CHAPTER XVI 

 FOOD MANUFACTURE 



IV. SYNTHESIS OF FATS AND PROTEINS 



At ordinary temperatures fats occur in plants as both solids and liquids. 

 The hquid fats are commonly called oils. The protoplasmic system of any 

 living cell seems to contain all the conditions necessary for the trans- 

 formation of sugar to fats or oils. This transformation may occur in light 

 or darkness, and in both plant and animal cells. You have probably 

 known for some time that fats may be formed from sugar in the human 

 body. 



Fat Synthesis 



First of all, sugar is transformed to glycerin (glycerol) and fattv 

 acids primarily by oxidation-reduction processes. Then 3 molecules of 

 fatty acid unite with 1 molecule of glycerin by condensation, and the 

 final result is a fat or oil. Many intermediate steps are involved, includ- 

 ing interactions with enzymes. The more obvious transformations may 

 be represented briefly: 



Sugar > Glycerin^ 



y > Water -|- Fat or oil 



Sugar > Fatty acids^ (condensation) 



(oxidation- 

 reduction) 



Many kinds of fatty acids are formed in cells. Among the more 

 abundant ones are palmitic (Ci.-.HsiCOOH), stearic (CitH^.-.COOH), 

 and oleic (Ci-Ha.iCOOH). When the proportion of carbon to oxygen in 

 sugar and in these fatty acids is compared, it is evident that the trans- 

 formation of sugar to fatty acids involves the liberation of chemically 

 bound oxygen. That is, it involves a reduction or energy-storing process; 

 a pound of fat has about 2/4 times as much potential energy as a pound 

 of sugar. Since this transformation may occur in plants in the dark and 

 also in the cells of animals, it is perhaps evident that the additional 

 energy in fats must come from the potential energy in sugar, that some 



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