Processing cottonseed

Figure 12. E ect of succinylation on the foam and protein solubility properties of liquid cyclone processed cottonseed flour in suspensions at various pH values...

These data demonstrate that changes in foam properties of liquid cyclone processed cottonseed flour are inducible by treatment with succinic anhydride. Gel electrophoretic and solubility data show that there are alterations in the physical and chemical properties of proteins, and in certain cases these changes improve foam properties, that is, improve solubility and polypeptide dissociation of proteins at the interface of the foaming solution. Similar results have been reported for succinylated soybean and sunflower seed proteins (44. 46). 

Flash and Fire Point. Flash point is the temperature at which the volatile products are evolved at such a rate that they are capable of being ignited but not supporting combustion. At the fire point, the accumulated breakdown products are capable of supporting a flame on their own. A crude cottonseed oil with a fatty acid content of 1.8% was found to have a flash point of 560°F or 293.3°C. Solvent-extracted oils can have a low flash point because of a solvent residue. A flash point analysis would identify this crude oil deficiency to prevent an accidental fire or explosion in an atmosphere that was not explosion proof. Crude vegetable oil shipments received with a flash point below 250°F are rejectable by most trading rules. Figure 1 shows the relationship between free fatty acid content, smoke, flash, and fire points of processed cottonseed and peanut oils. 

TABLE 12. AOCS Color Measurements of Membrane-Processed Cottonseed Oils. 

The National Cottonseed Products Association, Inc., whose main office is in Memphis, Tenn., assembles some statistics covering cost of processing cottonseed. A book of Rules Governing Transactions between Members of the National Cottonseed Products Associa-... 

Continuous expeller expelling essential oils prepress capacity 0.02 to 5 kg/s prepress capacity (which will be followed by leaching. Section 16.11.5.14) = 2 x full press capacity (where only expelling is used to remove the essential oils) prepressing 2.2 Mg/d cotton-seed/rpm relative capacities depend on seed being processed cottonseed and soybean x 1 copra, wet com germ, canola x 0.75 to 0.82 flax seed, safflower x 0.62 power 100 to 200 kJ/kg cottonseed prepress with the valne increasing with feed capacity. 

Since feeds contain other substances than those required by the animals of interest, studies have also been conducted on antinutritional factors in feedstuffs and on the use of additives. Certain feed ingredients contain chemicals that retard growth or may actually be toxic. Examples are gossypol in cottonseed meal and trypsin inhibitor in soybean meal. Restriction on the amount of the feedstuffs used is one way to avoid problems. In some cases, as is tme of trypsin inhibitor, proper processing can destroy the antinutritional factor. In this case, heating of soybean meal is effective. 

Other than fuel, the largest volume appHcation for hexane is in extraction of oil from seeds, eg, soybeans, cottonseed, safflower seed, peanuts, rapeseed, etc. Hexane has been found ideal for these appHcations because of its high solvency for oil, low boiling point, and low cost. Its narrow boiling range minimises losses, and its low benzene content minimises toxicity. These same properties also make hexane a desirable solvent and reaction medium in the manufacture of polyolefins, synthetic mbbers, and some pharmaceuticals. The solvent serves as catalyst carrier and, in some systems, assists in molecular weight regulation by precipitation of the polymer as it reaches a certain molecular size. However, most solution polymerization processes are fairly old it is likely that those processes will be replaced by more efficient nonsolvent processes in time. 

Protein-Based Substitutes. Several plant and animal-based proteins have been used in processed meat products to increase yields, reduce reformulation costs, enhance specific functional properties, and decrease fat content. Examples of these protein additives are wheat flour, wheat gluten, soy flour, soy protein concentrate, soy protein isolate, textured soy protein, cottonseed flour, oat flour, com germ meal, nonfat dry milk, caseinates, whey proteins, surimi, blood plasma, and egg proteins. Most of these protein ingredients can be included in cooked sausages with a maximum level allowed up to 3.5% of the formulation, except soy protein isolate and caseinates are restricted to 2% (44). 

