Carroll L. Hoffpauir

Ion-Exchange Characteristics of Chemically Modified Cotton Fabrics

A method is described for comparing microscopically the cross-sectional areas of the same cotton fiber in wet and dry conditions, for evaluation of swelling. Results indicate the change in cross-sectional area of raw cotton fibers to be between 21 % and 34% of the dry area regardless of variety of cotton or degree of maturity of the fiber. Immature samples show slightly less mean swelling than mature samples, but this is believed to be due to the presence of fibers with no secondary thickening at all which tend to shrink in cross-sectional area rather than swell. In the immature fibers deformation (defined as change in circularity) is slightly more than that of mature fibers. This, coupled with the fact that in a given weight of immature fibers there are approximately twice as many fibers as in a like weight of mature fibers, helps to explain the greater closing capacity of yarns made from immature cotton. Flax and a sample of viscose rayon show twice the swelling of cotton, Fortisan two-thirds as much, and nylon no crosssectional swelling at all.

3-amino-1-propanol as a complexing agent in the determination of total gossypol

SummaryA method is proposed for the determination of total gossypol in cottonseed meals, crude oils, and soapstocks based on a rapid extraction of gossypol by neutralized 3-amino-1-propanol in dimethylformamide to form a stable complex, followed by colorimetric analysis of an aliquot of the extract by means of an aniline reaction. A determination can be completed in about 2 hrs. and with minor modification in 1 hr. compared to about 7 hrs. for current methods. Results obtained by the proposed procedure on meals, oils, and soapstocks are in essential agreement with those found by use of other accepted methods. Desirable features, such as stability of reagents and extracts and a high degree of reproducibility, suggest that the procedure will satisfy the requirements for a rapid and simplified method for the analysis of all cottonseed products for total gossypol.

Prepress-solvent extraction of cottonseed, processing conditions and characteristics of products

SummaryA study has been made of the relation between processing conditions and the chemical characteristics of cottonseed meals and oils produced by prepressing-solvent extraction. Twenty-six complete sets of mill samples of known processing history and representative of the production at 11 mills were used in the investigation.Cooking conditions were the major factor influencing the distribution of the gossypol between the meal and oil. Reduction in free gossypol during cooking was due to binding with meal components while that occurring during prepressing and solvent extraction resulted mainly from removal of gossypol in the prepressed and solvent-extracted oils.Nitrogen solubility data, which have been suggested as a measure of protein damage, indicated that the major change or reduction in nitrogen solubility occurred during cooking. Very little reduction was noted for prepressing or solvent extraction. The reduction in nitrogen solubility during prepressing is much smaller than that previously reported for normal screw-pressing operations.Prepressed oils gave lower refining losses and lower refined and bleached color than did the solvent-extracted oils. Bleach color reversion, after storage of crude oils for 30 days at 100°F., was greater for solvent-extracted than for prepressed oils.A number of meals exhibited the desirable characteristics of low free gossypol content and high nitrogen solubility. Values calculated for chemical indexes of protein quality, as suggested by Lyman and associates (11), indicate that many of the meals should have good protein quality.

Influence of variety and environment on the iodine value of cottonseed oil

SummaryData are reported on the variation of the iodine value of the oil from the seed of eight varieties of cotton grown at 13 locations during three years. Analysis of variance showed the influence of variety and of station-years to be highly significant statistically. Iodine value was found to be negatively correlated with the temperatures. The highest correlation was obtained for the period of maturation (35 days before the bolls open) when the oil is being synthesized. The coefficients for the relations with mean temperatures were higher than those for maximum and minimum temperatures.Simple correlations for the relations between iodine value of the oils from seed of individual varieties and mean temperatures during two periods of boll and seed development were negative and highly significant. For the maturation period (35 days before boll opening) and the combined periods for squaring, fiber elongation, and maturation (73 days before boll opening) the average reductions in iodine value per °F. increase in temperature were found to be 0.760 and 1.172 units, respectively. Of the eight varieties investigated, temperature influenced the iodine value of the oil least for Stoneville 2B and most for Coker Wilds.

Relation between fatty acid composition and iodine value of cottonseed oil

SummaryThe regularity in the increase in linoleic, and in the decrease in oleic and saturated acids with increase in iodine value of cottonseed oils has been shown by obtaining the regression equation for the glyceride of each acid on the iodine value by use of the compositional data on 48 samples of oil ranging from 89.8 to 117.0 in iodine value. These equations offer a ready means of approximating the fatty acid composition of cottonseed oils from their iodine values. Such approximations may prove useful in the segregation of oils for different end uses.The compositional pattern of cottonseed oils is compared with those reported in the literature for soybean and linseed oils.

