Effect of ultrasonic comminution on liquid classification of cottonseed protein and gossypol pigment glands

Slurries of pin-milled full-fat and flaked, extracted cottonseed were ultrasonically comminuted in hexane and liquid-classified using laboratory differential settling techniques. Sonication of full-fat cottonseed slurries increased the liquid-classified protein fraction recovery from 25.9% (nonsonicated control) to over 60%, while the protein content of the fraction remained basically constant at 67%, and free gossypol increased slightly from 0.027 to 0.032%. Sonication of flaked, solvent-extracted (fat-free), slurried cottonseed yielded a 28% classified fraction containing 72% protein and 0.032% free gossypol. Although it was demonstrated on laboratory scale only, ultrasonic comminution may make the price of edible cottonseed protein concentrates produced from glanded seed (via a process such as the liquid cyclone process) competitive with other edible protein products. Presented at the AOCS Annual Meeting, 1981, New Orleans.     

Edible cottonseed flour by air classification of glanded seed: Cost analysis

A new, edible, 65%-protein cottonseed flour having the characteristics of flour produced from glandless cottonseed has been prepared from milled, hexane-extracted glanded cottonseed flakes by a simple, practical, economical air classification process. The product has physical and functional characteristics that make it attractive for use in food formulation and it meets the free gossypol standards of both the U.S. Food and Drug Administration and the Protein Advisory Group of the United Nations System. A process flowsheet and a material balance are given: capital costs, manufacturing costs, general expenses, profitability and selling prices are indicated for annual productions of up to 17.5 and 35 million lb of flour in hypothetical industrial-scale satellite plants having daily capacities of 25 and 50 tons of flour, respectively. It is estimated that fixed capital investment for a 25-ton/day plant would be $4.0 million, and for a 50-ton/day plant, $5.5 million. Production of edible flour from prime-quality cottonseed kernels would cost as little as 15.8 cents/lb and the selling price of flour, allowing for the value of coproducts, would be as low as 23.6, 18.9, and 16.5 cents/lb for payout periods of 2, 3 and 4 years, respectively. Selling price would be competitive with the price of soy protein concentrate over most of the production range studied. Presented at the AOCS Annual Meeting, 1981, New Orleans. One of the facilities of the Southern Region, Agricultural Research Service, U.S. Department of Agriculture.     

Continuous extrusion cooking of cottonseed kernels and of partially defatted meal

Continuous extrusion cooking produces a short time pressure cooking of the material in process. The Wenger extruder-cooker has been successfully applied by others to soybeans for manufacture of full fat flour. This is a report of an investigation of the extruder-cooker applied to glanded cottonseed kernels and to partially defatted cottonseed meal. The purpose was production of cottonseed flour for human food. The principal objective in extruder processing was lowering of free gossypol to 0.12% of protein. On full fat kernels the extruder system was effective in lowering free gossypol. Most of the binding occurred in the preconditioner, and the extruder itself was relatively ineffective in binding gossypol. However the contribution of the extruder was necessary to allow free gossypol levels of 0.12% of protein to be reached. Flaked kernels cooked in this manner and then dried were successfully screwpressed. The extruder system was effective also in binding gossypol in ground, screened (through 30 mesh) meal but not in ground, unscreened meal. Presented at the AOCS Meeting, San Francisco, April 1969.     

Food uses for cottonseed protein

Cottonseed, available in many countries located in both temperate and tropical climates, is rarely used as a source of edible protein even though its use as food was suggested as carly as 1876. Development of edible protein products from cottonseed has been impeded by the presence of gossypol-containing pigment glands in the kernels, and the economic value of the oil. Cottonseed flour produced by mechanical pressing has been marketed in limited quantities as two edible protein products. One, known as “Proflo,” is used primarily to impart functional characteristics to baked and confectionery products. The other is used as an ingredient in “Incaparina” to combat malnutrition in Latin America. Because of the manner in which these cottonseed protein products are processed, their full nutritional and functional potentials and versatiliity have not been realized. Recent advances in breeding glandless cottonseed, processing glanded cottonseed (e.g., the liquid cyclone process), and related technology have increased the potential of cottonseed protein for food uses. Flours, concentrates, and isolates differ qualitatively and quantitatively in protein and amino acid composition. Consequently, they have different functional and nutritional characteristics and end uses. Flours and concentrates as well as their texturized counterparts are acceptable as functional and nutritional additives to meat products, baked goods, and cereals. Three isolates including storage protein, nonstorage protein, and a mixture of both have been prepared from flours and concentrates. The storage protein isolate imparts functional characteristics, such as texture, acid solubility and foam stability. The non-storage protein isolate has good nutritional characteristics primarily because of its high lysine content.     

