Agricultural and Biological Chemistry 



The Carbohydrates in Pasture Grasses 



The results of investigations made in cooperation with the U. S. Re- 

 gional Pasture Research Laboratory at Pennsylvania State University, 

 dealing with chemical changes in grasses as they mature, can be summarized 

 as follows : 



Eight grasses common to the Northeastern United States were grown 

 in small plots at State College, Pennsylvania, and analyzed for their major 

 organic constituents, particularly for the carbohydrates. Analyses were 

 made on samples taken during the spring months when the grasses were 

 normally cut for silage or hay. All of the grasses during this period of time 

 underwent continuous decreases in protein, acid-soluble ash, and ether ex- 

 tract, and showed a continuous increase in lignin. All varieties show^ed an in- 

 crease in crude fiber and in true cellulose and natural cellulose up to the 

 flowering stage and in some grasses up to the seed-dough stage. In some, 

 fiber decreased after the flowering stage. On the basis of changes in lignin 

 and fiber, lignin is perferred over fiber as a criterion of feeding value. 

 Highly significant positive correlations were found among lignin, cellulose, 

 and fiber, and among protein, ether extract, and acid-soluble ash ; significant 

 negative correlations were found between the constituents of the two groups. 

 On the basis of chemical composition alone, grasses high in feeding quality 

 appear to be, in order, reed canarygrass, Alta fescue, and Kentucky blue- 

 grass ; of low relative quality were timothy and red top ; intermediate were 

 bromegrass, orchardgrass. and tall oatgrass. 



In the second part of the project, chemical changes in grades in suc- 

 cessive cuttings at pasture stage were studied. The chemical analyses have 

 been completed and the results are being prepared for publication. 



T. G. Phillips 



Efifect of D-Amino Acids on Growth of Lactobacilli 



Some D-amino acids, when present in relatively high concentration, 

 repress growth of various lactobacilli. In some cases, the L-forms of these 

 amino acids cause a similar, but more moderate, repression, indicating that 

 these D-amino acids do not act as antimetabolites for the L-forms. That 

 the effect is not permanent is indicated by the fact that repressions were ob- 

 tained only when the incubation period was relatively short. This suggests 

 a possible conversion of the D- to the L-form before utilization. 



A. E. Teeri 



Chemical Studies Concerning the Determination 

 of Ascorbic Acid in Foods 



Results obtained during breeding trials to develop a high vitamin C 

 tomato variety have been compiled. The studies reveal the presence of an 

 enz3ane in the parent plant, but not in all the progeny. The enzyme is cap- 

 able of destroying ascorbic acid, and its presence (or absence) must be 

 taken into consideration in breeding work carried out to obtain tomato va- 

 rieties with high Vitamin C content. 



