狗母魚 （Trachinocephalus myops）內生蛋白酶與食品添加物對於魚漿煉製品凝膠能力的影響

The influence of endogenous proteinase and food additives on the gel-forming ability of lizardfish （Trachinocephalus myops）surimi

邱名玉(Ming-Yu Chiu)

指導教授 ： 吳如雯

中臺科技大學/健康科學院/食品科技研究所/碩士(2012年)

摘要

大頭花桿狗母魚（Trachinocephalus myops）主要因為價格低廉與白度高，一般在魚漿煉製品加工過程中，作為蛋白質增加魚漿形膠能力，並增加魚漿之重量的添加物，但是魚漿的內生蛋白酶活性所造成的弱凝膠能力可能限制它的使用價值。 本論文研究大頭花桿狗母（Trachinocephalus myops）魚漿造成自解作用的蛋白酶之生化特性以及探討內外在因素對於狗母魚漿煉製品凝膠能力之影響。方法包括探討外在因素如pH、溫度與鹽濃度對於狗母魚漿蛋白酶自解活性的影響，並利用化學抑制劑鑑定狗母魚漿造成自解活性的蛋白酶特性。另外探討食用級添加物對於狗母魚漿自解活性與凝膠能力之影響。 結果顯示狗母魚漿內生蛋白酶自解最適活性分別在pH 8.5及60℃。在抑制劑研究中，Serine 型蛋白酶抑制劑，如AEBSF與蕃茄葉萃取物，顯著抑制狗母魚漿自解活性。此外，狗母魚漿添加0-5 %之食鹽，似乎不影響狗母魚漿蛋白酶自解活性。 在溫度靜置試驗中，結果顯示煉製品形膠條件以4℃靜置8小時後再水煮95℃，15分鐘效果最佳，另外60/95℃的加熱方式明顯降低魚漿煉製品的凝膠強度，依據TCA可溶性胜肽結果顯示，主要是因為內生蛋白酶在60℃被活化。 在多醣類添加物對於狗母魚漿凝膠強度的研究中，魚漿煉製品膠的破裂度及變形度均隨著馬鈴薯澱粉或卡德蘭膠添加量的增加而提高，尤其是添加20 %馬鈴薯澱粉的狗母魚漿煉製品膠強度最高。然而添加4 %以上的卡德蘭膠雖可增加破裂度，但變形度與摺疊試驗相對減少。至於蛋白質添加物部份，則以添加2% 猪血漿蛋白使狗母魚漿煉製品的膠強度最高，其次依序為蛋白、大豆蛋白、最後為乳清蛋白。其質地測定結果與狗母魚漿 II 自解活性被抑制的結果相符合，2 % 猪血漿蛋白、蛋白、大豆蛋白及乳清蛋白分別抑制魚漿內生蛋白酶活性為83.03 %、78.20 %、64.69 %、49.37 %。 在色澤方面，兩種醣類添加物隨著含量增加，狗母魚漿煉製品白度均相對降低。而蛋白質添加物中，猪血漿蛋白粉與濃縮乳清蛋白隨著蛋白質含量增加煉製品白度也隨著降低。只有添加蛋白對於色澤亮度與白度有顯著性上升。此外，大豆蛋白的添加在白度上並無較大差異。 綜合以上結果，蛋白質添加物可以有效抑制狗母魚漿自解活性及在加熱過程中改善狗母魚漿的凝膠能力。

關鍵字

狗母魚 ； 蛋白酶 ； 膠強度 ； 魚漿 ； 靜置 ； 煉製品

並列摘要

Lizardfish (Trachinocephalus myops) surimi is commonly used for a additive in surimi-based product processing because of the low price and appreciable whiteness. However, the poor gel-forming ability of lizardfish surimi caused by endogenous proteinase activities might limit their use value.
The objective of this study is to determine the biochemical properties of the autolytic proteinases in lizardfish surimi and to investigate the influence of intrinsic and extrinsic factors on gel-forming ability of lizardfish surimi. The influence of extrinsic factors, e.g. pH, temperature and NaCl on the autolytic activities in lizardfish surimi is investigated. Chemical inhibitors are used to characterize the proteinase(s) with autolytic activities in lizardfish surimi. On the other hand, effect of food grade additives on autolytic activity and gel-forming ability of lizardfish surimi are determined.
The results indicated the optimal pH and temperature for autolytic activities of lizardfish surimi were 8.5 and 60℃, respectively. Based on the inhibitor study, autolytic activities of lizardfish surimi are significantly inhibited by serine type proteinase inhibitors, i.e. AEBSF and tomato leaves extract. Furthermore, the salt, NaCl at a level of 0-5 % (w/w) seems not to affect the autolytic activities of lizardfish surimi apparently.
In the test of temperature setting, the optimal gel strength of lizardfish surimi-based product is obtained by 4℃ setting for 8hr following by 95℃ cooking for 15 min. On the other hands, the gel strength of lizardfish surimi-based products is significantly reduced while cooking at 60/95℃ condition. Based on TCA-soluble peptide assay, it is shown that the deterioration of gel-forming ability for lizardfish surimi results in endogenous proteinase activated at 60℃.
In the study of effect of food grade additives on lizardfish surimi gelling ability, breaking force and deformation of lizardfish surimi gels added with potato starch or curdlan increased as the amount of potato starch or curdlan
IV
added increased. In particular, lizardfish surimi-based products mixed with potato starch at a level of 20 % gained the highest gel strength. However, deformation and folding test of lizardfish surimi gels started to decrease added with curdlan at a level of 4 % even though breaking force increased. On the part of protein additives, the highest gel strength of lizardfish surimi-based products was obtained by porcine plasma proteins added up to 2 %, followed by egg white proteins, soybean protein iosolate, and whey protein isolates, the last. This result of texture test was in agreement with the outcome in TCA-soluble peptide assay for lizardfish surimi autolytic activity inhibition. The porcine plasma protein, egg white protein, soybean protein isolates and whey protein isolates showed the inhibition of 83.0 %, 78.2 %, 64.7 % and 49.4 % against autolytic activities in lizardfish surimi, respectively.
In the color test, the increase of potato starch or curdlan added in the lizardfish surimi caused the decrease in whiteness. The increase of porcine plasma protein or whey protein isolates added in the lizardfish surimi also caused the decrease in whiteness. Only the increase of egg white added in the lizardfish surimi caused the increase in L value and whiteness. Furthermore, there is no significant difference in whiteness with soybean protein isolates addition. In conclusion, protein additives might effectively inhibit the autolytic activities and improve the gel-forming ability in lizardfish surimi during heat processing.

並列關鍵字

proteinase ； surimi ； Lizardfish ； surimi-based products ； setting ； gel strength

參考文獻

林裕閔，2003。雞胸肉鹽溶性蛋白質與乳清蛋白熱交互作用之研究。靜宜大學食品營養研究所碩士學位論文，台中。

張家銘，2008。Stenotrophomonas maltophilia PU-LS07 角蛋白酶之純化與特性研究。靜宜大學食品營養研究所碩士學位論文，台

Reppond, K. D. 1993. Evaluation of protease inhibitors in Pacific whiting surimi. Journal of Aquatic Food Product Technology. 2:79-95.

Akahane, Y., and Shimizu, Y. 1989. Effect of pH and sodium chloride on the water holding capacity of surimi and its gel. Nippon Suisan Gakkaishi. 55:1827-1832.

Alvarez, C., Couso, I. and Tejada, M. 1995. Sardine surimi gels as affected by salt concentration, blending, heat treatment and moisture. Journal of food science. 60:622-634.