FISHERY' BULLETIN: VOL, 69, NO. 3 



not differ essentially from that of the gibbed 

 herring brine (Figure 2). With the methods 

 used, no obvious difference was found between 

 the natural and the artificial ripening pro- 

 cess. 



THE ARTIFICIAL RIPENING OF LEAN 



HERRING AND ITS RELATION TO 



CHANGES IN THE RESULTS OF BRINE 



ANALYSIS 



Fresh herring caught in the North Sea at the 

 beginning of April were used. The protein 

 content was 16.7%; fat content, 10.6%. 



Two variations were studied: (a) gutted; 

 (b) gutted and with 1.0 g of Pr 35 per kg of 

 herring added. One part of salt was added to 

 10 parts of herring. The fish was kept at 3° C. 

 Samples for analysis were taken after 11, 17, 

 24, and 31 days. Organoleptic evaluation was 

 carried out after 24 days. 



The brine was analyzed as described ear- 

 lier. 



After 24 days at 3° C, organoleptic evaluation 

 showed: variation (b) had a soft texture and a 

 well-ripened flavor, whereas variation (a) was 

 still firm and had less flavor. 



Results of chemical analysis of the brine are 

 plotted in Figure 5 and summarized in Table 6. 



The salt content in the brines was 16 ± 2% 

 w/'v. 



During the ripening process there is a steady 

 increase in biuret value, total N, and amino N 

 in the brine. This finding demonstrates again 

 the relation between these values and the degree 

 of ripening. 



THE ARTIFICIAL RIPENING OF FRESH 



LEAN HERRING WITH DIFFERENT 



AMOUNTS OF A PROTEASE 



PREPARATION 



Fresh spent herring caught near the Hebrides 

 in August was used. This herring contained 

 17.4% of protein and 8.2% of fat. 



In this experiment an enzyme pi-eparation 

 CH 32/67 A was tested, with a proteolytic ac- 

 tivity of 1.93 times NF XIII units and a lipolytic 

 activity of 0.3 Desnuelle units per mg. 



One part of salt was added to 10 parts of fish. 

 Six variations were tested: (a) gutted; (b) 

 gibbed; (c, d, e, f) gutted and 0.5, 1.0, 2.0, and 

 5.0 g of CH 82/67 A added, respectively. The 

 fish was kept at 3° C for a month, then evaluated 

 and analyzed. 



The brine was analyzed as discussed earlier. 

 Results are shown in Table 7. 



J 8o 2500 



7.0 itm. 



z 6.0 > 1500 



< a 



° S.O m 1000 



Total n 

 biuret value 



AMINO N 





Figure 5. — Results of analyses 

 of clarified brines of gutted her- 

 ring with and without addition 

 of Pr 35, in experiment on the 

 artificial ripening of lean herring 

 and its relation to changes in the 

 result of brine analysis. 



30 

 DAYS STORED 



652 



