The effects of enzymatic hydrolysis of casein on apparent yield stress and some emulsion properties
The effects of enzymatic hydrolysis of casein on apparent yield stress and some emulsion properties
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DOI：
10.1016/j.foodhyd.2005.04.003
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发表时间：
2006-06
影响因子：
10.7
通讯作者：
Y. Tunçtürk;Ö. Zorba
中科院分区：
文献类型：
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作者：
Y. Tunçtürk;Ö. Zorba
本研究采用中性蛋白酶对酪蛋白进行不同水平的蛋白质降解，研究了蛋白质降解对酪蛋白乳化力(EC)、乳状液稳定性(ES)、乳状液密度(ED)和表观屈服应力(AYS)的影响。为了阐明蛋白质降解对蛋白质的影响，对不同水平的蛋白质进行了尿素-PAGE和SDS-PAGE分析。蛋白水解度、EC、Es、ED、Ays值与蛋白质水解度有极显著差异(p<；0.01)。在试验中，酶和酶抑制剂(乙二胺四乙酸，EDTA)对参数没有显著影响(p>；0.05)；这种差异被发现与蛋白质分解的结果有关。蛋白水解率在20min时迅速增加，80min后缓慢增加。还观察到酪蛋白组分的尿素-PAGE和SDS-PAGE图谱与蛋白水解度完全一致，但主要蛋白条带因时间的推移而显著减弱。直到80min，观察到新的多肽带的组成，但在此之后这些带消失了。另一项发现成为我们在整个实验试验中关注的主要焦点是EC、ES、ED和AYS的值通常在5分钟内得到改善；然而，从那段时间到20分钟它没有变化。从这段时间开始，这些值受到负面影响，而从80min(0.136 An/TN)开始，乳液性能显著恶化。
In this investigation, casein was proteolysed at different levels using a neutral proteinase (Neutrase) and the effects of proteolysis on emulsion capacity (EC) of casein, emulsion stability (ES), emulsion density (ED), and apparent yield stress (AYS) values of emulsions have been investigated. In order to clarify the effect of proteolysis on proteins, the proteolysis-applied proteins at different levels went through urea-PAGE and SDS-PAGE analysis. The proteolysis level exerted a statistically very significant difference on proteolysis degree, EC, ES, ED, AYS values (p<0.01). In the trial, no significant effect of enzyme and enzyme inhibitor (ethylenediaminetetraacetic acid, EDTA) on parameters was determined (p>0.05); the difference was found to be associated with an outcome from proteolysis. While proteolysis increased rapidly up to 20th minute, it increased slowly from 80min. It was also observed that urea-PAGE and SDS-PAGE patterns belonging to casein fractions were quite in perfect harmony with proteolysis degrees, whereas a remarkable weakening in main protein bands due to the period was seen. A constitution of new peptide bands was observed up to 80min, but these bands vanished after this period. Another finding, which became the chief focus of our concern throughout our experimental trials was that EC, ES, ED and AYS values generally improved up to 5min; however, it did not change from that period up to 20min. From that period, these values were negatively affected, whereas from 80min (0.136 AN/TN) a remarkable deterioration was observed in emulsion properties.