NL2029813B1 - Preparation method and application of critical time-temperature indicator for monitoring accumulated time-temperature history of cold chain logistics of aquatic products - Google Patents

Abstract

The present invention discloses a preparation method of a critical time-temperature indicator for recording thermal history of the cold chain logistics of aquatic products and its application. The preparation method of the critical time-temperature indicator for recording thermal history of the cold chain logistics of aquatic products includes the following steps: Preparation of phosphate buffer: Weigh 3.58 g of solid disodium hydrogen phosphate and dissolve in 50 ml of ultrapure water to form the first aqueous solution; weigh 1.56 g of solid sodium dihydrogen phosphate and dissolve in 50 ml of ultrapure water to form the second aqueous solution; the above-mentioned first aqueous solution and the second aqueous solution are mixed to form the phosphate buffer. The present invention is a low temperature-sensitive indicator and can indicate the temperature during the whole cold chain logistics process of aquatic products.

Description

PREPARATION METHOD AND APPLICATION OF CRITICAL TIME-TEMPERATURE INDICATOR FOR MONITORING ACCUMULATED TIME-TEMPERATURE HISTORY OF COLD CHAIN LOGISTICS OF AQUATIC PRODUCTS

FIELD OF THE INVENTION The invention belongs to the field of food monitoring and indication, in particular to a critical time-temperature indicator based on Maillard reaction and its application, which can be used to monitor the temperature abuse of aquatic products in the cold chain logistics process.

BACKGROUND Fresh seafood from catch to consumers still need to undergo a variety of logistics processes including loading, unloading, transportation, storage, distribution, etc., where effective temperature management is extremely crucial. However, the quality assurance of seafood cannot completely rely on cold chain logistics, because there are cold chain rupture and other accidental factors. Studies have shown that aquatic products often deviate from the recommended temperature conditions in the process of cold chain-transportation. However, traditional monitoring techniques cannot accurately monitor the time and temperature accumulation of single or batch aquatic products exposed to room temperature. Ideally, an economical and effective method is needed to indicate whether there is temperature abuse in the whole cold chain logistics process of aquatic products, so as to show the real safety and quality of aquatic products. At present, there is no corresponding product can achieve this function.

BRIEF SUMMARY OF THE INVENTION The purpose of the present invention is to provide a method for preparing a critical time-temperature indicator for recording thermal history of aquatic products cold chain logistics, so as to solve the technical problem of how to indicate whether there is temperature abuse of aquatic products during the entire cold chain logistics process. Another object of the present invention is to provide an application for providing the above critical time-temperature indicator. The preparation method of the critical time-temperature indicator for recording thermal history of the cold chain logistics of aquatic products includes the following steps: a. preparation of phosphate buffer: weigh 3.58 g of solid disodium hydrogen phosphate and dissolve in 50 ml of ultrapure water to form the first aqueous solution; weigh 1.56 g of solid sodium dihydrogen phosphate and dissolve in 50 ml of ultrapure water to form the second aqueous solution; the above-mentioned first aqueous solution and the second aqueous solution are mixed to form the phosphate buffer.

b. preparation of reaction substrate: a plurality of reducing sugars and polypeptides are respectively dissolved in the above-mentioned phosphate buffer to form aqueous solutions of different concentrations to form a critical time-temperature indicator.

In the step a, the concentration of phosphate buffer is 0.05-0.4 mol/L, the pH is 6.0-8.0.

The concentration of the phosphate buffer 1s 0.2 mol/L and the pH is 7.0.

In the step b, the reducing sugar is one or a combination of xylose and fructose, and the polypeptide is the protein hydrolysate of scraps of the aquatic products.

The reducing sugar is fructose with a concentration of 0.4-1.4 mol/L, and the polypeptide is a hydrolyzed polypeptide of large yellow croaker with a concentration of 1.0-3.0 mol/L.

The critical time-temperature indicator for recording thermal history of cold chain logistics of aquatic products is used to monitor the abnormal temperature of aquatic products in the cold chain logistics process.

The beneficial effects of the invention are as follows: The critical time-temperature indicator of the invention is abbreviated as CTTL which takes reducing sugar and polypeptide as initial reactants and is dissolved in phosphate buffer. It has the advantages of non-toxic and harmless, cost-effective, simple to prepare, good color effect, suitable for commercial production and sensitive to high temperature. It can be used as a packaging material for aquatic products or placed next to the aquatic products to be monitored to make a clear indication that the refrigerated aquatic products beyond the storage temperature by color change, which is irreversible. In this way, monitoring whether there is temperature abuse in the process of transportation, storage, processing and sale of aquatic products can provide visual information for relevant management personnel in order to adjust the temperature conditions in time.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a curve diagram showing the optical density values of different concentrations of peptides with time;

