Method for storing fresh-cut pears by using electrolyzed functional water

Abstract

The invention relates to a method for storing fresh-cut pears with electrolyzed functional water, and belongs to the technical field of fresh-keeping methods. Comprising the following steps: step 1, firstly, soaking fresh-cut pears with 0.1% of electrolyzed functional water for 5 minutes, and after soaking is completed, absorbing moisture on the surfaces of the fresh-cut pears; and 2, putting the fresh-cut pears into a fresh-keeping bag, and storing in an environment with the temperature of 2-5 DEG C and the humidity of 50%. When the preservative is used, the storage quality of the fresh-cut pear slices can be effectively maintained, the increase of relative conductivity and the decrease of soluble solid content are slowed down, the decrease of total phenol content is slowed down, and the hardness of the pear slices is effectively maintained, so that the storage life of the fresh-cut pear slices is prolonged, and the commodity value of the fresh-cut pear slices is improved; the problems that the fresh-cut pears are difficult to store in a traditional fresh-cut pear storage method, so that the fresh-cut pears are easy to rot and inconvenient to transport and store are solved.

Description

Technical Field

[0001] The invention relates to the technical field of fresh-keeping methods, and in particular to a method for storing fresh-cut pears with electro-generated functional water. Background Art

[0002] Pears are a fruit rich in various nutrients that help maintain a healthy body. The fiber in pears helps promote digestion and effectively prevents constipation. The vitamin C in pears has excellent antioxidant properties and can effectively slow down the aging process. The potassium in pears helps maintain a healthy heart and normal blood pressure levels. The natural sugars in pears provide a beneficial source of energy for the body.

[0003] As an important agricultural product, pears have been widely planted and consumed worldwide and have become an indispensable part of people's dining tables. However, due to the development of modern logistics and trade, pears often need to be transported over long distances, which may lead to the loss of quality and nutrition. Nowadays, people prefer convenient and processed foods, which may reduce the status of pears as natural and healthy foods. The current industrial status cannot meet the consumer demand for the supply of fresh fruit market, and the profit margins of fruit farmers and dealers are limited, which affects the healthy development of China's pear industry. In addition, the quality of most fruits will deteriorate during the storage and processing after harvest due to chilling or mechanical processing, and they are prone to browning and rotting. This problem is particularly serious in pears because pears are rich in polyphenols and are extremely sensitive to enzymatic browning. The quality deterioration after storage seriously shortens the shelf life and shelf life of pears, causing huge economic losses to fruit farmers and businesses, and has become an urgent problem to be solved in my country's pear industry. Therefore, choosing effective preservation technology to slow down the decline in quality is of great significance to the pear industry and the preservation industry.

[0004] Based on this, the present invention proposes a method for storing fresh-cut pears using electro-functional water to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0005] In view of this, the main purpose of the present invention is to provide a method for storing fresh-cut pears with electro-functional water, so as to solve the problem that the traditional fresh-cut pear storage method is difficult to store fresh-cut pears, resulting in the fresh-cut pears being easy to rot and inconvenient to transport and store.

[0006] The technical solution of the present invention is achieved in this way:

[0007] A method for storing fresh-cut pears using electro-generated functional water, comprising:

[0008] Step 1: First, soak the fresh-cut pears in 1.0‰ electro-functional water for 5 minutes. After soaking, gently dry the surface moisture of the fresh-cut pears with a paper towel;

[0009] Step 2: Put the fresh-cut pears into a fresh-keeping bag and store them in an environment of 2-5℃ and 50% humidity.

[0010] In a preferred embodiment, the electro-generated functional water is prepared by electrolyzing a 1‰ calcium chloride solution, and the treatment conditions for preparing the electro-generated functional water are: an oxidation-reduction potential of 1550 mV, a pH of 2.8, and an effective chlorine concentration of 90 mg / L.

[0011] In a preferred embodiment, the storage time of fresh-cut pears according to the present method does not exceed 7 days.

[0012] In a preferred embodiment, the method further comprises a process for determining the total phenol content in fresh-cut pears, and the process for determining the total phenol content in fresh-cut pears comprises the steps of:

[0013] (1) Mother liquor extraction: 2 g of fresh-cut pear sample was thoroughly ground in 20 mL of 80% ethanol solution. After grinding, the mixture was centrifuged in a high-speed centrifuge for 10 min at 4000 r / min. The supernatant was extracted and stored at -40°C in the dark for later determination of total phenol content.

[0014] (2) Establishment of standard curve for total phenol determination:

[0015] (3) Sample determination: Pear extract was used instead of gallic acid solution and the reaction was carried out step by step according to the standard curve determination process. The absorbance was measured at 760 nm and the total phenol determination standard curve was substituted to calculate the content of phenolic substances in pears. The experiment was repeated three times.

