Changes in ATP and related compounds, TMAO, TMA, creatine and creatinine were analyzed to establish the processing conditions for rapid- and low salt-fermented liquefaction of anchovy(Engrulis japonica) extracts during fermentation. Experimental sample A: chopped whole anchovy, adding 20% water, heating at 50℃ for 9 hrs and then adding 10% NaCl. Sample B: chopped whole anchovy, adding 20% water, heating at 50℃ for 9 hrs and then adding 13% NaCl. Sample C: chopped whole anchovy adding 13% NaCl. Sample D: whole anchovy adding 17% NaCl. ATP, ADP, AMP and IMP were broken down during fermentation period, while inosine and hypoxanthine or hypoxanthine were detected in each fermented liquefaction of anchovy. However the amounts of them were varied from collection to collection according to the pretreatment methods. Possibly ATP and their related compounds will not make a great contribution to the umami taste in fermented liquefaction of anchovy. The contents of TMAO were decreased during fermentation period, ranging from 3 to 15 mg/100g in the fermented liquefaction of anchovy after 180 days. The TMA contents were increased slowly during fermentation period, ranging from 60 to 114 mg/100g in the 180 days specimens, however their contents were varied from sample to sample. The contents of creatine and creatinine were increased during early fermentation period, and then they were decreased in the last period. As for distribution of nitrogen in the anchovy extracts, the contribution of creatine and creatinine to the extractive nitrogen was occupying 6.8, 5.7, 4.6 and 5.7% in the experimental sample A, B, C and D, respectively. The contribution of ATP and related compounds to the extractive nitrogen was occupying 2.1, 2.4, 2.2 and 2.7% in the experimental sample A, B, C and D, respectively. The contribution of TMAO and TMA to the extractive nitrogen was very low as they are occupying 0.7~1.2% in the four experimental samples.
In order to establish the processing conditions for salt-fermented liquefaction of anchovy(Engrulis japonica), changes in the amino acid composition from oligopeptides during fermentation periods were analyzed. Experimental sample A: chopped whole anchovy, adding 20% water, heating at 50℃ for 9 hrs and then adding 10% NaCl. Sample B: chopped whole anchovy, adding 20% water, heating at 50℃ for 9 hrs and then adding 13% NaCl. Sample C: chopped whole anchovy adding 13% NaCl. Sample D: whole anchovy adding 17% NaCl. The total amino acids from oligopeptides in fermented liquefaction of anchovy increased in early fermentation period and reached highest level, and then they declined irregularly during fermentation. Their maximum amounts were just after heating at 50℃ for 9 hrs in sample A, after 15 days in sample B, and after 60 days in samples C and D. The fermented liquefaction of anchovy extracts were rich in glutamic acid, aspartic acid, proline, glycine, alanine, lysine and valine. However, the contents of most amino acids fluctuated by the experimental specimens and fermenting periods. Among them glutamic acid was the most abundant amino acid which was occupied 0.6~27.7%(average 24.0%) in the content of total amino acids from oligopeptides. The contribution of the amino acid composition from oligopeptides to extractive nitrogen was occupying average 20.8 and 17.5% in rapid- and low salt-fermented liquefaction(sample A, B and C) and traditional fermented liquefaction(sample D), respectively.
In order to establish the processing condition of rapid- and low salt-fermented liquefaction of anchovy (Engrulis japonica), effect of temperature on crude enzyme activity of anchovy viscera, pretreatment conditions, and the minimum content of adding NaCl were investigated. The minimum limitation of NaCl content for anchovy liquefaction was 10%. Sample A(water adding, heating, adding 10% NaCl): chopped whole anchovy adding 20% water and then heating for 9 hrs at 50℃ and then adding 10% NaCl and then fermented at room temperature(8-29℃) for 180 days. Sample B(water adding, heating, adding 13% NaCl): chopped whole anchovy adding 20% water and then heating for 9 hrs at 50℃ and then adding 13% NaCl and then fermented at room temperature for 180 days. Sample C(adding 13% NaCl): chopped whole anchovy and then adding 13% NaCl and then fermented at room temperature for 180 days. Sample D(adding 17% NaCl): whole anchovy adding 17% NaCl and then fermented at room temperature for 180 days. The content of free amino acids such as aspartic acid, serine and threonine fluctuated severely according to the pretreatment methods. Possibly they might be recommend quality indices of standardization for salt-fermented liquefaction of anchovy. As for the relation between fermentation period(X) and individual free amino acid(Y), five kinds of free amino acids such as glutamic acid, valine, glycine, lysine, and alanine showed highly significant in their coefficient of determination in most of samples. They might be recommend as quality indices for salt-fermented liquefaction of anchovy during fermentation. The difference of taste between products of the rapid- and low salt-fermented liquefaction and the traditional salt-fermented liquefaction were caused by their composition of the free amino acids ratios, in which were umami, sweet, and bitter taste in the extracts of anchovy during fermentation. The appropriate fermentation period of the sample A was shorten 30 days than the sample B and 60 days than the samples C and 90 days than the sample D in the processing of anchovy.