The processing and storage characteristics of glandless cottonseed

Two consecutive storage tests of seven and six-months' duration were conducted to determine the relative effects of adverse storage conditions on glandless and glanded cottonseed and the products derived from each. The moisture conditions during storage resulted in extreme quality deterioration in both glandless and glanded seed. The damage sustained by glandless seed was not substantially different from damage occurring to glanded seed. Neither did glandless seed appear to deteriorate at a faster rate. Normal direct solvent extraction processing methods were followed to process seed for products quality evaluations as measured by nitrogen solubility, epsilon amino free lysine, and gossypol content for meals and FFA, cup refining loss, refined color, bleach color and gossypol content for oils. Oil from glandless seed refined and bleached to lower AOCS colors than corresponding glanded seed oils. Refining losses for oils from damaged seed were slightly higher for glandless seed oils. The meal quality from glandless seed was superior in all categories measured. A laboratory of the Cotton Research Committee of Texas operated by the Texas Engineering Experiment Station.     

Gossypol and some other terpenoids,flavonoids, and phenols that affect quality of cottonseed protein

Recent interest in gossypol, the biologically active phenol characteristic of the cotton genusGossypium, has been generated by concerns beyond its physiological effects on animals. These concerns are primarily investigations into possible natural pest resistance factors in cotton and were prompted by differences noted in glanded and glandless varieties. This work has led to the characterization of gossypol-like compounds in other parts of the plant as well as in the seed. Likewise, work on the investigation of color and flavor components of cottonseed, carried out in an effort to characterize the product for food flavonoids. Phenolic acid fractions have also been indicated in flour preparations of both glandless and glanded cottonseed.     

Color stability of glandless cottonseed oil

The color stability of oil extracted from glandless cottonseed contaminated with various levels of glanded cottonseed was studied. The rate of darkening in bleached color of cottonseed oil during storage was proportional to the original glanded cottonseed or gossypol content in the oil and to time and temperature of storage. Glandless cottonseed with 0–10% glanded seed contamination, as might be expected in commercial production of glandless cotton, yielded oil with equivalent or better color when conventionally refined and bleached after 30 days storage at 25 to 40 C than miscella refined oil from glanded cottonseed. This indicates that new oil mills for extracting glandless cottonseed need not invest in miscella-refining units in order to produce high quality oil.     

Production of food-grade cottonseed protein by the liquid cyclone process

A brief background is presented on the development of the Liquid Cyclone Process as modified to process glanded cottonseed kernels from the Texas high plains into a gland-free 65+% protein flour. Southern Regional Research Center's pilot plant process is described and related to the commercial process that will become operational in early 1974 at Plains Cooperative Oil Mill, Lubbock, Texas. Some of the functional properties of the flours and results of their evaluation in food application are discussed. One of seven papers presented at the symposium, “Processing Methods for Oilseeds,” AOCS Spring Meeting, New Orleans, April 1973. ARS, USDA.     

Evaluation of the food use potential of sixteen varieties of cottonseed

Sixteen new or experimental varieties of cotton-seed, eight glandless and eitht glanded, were extensively analyzed in this study. Ginned seed from each were studied and then kernel samples and finally oil and flour samples prepared from the kernels. Mean values determined for each attribute measured are presented for each type seed. These data are useful for (a) showing the magnitude of particular desirable properties presently being achieved in varieties of each type seed, (b) showing something of the variation of these properties among varieties within seed types, and (c) comparing glandless and glanded seed types for compositional differences.     

The plant geneticist’s contribution toward changing the lipid and amino acid composition of cottonseed

Gossypol is well known to be responsible for the troublesome dark color of cottonseed oil. It may depress growth, cause discoloration of eggs, and create metabolic disturbances when fed to nonruminant animals in excessive amounts. All but a trace of seed gossypol is contained in pigment glands present in the cottonseed kernel. Genetical research conducted by USDA scientist, S.C. McMichael, led to his discovery of a glandless seeded cotton in 1953. Glandless cottonseed are essentially free of gossypol. Using McMichael’s genetic lines as gene sources, cotton breeders have developed breeding programs in the last 10 years from which three commercial glandless cotton varieties have so far been released. More glandless cotton varieties are on the way. Due to the elimination of gossypol, the color of the oil and utility of the meal from glandless cottonseed is distinctly superior to that from glanded cottonseed. The advent of glandless cottonseed, its potential value in the field of human protein nutrition, and the success in breeding improved oil and protein quality in other oilseeds, have recently caused cotton geneticists to become interested in the possibility of genetically manipulating lipid and amino acid composition in cottonseed. However specialized genetic techniques involving interspecific gene transfer or use of wild photoperiodic uplands may be required in making such improvements. One of seven papers presented at the Symposium, “The Plant Geneticist’s Contribution Toward Changing the Lipid and Amino Acid Composition of Oilseeds,” AOCS Meeting, Houston, May 1971.     

