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Pilot‐plant development of the alkali‐cooking process for cottonseed meats. III. Quantitative effect of cooking variables on solubility of meal nitrogen
Author(s) -
King W. H.,
Knoepfler N. B.,
Hoffpauir Carroll L.
Publication year - 1958
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02582740
Subject(s) - solubility , chemistry , cottonseed meal , cottonseed , denaturation (fissile materials) , nitrogen , water content , food science , moisture , meal , thermodynamics , organic chemistry , nuclear chemistry , soybean meal , raw material , physics , geotechnical engineering , engineering
Summary and Conclusions A 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% m o i s t u r e + 10 100 , an approximate, consistent value is obtained which is commensurate with the reduction in nitrogen solubility of the meal cooked under those conditions. The observation suggests the desirability of continuing the study with additional, carefully obtained data under laboratory and plant conditions. It is entirely possible that experiments designed to show the independent effect of moisture content on denaturation at constant temperature may help to explain the theoretical basis for the the equation developed. Such information should be a valuable addition to the knowledge of protein chemistry.