碩士 / 中臺科技大學 / 食品科技研究所 / 100 / 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.
| Identifer | oai:union.ndltd.org:TW/100CTC05252001 |
| Date | January 2012 |
| Creators | Ming-Yu Chiu, 邱名玉 |
| Contributors | Ju-wen Wu, 吳如雯 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 108 |
Page generated in 0.0109 seconds