Free gossypol

Studies incorporating cottonseed into many different foods have yielded acceptable products with improved protein quantity and quality. The presence of free gossypol and cyclopropenoid fatty acids (CPFA) potentially limits the use of cottonseed in human foods. 

The levels of free gossypol and CPFA are reduced in processing the seed and preparation of food. The amount of free gossypol and CPFA in the food as eaten should be determined. The American Oil Chemists ... 

A protocol approved by the FDA to determine the safety of low gossypol cottonseed kernels for human consumption was the basis for the second study by Reber (7 ). To prepare raw cottonseed flour, raw kernels were ground to meet Ro-tap sieve specifications of lab chow. To prepare roasted cottonseed flour, raw kernels were dry roasted at not less than 121°C for not less than 5 min. To prepare cooked cottonseed flour, raw kernels were cooked in steam until batch temperature had been at or above 121°C for 5 min. All cottonseed kernels were ground in the manner described above. The kernels contained not more than 0.037% (370 ppm) of free gossypol. They were free of Salmonella and did not contain detectable amounts of aflatoxin. The proximate analyses of the cottonseed flours are shown in Table I. 

Table VI. Percentage of Free Gossypol Change in Food Products...

Method of Preparation Food Product Change in Free Gossypol,%... 

Research studies concluded that diets containing 200 ppm or less of free gossypol as cotton-seed meal was safe for Holstein calves. At 400 ppm, there was an increase in cardiovascular and lung lesions, leading to increased calf losses. Mature beef cows can be safely fed cotton-seed meal as their entire protein supplement as this is generally kept relatively low, whereas dairy cows should not receive more than 3.6 kg/head/day (reviewed by Cheeke, 1998). 

TABLE 7. Reported Effect and No Effect Levels of Free Gossypol (35). 

When cottonseed first underwent direct extraction with hydrocarbon solvents, large amounts of free gossypol remained in the meal, causing a serious complication. As... 

Barraza, M. L., Coppock, C. E., Brooks, K. N., Wilks, D. L., Saunders, R. G., and Laimer, G. W., Jr. (1991). Nutrition, feeding, and calves-iron sulfate and feed pelleting to detoxify free gossypol in cottonseed diets for dairy cattle. Dairy Sci. 74, 3457-3467. 

Bressani, R., Elias, L. G., Jarquin, R., and Brham, J. E. (1964). All-vegetable protein mixture for human feeding Effect of cooking mixtures containing cottonseed flour on free gossypol content. Food Tech. 18,1599-1603. 

Calhoun, M. C., Huston, J. E., Kuhlmann, S. W., Baldwin, B. C., Jr., Engdahl, B. S., and Bales, K. W. (1990b). Comparative toxicity of gossypol acetic acid and free gossypol in cottonseed meal and Pima cottonseed to lambs. In "Sheep and Goat, Wool and Mohair, Research Reports. PR 4779." Texas A M University System, College Station, TX. 

---