时间—温度指示系统的研制及其在生鱼片鲜度监测中的应用

发布时间：2018-04-27 07:00

本文选题：时间温度指示器 + 大菱鲆生鱼片　；参考：《中国海洋大学》2014年硕士论文

【摘要】：温度对食品在储藏和运输过程中的质量变化有着十分重要的影响。然而目前，我国以时间为基础的食品标签制度虽然可以提供指示食品腐败程度的保质期，但是由于其无法直接反映食品在实际储存和运输过程中所经历的温度历史，所以难以精确指示食品的新鲜程度。而对于一些直接生食的高端水产品或者鲜度要求极高的食品而言，简单准确判断食品鲜度十分重要。因此需要一种有效而直观的方式同时指示食品所经历的温度和时间。时间温度指示器(Time temperatureindicator, TTI)是一种简单方便、经济有效的指示时间温度的方法。然而，目前我国对于TTI的研究尚处于起步阶段，理论研究不系统，开发的TTI产品因存在诸多问题而鲜有应用。本论文以酪氨酸和酪氨酸酶为研究对象，利用酶促反应原理，开发一种新型固态酶型TTI。经可行性分析、指示时间优化、动力学分析等系统的理论研究后，设计了一种可以指示食品鲜度的TTI产品，并将其初步应用于大菱鲆生鱼片的质量指示。主要研究内容如下： 1、分析了酪氨酸酶与酪氨酸液相反应体系的褐变趋势，发现不同温度和时间条件下酶促反应体系的褐变程度有着显著的不同，阐明了开发以酪氨酸酶促反应为基础的TTI的可行性。为进一步证实开发固态TTI产品的可行性，研究了固定化底物释放速率的单因素实验，结果表明：酪氨酸在固定化后可以从聚乙烯醇凝胶薄膜中缓慢释放并与酪氨酸酶进行反应，且在聚乙烯醇浓度为15%，酪氨酸含量为0.6mg/mL，反复冷冻-解冻循环法成膜的条件下，固相体系酪氨酸的释放速率最低，体系达到反应终点的时间约为18h。 2、将酪氨酸和酪氨酸酶分别固定化于聚乙烯醇凝胶缓释薄膜，开发新型的以酪氨酸酶促褐变为基础的固态酶型时间温度指示器，并根据指示时间优化其制备条件。采用总体颜色变化ΔE来判断TTI指示时间，选取ΔE值不再有显著变化时的值（ΔE=38.21±2.00左右）作为TTI的指示终点。通过响应面实验，成功建立了以TTI指示时间为响应值，以酪氨酸含量、酪氨酸酶含量以及聚乙烯醇浓度为自变量的数学模型，其公式为：t=50.40+0.25A+0.50B+1.50C-10.33A2-7.83B2-8.83C2-3.75AB+0.75AC+1.25BC，其中t为指示时间，A为酪氨酸含量，B为酪氨酸酶含量，C为聚乙烯醇浓度。根据模型预测，确定了TTI达到最长指示时间时各自变量的取值：酪氨酸30.08mg，，酪氨酸酶0.30mL，聚乙烯醇15.18%，此时TTI的最长指示时间可以达到50.48h。 3、选取响应面实验优化的TTI制备条件，制备了一种新型固态酶型TTI，并对其进行动力学分析，为指示产品的选择及TTI的应用提供理论基础。结果表明该TTI的反应活化能Ea=0.409kJ/mol，指前因子A=2.91。采用SAS软件对TTI进行数学模型的分析，结果表明，时间t、温度T和颜色响应值F(X)之间满足一个二元二次函数关系式F(X)=-0.00586T2-0.24002T+0.00902T×t-0.02060t-1.73930，该式中R2=0.9661，说明模型拟合度良好。此模型建立了该TTI体系颜色变化与所处时间温度之间的关系，为指示器的应用打下基础。 4、选取了鲜度要求高且附加值高的大菱鲆生鱼片作为TTI指示的产品，首先研究了其鲜度变化。通过测定大菱鲆从初始至死亡48h内，不同温度(4、12、18℃)下大菱鲆鱼肉中菌落总数、TVBN、pH和失重率变化情况，阐明了大菱鲆生鱼片从0h至48h的鲜度变化情况。实验结果表明，大菱鲆生鱼片菌落总数在48h内变化显著，且4℃下储藏48h左右的大菱鲆生鱼片已超出生食标准；而TVBN、pH和失重率在48h内则无明显变化。因此，选用菌落总数表征大菱鲆生鱼片的鲜度指标。通过对大菱鲆生鱼片鲜度变化的动力学分析，计算鲜度活化能为0.009kJ/mol，这与之前计算的TTI的活化能（0.409kJ/mol）接近，符合TTI对应产品的标准（产品活化能与TTI活化能相差小于40kJ/mol）。这表明本实验中设计的TTI可以很好地应用于大菱鲆生鱼片的鲜度指示。实验中同时设计了TTI结构，该结构可以粘附到生鱼片产品外包装表面，易于激活，保护性良好，结构小巧，且透明材质的设计，方便消费者观察。研究表明开发出的新型固态酶型TTI，反应体系简单，颜色变化明显，可以用于判断极易腐败低温流通食品（如大菱鲆生鱼片）的新鲜程度，为生鱼片供应链中的制造商、流通商以及零售商提供了一种有效地产品质量控制手段，同时对于消费者更准确地判定此类食品是否适于生食有着积极的意义。
[Abstract]:Temperature has a very important impact on the quality of food in storage and transportation. However, the time based food labeling system in our country can provide a shelf life indicating the degree of food corruption, but it does not directly reflect the temperature history of the food in the actual storage and transportation process. It is difficult to accurately indicate the freshness of the food. It is important to determine the food freshness simply and accurately for some high end aquatic products with direct food or high freshness. Therefore, an effective and intuitive way is needed to indicate the temperature and time of the food at the same time. The time temperature indicator (Time temperaturein) Dicator, TTI) is a simple, convenient, economical and effective method to indicate time and temperature. However, at present, the research on TTI is still in its infancy, the theoretical research is not systematic, and the developed TTI products are rarely applied because of many problems.
In this paper, using tyrosine and tyrosinase as the research object, using the principle of enzymatic reaction, we developed a new solid-state enzyme type TTI. through the feasibility analysis, indicating time optimization, dynamic analysis and other systems. A kind of TTI product which can indicate food freshness was designed and applied to the quality of turbot sashimi slices. The main contents of the study are as follows:
1, the browning trend of tyrosinase and tyrosine liquid phase reaction system was analyzed. It was found that the browning degree of the enzyme catalyzed reaction system was significantly different under different temperatures and time conditions. The feasibility of developing TTI based on tyrosinase catalyzed reaction was clarified. The immobilization was studied to further confirm the feasibility of developing solid TTI products. The single factor experiment of the rate of substrate release shows that tyrosine can be released slowly and react with tyrosinase after immobilization, and the release rate of tyrosine in solid phase system is the most in the condition of the concentration of polyvinyl alcohol 15%, the tyrosine content is 0.6mg/mL, and the repeated freezing thawing cycle method is used. Low, the time for the system to reach the end of the reaction is about 18h.