Technical news feature

Hull-free kernels from confectionary-type sunflower seed were prepressed with two levels of heat treatment and two levels of severity of pressing. Cakes were solvent extracted, desolventized in a continuous, pilot size extractor, and ground into flour. For comparison, kernels were also pressed into flour using direct solvent extraction and desolventizing at room temperature. Qualities of oil and of flour from different treatments were compared. Oils were all of good quality with no differences among treatments. Flours showed no distinct differences in dispersible nitrogen at pH values between 2 and 12, indicating that processing conditions did not damage the solubility of the protein. All cake and flour samples were high in residual hexane, showing the need for a deodorizer in the pilot plant. Treatments did not affect particle size distribution in flours. The flour samples all fell within the range for satisfactory microbiological quality, although bacteria count increased considerably during grinding of cake into flour. Treatments affected dry color but not wetted color of flour, with the more intense heating and pressing producing slightly darker flours. Amino acid compositions were not affected by process treatments.     

Effect of temperature on the content of pigments of stored cottonseed

Summary Three pure-bred varieties of cottonseed,G. hirsutum, which were planted and grown under similar environmental conditions were stored at 38°, 77°, and 85°F. After determining the initial contents of lipids, nitrogen, moisture, gossypol, and gossypurpurin each lot of seed was stored at the different temperatures and analyzed periodically with respect to changes in pigmentation. The content of gossypurpurin was found to increase during storage in all of the samples. Its increase was proportional to the temperature and length of storage. On the other hand, gossypol decreased during storage of all samples. The antimony trichloride test for gossypol was found to be applicable only to extracts prepared from fresh cottonseed. During storage of the seed another yellow-colored pigment(s) developed which could be separated from gossypol by alkaline extraction of the original chloroform extract of the stored seed. The alkali extractable portion of the chloroform extract gave a red-colored antimony trichloride reaction product characteristic of gossypol. It is postulated that at least a fraction of the non-acidic pigment(s) in the crude chloroform extracts obtained from stored cottonseed is diaminogossypol. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Stability of bound gossypol to digestion

Summary Bound gossypol is largely unabsorbed in the rat. In cottonseed flour it is largely associated with the denatured (salt-insoluble) protein fraction. Evaporation of an ether solution of gossypol on isolated cottonseed protein does not bind the gossypol to the protein (see reference 4) as in the moist cooking of seed. The percentages of bound gossypol, 1.9 in the rat feces and 1.74 in the flour residue, after salt extraction, are the highest reported in a biological product.     

Relations between oil,nitrogen, and gossypol in cottonseed kernels

Summary A study was made of the relations between oil, nitrogen, and gossypol contents of cottonseed kernels from the seed of eight commercial varieties of cotton grown at 13 locations during three years. Both variety of seed and environment had a highly significant influence on each constituent whether expressed as percentage of the kernel or as weight of constituent per 100 kernels. Each variety showed a significant positive correlation between oil and gossypol and significant negative correlations between oil and nitrogen and between gossypol and nitrogen, on the basis of percentage-constituent in the kernel. The amount of both oil and nitrogen elaborated in the kernel tends to be related to the size of the kernel; each of these constituents increases with increased kernel size. The highly significant positive relationship between grams of oil and grams of gossypol per 100 kernels which is evident even when nitrogen is held constant can be explained on the basis that these two constituents are synthesized during the same stage of seed development. Rainfall or temperature had no significant over-all influence on the nitrogen content of the kernels. Grams of nitrogen per 100 kernels showed a significant negative correlation with mean minimum temperature for 5 of the varieties but was not significantly correlated with total rainfall during the maturation period for any of the varieties. Grams of oil and gossypol per 100 kernels tended to increase with increasing rainfall and decrease with increasing mean temperature. The ratio of nitrogen to gossypol is negatively correlated with the oil content of the kernels. The variation attributed to varietal influence decreases as the oil content of the kernel increases. It is postulated that high ratios are desirable for the production of meals containing a low free-gossypol content. Presented before the American Oil Chemists’ Society, Houston, Tex., April 23–25, 1956. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Acidic ethanol extraction of cottonseed

