Steam deodorization

Since alpha-tocopherol was an essential component of the Swoboda and Peers system (52) which yielded metallic/fIshy flavors, its structural role in the directing of the flavor was of Interest. Either alpha-tocopherol (670 ppm) or Trolox C (1000 ppm) were added to steam deodorized menhaden oils (2 h at 130°C, 4 mm Hg 32) and allowed to oxidize while exposed to air and protected from the light at 65 C. As observed In previous studies (54-56), the high level of alpha-tocopherol exhibited a prooxldant effect whereas Trolox C possessed a distinct antioxidant effect in oxidizing menhaden oils (57). 

Refining of crude rice oil involves dewaxing, degumming, neutralization of free fatty acids, bleaching to improve color, and steam deodorization. Refined rice bran oil is a light yellow color (Lovibond 3.0 R 30Y) with a mild background odor and flavor reminiscent of rice. Similar to peanut oil, the flavor and odor are complementary to the flavor of many fried foods, such as fish, chicken, and chips. 

Figure 6. Stability tests (aeration at 110° C) of (A) hydrogenated peanut oil after oxidation to near rancidity, (B) oxidized oil alter steam deodorization, and (C) hydrogenated peanut oil. (Arrows indicate points of organoleptic rancidity.)...

Sparge steam %) Deodorization time (min) Finai acidity % FFA) Trans fatty acids (%) Tocopheroi ioss (%) ... 

The process developed by Gupta (19-22) processed crude oils with a combination of UF membrane separation and silica gel column percolation. The soybean and rapeseed-hexane miscellas were passed through various UF membranes. The solvent was removed from the permeate, and the degummed oil was then treated with bleaching clay, silica, and/or acid and finally was steam deodorized to produce refined, bleached, and deodorized oil. The color readings of the oils obtained... 

Obtained by alkali-refining, clay bleaching, and steam-deodorizing. 

Eddy R. Hair presented steam deodorization as a technique to improve the performance of fryer oil in his International Patent, WO 91/12304. In this process, a small portion of the fryer oil is continuously pulled out of the fryer, deodorized with live steam under vacuum at 148-260°C (300-500T) and fed back into the fryer. The inventor claims that the oil and product flavor are improved. 

Steam stripping system is more complex and can be cost prohibitive. Figure 11.2 shows a schematic diagram for a steam deodorization system. In order to get the full benefit of this type of treatment, one must have a system where the adsorbent treatment precedes the steam deodorization step. 

DeodoriZation. Removal of volatile odorous material and residual fatty acids is the final step ki ok processkig prior to packagkig or filling for bulk shipment (28). The ok is heated to 230—260°C under vacuum. Steam is passed through the ok to assist ki carrying over the volatile material. 

Deodorization can be carried out ki batch, continuous, or semicontkiuous systems. Figure 4 shows a typical design for a semicontkiuous deodorizer. The heated ok is passed through a series of trays under vacuum. Steam is passed through the ok through a steam sparge ki the bottom of the tray. Volatiles are carried through the headspace and condensed. In addition to fatty acids and compounds responsible for odor, some tocopherols and sterols are also distilled kito the condensate. The amount of tocopherols distilled depends on deodorization temperature and vacuum. 

Pine Oil. This oil is obtained by extraction and fractionation or by steam distillation of the wood of Pinuspalustris Mill, and other species. Most of the oil is produced ia the southeastern United States. The composition of the oil depends on the fractions chosen, but the chief constituents are terpene alcohols, mainly terpiaeol. Piae oil finds use as a germicide ia disiafectants and soaps as an ingredient ia iasecticides, deodorants, poHshes, sweepiag compounds, and catde sprays and as raw material for the manufacture of perfumery-grade terpiaeol [8000-41 -7], anethole [104-46-1], fenchone (137), and camphor (35). 

Methyl Dihydroabietate (Commercial product developed by Hercules Powder Co under name Hercolyn . Another product is Hercolyn-D , which is Hercolyn deodorized by steam-blowing), C19H31COOCH3,mw 318.48, colorl to faintly amber colored liq mp, does not freeze at —40°, but becomes very viscous bp 356—70° with si decompn d 1.020—1.030g/cc for Hercolyn flash p 183° and fire p 218° (Cleveland open... 

Portions of the treated hay were extracted with benzene, and aliquots of the benzene solution were evaporated to dryness on the steam bath, with a gentle air current to remove the last traces of solvent. The residues were then taken up in deodorized kerosene and tested against houseflies by the turntable method. For comparison, extracts were made up to contain the same amounts of technical toxaphene as were indicated by the chlorine determinations to be present in the treated hay. 

Deodorizing—crude ofls tend to have undesirable odors and tastes. These are due to the presence of various volatile components. These are removed by passing steam through the heated oil under diminished pressure. 

Terpenes are a diverse family of compounds with carbon skeletons composed of five-carbon isopentyl (isoprene) units. Terpenes are commonly isolated from the essential oils of plants the fragrant oils that are concentrated from plant material by steam distillation. The term essential oils literally means oils derived from the essence of plants. They often have pleasant tastes or aromas, and they are widely used as flavorings, deodorants, and medicines. Figure 25-12 shows the structures of four terpenes that are isolated from essential oils. 

The volatile peroxides, other oxidation decomposition products, and odiferous compounds form reduced-boiling point azeotropes with water in the steam, at high temperatures, 250-260°C/482-500°F, and very low absolute pressures ( 3 mbar). This is above the smoke point of soybean oil, but below the flash point, and oxygen must be excluded. Considerable heat bleaching of yellow-red carotenoids also occurs at this temperature. Typically the deodorization process requires 20-40 min after come-up time, uses 0.5-2.0 percent spaiged steam (the higher level if tocopherols are recovered), operates at between 2 and 4 mbar, and produces a product with about 0.03-0.05 percent FFA.143... 

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