2, tyrosine and tyrosinase were immobilized on the slow-release film of polyvinyl alcohol gel, and a new type of solid-state temperature indicator was developed based on tyrosinase promoting browning, and the preparation conditions were optimized according to the indication time. The TTI indication time was determined by the overall color change Delta E, and the value of delta E was no longer significantly changed. The value (delta E=38.21 + 2) is the terminal point of the TTI. Through the response surface experiment, a mathematical model with the content of tyrosine, tyrosinase and the concentration of polyvinyl alcohol as the independent variable is established by the response surface experiment. The formula is: t=50.40+0.25A+0.50B+ 1.50C-10.33A2-7.83B2-8.83C2-3.75AB+0.75AC+1.25BC, of which t For the indication time, A is tyrosine content, B is tyrosinase content and C is polyvinyl alcohol concentration. According to the model prediction, the values of each variable are determined when TTI reaches the longest indication time: tyrosine 30.08mg, tyrosinase 0.30mL, polyvinyl alcohol 15.18%, and at this time the longest time of TTI can reach 50.48h.
3, a new solid-state enzyme type TTI was prepared by selecting the TTI preparation conditions optimized by the response surface experiment. The kinetic analysis was carried out to provide a theoretical basis for the selection of the product and the application of TTI. The results showed that the activation energy of the TTI was Ea=0.409kJ/mol and the former factor A=2.91. was analyzed by SAS software for the mathematical model of TTI. It shows that the time t, the temperature T and the color response value F (X) satisfy a two element two function relation F (X) =-0.00586T2-0.24002T+0.00902T x t-0.02060t-1.73930, which indicates that the model has good fitting degree. This model establishes the relationship between the color change of the TTI system and the temperature of the time, and lays the foundation for the application of the indicator. Foundation.
4, the freshness of turbot sashimi slices with high freshness and high added value was selected as a TTI indicator. First, the freshness of turbot was studied. The total number of colonies, TVBN, pH and weight loss of turbot turbot in turbot turbot from initial to death 48h and at different temperatures (4,12,18 degrees C) were determined. The fresh fish slices from 0h to 48h were clarified. The results showed that the total number of the total colony of turbot sashimi slices changed significantly in 48h, and the sashimi slices of turbot turbot, which was stored for about 48h at 4 C, had exceeded the standard of birth food, while the TVBN, pH and weightlessness rate had no obvious changes in 48h. The kinetic analysis of the fresh degree change shows that the activation energy of the freshness is 0.009kJ/mol, which is close to the activation energy (0.409kJ/mol) of the previously calculated TTI, which is in line with the standard of the corresponding product of the TTI (the difference between the activation energy of the product and the activation energy of TTI is less than 40kJ/mol). This shows that the designed TTI can be well applied to the freshness indication of the sashimi slices of turbot. The TTI structure was designed at the same time. The structure can be attached to the surface of the sashimi product on the outside of the packaging. It is easy to activate, with good protection, small structure, and a transparent material design, which is convenient for the consumer to observe.
The research shows that the new solid state enzyme type TTI has a simple reaction system and the color change is obvious. It can be used to judge the freshness of the highly corrupt low temperature circulation food (such as the turbot sashimi). It provides an effective means of quality control for the manufacturers, tradable merchants and retailers in the supply chain of sashimi. It is of great significance to judge more accurately whether this kind of food is suitable for raw food.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TS254.7

【参考文献】