[0016] In a preferred embodiment, the process of establishing the standard curve for total phenol determination includes:

[0017] Firstly, six groups of gallic acid solutions with different concentrations were prepared using 80% methanol solution, namely 0, 50, 100, 150, 200, and 300 μg / mL;

[0018] Subsequently, 120 μL of gallic acid solution with different concentrations was mixed with 120 μL of Folin phenol reagent, and the reaction was completed within 10 min;

[0019] Then, 1.25 mL of 7% sodium carbonate solution was added, the volume was made up to 10 mL with distilled water, and the reaction was allowed to proceed in the dark for 100 min;

[0020] Finally, three experiments were performed at a wavelength of 760 nm to determine the absorbance value of each group of reaction solutions;

[0021] Finally, a standard curve for total phenol determination was drawn based on the experimental data.

[0022] In a preferred embodiment, the method further comprises a process of determining the soluble solid content in the fresh-cut pears, and the process of determining the soluble solid content in the fresh-cut pears comprises:

[0023] Squeeze the juice out of fresh-cut pears, drop it on the refractometer, and read the reading; repeat the measurement 3 times for each treatment.

[0024] In a preferred embodiment, the method further comprises a process of measuring the relative conductivity of the fresh-cut pears, and the process of measuring the relative conductivity of the fresh-cut pears comprises:

[0025] (1) Three fresh-cut pear samples were randomly selected from each group. 2 g of the treated fresh-cut pear samples were placed in a conical flask, 35 mL of distilled water was added, and the mixture was soaked for a while. After soaking, the mixture was placed in an oscillator and shaken for 1 h.

[0026] (2) The conductivity value γ1 is measured by a conductivity meter, and then the conical flask is placed in an electric heating mantle and heated to boiling for 20 minutes, then cooled to room temperature and the conductivity value γ0 is measured once;

[0027] (3) Cell membrane permeability can be characterized by the conductivity ratio γe before and after boiling;

[0028] Each operation needs to be repeated three times.

[0029] In a preferred embodiment, the method further comprises a process of measuring the hardness of fresh-cut pears, and the process of measuring the hardness of fresh-cut pears comprises:

[0030] The hardness test was carried out using a texture analyzer to determine the hardness parameters of fresh-cut pear samples; the data recorded by the measuring instrument was measured based on the maximum pressure.

[0031] In a preferred embodiment, the method further comprises determining the color difference value of the fresh-cut pears, and the process of determining the color difference value of the fresh-cut pears comprises:

[0032] Take out the fresh-cut pear sample, wipe its surface dry, and then use a grating spectrophotometer to measure the L* of the fresh-cut pear slices. The L* value represents the lightness index of the peel surface.

[0033] Under the same conditions, colorimetric tests were performed on fresh-cut pear samples from different parts; each operation was repeated five times.

[0034] Compared with the prior art, the present invention provides a method for storing fresh-cut pears using electro-generated functional water, which has the following beneficial effects:

[0035] 1. The present invention uses fresh-cut pear slices as test materials to study the effect of different concentrations of calcium chloride electrolyzed water treatment on the storage quality of fresh-cut pear slices, and records the changes in total phenol content, soluble solids content, color difference value, hardness and relative conductivity of the fresh-cut pear slices during storage. The experimental results show that after storage at 21°C for 5 days, compared with the control group treated with room temperature film, different concentrations of calcium chloride electrolyzed water (0.5‰, 1.0‰, 1.5‰, 2.0‰) can effectively maintain the storage quality of fresh-cut pear slices, among which the concentration of 1‰ can maintain the storage quality to the greatest extent; in addition, the L* value of fresh-cut pear slices treated with 1.0‰ calcium chloride electrolyzed water remains high, and at the same time, it effectively slows down the increase in relative conductivity and the decrease in soluble solids content, delays the decrease in total phenol content, and effectively maintains the hardness of the pear slices, thereby improving the storage life and commercial value of fresh-cut pear slices; it solves the problem of traditional fresh-cut pear storage methods that it is difficult to store fresh-cut pears, which makes fresh-cut pears easy to rot and inconvenient to transport and store.

[0036] 2. It can be seen from the results of the present invention that the application of electro-generated functional water in the preservation of fruits and vegetables has huge economic benefits. This is a breakthrough in the research on the preservation function of electro-generated functional water, which can further meet the needs of the market and is also the direction of future development of preservation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained like these drawings without paying creative work.

