CN104267163B - Shelf life storage indicator, preparation method and the method for inspection - Google Patents

Abstract

The invention relates to a food shelf life indicator, a preparation method and a testing method. The preparation method comprises: pulverizing raw materials, extracting with ethanol solution with a mass concentration of 5-9%, filtering to obtain filtrate, and sealing it in a container as a food preservation indicator; the raw materials are leeks or roses. The indicator is a short-term indicator that uses leeks as raw material and can indicate the shelf life within 6-8 days below 4°C, or a long-term indicator that uses roses as raw material and can indicate the shelf life within 1 month below 4°C . The inspection method includes: on the date of food production, prepare the required indicator and place it together with the food, and then judge the food preservation status according to the status of the food shelf life indicator. The invention can visually indicate the preservation state of the food, and is simple and easy to implement.

Description

Food shelf life indicator, preparation method and inspection method

technical field

The invention relates to a food storage life indicator, a preparation method and a testing method, and is especially suitable for the storage life indication of food stored at 4°C, and belongs to the technical field of food storage testing.

Background technique

Shelf life refers to the time during which the product maintains its quality and safety under specified storage temperature conditions. The shelf life of the product refers to the quality assurance period of the product under normal conditions. The shelf life of the product is provided by the manufacturer and marked on the product for limited use. During the storage period, the manufacturer of the product is responsible for the quality of the product meeting the relevant standards or the quality conditions of the express guarantee. Sellers can sell these products with confidence, and consumers can use them safely.

The storage period is not the only criterion for identifying whether food and other products have deteriorated. It may be prematurely deteriorated due to changes in storage methods and environmental factors. Therefore, food and other products should be eaten in time before the storage period expires.

At present, the conventional production date labeling method cannot reflect the temperature changes during food preservation, especially some unexpected changes in temperature. However, some foods may encounter unexpected high temperatures during storage, which can easily breed bacteria and cause food deterioration. However, this situation can only be detected through quality inspection, and it is difficult to judge intuitively.

Contents of the invention

The purpose of the invention to be realized by the present invention is: to overcome the problems existing in the prior art, to provide a method for preparing a food shelf life indicator, and to prepare an indicator for intuitively indicating the food preservation state with simple steps; at the same time, it also provides the Indicators and their uses, as well as methods for testing shelf life of foods using the indicators.

To achieve the above object, the technical scheme of the present invention is as follows:

A method for preparing a food shelf life indicator, comprising the following steps:

After pulverizing the raw materials, add ethanol solution with a mass concentration of 5-9%, the weight ratio of raw materials and ethanol solution is 1:4-6; after shaking and extracting, filter the filtrate, seal the filtrate in a container, and obtain the shelf life of the food Indicator; the raw material is leek or rose; when the raw material is leek, the food shelf life indicator is a short-term indicator that can indicate the shelf life within 6-8 days below 4°C; when the raw material is rose, the food shelf life indicator The reagent is a long-term indicator that can indicate the shelf life within 1 month below 4°C.

Preferably, the weight ratio of the raw material to the ethanol solution is 1:5.

Preferably, a blender is used for pulverization; vortex extraction is used for at least 2 minutes for vibration extraction; and a microporous membrane below 0.22 μm is used for filtration.

Preferably, the container is made of transparent material.

More preferably, the container is made of transparent plastic or transparent glass.

The present invention also provides:

A food shelf life indicator prepared by the above preparation method.

The present invention also provides:

The above-mentioned food shelf life indicator is used to indicate the food shelf life.

The present invention also provides:

A method for testing shelf life of food, comprising the following steps:

Step 1. On the day of food production, prepare the food shelf life indicator according to the aforementioned preparation method, and transport, store, and sell the sealed container containing the food shelf life indicator together with the corresponding food; When the shelf life is within 6-8 days below 4°C, prepare a short-term indicator, and when the storage period of the food is within 1 month below 4°C, prepare a long-term indicator;

The second step is to judge the food storage status according to the status of the food storage life indicator:

When a short-term indicator is used, in a static state, if the indicator is in the form of a suspended green dispersion, the food has not expired; if the indicator is in a state of green precipitation and liquid layering, judge according to the date of production of the food: If it is more than 6-8 days from the production date of the food, the food has expired; if it is not more than 6-8 days from the production date of the food, the food has been stored in a high-temperature environment above 35°C for at least 3 hours;

When a long-term indicator is used, if the color of the indicator is rose, the food has not expired; if the color of the indicator is orange or orange, judge according to the production date of the food: if the production date of the food has exceeded 1 month means that the food has passed the shelf life. If it is less than 1 month from the production date of the food, the food has been stored in a high temperature environment above 35 ℃ for at least 1 day; the inspection is over.