Fig. 2 is a curve diagram showing the optical density values of different concentrations of reducing sugars varying with time; Fig. 3 is a curve diagram showing the variation of optical density of phosphate buffers with different concentrations over time; Fig. 4 is a curve diagram showing the optical density of phosphate buffers of different concentrations at different PH values; and Fig. 5 is a diagram of the color change trend of the critical time temperature indicator with time in example 1.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figs. 1 to 5, the present invention 1s described in detail below in combination with specific implementation cases, but the implementation of the present invention is not limited to this: Example 1: The critical time-temperature indicator of this embodiment is made by the following methods: The phosphate buffer solution of pH 7.0 and the concentration of 0.2 mol/L was prepared. Then, a certain amount of fructose and polypeptide were dissolved in the phosphate buffer solution above to form the first aqueous solution of 0.4 mol/L and the second aqueous solution of 2.0 mol/L, respectively. According to the ratio of 1:1, take 400 micro-liters of the mixture formed by mixing the two aqueous solutions above and add it to the packing bag to make a critical time-temperature indicator with a size of 25 * 20 mm. Example 2: The critical time-temperature indicator of the present embodiment is made by the following methods: The phosphate buffer solution of pH 6.5 and the concentration of

0.1 mol/L was prepared. Then, a certain amount of fructose and polypeptide were dissolved in the phosphate buffer to form the first aqueous solution of 0.6 mol/L and the second aqueous solution of 1.0 mol/L, respectively. According to the ratio of 1:1, take 400 micro-liters of the mixture formed by mixing the two aqueous solutions above and add it to the packing bag to make a critical time-temperature indicator with a size of 25 x 20 mm. Example 3: The critical time-temperature indicator of the present embodiment is made by the following methods: The phosphate buffer solution of pH 7.0 and the concentration of

0.05mol/L was prepared. Then a certain amount of fructose and polypeptide were dissolved in the phosphate buffer to form the first aqueous solution of 0.4 mol/L and the second aqueous solution of 1.5 mol/L, respectively. According to the ratio of 1:1, take 400 micro-liters of the mixture formed by mixing the two aqueous solutions above and add it to the packing bag to make a critical time-temperature indicator with a size of 25 » 20 mm.

Example 4: The critical time-temperature indicator of the present embodiment is made by the following methods: The phosphate buffer solution of pH 7.0 and the concentration of

0.4 mol/L was prepared. Then a certain amount of fructose and polypeptide were dissolved in the phosphate buffer to form the first aqueous solution of 1.4 mol/L and the second aqueous solution of 3 mol/L, respectively. According to the ratio of 1:1, take 400 micro-liters of the mixture formed by mixing the two aqueous solutions above and add it to the packing bag to make a critical time-temperature indicator with a size of 25 x 20 mm.

Example 5: The critical time-temperature indicator of the present embodiment is made by the following methods: The phosphate buffer solution of pH8.0 and the concentration of

0.2 mol/L was prepared. Then a certain amount of fructose and polypeptide were dissolved in the phosphate buffer to form the first aqueous solution of 1 mol/L and the second aqueous solution of 2 mol/L, respectively. According to the ratio of 1:1, take 400 micro-liters of the mixture formed by mixing the two aqueous solutions above and add it to the packing bag to make a critical time-temperature indicator with a size of 25 x 20 mm.

The temperature critical point of the critical time-temperature indicator in this embodiment is 4 °C. Above this temperature, the indicator will have an obvious irreversible color change, and the time and temperature experienced by the indicator can be estimated based on an mathematical model. Put the critical time-temperature indicator in the refrigerators at different temperatures to verify the accuracy of the indicator. By calculating the storage time and temperature of CTTIL the accuracy of CTTI can reach more than 0.9.

The critical time-temperature indicator of the invention can be better applied to the monitoring of the temperature change of aquatic products in the cold chain logistics process. The color change is obvious, which can visually indicate the temperature change that can help managers monitor the temperature change of seafood products cold chain logistics.

The present invention has been illustrated by the above embodiments, but it should be understood that the above embodiments are exemplary and cannot be understood as a limitation to the present invention. In addition, those skilled in the field can understand that the present invention 1s not limited to the above embodiments. More variants, modifications, replacements and contents used to indicate temperature breakage during the cold chain logistics of aquatic products based on the contents of the present invention fall within the scope of protection required by the present invention.