[0038] Figure 1 This is a flow chart of the method for storing fresh-cut pears with electro-generated functional water according to the present invention;

[0039] Figure 2 The figure is a curve diagram showing the influence of different treatments on the soluble solid content of fresh-cut pear slices;

[0040] Figure 3 It is the total phenol standard curve of the present invention;

[0041] Figure 4 The graph is a graph showing the effects of different treatments on the total phenol content of fresh-cut pear slices;

[0042] Figure 5 The graph is a graph showing the influence of different treatments on the relative conductivity of fresh-cut pear slices according to the present invention;

[0043] Figure 6 The graph is a graph showing the effects of different treatments on the hardness of fresh-cut pear slices according to the present invention;

[0044] Figure 7 This is a graph showing the effects of different treatments on the L* of fresh-cut pear slices according to the present invention. DETAILED DESCRIPTION

[0045] The process and principle of the method for storing fresh-cut pears with electro-generated functional water will be further described in detail below in conjunction with the accompanying drawings and embodiments of the present invention.

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0048] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0049] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0050] Embodiment 1:

[0051] As the instruction manual Figure 1 -Attached Figure 6 As shown, this embodiment provides a technical solution: a research method for the effect of electro-functional water treatment on the storage quality of fresh-cut pears. This method selects fresh-cut pear slices as test materials, examines the effect of different concentrations of calcium chloride electrolyzed water treatment on the maintenance of the storage quality of fresh-cut pear slices at room temperature of 21°C and humidity of 50%, and compares and analyzes 4 different concentrations of calcium chloride electrolyzed water treatment groups compared with the room temperature film treatment group, the pure water treatment group compared with the room temperature film treatment group, and the 4 different concentrations of calcium chloride electrolyzed water treatment groups. After multiple groups of experiments, the data of relative conductivity, color difference value, hardness, soluble solids content and total phenol content of fresh-cut pear slices during storage are measured to give full play to the role of electro-functional water in maintaining storage quality, thereby achieving the purpose of extending the shelf life of fresh-cut pear slices, and laying a theoretical foundation for the field of preservation.

[0052] The specific experimental process of this method includes:

[0053] Step 1: Prepare materials and reagents

[0054] Step 1.1: Prepare experimental materials

[0055] Fresh pears: Available in the market, the variety is Crown Pear. Choose fruits with uniform shape and size;

[0056] Step 1.2: Prepare experimental reagents

[0057] 80% ethanol solution, gallic acid solution, Folin phenol reagent, 7% sodium carbonate solution, distilled water, solid calcium chloride, etc.;

[0058] Step 2: Prepare instruments and equipment

[0059] Step 2.1: Prepare your equipment

[0060] Electro-generated sterilizing water generator (XYS-C-12 model), Baoji Xinyu Optoelectronics Co., Ltd.: The main structure of this machine includes electrical appliances, electrolytic cell and salt solution pump, and external salt water mixing tank.

[0061] ①The machine housing is made of ABS plastic, which is anti-corrosion, anti-rust, hygienic and beautiful. The electrical box is designed to be detachable, which is beneficial for daily maintenance;

[0062] ② The electrical control system components inside the main unit are connected to the front operation panel and display screen; the cooling fan is built in, and the back panel is equipped with vents; a water circuit detection and control system is installed: the main components include a salt adding device, an electric working tank, a programmable solenoid valve, a sensor, etc. The built-in salt liquid tank is convenient for daily salt replenishment;

[0063] ③>20L brine mixing tank (self-provided);

[0064] ④ External submersible pump; This product is a volumetric diaphragm electrolysis device, which can be used in the laboratory to make acid-base potential water;

[0065] Step 2.2: Prepare experimental equipment and utensils

[0066] Conductivity meter (Shanghai Leici DDS-307A), grating spectrophotometer (YS3060): Shenzhen Sanenshi Technology Co., Ltd., handheld refractometer, texture analyzer (13-0268-07), high-speed centrifuge, temperature-controlled electric heating jacket (ZDHW), UV-visible spectrophotometer, volumetric flask (500mL, 1000mL), pipette (10mL), test tube, stopwatch, mortar, basin, precision electronic balance, speed-adjustable multi-purpose oscillator (HY-2);

[0067] Step 3: Sample processing

[0068] The experiment designed five treatment groups, namely the treatment groups with calcium chloride electrolyzed water concentrations of 0.5‰, 1.0‰, 1.5‰, and 2.0‰, the pure water immersion treatment group, and the control group covered at room temperature. Three fresh-cut pear slice samples were selected for each treatment group and control group every day for the experiment. Take 6 fresh pear fruits and cut them into small pieces of the same shape and size, 4mm. Pour each group of treatment liquid into different containers, put in multiple pear slice samples, soak for 5 minutes, then take out all the pear fruits of each treatment group and control group, gently absorb the surface moisture with a paper towel, put them in a fresh-keeping bag, and store them at room temperature 21℃ and humidity 50% in an environment for subsequent determination of relevant indicators.

