| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 92 === The 15 samples of dried flying fish were collected from southern and eastern area in Taiwan to investigate their appearance, chemical composition, biogenic amines contents and sensory acceptance. The chemical composition of fresh fish was analyzed for comparison with those of dried fish. Changes in the quality of dried fish during storage at different temperatures were also studied.
The appearance and package types of the products were different. Except for Shaeu-Liou-Chyou’s sample packed in a bag and Dong-Gaang’s sample in vacuum-package, the hygienic condition and package of other samples were not meet the requirement of consumers.
The flying fish had a higher protein and lower lipid content. The major free amino acids were histidine (85.2%) and taurine (8.1%). The profile was similar to that of migratory fish. However, the pH value (6.36±0.01) was higher than those of dark-fleshed fish which were rich in histidine.
There was a significant difference in salt content among the products of different areas. The samples collected from the same area had a similar content. The average salt added in fish was 4.83±3.05%, which was the limited value for grouping the dried product, for sold (Group A) and for producers themselves (Group P). Group A products purchased from Dong-Gaang, Ken-Ting, Dong-Her and Cherng-gong had a lower salt content
than this value to meet the requirement of consumers. Group P collected from Fang-Liau, Lan-yeu and Nan-Fang-Aw had a higher salt content to extend storage shelf-life.
A significant difference in the degree of dehydration between two groups was also found. Water activity (Aw) of Group A ranged from 0.77 to 0.97; therefore, the products needed frozen storage. The samples of Group P had Aw with 0.65 to 0.79, they could be stored at ambient temperature.
The lipid oxidation of dried flying fish was found in many products. Group P with lower Aw had more serious oxidation than Group A. Although he quality of dried fish were acceptable, but the contents of biogenic amines particularly histamine were higher. The results of sensory evaluation indicated that the products with lower salt content, higher Aw (much more softer), and seasoned (or smoked) treatment were more acceptable.
The results of storage tests indicated that the shelf-life of lower moisture samples stored at ambient temperature was 3 months, and that in higher moisture samples stored at 4 oC was 5-7 days. The latter products needed refrigeration storage.
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