Ethanol (EtOH) is being evaluated as an alternate solvent to hexane for the extraction of glanded cottonseed. Hot EtOH, needed for efficient oil and aflatoxin extraction, binds gossypol to protein. However, this binding can be minimized by acidifying aqueous EtOH with a tribasic acid, such as phosphoric or citric. While this solvent extracts oil and gossypol, it does not affect EtOH’s ability to extract aflatoxin. The defatted cottonseed meals produced from this process contained 0.03% total gossypol (which is lower than meal prepared by most other processes) and the aflatoxin content was reduced from 69 to 2.9 ppb. These are preliminary results and additional research is needed to determine commercial feasibility. The removal of essentially all gossypol from an extracted meal has the potential to expand the use of cottonseed meal as a feed, increasing its value to both the cotton farmer and the seed processor. Presented in part at the 40th Oilseed Processing Clinic, March 4, 1991, New Orleans, LA.     

热碱法脱除游离棉酚的实验研究

介绍了用热碱法对棉籽粕进行脱酚的工艺原理,并对棉籽粕进行了脱酚实验研究。通过正交试验,热碱法脱酚的最适合条件为pH值8～9,温度60℃,时间3h,最终棉籽蛋白液棉酚含量为12×10-6,完全低于联合国咨询委员会规定的食用棉籽蛋白质中游离棉酚含量≤0.06%标准。     

Pretreating delintered cottonseed to increase yield of whole kernels

Pretreatment of delintered glandless seed before decortication by (a) heating seed containing different kernel moistures with live steam followed by drying with indirect heat, (b) heating seed containing different kernel moistures with live steam followed by rapid cooling with air, (c) heating seed containing different kernel moistures with superheated steam followed by drying with indirect heat, and (d) heating seed containing different kernel moistures with super-heated steam followed by rapid cooling with air to ambient temperatures, was investigated. Also reported are analytical data which allow an assessment of any changes in protein quality resulting from the treatments applied and data from organoleptic evaluations of treated and untreated glandless cottonseed kernels prepared as high-protein edible nuts. Operated by the Texas Engineering Experiment Station for the Cotton Research Committee of Texas.     

Determination of free gossypol in cottonseed materials

Summary A method for the determination of free gossypol in cottonseed materials is described. The method consists of extraction of gossypol with a measured volume of 70% aqueous acetone on a shaker for one hour, filtration, and colorimetric analysis for gossypol in an aliquot of the filtrate by means of the reaction between gossypol andp-anisidine. The conditions for complete extraction of gossypol from various types of cottonseed materials have been investigated, the stability of gossypol in aqueous acetone has been demonstrated, and data are presented on recovery of gossypol added to cottonseed materials. The method has been compared with the method of Smith (2). One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Note on acetone-soluble material in cottonseed meals

Summary In connection with a study of methods of eliminating traces of “free” gossypol from cottonseed meals a procedure for isolation of gossypol from the 70% acetone extracts of the meals by transfer to benzene solution has ben developed. A procedure is also given for quantitative determination of the isolated gossypol. Analysis of four samples of cooked cottonseed meats and meal by the method showed that in each instance substances other than gossypol are measured by the A.O.C.S. method for “free” gossypol in meals containing low concentrations of residual “free” gossypol. This procedure promises to provide another analytical tool for the study of residual material in processed cottonseed meal that causes egg discoloration when fed to laying hens. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Cottonseed oil

Research on the effects of genetics and growing location on cottonseed has shown that oil and fatty acid composition could be improved if geneticists and agronomists would strive for improved seed quality as vigorously as they do for improved fiber quality. Breeding of glandless or gossypol-free cottonseed was a genetic breakthrough. Glandless varieties are now available that produce yields having the quality of fiber and seed equivalent to those of glanded cultivars. Oil, food-grade lecithin and meal byproducts are readily processed from glandless cottonseeds because of the absence of gossypol. Major research programs on cottonseed processing include: (a) testing alternative screw-press and extrusion operations for efficient direct solvent oil extraction; (b) developing alternative solvent extraction systems with ethanol, isopropanol and supercritical fluids; (c) using gas chromatographic/mass spectrophotometric techniques to characterize enzymatic and nonenzymatic mechanisms that produce secondary oxidation off-flavor products; and (d) controlling hexane losses in solvent extraction systems.