FISHERY BULLETIN: VOL, 69, NO. 3 

 Table 3. — Results of organoleptic evaluations and chemical analyses from experiment using two enzj-me preparations. 



The salt content in the brine was 20 ± 2% w/v 



The brine was analyzed as described earlier, 

 but with the omission of the amino-N determina- 

 tion. 



The results of the organoleptic evaluations and 

 the chemical analyses are shown in Table 3. 

 They show that, by the addition of enzyme 

 preparations to gutted herring, it is possible to 

 obtain a product with "maatjes-cured" organ- 

 oleptic properties. A high lipolytic activity, 

 however, seems to be undesirable. 



Both the biuret value and the total nitrogen 

 content in the brine increase during the ripening 

 period. There seems to be a relation between 

 the values found and the degree of ripening. 



ARTIFICIAL RIPENING OF 



FRESH SPENT HERRING WITH 



ENZYME PREPARATIONS LOW IN 



LIPASE ACTIVITY 



After the herring has spawned, the uptake of 

 food steps and the fat content decreases grad- 

 ually to relatively low values, e.g., 5 to 8"^^ . Since 

 the proteolytic activity of the appendices plyo- 

 ricae is low in this ijeriod, the fish as such is un- 

 suitable for the manufacture of maatjes-cured 

 herring. 



Fresh, spent herring, caught in February in 

 the Irish Sea were used. The protein content 

 was 17.1% and the fat content 5.2 '"^ . 



Activity of the enzyme preparations tested is 

 shown in Table 4. 



In view of the results obtained in the exper- 

 iment on spawning herring, the proteolytic ac- 

 tivity in the artificial maatjes-cured herring was 

 reduced in this experiment. 



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



gibbed; (c, d, e, f) gutted and added respec- 

 tively: 1.0 g Pr 34, 1.0 g Pr 35, 1.0 g Pr 11/66 

 and 55 mg W per kg of fish. The fish was kept 

 at 3° C for 3 weeks. One part of salt was added 

 to 10 parts of herring. 



The brine was analyzed as described earlier. 

 In analyses of the herring, 30 g of ground her- 

 ring fillets were homogenized with 100 ml of 

 water in an Ultra-Turrax mixer. The mixture 

 was heated to 80° C and, after cooling to room 

 temperature, filtered through fluted filter paper. 

 In the extract thus obtained, the same analyses 

 as earlier described for the brine were carried 

 out. Gel chromatography was performed as de- 

 scribed earlier. 



The results of the organoleptic evaluations 

 and the chemical analyses are shown in Table 5. 



The brines of the variations "gutted" and 

 "gutted + Pr 35" were chromatographed. The 

 results are plotted in Figures 3 and 4. 



With the preparations Pr 35 and Pr 11/66, 

 an acceptable product was obtained. W gave 

 rise to a good texture but developed le.ss flavor. 

 Pr 34 caused some ofll'-flavor, probably because 

 of the comparatively high lipolytic activity. It 

 seems to us that a lipolytic activity lower than 

 1 U/mg is desirable for a preparation which has 

 a protease activity equivalent to the minimum 

 activity required by NF XIII. 



Table 4. — Proteolytic and lipase activities of enzyme 

 preparations. 



650 