The applicant has found through in-depth practical research that the leek extract and rose extract prepared by the above preparation method are bright in color and have sufficient color depth; at the same time, after the two are stored at low temperature for several days, or after short-term storage at high temperature, It will produce obvious state changes, which is convenient for judging the food preservation state; in addition, the short-term indicator with leek as raw material can be used to indicate the storage period within 6-8 days below 4°C, and the long-term indicator with rose as raw material can be used to indicate 4 The storage period of 1 month below ℃ is consistent with the storage period of many existing foods, and has broad promotion prospects.

Compared with prior art, advantage of the present invention is as follows:

1. It can capture and record the unexpected high temperature storage environment (such as above 35°C) during the food storage period;

2. The steps of the preparation method are simple;

3. The raw materials are cheap and will not increase the product cost too much;

4. Pure natural plant extracts are easy to be accepted psychologically by the public.

Description of drawings

1 to 8 are schematic diagrams of the results of Example 2 of the present invention.

9 to 44 are schematic diagrams of the results of Example 3 of the present invention.

detailed description

The present invention is further described below by embodiment, but the present invention is not limited to these examples.

Embodiment 1 prepares food shelf life indicator

Specific steps are as follows:

After pulverizing the raw materials with a mixer, add ethanol solution with a mass concentration of 5-9%, and the weight ratio of raw materials to ethanol solution is 1:4-6 (preferably 1:5); after vortex extraction for at least 2 minutes, use 0.22μm The following microporous filter membrane is filtered, the filtrate is taken, and the filtrate is sealed in a container made of a transparent material such as transparent plastic or transparent glass material to obtain a food shelf life indicator.

The raw material is leeks or roses; when the raw material is leeks, the food shelf life indicator is a short-term indicator that can indicate the shelf life within 6-8 days below 4°C; when the raw material is roses, the food shelf life indicator is an energy A long-term indicator that indicates the shelf life within 1 month below 4°C.

Embodiment 2 Food shelf life indicator effect experiment

The short-term indicator and the long-term indicator prepared in Example 1 were stored under four conditions respectively, and then the state changes of the short-term indicator and the long-term indicator were observed.

The four conditions for the short-term indicator are: 1 hour at 4°C, 3 days at 4°C, 7 days at 4°C, 2 days at 4°C and 1 day at 35°C. The results are shown in Figures 1 to 4: the state of the indicator in Figure 1 and Figure 2 is a suspended green dispersion, the indicator in Figure 3 and Figure 4 is in the state of green precipitation and liquid layering, and the color of the liquid in Figure 4 is Lighter than the color of the liquid in Figure 3, the color of the liquid in Figure 3 is lighter than the color of the indicator in Figure 2, and the color of the indicator in Figure 2 is basically the same as the color of the indicator in Figure 1. The results show that: the short-term indicator can indicate the storage period of food within 6-8 days below 4°C, and if it has been in a high temperature state during this period, the short-term indicator will also change its state.

The four conditions for the long term indicator are: 1 hour at 4°C, 15 days at 4°C, 1 month at 4°C, 15 days at 4°C and 1 day at 35°C. The result is as shown in Figures 5 to 8: the indicator color is rose in Figure 5 and Figure 6, and the indicator color is orange in Figure 7 and Figure 8. The results show that the long-term indicator can indicate the storage period of food within 1 month below 4°C, and if it has been in a high temperature state during this period, the long-term indicator will also change its state.

The influence of embodiment 3 ethanol solution concentration on indicating effect

(1) For the leek extract corresponding to the short-term indicator: use ethanol solutions with a mass concentration of 5%, 15%, and 25% respectively, and prepare four kinds of leek extracts according to the preparation method of Example 1; The extracts were stored under four conditions respectively, and then the state changes of each extract were observed.

Among them, the four conditions are: 0 hour, 3 hours at 35°C, 24 hours at 35°C, 6 days at 4°C, and 7 days at 4°C.

The results are shown in Figures 9 to 20.

