Extraction and Processing of Sunflower Oil

The procedures used for the extraction and processing of sunflower oil are broadly the same as for other seed oils. Focus will be made on those operations or details specific of the production of sunflower oil. Sunflower oil is usually extracted through pressing of seed and later extraction by solvent. The crude oil is usually subjected to traditional refining stages. Otherwise, cold-pressed sunflower oil is currently valued as a new extra virgin oil. 

The content and ratio of NHP in an oil differs significantly depending on the method applied (Table 17). The NHP content is lower in extracted and mixed oils (67). The NHP content of sunflower oil is low, and degumming may readily be accomplished. Dimic et al. (67) studied a simplified process for pretreatment of sunflower oil with the application of multiple acid degumming stages. 

Favati, F., Florentini, R.and De Vitis, V. (1994) Supercritical fluid extraction of sunflower oil Extraction dynamics and process optimization, Proceedings of the 3rd International Symposium on Supercritical Fluids, Institut National Polytechnique de Lorraine, Nancy, France, pp. 305-310. 

About 60-70% of the tocopherols in oilseeds are retained during the oil extraction and refining process (cf. 14.4.1 and Table 3.54). Some oils with very similar fatty acid compositions can be distinguished by their distinct tocopherol spectrum. To illustrate this, two examples are provided. The amount of P-tocopherol in wheat germ oil is quite high (Table 3.54), hence it serves as an indicator of that oil. The blending of soya oil with sunflower oil is detectable by an increase in the content of linolenic acid (cf. 14.5.2.3). However, it is possible to make a final conclusive decision about the presence and quantity of soya oil in sunflower oil only after an analysis of the composition of the tocopherols. 

An alternative method of producing hydrocarbon fuels from biomass uses oils that are produced in certain plant seeds, such as rape seed, sunflowers, or oil pahns, or from aquatic plants (see Soybeans and other oilseeds). Certain aquatic plants produce oils that can be extracted and upgraded to produce diesel fuel. The primary processing requirement is to isolate the hydrocarbon portion of the carbon chain that closely matches diesel fuel and modify its combustion characteristics by chemical processing. 

Phospholipids The phospholipid content of crude sunflower oil ranges between 0.5% and 1.2%. Oils extracted by solvent generally have a higher content of phosphlipids than those obtained by pressing. Major phospholipids are phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidic acid. Most are hydratable and may be removed from the cmde oil through a water-degumming process (See Section 5.3.1.)... 

From a commercial point of view, soybean is the most important source for lecithin however, lecithin production from sunflower (180) and rapeseed (181-183) wet gum has also been successful. Wet gum is removed during the first refining step of crude oil that is the degumming process. Traditionally, crude oil obtained from solvent-extraction process is agitated with 1-3% water at elevated temperatures (70-80°C). Under these conditions, phosphohpids and glycohpids start to swell and become insoluble in the oil. The hydrated mass is removed via centrifugation, and the dehydration is carried out under vacuum until the residual moisture is below 1%. 

Sunflower Meal. The vegetable oil extraction industry produces three types of sunflower meal undehulled meal containing 28% protein and 25-28% fiber, partially dehulled meal containing 35-37% protein and 18% fiber, and double-dehuUed sunflower meal containing 40 2% protein and 12-14% fiber. Thus, the composition of sunflower meal is dependent on the efficiency of the dehulhng process (34). 

Processes for production of ethanol and acetone-butanol-ethanol mixture from fermentation products in membrane contactor devices were presented in Refs. [88,89]. Recovery of butanol from fermentation was reported in Ref. [90]. Use of composite membrane in a membrane reactor to separate and recover valuable biotechnology products was discussed in Refs. [91,92]. A case study on using membrane contactor modules to extract small molecular weight compounds of interest to pharmaceutical industry was shown in Ref. [93]. Extraction of protein and separation of racemic protein mixtures were discussed in Refs. [94,95]. Extractions of ethanol and lactic acid by membrane solvent extraction are reported in Refs. [96,97]. A membrane-based solvent extraction and stripping process was discussed in Ref. [98] for recovery of Phenylalanine. Extraction of aroma compounds from aqueous feed solutions into sunflower oil was investigated in Ref. [99]. 

Solvent extraction is used extensively to recover chemicals from natural products. Solvents are used to extract and concentrate natural oils and products in the bioprocessing industries (nutraceu-tical, food, pharmaceutical, feed, cosmetic, biotechnology) in quantities from grams to metric tons. Biotechnology applications include the recovery of primary and secondary metabolites [4]. Extraction is used to recover vegetable oils and food products. It is used to process a variety of materials including groundnut, mustard seed, soybean, pahn kemal, sunflower, rice bran, copra, cottonseed, and minor oil seeds like neem, mahua, watermelon seed, castor seed, and so on. 

Only when soybeans are processed in plants designed for other oilseeds (e.g., cottonseed, sunflower seed, etc.), which must be prepressed, are soybeans subjected to prepress solvent extraction. Soybeans do not contain sufficient oil to require or justify prepressing and are rarely, if ever, prepress solvent extracted. In prepress solvent extraction, part of the oil, that which is easily removed, is pressed out, generally as de-... 

---