| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 97 === Hagfish is the most primitive non-jaw vertebrate which was mainly distributed in Yilan, Pingtong and Taitung areas of Taiwan. The main purposes of this research are to investigate the changes in chemical compositions of hagfish tissues during storage and their antioxidant activities of enzymatic hydrolysates. The pH value of Eptatretus burgeri muscle increased gradually during storage at 25℃. When stored at 4℃, however, the pH value decreased and then increased. For mucus glands, no significant changes in pH value were found. The volatile basic nitrogen (VBN) in the initial stage of the muscle was 5 mg/100 g. After storage at 4℃ for 12 days, VBN exceeded the limited value of 25 mg/100 g, and the value reached 37.87 mg/100 g after storage at 25℃ for 24 hours. The increase of VBN in the muscle was more quickly than that of mucus gland. The dominant ATP-related compounds in the muscle and mucus gland were uridine monophosphate (UMP), inosine-5’-phosphate (IMP), inosine (HxR) and hypoxanthine (Hx). No significant change in the UMP was found during storage. But the decomposition of IMP and HxR resulted in the accumulation of Hx. K value increased during storage, and mucus glands showed more significant changes. The major free amino acid (FAA) of muscle and mucus glands was proline. The total FAA amount increased in the beginning and decreased in the later stage of storage at 4℃and 25℃. The scavenging effect of DPPH radical significantly increased after storage at 4℃ for 9 days and 12 days, but no significant change was found at 25℃. Reducing power showed no marked difference between tissues during storage. The chelation of ferrous ion of the muscle decreased gradually during storage. For mucus glands it increased in the beginning and decreased in the later stage of storage at 4℃, but increased at 25℃.
The soluble protein of Eptatretus okinoseanus muscle and mucus glands hydeolysates with Alcalase and Protamex increased during hydrolysis, but fish skin hydrolysate decreased gradually. The amino group of three tissue hydrolysates increased gradually during hydrolysis, of which fish skin hydrolysate had the highest value. The predominant FAA in Eptatretus okinoseanus muscle, skin and mucus glands was proline, accounting for 15% to 19% of the total FAA. The FAA of Protamex skin hydrolysate decreased after 15 hour hydrolysis, but other tissue hydrolysates increased gradually during hydrolysis. The amino group of Protamex hydrolysate had a higher amount than Alcalase. The total constituted amino acid (CAA) in fish skin hydrolysate was higher than that of other hydrolysates. The production of peptides with Protamex hydrolysis on the muscle had the higher efficiency than Alcalase. The scavenging effect of DPPH radical of all hydrolysates increased significantly with the hydrolysis time, and the muscle hydrolysate had the highest ability. All tissue hydrolysates possessed the ability to inhibit linoleic acid autoxidation. The reducing power of all hydrolysates showed no significant change during hydrolysis. In addition, the ferrous ion chelation of the hydrolysates decreased with the increase of time.
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