Among them, Fig. 9 to Fig. 12 are state diagrams of leek extract solution with mass concentration 5% ethanol solution under four kinds of conditions, Fig. 9 is a suspended green dispersion liquid, Fig. 10, Fig. 11, Fig. 12 are between green precipitate and liquid separation The state of the layer, and the color of the liquid in Figure 11 is lighter than the color of the liquid in Figure 10, and the color of the liquid in Figure 10 is lighter than the color of the liquid in Figure 12.

Figure 13 to Figure 16 are state diagrams of the leek extract with a mass concentration of 15% ethanol solution under four conditions, Figure 13 is a suspended light green dispersion, and the color of Figure 13 is obviously lighter than that of Figure 9; 15. Figure 16 is in the state of green precipitation and liquid layering, and the color of the liquid in Figure 15 is lighter than that of Figure 14, and the color of the liquid in Figure 14 is lighter than that of Figure 16.

Figures 17 to 20 are state diagrams of leek extracts with a mass concentration of 25% ethanol solution under four conditions, all of which are basically colorless and transparent liquids without precipitation.

It can be seen that for leek extract, the higher the mass concentration of ethanol solution, the lighter the color of the extract, and the less sensitive to temperature changes and storage time. Based on this, the applicant has determined through further experiments that the mass concentration of the ethanol solution of the leek extract is 5-9%, so as to ensure the indicating effect of the indicator.

(2) For the rose extract corresponding to the long-term indicator: respectively adopt ethanol solutions with a mass concentration of 5%, 15%, 25%, 50%, 75%, and 95%, and prepare six kinds according to the preparation method of Example 1 Rose extract; these six rose extracts were preserved under four conditions respectively, and then the state changes of each extract were observed.

Among them, the four conditions are: 0 hour, 24 hours at 35°C, 24 hours at 35°C and 6 days at 4°C, and 7 days at 4°C.

The results are shown in Figures 21 to 44.

Among them, Fig. 21 to Fig. 24 are state diagrams of the rose extract in 5% ethanol solution under four conditions, Fig. 21 and Fig. 24 are all rose, Fig. 22 is orange, and Fig. 23 is orange.

Fig. 25 to Fig. 28 are state diagrams of the rose extract of mass concentration 15% ethanol solution under four kinds of conditions, Fig. 25 is rose color, and the color of Fig. 25 is obviously lighter than Fig. 21 color; Fig. 28 is rose color, Fig. 26 is orange, and Figure 27 is orange.

Figures 29 to 32 are state diagrams of rose extracts with a mass concentration of 25% ethanol solution under four conditions. Figures 29 and 32 are orange-red, and Figures 30 and 31 are orange-yellow.

Fig. 33 to Fig. 36 are state diagrams of the rose flower extract with a mass concentration of 50% ethanol solution under four conditions, all of which are orange-yellow.

Fig. 37 to Fig. 40 are state diagrams of the rose extract in 75% ethanol solution under four conditions, all of which are orange.

Fig. 41 to Fig. 44 are state diagrams of the rose flower extract solution with a mass concentration of 95% ethanol solution under four conditions, all of which are light orange.

It can be seen that for the rose extract, the higher the concentration of ethanol solution, the color of the extract gradually turns orange or even light orange, and it is less and less sensitive to temperature changes and storage time. Based on this, the applicant has determined through further experiments that the mass concentration of the ethanol solution of the rose extract is 5-9%, so as to ensure the indicating effect of the indicator.

The influence of embodiment 4 high temperature environment on the absorbance of extract

First, three leek extracts and three rose extracts were prepared by using ethanol solutions with a mass concentration of 5%, 15%, and 25%, respectively, according to the preparation method of Example 1. During the preparation, 5 parallel samples were made respectively.

Then, each extract was placed in a high-temperature environment of 35°C, and the absorbance data was detected at time points 0h, 3h, 6h, 12h, 18h, and 24h; the detection wavelength of the leek extract was 638nm, and the detection wavelength of the rose extract was 480nm.

The results are shown in the table below:

From the above results combined with observations, it can be seen that:

(1) The greater the ethanol concentration, the smaller the absorbance value of the extract at 0 h, and the less obvious the change trend of the absorbance value of the extract, which is not conducive to indication. This point is consistent with the result of Example 3.

(2) For the leek extract, in the case of using a 5% ethanol solution with a mass concentration of 35°C for 3 hours, not only the absorbance value decreased significantly, but also a very obvious precipitation appeared, and the green color of the supernatant became lighter obviously. This shows that the short-term indicator prepared in Example 1 can indicate the situation of being placed at 35° C. for more than 3 hours.

