|Abstract: ||中文摘要 本研究探討吳郭魚(Oreochromis niloticus x O. aureus)、烏魚(Mugil cephalus) 及虱目魚 (Chanos chanos)等國內大宗養殖魚類魚鱗之一般成分、膠原蛋白萃取與去灰分條件、膠原蛋白類型與特性、胺基酸組成及其酵素水解物之抗氧化性與細胞增生效果。吳郭魚、烏魚、養殖及野生虱目魚魚鱗之蛋白質含量分別為48、54、61及56%，灰分則為45、41、36及38%，養殖與野生虱目魚魚鱗以0.2 M HCl處理30分鐘，吳郭魚及烏魚以0.3 M HCl處理40分鐘去灰分，粗膠原蛋白收率皆在45%以上。四種魚鱗膠原蛋白均含有相異的α-chain，α1及α2，為TypeⅠ類型，養殖與野生魚間無差異，而其SDS-PAGE圖譜與牛皮Type I膠原蛋白類似，胺基酸組成以Gly、Pro、Hyp及Ala等含量較高。吳郭魚魚鱗粗膠原蛋白以2% Alcalase、3% Protease Type ⅩⅣ及1% Collagenase進行一次及二次水解0、1、2、3、4及5小時後，評估水解物清除DPPH (α,α-diphenyl-β-picrylhydrazyl)自由基、還原力及螯合銅離子能力，結果顯示以2% Alcalase 在50℃下水解4小時之抗氧化性較強。水解1小時後游離及複合胺基酸含量分別增加3.5與2倍，似與抗氧化性增強有關。經超過濾依分子量將水解液劃分，其中5~10 kDa及< 5 kDa之清除DPPH能力較強，還原力則隨分子量增加而有增加的趨勢，分子量5~10 kDa 及< 5 kDa之螯合銅離子能力高於> 10 kDa之水解物，水解物小分子胜肽類具較強抗氧化性。吳郭魚魚鱗純膠原蛋白、>10 kDa、5~10 kDa及< 5 kDa之酵素水解物對人類角質細胞株細胞存活率分別為113%、149%、136%及133%，均高於控制組，顯示水解物在適當濃度下具有促進細胞生長能力。|
Abstract The objectives of this study are to investigate the proximate composition, amino acid constituents, decalcifying condition for extraction of collagen, collagen type and characteristics of fish scales from tilapia (Oreochromis niloticus x O. aureus), striped mullet (Mugil cephalus), and milkfish (Chanos chanos). The antioxidant activities and cell viability of collagen hydrolysates were also studied. The crude protein contents of tilapia, striped mullet, cultured and wild milkfish scales were 48, 54, 61 and 56%, and ash contents were 45, 41, 36 and 38%, respectively. The decalcification condition for milkfish scales (cultured and wild) was 0.2 M HCl treatment for 30 min, and tilapia and striped mullet were 0.3 M HCl for 40 min. The yield of collagen extracted from all fish scales was higher than 45%. Four kinds of fish scale collagen were heterotrimers with α-chain, α1 and α2, indicating that these scale collagen were Type I collagen. No difference was observed between cultured and wild fish. The profiles of SDS-PAGE were also similar to that of calf skin collagen Type I. The dominant amino acids of collagen were Gly, Pro, Hyp and Ala. The crude fish scale collagen of tilapia was treated with 2% Alcalase (w/w), 3% Protease type ⅩⅣ and 1% Collagenase for 0, 1, 2, 3, 4 and 5 hour. The antioxidant activites of the hydrolysates were measured using the methods including the scavening effect on α,α-diphenyl- β-picrylhydrazyl (DPPH) radical, reducing power and chelating ahilities of metal ion Cu2+. Results showed the highest antioxidant activity was found in 2% Alcalase hydrolysates at 50℃ for 4 hour. Free and combined amino acids increased by 3.5 and 2 times after 1 hour hydrolysis. The increased free and combined amino acids might be associated with the increase of antioxidant activity. The Alcalase hydrolysates were then separated by ultrafiltration, and the fraction with MW 5~10 kDa and <5 kDa were observed to have the highest scavening effect on DPPH radical. Reducing power increased with increasing MW of the UF fraction. The chelating of Cu2+ for MW 5~10 kDa and <5 kDa were higher than that of >10 kDa. Results indicated the peptides of hydrolysates possessed antioxidant activities. The cell viability of human keratinocye treated with tilapia scale collagen and it hydrolysate with MW >10 kDa, 5~10 kDa and <5 kDa were 113%, 149%, 136% and 133%, respectively. Results revealed that tilapia scale collagen and its hydrolysate with proper concentration could enhance the growth of human keratinocyte.