Pilot plant development of the alkali cooking process for cottonseed meats. I. Effect of flake, thickness and of time, temperature, and moisture content during cooking

Summary and ConclusionsResults obtained from alkaline cooking experiments show that all of the four variables studied—cooking mousture content, temperature, time and flake thickness—influenced the properties of the resultant meals in varying degrees. Under the experimental conditions used a high initial moisture content, above 18%, is necessary to lower the free gossypol content in the finished meal to less than 0.04%. When this amount of moisture is used, a plastic mass results at the beginning of the process which requires special equipment to supply the mechanical action necessary to break the pigment glands at a low temperature. In the presence of high moisture content and alkali the gossypol, which is released when the glands are ruptured, is bound to the meal. When sufficient initial moisture is present (24–31%), only traces of gossypol (0.010% or less) are found in the extracted crude oil.High temperatures in the presence of high moisture content reduce the solubility of the meal protein (in 0.02N NaOH). Under the conditions of moisture, temperature, and time of cooking used in the experiments the maximum nitrogen solubility obtained under conditions necessary to produce low free gossypol content was 64%. This differs from results obtained in previous work performed under different conditions. A probable reason for the difference is given based on the interrelationship of the three variables.The results demonstrated further that finer comminution of the raw meats by rolling to 0.005-in. thick flakes results in lower free gossypol content in the finished meal and lower gossypol content of the oils as well as more complete removal of the oil by the filtration-extraction procedure used.

The difficultly extractable lipides of cottonseed meats, their composition and effect on the refining characteristics of the crude oils

Summary and ConclusionsCrude lipides fractions were produced from raw, tempered, and cooked meats from two lots of cottonseed by a series of successive stepwise extractions, designed to obtain fractional portions of the total lipides in the order of the difficulty of their extraction. The proximate composition of the crude lipides fractions was determined. It was found that the composition of successive lipides fractions varied with the degree of exhaustiveness of extraction. The fractions obtained by more exhaustive extraction contained greater amounts of undesirable non-neutral oil material and lesser amounts of desirable neutral oil. It was also established that the method used in preparing meats for extraction was of paramount importance in its effect on the composition of the crude lipides obtained. The crude lipides fractions from raw and tempered meats contained large amounts of impurities while the crude lipides fractions similarly obtained from cooked meats were relatively low in impurities.Crude oils equivalent to varying degrees of total lipides extraction were reconstituted from the crude lipides fractions and evaluated for refining characteristics. The impurities content of the reconstituted oils varied as the degree of total lipides extraction and increases in the impurities content of the oils were generally reflected in disproportionate increases in refining losses and/or refined oil color. The oils obtained from the cooked meats at all degrees of extraction were outstandingly low in refining losses as compared to the oils from the raw and the tempered meats.

Estimation of skin content of peanut meals and relative skin pigment content of isolated proteins

SummaryA method for estimating the skin content of peanut meals and relative skin pigment content of peanut proteins is described. The method is based on the fact that the pigments consist predominantly of a catechol tannin and related compounds which give a red product with characteristic absorption when heated with alcoholic hydrochloric acid.Any residue of red skins imparts color to peanut meals and protein products derived from them. Since this color is objectionable to the use of these products for industrial purposes and may be an important consideration in the future use of extracted peanut meal in foods, the method was applied to meals containing known amounts of skins and to proteins of known processing history. The results obtained indicate that the method may be used to estimate the degree of skin removal in the preparation of peanut meals and also to evaluate proteins for skin pigment content.

Pilot-plant development of the alkali-cooking process for cottonseed meats. III. Quantitative effect of cooking variables on solubility of meal nitrogen

Summary and ConclusionsA study was made of previously published data resulting from experimental cooking of cottonseed from the viewpoint of quantitative relationship between cooking conditions and denaturation of the protein as measured by the solubility of the meal nitrogen in 0.02N NaOH. It was observed that the rate of denaturation of hexane- and butanone-extracted cottonseed meal, autoclaved at constant temperature and moisture content for various lengths of time, closely followed the equation for a firstorder reaction. The average reaction velocity constant is 0.012. Since, in commercial oil mill operations, temperature and moisture content of the meats vary during cooking, an analysis of laboratory data obtained under such conditions was made, which resulted in an observation of an empirical relationship between rate of reduction of nitrogen solubility and the three principal factors which affect the rate of denaturation under practical conditions. The factors studied were moisture content, temperature, and duration of the cooking period. In these experiments the meats were adjusted to a constant pH of 8.2. Mathematical treatment of this observation led to an empirical formula relating cooking conditions and denaturation which correlated well with the cooking data. This formula indicates that the temperature increment above 135°F. in degrees F. has about the same effect, numerically, as the cooking time in minutes under the conditions studied. When the sum of these two factors is multiplied by the moisture factor