(3) For the rose extract, when the ethanol solution with a mass concentration of 5% is used, the absorbance value has decreased significantly after being placed at 35° C. for 24 hours, and the color has turned to orange. This shows that the long-term indicator prepared in Example 1 can indicate the situation of being placed at 35° C. for more than 24 hours.

(4) In the case of using a 5% ethanol solution, at each time point, the absorbance values between the parallel samples of leek or rose extracts are very stable, and the standard error is small. It can be seen that the extract prepared by the preparation method in Example 1 has good repeatability, and the indication effect is stable and reliable.

The results of comprehensive embodiments 2 to 4 can draw the food shelf life test method, including:

The first step, on the day of the food production date, prepare the food shelf life indicator according to the preparation method of Example 1, and transport, store, and sell the sealed container containing the food shelf life indicator together with the corresponding food; When the food storage period is below 4°C within 6-8 days, prepare a short-term indicator, and when the food storage period is below 4°C within 1 month, prepare a long-term indicator;

The second step is to judge the food storage status according to the food storage life indicator:

When a short-term indicator is used, in a static state, if the indicator is in the form of a suspended green dispersion, the food has not expired; if the indicator is in a state of green precipitation and liquid layering, judge according to the date of production of the food: If it is more than 6-8 days from the production date of the food, the food has expired; if it is not more than 6-8 days from the production date of the food, the food has been stored in a high-temperature environment above 35°C for at least 3 hours;

When a long-term indicator is used, if the color of the indicator is rose, the food has not expired; if the color of the indicator is orange or orange, judge according to the production date of the food: if the production date of the food has exceeded 1 month means that the food has passed the shelf life. If it is less than 1 month from the production date of the food, the food has been stored in a high temperature environment above 35 ℃ for at least 1 day; the inspection is over.

The indicator and test method can be used to indicate the shelf life of fresh foods such as milk, beverages, bread, and cakes.

Claims (8)

1. A method for preparing a food shelf life indicator, characterized in that it comprises the following steps: After pulverizing the raw materials, add ethanol solution with a mass concentration of 5-9%, the weight ratio of the raw materials and ethanol solution is 1:4-6; shake and extract, filter and take the filtrate, seal the filtrate in a container, and obtain the food shelf life indicator; the raw material is leek or rose; when the raw material is leek, the food shelf life indicator is a short-term indicator that can indicate the shelf life within 6-8 days below 4°C; when the raw material is rose , the food shelf life indicator is a long-term indicator that can indicate the shelf life within 1 month below 4°C. 2. The method for preparing the food shelf life indicator according to claim 1, wherein the weight ratio of the raw material to the ethanol solution is 1:5. 3. The preparation method of the food shelf life indicator according to claim 1, characterized in that, a blender is used for pulverization; vortex vibration is used for extraction for at least 2 minutes during vibration extraction; and a microporous membrane below 0.22 μm is used for filtration. 4. The method for preparing the food shelf life indicator according to claim 1, wherein the material of the container is a transparent material. 5. The method for preparing the food shelf life indicator according to claim 4, wherein the container is made of transparent plastic or transparent glass. 6. A food shelf life indicator prepared by the preparation method described in any one of claims 1 to 5. 7. The food shelf life indicator as claimed in claim 6 is used to indicate the food shelf life. 8. A method for testing shelf life of food, characterized in that it comprises the following steps: Step 1. On the day of food production, prepare the food shelf life indicator according to the preparation method described in any one of claims 1 to 5, and transport and store the sealed container containing the food shelf life indicator together with the corresponding food , and sales; among them, when the food storage period is below 4°C within 6-8 days, prepare a short-term indicator, and when the food storage period is below 4°C within 1 month, prepare a long-term indicator; The second step is to judge the food storage status according to the status of the food storage life indicator: When a short-term indicator is used, in a static state, if the indicator is in the form of a suspended green dispersion, the food has not expired; if the indicator is in a state of green precipitation and liquid stratification, judge according to the date of production of the food: If it is more than 6-8 days from the production date of the food at this time, the food has expired; if it is not more than 6-8 days from the production date of the food at this time, the food has been stored in a high temperature environment above 35°C for at least 3 hours; When a long-term indicator is used, if the color of the indicator is rose, the food has not expired; if the color of the indicator is orange or orange, judge according to the production date of the food: if the production date of the food has exceeded 1 month means that the food has passed the shelf life. If it is less than 1 month from the production date of the food, the food has been stored in a high temperature environment above 35 ℃ for at least 1 day; The inspection is over.