Claims (6)

CONCLUSIESCONCLUSIONS 1. Een bereidingswijze van een kritieke tijd-temperatuurindicator voor het registreren van de thermische historiek van de koudeketenlogistiek van aquatische producten, 5 gekenmerkt door volgende stappen: a. het bereiden van fosfaatbuffer: door afweging van 3,58 g vast dinatriumwaterstoffosfaat en het oplossen van het vast dinatriumwaterstoffosfaat in 50 ml ultrapuur water om een eerste waterige oplossing te bekomen, het afwegen van 1,56 g vast natriumdiwaterstoffosfaat en het oplossen van het vast natriumdiwaterstoffosfaat in 50 ml ultrapuur water om een tweede waterige oplossing te bekomen; het mengen van de eerste waterige oplossing en de tweede waterige oplossing om de fosfaatbuffer te bekomen; b. het bereiden van reactiesubstraat: respectievelijk door het oplossen van een aantal reducerende suikers en polypeptiden in de fosfaatbuffer tot waterige oplossingen van verschillende concentraties om de kritische tijd-temperatuurindicator te bekomen.1. A method of preparing a critical time-temperature indicator for recording the thermal history of the cold chain logistics of aquatic products, characterized by the following steps: a. preparing phosphate buffer: by weighing 3.58 g of solid disodium hydrogen phosphate and dissolving the solid disodium hydrogenphosphate in 50 ml of ultrapure water to obtain a first aqueous solution, weighing 1.56 g of the solid sodium dihydrogenphosphate and dissolving the solid sodium dihydrogenphosphate in 50 ml of ultrapure water to obtain a second aqueous solution; mixing the first aqueous solution and the second aqueous solution to obtain the phosphate buffer; b. preparing reaction substrate: respectively by dissolving a number of reducing sugars and polypeptides in the phosphate buffer to aqueous solutions of different concentrations to obtain the critical time-temperature indicator. 2. De bereidingswijze van de kritische tijd-temperatuurindicator voor het registreren van de thermische historiek van de koudeketenlogistiek van aquatische producten volgens conclusie 1, gekenmerkt door het feit dat in stap a, de concentratie van fosfaatbuffer 0,05 - 0,4 mol/l is en de pH 6,0 - 8,0 is.The preparation method of the critical time-temperature indicator for recording the thermal history of the cold chain logistics of aquatic products according to claim 1, characterized in that in step a, the concentration of phosphate buffer is 0.05 - 0.4 mol/l is and the pH is 6.0 - 8.0. 3. De bereidingswijze van de kritische tijd-temperatuurindicator voor het registreren van de thermische historiek van de koudeketenlogistiek van aquatische producten volgens conclusie 2, gekenmerkt door het feit dat de concentratie van fosfaatbuffer 0,2 mol/l is en de pH 7,0 is.The preparation method of the critical time-temperature indicator for recording the thermal history of the cold chain logistics of aquatic products according to claim 2, characterized in that the concentration of phosphate buffer is 0.2 mol/l and the pH is 7.0 . 4. De bereidingswijze van de kritische tijd-temperatuurindicator voor het registreren van de thermische historiek van de koudeketenlogistiek van aquatische producten volgens conclusie 1, gekenmerkt door het feit dat in stap b de reducerende suiker één of een combinatie van xylose en fructose is en het polypeptide het eiwithydrolysaat van het afval van de aquatische producten is.The preparation method of the critical time-temperature indicator for recording the thermal history of the cold chain logistics of aquatic products according to claim 1, characterized in that in step b the reducing sugar is one or a combination of xylose and fructose and the polypeptide is the protein hydrolyzate of the aquatic product waste. 5. De bereidingswijze van de kritische tijd-temperatuurindicator voor het registreren van de thermische historiek van de koudeketenlogistiek van aquatische producten volgens conclusie 4, gekenmerkt door het feit dat de reducerende suiker fructose is met een concentratie van 0,4-1,4 mol/l en dat het polypeptide een gehydrolyseerd polypeptide van grote gele croaker met een concentratie van 1,0 - 3,0 mol/l 1s.The preparation method of the critical time-temperature indicator for recording the thermal history of the cold chain logistics of aquatic products according to claim 4, characterized in that the reducing sugar is fructose with a concentration of 0.4-1.4 mol/ 1 and that the polypeptide is a hydrolyzed large yellow croaker polypeptide at a concentration of 1.0 - 3.0 mol/l 1s. 6. Een toepassing van de bereidingswijze van de kritische tijd-temperatuurindicator voor het registreren van de thermische historiek van de koudeketenlogistiek van aquatische producten volgens conclusie 1, gekenmerkt door het feit dat de bereidingsmethode wordt gebruikt om de abnormale temperatuur van aquatische producten in het logistieke proces van de koudeketen te bewaken.An application of the preparation method of the critical time-temperature indicator for recording the thermal history of the cold chain logistics of aquatic products according to claim 1, characterized in that the preparation method is used to detect the abnormal temperature of aquatic products in the logistics process of the cold chain.