[0069] Step 4: Experimental measurement indicators and methods

[0070] Step 4.1: Preparation of electrogenerated functional water

[0071] The electro-functional sterilizing water generator of this laboratory is used to produce electro-functional water. It can mix tap water and a trace amount of calcium chloride solution, and then generate high-quality high-efficiency disinfecting water with high redox potential indicators through special electrochemical transformation. The specific steps are as follows:

[0072] Step 4.1.1: Fill the water tank with filtered distilled water;

[0073] Step 4.1.2: Add CaCl at a ratio of 0.5‰-2‰ 2 Pour into the water tank and stir evenly;

[0074] Step 4.1.3: Place the submersible pump into the box and lay it flat with the suction port facing downwards;

[0075] Step 4.1.4: Turn on the power pump to fill the water tank; the water tank will be full within two minutes; water production starts and the ammeter will indicate; if the water filling exceeds two minutes, the water inlet indicator will flash and the buzzer will sound. Press the reset switch to refill the water to the liquid level detection value before water production can begin;

[0076] Step 4.1.5: When making water, the current meter displays a value of 8-10A at the beginning and a value of <30A at the end;

[0077] Step 4.1.6: The machine has a manual voltage adjustment knob 0-24V, which can change the electrolyte water quality parameters;

[0078] Step 4.1.7: The proportion of salt in the electrolyte can also be adjusted by adjusting the voltage to produce acidic and alkaline electric water with different parameters;

[0079] Step 4.1.8: Delay switch adjustment; the factory setting is 5 minutes per electrolysis; if you want to adjust the electrolysis time, you need to open the electrical control cover and adjust the delay switch position inside the machine: turn the adjustable switch on the circuit board to the ON direction, and the nominal time is in minutes;

[0080] (1) Turn "1" and "4" to the ON direction at the same time to delay for 5 minutes;

[0081] (2) Turn "2" and "4" to 0N at the same time, delaying for 6 minutes;

[0082] (3) Turn "1", "2" and "3", "4" to the ON direction at the same time to delay for 10 minutes;

[0083] As the time increases, the electrolysis temperature will increase, the error of the ammeter indication will increase, and the precipitation of chloride ions will increase;

[0084] Step 4.1.9: By adjusting the electrolysis voltage, salt ratio, and electrolysis time, acid-base potential water with different parameters can be produced;

[0085] Step 4.1.10: When the water production is finished, turn off the control power of the host socket, and turn off the indoor host water inlet valve and power supply;

[0086] Also note: when starting up, open the water valve first, then connect the main power of the host; when shutting down, first turn off the host power switch, then turn off the water supply valve and power.

[0087] Step 4.2: Determination of total phenolic content of samples

[0088] Step 4.2.1: Mother liquor extraction: 2 g of pear slice sample was fully ground in 20 mL of 80% ethanol solution in a mortar, placed in a centrifuge tube, and centrifuged in a high-speed centrifuge for 10 min (4000 r / min). The supernatant was extracted and stored at -40 °C in the dark for later determination of total phenol content;

[0089] Step 4.2.2: Establish a standard curve for total phenol determination: First, use 80% methanol solution to prepare six groups of gallic acid solutions with different concentrations, namely 0, 50, 100, 150, 200, and 300 μg / mL; then, mix 120 μL of gallic acid solutions of different concentrations with 120 μL of Folin phenol reagent, and complete the reaction within 10 minutes; then, add 1.25 mL of 7% sodium carbonate solution, make up to 10 mL with distilled water, and react in the dark for 100 minutes; finally, perform three experiments at a wavelength of 760 nm to determine the absorbance value of each group of reaction solutions; finally, draw a standard curve for total phenol determination based on the experimental data.

