The effect of processing conditions on the properties of screw‐press cottonseed meal and oil

Abstract

SummaryProcessing conditions, particularly cooking procedures, have a marked influence on the chemical properties of screw‐pressed meal and oil. Cooking prepared meats at 240–250°F., as in normal mill practice, produced meals with low free gossypol content but at the expense of considerable protein damage. The resultant crude oils showed some color reversion upon storage at 95°F. Dry cooking (7% moisture) at temperatures not exceeding 200°F. gave meals of improved chemical properties, but the crude oils exhibited considerable color reversion on storage.Wet low‐temperature cooking (200–210°F.), followed by evaporative cooling, yielded a meal intermediate in quality between that for normal mill practice and dry low‐temperature cooking. The crude oils, which corresponded to hydraulic‐pressed oil, did not exhibit any appreciable color reversion upon storage at elevated temperatures.The selection of processing conditions, notably cooking, enables wide variations in the distribution of gossypol between meal and oil.The increase in the bleach color of crude oils stored at 95–100°F. was found to be directly related to the initial gossypol content of the crude oils.

Trials to improve the colour of colour fixed cottonseed oil using sodium oleate and sodium stearate in the absence and presence of azeotropic extract of cottonseed meal

“…This efficiency may be probably due to the alkaline character of sodium stereate as well as sodium oléate. From previous investigations, gossypol proved to be the responsible factor for colour fixation of cottonseed oil (1,6,14). Colour fixation is more pronounced in the refined and bleached oil samples, also in the fixed refined and bleached oil samples containing gossypol.…”

A comparison of five commercial solvents for extraction of cottonseed

“…The high percentage of the original gossypol in each batch of flakes, which was shown (Table V) to be unaccountable, evidently had degraded or altered into a form which no longer reacted as gossypol on analysis. This alteration of gossypol, which has been reported to result in the formation of very dark pigment materials (25), could have occurred only after extraction from the protective glands in which gossypol occurs (41) and while in solution in the miscella, and become a component of the crude oil. The maximum amount of non-oil material in each of the different solvent-extracted crude oils attributable to gossypol, gossypol-like compounds, and gossypol degradation products is shown in Table VII, column 8.…”

“…The high thiamine content of all five meals, ranging from 33.5 to 35.0 p.p.m, is of interest since the thiamine content of most commercial meals is well below this value. It has been reported recently that the thiamine content of a meal parallels its biological value (25).…”

The Glandless Leaf Phenotype in Cotton and its Association with Low Gossypol Content in the Seed1

“…The quantity in the seed varies with variety, season, and location where grown ( 3,7,10). The usual processing of cotton seed imparts color from gossypol into the oil (1,12) and reduces the nutritive value of the meal by effecting a combination of gossypol with the protein from the seed 3 (2, 5). Gossypol affects the economy of the cotton industry and results in a system of discounted prices for cotton seed products, thus a reduction in gossypol content is desirable (1).…”