In the present study, we evaluated the changes in quality that can occur during the distribution of nonheated anchovy ( Engraulis japonicus) fish sauce after packaging. The pH values of all samples ranged from 5.5 to 5.8, and there were no significant differences ( P > 0.05) in pH among the samples during storage regardless of storage temperature or salt concentration. The initial total volatile base nitrogen concentration in all samples after bottling was 115 to 121 mg/100 mL, but this concentration increased gradually with storage time. After 1 year of storage, total volatile base nitrogen concentration had increased to approximately 170% of the initial concentration (166 to 194 mg/100 mL). Amino nitrogen increased slightly during storage but was significantly lower than the increase in amino nitrogen during general anchovy fish sauce fermentation with anchovy flesh. Most of the free amino acids increased slightly during the storage period regardless of storage temperature or salt concentration, but tyrosine and histidine increased and then decreased during the storage period. The histamine concentration of the anchovy fish sauce at a salt concentration of 20% was 43.3 mg/100 mL initially, but after 1 year the histamine concentration was 89.7 mg/100 mL in samples stored at 10°C, 102.6 mg/100 mL in samples stored at 25°C, and 116.8 mg/100 mL in samples stored at 35°C . Changes in putrescine and cadaverine concentrations were similar to those in histamine; concentrations increased about twofold from the initial concentrations after 1 year of storage. However, the rate of increase in putrescine from 4 months after storage was very high, and cadaverine slightly decreased by 12 months of storage. High scores for umami and aroma sensory characteristics were given to samples stored at 10°C, but samples stored 35°C were given high scores for rancid. Despite the overall low scores for aroma and umami for samples stored at 35°C, the quality of the anchovy fish sauce as a fermented food was considered acceptable.
We investigated the effect of initial freshness of raw oysters on the quality and storage period of oysters during freezing storage. The expressible drips of the oysters were more effused as the freezing storage period increased. Also, the lower the initial freshness of the oysters, the more drips were released after thawing. The pH values decreased slightly during freezing storage at -20 °C for 12 months, but there was no significant difference (p > 0.05) according to initial freshness of raw oysters. The initial glycogen contents of oysters before freezing was between 722 and 585 mg/100 g whereas the glycogen contents of the oysters after freezing for 12 months ranged from 667 to 522 mg/100 g. The initial TVB-N value of S-1 with freshness of "good quality" was 3.9 mg N/100 g, but gradually increased during the freezing storage period and its value was 7.9 mg N/100g at 12 months of storage. S-7 of with an initial TVB-N value of 15.2 mg N/100 g increased sharply during freezing storage, reaching a maximum of 36.2 mg N/100g at 8 months after storage and then slightly decreased to 32.2 mg N/100g at 12 months of storage. S-5 with an initial PV of 12.6 meq/kg showed the highest value of 33.7 meq/kg at the 10 months of storage and S-7 with an initial PV of 17.5 meq/kg showed the highest value of 44.6 meq/kg at 8 months of storage. PL of oysters decreased with increasing storage period regardless of their initial freshness in all samples, while FFA increased during freezing storage The scores of all sensory evaluation parameters of S-1, which is the freshest sample of raw oysters before freezing, showed little change until 4 months after storage, and their scores began to slowly decrease after 4 months of storage and still could be accepted (scores of more than 6.0) at the end of storage. Sensory evaluation scores on color, taste and odor of S-7 after 8 months of storage showed unacceptable score of 6 or less, and fishy and sour taste were slightly stronger at 12 months of storage. These results indicate that raw oysters with TVB-N and PV of 3.9 mg/100 g and 4.2 meq/kg can maintain oyster quality for more than one year at -20°C. On the other hand, it is suggested that raw oysters with TVB-N and PV of 15.2 mg N/100 g and 17.5 meq/kg may not be stored for more than 8 months at -20°C.
Fish snacks were prepared by adding starch, gelatin and oligosaccharide. Among the snacks with fish meat contents of 50, 60 and 70%, the salmon-70 and the conger-70 snacks (70% fish meat) received the highest score in sensory evaluation. The hardness of the snacks containing 50% or higher fish meat content tended to increase as the amount of added starch increased. The protein content of the salmon-70 snack was 32.4%, and for the conger-70 snack, it was 38.6%; salmon-70 snack (16.4%) contained more lipids than conger-70 snack (10.5%). The acid value (AV) and peroxide value (PV) of the fish snacks with high lipid contents increased with storage period. PV did not exceed the standard value during the storage period when applying the Codex standard for the seasoning dried laver. During the storage, the volatile basic nitrogen of the snacks was almost unchanged. Fatty acid composition of the salmon-70 snack containing only salmon frame, which was composed of 40% oleic acid, 16.4% linoleic acid, and 4.3% and 7.3% EPA and DHA, respectively. In the conger-70 snack, oleic acid (23.6%) and DHA (22.8%) were highest among the fatty acids, followed by palmitic acid (16.4%) (which the saturated fatty acid) and EPA, by 9.2%.
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