[0090] Step 4.2.3: Sample determination: Use pear extract to replace gallic acid solution and react step by step according to the standard curve determination process, determine at 760nm absorbance, substitute into the total phenol determination standard curve, calculate the content of phenolic substances in pear, and repeat the test 3 times;

[0091] The effects of different treatments on the total phenol content of fresh-cut pear slices were obtained by the above method: Figure 3 and Figure 4As shown in the figure, with the extension of storage time, the five treatment groups and the control group all showed a trend of first increasing and then decreasing; first, compared with the pure water treatment group, the soluble solid content of the control group increased slowly in the first 2 days of storage; while the soluble solid content of the pure water treatment group increased faster than that of the control group, and the total phenol content was lower than that of the control group after 5 days, indicating that the use of pure water treatment has a certain effect on maintaining the storage quality of fresh-cut pear slices; then, compared with the control group, the four different concentrations of calcium chloride electrolyzed water treatment groups all showed a significant difference in the content of soluble solids. The results showed that the content of total phenol in the treated group was better than that in the control group, indicating that different concentrations of calcium chloride electrolyzed water can maintain the storage quality of fresh-cut pear slices; finally, compared with the four groups treated with calcium chloride electrolyzed water of different concentrations, the treatment effect of 1.0‰ calcium chloride electrolyzed water was the best, and its total phenol content decreased more slowly, while the effect of 2‰ calcium chloride electrolyzed water was the worst, even worse than that of the pure water treatment group; after treatment with 0.5‰ and 1.5‰ calcium chloride electrolyzed water, the total phenol content increased in the first 3 days and then gradually decreased. The effects of these two treatments on total phenol were not obvious.

[0092] In summary, compared with other treatment groups, the use of 1‰ calcium chloride electrolyzed water treatment can more effectively delay the decline of total phenolic content in fresh-cut pear slices; this conclusion can provide ideas for the storage and preservation of pear slices and other fruits.

[0093] Step 4.3: Determine the soluble solids content of the sample

[0094] The refractometer was used for determination. Juice was squeezed out of the pear slices, and the juice was dropped onto the refractometer to read the reading. Each treatment was measured 3 times.

[0095] The effects of different treatments on the soluble solids content of fresh-cut pear slices obtained by the above method are as follows: According to the above treatment methods, the soluble solids content of fresh-cut pear slices was monitored and compared for 5 days. Figure 2As shown in the figure, with the extension of storage time, the five treatment groups and the control group all showed a trend of first rising and then falling; first, compared with the pure water treatment group, the soluble solid content of the control group increased slowly in the first 3 days of storage; while the soluble solid content of the pure water treatment group increased faster than that of the control group, and the soluble solid content was lower than that of the control group after 5 days, indicating that treatment with pure water has a certain effect on maintaining storage quality; then, compared with the control group, the soluble solids of the four different concentrations of calcium chloride electrolyzed water treatment groups decreased significantly slower than that of the control group, indicating that different concentrations of calcium chloride electrolyzed water can maintain the storage quality of fresh-cut pear slices. Finally, compared with the four different concentrations of calcium chloride electrolyzed water treatment groups, 1.0‰ calcium chloride electrolyzed water had the best treatment effect, and 2‰ calcium chloride electrolyzed water had the worst treatment effect; in addition, it can be seen from the figure that the 2‰ calcium chloride electrolyzed water treatment group was not as good as the pure water treatment group, indicating that the higher the concentration of calcium chloride electrolyzed water, the worse the effect of maintaining the storage quality of fresh-cut pear slices. In general, the effect of treating fresh-cut pear slices with 1.0‰ calcium chloride electrolyzed water was the best, which could effectively slow down the decline of soluble solids content, while the effects of other treatment methods were relatively poor.

[0096] Step 4.4: Determine the relative conductivity of the sample

[0097] Step 4.4.1: Conductivity was measured using a Shanghai Leici DDS-307A conductivity meter; three pear slices were randomly selected from each group, 2 g of the treated pear slices were placed in a conical flask, 35 mL of distilled water was added, and the mixture was soaked for a while, and then placed in an oscillator for 1 hour;

[0098] Step 4.4.2: Use a conductivity meter to measure the conductivity value γ1, then place the conical flask in a heating mantle and heat it to boiling for 20 minutes, then cool it to room temperature and measure the conductivity value γ0 once;

[0099] Step 4.4.3: The cell membrane permeability can be characterized by the conductivity ratio γe before and after boiling; each operation needs to be repeated three times;

[0100] The effects of different treatments on the relative conductivity of fresh-cut pear slices obtained by the above method are as follows: Figure 5 As shown in the figure, after different treatments were performed on fresh-cut pear slices, their relative conductivity was measured and the changing trend within 5 days was recorded; the following are the results of these treatments and the comparative analysis: Figure 5As shown, with the extension of storage time, the five treatment groups and the control group all showed an upward trend. First, the relative conductivity of the control group increased the fastest, followed by the pure water treatment group, which remained stable at a level slightly lower than the control group, about 5%; compared with the control group, the four different concentrations of calcium chloride electrolyzed water treatment groups had a significantly slower increase rate than the control group, indicating that different concentrations of calcium chloride electrolyzed water can maintain the storage quality of fresh-cut pear slices; among them, the relative conductivity of fresh-cut pear slices treated with 2‰ calcium chloride electrolyzed water increased to gradually approach that of the pure water treatment group, indicating that the treatment effect of the four different concentrations of calcium chloride electrolyzed water on fresh-cut pear slices was poor; and the treatment effect of 1.0‰ calcium chloride electrolyzed water was the best, at Figure 4 It can be clearly seen that the relative conductivity increases the slowest, about 20%;

