and weight of control and experimental 

 extracts at different time intervals 

 yield information on the state of the 

 protein molecules and will help deter- 

 mine the correctness of this hypothesis. 



Figure 12.--Measuring the viscosity of a fish muscle pro- 

 tein extract. 



The second hypothesis will be tested 

 by measuring the change in moisture - 

 vapor equilibria of frozen- stored sam- 

 ples as a function of the degree of 

 denaturation of the samples. This will 

 furnish information as to whether dry- 

 ness and toughness in long-time frozen- 

 stored samples are merely different 

 manifestations of the same phenomenon 

 or whether they are independent pheno- 

 mena taking place through similar types 

 of reactions involving different chem- 

 ical groups. 



Reserach findings to date suggest 

 that sulfhydryl groups are involved 

 in the stability of fish nnuscle albumins 

 when exposed to severe conditions of 

 denaturation such as boiling. There is 

 also evidence to the effect that sulf- 

 hydryl groups play a role in the solu- 

 bility of globular proteins in the pres- 

 ence of increasing concentrations of 

 p-chloromercuribenzoic acid. 



CONTRACT RESEARCH 



In cases where the high degree of 

 specialization required cannot be fur- 

 nished by the Bureau's laboratories, 

 research work is carried out under 



contract by a cooperating university or 

 research institution. All contract re- 

 search projects are given close super- 

 vision by the Bureau laboratory that 

 services the area in which the research 

 is being conducted. 



During the period covered by this 

 report, four contract re search projects 

 have been carried out in the New 

 England area under the supervision of 

 the staff of this laboratory. These proj- 

 ects dealt with; (1) development of a 

 device for automatically detecting 

 bones in fish fillets, (2) bacteriological 

 evaluation of commercial fishery prod- 

 ucts, (3) on-the-spot assistance to ves- 

 sel owners and fishermen in improving 

 the handling of fish on Massachusetts 

 fishing vessels, and (4) a similar proj- 

 ect on improving the handling of fish 

 on Maine fishing vessels. The following 

 is a brief description of the activities 

 conducted under these projects during 

 this past year. 



Automatic Bone Inspection of 

 Processed Fish. 



Many fishery products are essen- 

 tially "boneless." However, in certain 

 products, it is almost impos sible to find 

 all of the bones by visual examination 

 or by feel. As a result, many con- 

 sumers are bone -conscious and often 

 inspect their fish quite thoroughly to 

 make sure it is bone free. Also, many 

 do not buy fish because they are afraid 

 of bones, particularly for children. 

 Fish that were guaranteed to be bone- 

 less would increase the consumer de- 

 mand for this food tremendously. 



The Barkley and Dexter Laboratories 

 in Fitchburg, Mass., under contract 

 with the Bureau, are working on the 

 development of a device which will 

 automatically detect bones in fish fil- 

 lets, fish sticks, and portions, and will 

 reject from the production line those 

 that contain bones. The major problem 

 is to find a suitable method to obtain, 

 define, and measure changes in resolu- 

 tion between the bone and flesh of these 

 fishery products. 



Investigations have been conducted 

 using various X-ray techniques for this 

 purpose. Specifically, survey-type 



