooxidants. The addition of citric acid (25) or any other appropriate antioxidant in the last stages of deodor-ization of RED oils (see discussion) affords protection to the oil from oxidative rancidity. Crude coconut oil has natural and protective antioxidants. 

Palm oil and coconut oil are refined by the physical refining method. The crude oil is bleached with acid-activated clay and citric acid at elevated temperamres under vacuum. The objective is to remove phosphorus (phospholipids), trace metals, oil decomposition products, and some of the color bodies from the crude oil. The volatile impurities in the bleached oil are then removed via steam distillation under very low absolute pressure and high temperature in a deodorizer. 

Deodorizer distillate flow in physical refining can be 5% or more of the oil flow to the deodorizer, depending on the initial FFA content of the oil. Consequently, the theoretical concentration factor of the volatile contaminants in the deodorizer distillate will be around 20. Knowing that the concentration of light PAH in crude coconut oil can be high, levels of up to 10 ppm can be expected in coconut oil deodorizer distillate (Table 12). 

TABLE 12. Polycyclic Aromatic Hydrocarbon Content (PAH) of Refined Coconut Oil and the Corresponding Deodorizer Distillate (Data in ppb). 

In practice, NOF can be slightly higher as a result of hydrolysis of the refined oil during deodorization. Our own research showed that short-chain oils (e.g., coconut oil) are more prone to hydrolysis than long-chain oils (e.g., soybean oil). Hydrolysis during deodorization of coconut oil resulted in the production of 0.01-0.03% additional FFA (30). 

Timms (21) has heat of fusion to 17.7-22.3 kcal/kg for milkfat, 24-31 kcal/kg for fully hardened milkfat, 26-29 kcal/kg for cocoa butter in the p polymorph, 22.6 kcal/kg for refined, bleached, and deodorized (RBD) palm oil, 29.7 kcal/kg for RBD palm kernel oil, 26.0 kcal/kg for RBD coconut oil, 31.6 kcal/kg for fully hardened palm kernel oil, and 31.2 kcal/kg for fully hardened coconut oil. The heat of fusion is an empirical physical property dependent on the thermal history or tempering of the oil. 

Applications. The main application of fatty carboxylates is found in the soap bars used worldwide for hand-washing fabrics (generally based on tallow/coconut oil mixtures). Water-soluble soaps are mainly used in skin cleansers (soap bars or liquids), shaving products (sticks, foams, or creams), and deodorant sticks. Water-insoluble soaps form gels in nonaqueous systems and, due to their hydrophobicity, they can be appropriate surfactants for water/oil (w/o) emulsions. 

Coconut oil in its virgin form is clear in color. High heat exposure during deodorization process (230°C) normally will lead to polymerization and consequently the oil will turn yellow. Color of virgin coconut oil in this survey was in range of 0.1 Red and 0.5 Yellow max. 

The color of crude coconut oil varies from a light yellow to brownish yellow. The National Institute of Oilseed Products specification limit is 15.0 maximum Lovibond red color. Normal processing techniques will produce deodorized oils with very pale yellow colors. The odor and taste of coconut oil are largely due to the presence of small quantities of lactones (less than 150 ppm). Because coconut oil is low in rmsaturated fatty acids, it has a high resistance to oxidation however, coconut oil will hydrolyze two to ten time faster than normal oils to produce a disagreeable soapy flavor. Coconut oil hydrolysis proceeds slowly in the presence of free moisture alone, but rapidly when an enzyme lipase is present in the food product. Pastry dough and cake batters are examples of such products (O Brien 2008). 

The term 100% pure coconut oils are deseribing two eategories of oils a) 100% piu-e-natural (only minor treatments were used for obtaining pure oil) b) 100% pure-refined (the purity was achieved by refining, bleaching and deodorizing or other treatments). 

The potential use of electronic nose in detecting adulteration in virgin coconut oil was studied by Marina et al., 2010. An electronic nose (zNose ) was applied to the detection of adulteration of virgin coconut oil. The system is based on a surface acoustic wave sensor. Virgin coconut oil was mixed with refined, bleached and deodorized palm kernel olein at a level of adulteration fi-om 1 to 20% (weight/weight). 

The future challenge could consist of developing, validating and harmonizing analytical methods and quality parameters related to authenticity issues. The possible applications are related to the blend of virgin coconut oil with soft treated coconut oil (i.e., soft deodorized) and the blend of virgin coconut oil with other vegetable oil or refined coconut oil. 

The standard commercial type of coconut oil passes through the copra stage and undergoes the refining, bleaching and deodorization processes that include... 

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