[0101] In summary, 1.0‰ calcium chloride electrolyzed water can effectively delay the increase of relative conductivity and maintain a low level within a 5-day period; however, too high a concentration may cause negative effects such as toxicity and malnutrition, and the quality maintenance effect cannot meet expectations.

[0102] Step 4.5: Determine the hardness of the sample

[0103] When conducting a hardness test, a texture analyzer is required to determine the hardness (H / N) parameters of the pear slices. The data recorded by the measuring instrument is measured by the maximum pressure, covering the hardness index from the measurement starting point to the moment when the sample is broken.

[0104] The effects of different treatments on the hardness of fresh-cut pear slices were obtained by the above method: Figure 6 As shown in the results, after 5 days of treatment, the hardness of the pear slices in each group showed a downward trend; the hardness of the control group decreased rapidly, and the hardness decreased by about 35% after 5 days. Among the treatment groups, the hardness of the pear slices in the 1.0‰ calcium chloride electrolyzed water treatment group decreased the least, only about 5%; in contrast, the hardness of the pure water treatment group and the 2.0‰ calcium chloride electrolyzed water treatment group decreased by about 10%, and the hardness of the 1.5‰ calcium chloride electrolyzed water treatment group and the 0.5‰ calcium chloride electrolyzed water treatment group decreased by about 15%; through comparative analysis, compared with the control group, the four different concentrations of calcium chloride electrolyzed water were effective in maintaining the hardness of the pear slices, especially at a concentration of 1.0‰, which had the best treatment effect and could effectively maintain the hardness of the pear slices; because electro-functional water can increase the activity of water and contains a large amount of negative ions and trace elements, it helps to promote the metabolism and cell vitality of the pear slices, thereby maintaining the hardness of the pear slices;

[0105] In summary, 1.0‰ calcium chloride electrolyzed water treatment has the best effect and can effectively maintain the hardness of pear slices. This provides a useful reference for the food processing industry, and it is possible to consider using electro-generated functional water for treatment in the processing of pear slices and other foods.

[0106] Step 4.6: Determine the color difference value of the sample

[0107] Start the colorimeter for calibration, calibrate the zero position and the white plate, take out the pear slices in each container, wipe the surface with a clean cloth, and then use the grating spectrophotometer to measure the L* of the fresh-cut pear slices. The L* value represents the lightness index of the peel surface; under the same conditions, perform colorimetric tests on fresh-cut pear slices from different parts; each operation needs to be repeated five times;

[0108] The effects of different treatments on the color difference of fresh-cut pear slices obtained by the above method are as follows: By performing different treatments on fresh-cut pear slices, we obtained the changing trend and comparative analysis of their color difference values ​​L* within 5 days; Figure 7 As shown, with the extension of storage time, the five treatment groups and the control group all showed a gradual downward trend; first, the color difference value L* of the fresh-cut pear slices treated with the control group decreased the fastest within 5 days, and had the greatest impact on brightness. For the fresh-cut pear slices treated with pure water, the color difference value L* decreased more slowly after treatment than the control group, with a change range of about 5 units. This shows that the effect of pure water treatment on extending the shelf life of fresh-cut pear slices is not obvious, and it will also cause color changes, but the treatment effect is better than that of the control group. Compared with the four groups treated with calcium chloride electrolyzed water with different concentrations, the treatment with 0.5‰ calcium chloride electrolyzed water can slightly extend the shelf life of fresh-cut pear slices, which is slightly higher than the pure water treatment. The treatment effect of the four concentrations of calcium chloride electrolyzed water is the worst; while the treatment with 1.0‰ calcium chloride electrolyzed water has the best effect. Figure 7 It can be seen that its color difference value decreases the slowest; it can be seen that the preservation effect of using 2‰ and 1.5‰ calcium chloride electrolyzed water on fresh-cut pear slices is not as good as that of 1.0‰ electrogenerated functional water, and has a greater impact on brightness;

[0109] In summary, the effect of using 1.0‰ calcium chloride electrolyzed water to treat fresh-cut pear slices is the best, which has little effect on brightness and can effectively delay the decline of L*; the use of other treatments has relatively poor effects on the preservation and brightness of fresh-cut pear slices, and it is necessary to select the appropriate concentration according to the actual situation.

