38 MASS. EXPERIMENT STATION BULLETIN 378 



Texture is also highly correlated with dry matter (starch) or moisture 

 content. This relationship has been confirmed by additional analyses for 

 these constituents. It has been found that the specific gravity of the 

 potato closely parallels the average moisture content, but that different 

 parts of a tuber may vary considerably in moisture, specific gravity, and 

 texture. When the moisture content of raw potatoes was substantially 

 and uniformly increased, the specific gravities and, in many cases, the 

 texture scores were lower than in the controls. The results, however, did 

 not conclusively demonstrate a causal relationship between moisture con- 

 tent and texture. Moisture content of potatoes was successfully lowered 

 only at higher temperatures, and these moisture losses were not uniform. 

 Tubers lost 40 percent of their total moisture while the interior flesh lost 

 only 1 to 3 percent. 



The moisture-texture relationship has been investigated by studying 

 the water-binding capacity of potato tissue and starch. Since none of the 

 usual methods for the determination of bound water have been entirely 

 satisfactory for these materials, modifications and their application to 

 various starches and potato samples have been studied. 



Progressive Decomposition of Fish Muscle. (W. S. Ritchie and P. N. 



Simon.) Clianges in the physico-chemical nature of the proteins should 

 mark the first stages in the progressive decomposition of fish muscle. 

 Attempts to detect such changes have been made by extracting or pep- 

 tizing fresh haddock muscle with water and with sodium chloride solu- 

 tions of different concentrations and at different temperatures. 



Typical peptization curves were indicated by the total nitrogen ex- 

 tracted. The maximum amount was obtained with 10 percent sodium 

 chloride at 0°C for a 24-hour period. The slope of the curve varied with 

 the time and temperature of extraction. Significant differences in the 

 coagulable and non-coagulable protein fractions were obtained at 0° and 

 25° C with certain salt concentrations; but there was no significant change 

 in the values obtained at 0°C with storage up to eleven days. There was, 

 however, an apparent but unexplained increase in the total nitrogen of 

 haddock muscle with storage time. 



Twelve pounds of haddock muscle were stored for twenty days at 

 10° to 12°C and decomposition products were extracted with solvents. 



An ethyl alcohol extract yielded a dark-brown gummy residue which 

 was soluble in water but insoluble in ether and acetone. The components 

 of this residue could not be separated or crystallized by dehydration. 

 Separation by electrodialysis resulted in decomposition of the components 

 at the cathode. Treatment with HCl effected only a partial crystallization. 



N-butyl alcohol yielded mixtures of decomposition products that were 

 easily decomposed by such mild treatment as vacuum distillation. Picrate 

 derivatives were prepared, however, with some measure of success. Of 

 the sixteen picrate preparations some were very unstable on recrystalliza- 

 tion; all decomposed when heated in melting-point tubes. Identification 

 of the picrate derivatives is being attempted by ultimate analysis. 



The Influence of Base Exchange Capacity and of Exchangeable Ions in 

 Massachusetts Soils on the Availabilty of Potassium. (Dale H. Sieling.) 

 Samples of representative soils of Massachusetts have been collected and 

 are being prepared for laboratory investigation. The various horizons of 

 sixteen soils have been included in this collection, and from these samples 