Solvent Extraction. Extraction processes, used for separating one substance from another, are commonly employed in the pharmaceutical and food processing industries. Oilseed extraction is the most widely used extraction process on the basis of tons processed. Extraction-grade hexane is the solvent used to extract soybeans, cottonseed, com, peanuts, and other oilseeds to produce edible oils and meal used for animal feed supplements. Tight specifications require a narrow distillation range to minimize solvent losses as well as an extremely low benzene content. The specification also has a composition requirement, which is very unusual for a hydrocarbon, where the different components of the solvent must be present within certain ranges (see Exthaction). 

Fig. 5. Schematic outline for processing of cottonseed into oil and meal.

Screw-pressed oil is aUowed to stand to settle out suspended soUds, filtered through plate filter presses, and then pumped to storage. The oil-rich solvent (miscella) from the solvent-extraction process is filtered or clarified, and most of the solvent is removed in a long tube evaporator. FinaUy, the concentrated oil passes through a stripping column where sparging steam is injected to remove the residual solvent. A metric ton of cottonseed yields ca 91... 

U.S. exports of the other oilseeds are smaller and foUow different patterns (50). Exports accounted for only 2—3% of the cottonseed crop and 16—31% of the processed oil production for 1991—1994. Of the peanut crop ca one-half is consumed domestically as whole nut products and 15—20% is exported. Only about 10% of the sunflower seed crop is exported. From 1991 to 1994 an average of 70% of the oil was exported, but only about 11% of the meal was shipped overseas. 

Oil. Most cmde oil obtained from oilseeds is processed further and converted into edible products. Only a small fraction of the total oil from soybeans, cottonseed, peanuts, and sunflower seed is used for industrial (nonedible) purposes. 

Use of some oilseed proteins in foods is limited by flavor, color, and flatus effects. Raw soybeans, for example, taste grassy, beany, and bitter. Even after processing, residues of these flavors may limit the amounts of soybean proteins that can be added to a given food (87). The use of cottonseed and sunflower seed flours is restricted by the color imparted by gossypol and phenoHc acids, respectively. Flatus production by defatted soy flours has been attributed to raffinose and stachyose, which are removed by processing the flours into concentrates and isolates (88). 

The composition of common fats and oils are found in Table 1. The most predominant feedstocks for the manufacture of fatty acids are tallow and grease, coconut oil, palm oil, palm kernel oil, soybean oil, rapeseed oil, and cottonseed oil. Another large source of fatty acids comes from the distillation of cmde tall oil obtained as a by-product from the Kraft pulping process (see Tall oil Carboxylic acids, fatty acids from tall oil). 

The raw materials for the manufacture of soap, the alkali salts of saturated and unsaturated C10-C20 carboxylic acids, are natural fats and fatty oils, especially tallow oil and other animal fats (lard), coconut oil, palm kernel oil, peanut oil, and even olive oil. In addition, the tall oil fatty acids, which are obtained in the kraft pulping process, are used for soap production. A typical formulation of fats for the manufacture of soap contains 80-90% tallow oil and 10-20% coconut oil [2]. For the manufacture of soft soaps, the potassium salts of fatty acids are used, as are linseed oil, soybean oil, and cottonseed oil acids. High-quality soap can only be produced by high-quality fats, independent of the soap being produced by saponification of the natural fat with caustic soda solution or by neutralization of distilled fatty acids, obtained by hydrolysis of fats, with soda or caustic soda solutions. Fatty acids produced by paraffin wax oxidation are of inferior quality due to a high content of unwanted byproducts. Therefore in industrially developed countries these fatty acids are not used for the manufacture of soap. This now seems to be true as well for the developing countries. 

Seven diets were constructed from purified natural ingredients obtained from either C3 (beet sugar, rice starch, cottonseed oil, wood cellulose, Australian Cohuna brand casein, soy protein or wheat gluten for protein) or C4 foodwebs (cane sugar, corn starch, com oil, processed corn bran for fiber, Kenya casein for protein) supplemented with appropriate amounts of vitamins and minerals (Ambrose and Norr 1993 Table 3a). The amino acid compositions of wheat gluten and soy protein differ significantly from that of casein (Ambrose and Norr 1993). 

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