[0110] The above experimental results show that: by treating fresh-cut pear slices with different treatment methods, it can be found that each method has different degrees of influence on the browning of fresh-cut pears. In general, different concentrations of calcium chloride electrolyzed water have a maintenance effect on the storage quality of fresh-cut pear slices. However, the use of 1.0‰ calcium chloride electrolyzed water for treatment can significantly maintain the storage quality of fresh-cut pear slices, with the best maintenance effect. At the same time, it slows down the increase in relative conductivity and the decrease in soluble solids content, delays the decrease in total phenol content, and effectively maintains the hardness and lightness of pear slices, thereby improving the storage life and commodity value of fresh-cut pear slices (from the perspective of microorganisms or external factors: the use of 1.0‰ calcium chloride electrolyzed water destroys the cell structure of some microorganisms and inhibits the metabolic activities of most microorganisms; from the perspective of internal factors: the use of 1.0‰ calcium chloride electrolyzed water inhibits the expression of some enzymes inside fruits and vegetables, so it can keep fresh fruits and vegetables fresh for a certain period of time). Therefore, the application of electrogenerated functional water in the preservation of fruits and vegetables has huge economic benefits. This is a breakthrough in the research on the preservation function of electrogenerated functional water, which can further adapt to the needs of the market and is also the direction of future development of preservation technology.

[0111] Embodiment 2:

[0112] Different from the above-mentioned Example 1, based on the experiment described in Example 1, a method for storing fresh-cut pears with electro-generated functional water was obtained, such as Figure 1 As shown, including:

[0113] Step 1: First, soak the fresh-cut pears in 1.0‰ electro-generated functional water (AEW) for 5 minutes. After the soaking is completed, gently absorb the surface moisture of the fresh-cut pears with a paper towel;

[0114] The electro-generated functional water (AEW) is prepared by electrolyzing a 1‰ calcium chloride solution, and the processing conditions for preparing the electro-generated functional water (AEW) are an oxidation-reduction potential of 1550 mV, a pH of 2.8, and an effective chlorine concentration of 90 mg / L;

[0115] Step 2: Put the fresh-cut pears into a fresh-keeping bag and store them in an environment with a temperature of 2-5°C and a humidity of 50%;

[0116] To ensure the nutrition of fresh-cut pears, the storage time should not exceed 7 days.

[0117] As a preferred embodiment, during the treatment of fresh-cut pears by electro-functional water (AEW), the following indicators can be sampled to represent the completion of the treatment of fresh-cut pears by electro-functional water (AEW):

[0118] (1) Microbial reduction: The number of microorganisms on the surface of fresh-cut pears can be tested by sampling. When the number of microorganisms required by food safety regulations is reached, the treatment can be considered complete.

[0119] (2) Oxidation-reduction potential (ORP): Generally speaking, a higher ORP value indicates a stronger oxidizing ability and can kill microorganisms more effectively. The ORP value on the surface of the pear can be measured to determine whether the treatment is sufficient.

[0120] (3) pH value: The pH value of acidic electrolyzed water is usually low, which has an inhibitory effect on microorganisms. After soaking for a period of time at a certain pH value, the surface pH of the pear can be tested to see if it has reached stability.

[0121] Embodiment 3:

[0122] Different from the above-mentioned embodiment, the effect of the method of storing fresh-cut pears with electro-generated functional water is illustrated by the following embodiment.

[0123] (1) The optimal treatment conditions of SAEW were: effective chlorine concentration of 30.00 mg / L, solid-liquid ratio of 1:15 (m:V), treatment time of 3.69 min, and storage at 4°C. Under these conditions, SAEW treatment could effectively control the number of microorganisms on the surface of fresh-cut Yunnan red pears, delay the attenuation of vitamin C content and total sugar content during storage, inhibit the activity of polyphenol oxidase, and had no significant effect on mass loss rate and pH. Conclusion: SAEW has certain potential in controlling microbial damage on the surface of fresh-cut fruits and delaying quality attenuation. The relevant results will provide a theoretical basis for the application of SAEW in fresh-cut fruit processing.

[0124] (2) Fresh-cut Hami melons were washed with acidic electrolyzed water, near-neutral electrolyzed water, NaClO solution, and tap water for 15 minutes and stored at 4°C. The preservation effects of the four test groups were better than those of the blank control group. The acidic electrolyzed water washing had a significant effect on the maintenance of soluble solids, vitamin C, and titratable acid, and could effectively inhibit the increase of malondialdehyde and total bacterial count. This method can effectively extend the shelf life of fresh-cut Hami melons. In addition, since NaClO solution has a strong oxidizing ability, it has a great impact on the appearance and nutritional quality of fresh-cut Hami melons. Comparing the above four cleaning methods, AEW has the strongest bactericidal effect and can better maintain the storage quality of fresh-cut Hami melons. It is also safer than traditional chlorine disinfectants.

[0125] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The above-described embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A method for storing fresh-cut pears using electro-functional water, characterized in that: include: Step 1: First, soak the fresh-cut pears in 1.0‰ electro-functional water for 5 minutes. After the soaking is completed, absorb the moisture on the surface of the fresh-cut pears; Step 2: Put the fresh-cut pears into a fresh-keeping bag and store them in an environment of 2-5℃ and 50% humidity.

2. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: The electro-generated functional water is prepared by electrolyzing a 1‰ calcium chloride solution, and the processing conditions for preparing the electro-generated functional water are: an oxidation-reduction potential of 1550 mV, a pH of 2.8, and an effective chlorine concentration of 90 mg / L.

3. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: This method can be used to store fresh-cut pears for no more than 7 days.

4. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: The method further comprises a process for determining the total phenol content in fresh-cut pears, and the process for determining the total phenol content in fresh-cut pears comprises the steps of: (1) Mother liquor extraction: 2 g of fresh-cut pear sample was thoroughly ground in 20 mL of 80% ethanol solution. After grinding, the mixture was centrifuged in a high-speed centrifuge for 10 min at 4000 r / min. The supernatant was extracted and stored at -40°C in the dark for later determination of total phenol content. (2) Establishment of standard curve for total phenol determination: (3) Sample determination: Pear extract was used instead of gallic acid solution and the reaction was carried out step by step according to the standard curve determination process. The absorbance was measured at 760 nm and the total phenol determination standard curve was substituted to calculate the content of phenolic substances in pears. The experiment was repeated three times.

5. The method for storing fresh-cut pears using electro-functional water as claimed in claim 4, characterized in that: The process of establishing the standard curve for total phenol determination comprises: Firstly, six groups of gallic acid solutions with different concentrations were prepared using 80% methanol solution, namely 0, 50, 100, 150, 200, and 300 μg / mL; Subsequently, 120 μL of gallic acid solution with different concentrations was mixed with 120 μL of Folin phenol reagent, and the reaction was completed within 10 min; Then, 1.25 mL of 7% sodium carbonate solution was added, the volume was made up to 10 mL with distilled water, and the reaction was allowed to proceed in the dark for 100 min; Finally, three experiments were performed at a wavelength of 760 nm to determine the absorbance value of each group of reaction solutions; Finally, a standard curve for total phenol determination was drawn based on the experimental data.

6. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: The method further comprises a process of determining the soluble solid content in the fresh-cut pears, wherein the process of determining the soluble solid content in the fresh-cut pears comprises: Squeeze the juice out of fresh-cut pears, drop it on the refractometer, and read the reading; repeat the measurement 3 times for each treatment.

7. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: The method further comprises a process of determining the relative conductivity of the fresh-cut pears, wherein the process of determining the relative conductivity of the fresh-cut pears comprises: (1) Three fresh-cut pear samples were randomly selected from each group. 2 g of the treated fresh-cut pear samples were placed in a conical flask, 35 mL of distilled water was added, and the mixture was soaked for a while. After soaking, the mixture was placed in an oscillator and shaken for 1 h. (2) The conductivity value γ1 is measured by a conductivity meter, and then the conical flask is placed in an electric heating mantle and heated to boiling for 20 minutes, then cooled to room temperature and the conductivity value γ0 is measured once; (3) Cell membrane permeability can be characterized by the conductivity ratio γe before and after boiling; Each operation needs to be repeated three times.

8. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: The method further comprises a process of measuring the hardness of fresh-cut pears, wherein the process of measuring the hardness of fresh-cut pears comprises: The hardness test was carried out using a texture analyzer to determine the hardness parameters of fresh-cut pear samples; the data recorded by the measuring instrument was measured based on the maximum pressure.

9. The method for storing fresh-cut pears using electro-functional water according to claim 1, characterized in that: The method further comprises determining the color difference value of the fresh-cut pears, and the process of determining the color difference value of the fresh-cut pears comprises: Take out the fresh-cut pear sample, wipe its surface dry, and then use a grating spectrophotometer to measure the L* of the fresh-cut pear slices. The L* value represents the lightness index of the peel surface. Under the same conditions, colorimetric tests were performed on fresh-cut pear samples from different parts; each operation was repeated five times.

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