A method and device for color development of pickled vegetables with nitrite

Abstract

The invention relates to the technical field of optical detection, and in particular to a kimchi nitrite coloring method and device, comprising: crushing 20g of a vegetable sample; adding 10ml of saturated sodium borate and 150ml of distilled water to the vegetable sample, transferring the mixture to a 250ml volumetric flask, adding NaOH to adjust the pH to alkaline, fully stirring and shaking, heating the mixture at a certain temperature for a certain time by a water bath combined with a microwave combined heating method; adding 0.3g of activated carbon; adding a precipitant after cooling, and obtaining a sample pretreatment liquid after static filtration; coloring the pretreatment liquid, and measuring the absorbance at a wavelength of 538nm; calculating the nitrite content; after the sample is pretreated and color-developed, a fully reacted coloring liquid is obtained, a purple-red coupling product is generated, the absorbance of the product is measured at a wavelength of 538nm, and the kimchi nitrite content recovery rate is greater than 99%, thereby solving the problems of long detection time, unstable results and low recovery rate when the nitrite content in kimchi is detected by a naphthylethylenediamine hydrochloride method.

Description

Technical Field

[0001] The invention relates to the technical field of optical detection, and in particular to a kimchi nitrite color development method and device. Background Art

[0002] Kimchi has a unique flavor and is easy to preserve, making it an important part of daily food. There are different brands and types of kimchi in different places, but kimchi contains a certain amount of nitrite. Too high a nitrite content can cause poisoning. Therefore, nitrite colorimetric solution is often needed in the environmental monitoring and food safety industries to analyze and detect nitrite content.

[0003] At present, the national standard naphthylethylenediamine hydrochloride method is widely used for the determination of nitrite in food. This traditional method is accurate in the determination of meat products, but the nitrite recovery rate is about 81% to 87% when measuring the nitrite content of kimchi, and the detection time is long. The results are affected by the temperature, reaction rate, pH value, reagent addition amount during pretreatment, and reaction rate during color development treatment, and are not stable. Summary of the invention

[0004] The purpose of the present invention is to provide a kimchi nitrite color development method and device, aiming to solve the problem that the recovery rate of kimchi nitrite content determined by the traditional method is about 87%, the detection time is long, and the result is unstable.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present invention provides a method for preparing a kimchi nitrite color developing solution, comprising: crushing 20 g of a vegetable sample by a small crusher; adding 10 mL of saturated sodium borate and 150 mL of water to the vegetable sample and transferring the solution to a 250 mL volumetric flask, adding NaOH to adjust the pH to alkaline to obtain a first solution, then stirring the solution evenly with an oscillating stirrer, and finally heating the solution at a certain temperature for a certain time by a water bath combined with a microwave combined heating method; adding 0.3 g of activated carbon; cooling the first solution, and then adding 0.5 mL of a precipitant potassium ferrocyanide and zinc acetate, respectively, and letting the solution stand for 10 minutes, filtering and obtaining 20 mL of a filtrate to obtain a sample to be tested; performing a color development operation on the sample to be tested, adding water to a scale of 50 ml, and measuring the absorbance at a wavelength of 538 nm; and calculating the nitrite content.

[0006] The color development operation includes taking multiple tubes of 20.0 mL of the sample to be tested, adding 2.5 mL of p-aminobenzenesulfonic acid solution to each tube, mixing it with a shaking mixer, and letting it stand for 2 to 3 minutes; then adding 1.5 mL of naphthalene ethylenediamine hydrochloride solution, adding water to the scale, mixing it with a shaking mixer, and letting it stand for 10 minutes to obtain a color developing solution.

[0007] Wherein, NaOH is added to adjust the pH to alkaline, and the pH value is adjusted to 8.

[0008] On the other hand, a kimchi nitrite coloring device adopts the kimchi nitrite coloring method described above, including a small crusher, a microwave heater and an oscillating mixer; the oscillating mixer includes a base, a connecting seat, multiple hydraulic rods, a bracket, multiple sliding seats, multiple first springs, an elliptical ring, two first telescopic rods, two rolling balls, a placement ring and a rubber pad, and the connecting seat is arranged on the base; multiple hydraulic rods are fixed on the base; the bracket is fixed on the connecting seat; multiple sliding seats are slidably arranged in the bracket; multiple first springs and multiple sliding seats are fixedly connected and fixedly connected to the bracket; the elliptical ring and multiple sliding seats are rotatably connected; the placement ring is arranged in the elliptical ring; two first telescopic rods are fixedly connected to the placement ring and are located on both sides of the placement ring; two rolling balls are rotatably connected to the two first telescopic rods respectively and rotatably connected to the elliptical ring; the rubber pad is fixed in the placement ring.

[0009] Among them, the connecting seat includes a second telescopic rod, a rotating ball, a ball seat and a support plate, the second telescopic rod and the base are fixedly connected; the rotating ball and the output end of the second telescopic rod are fixedly connected and located above the second telescopic rod; the ball seat is arranged on the outside of the rotating ball; and the support plate is fixed above the ball seat.

[0010] Wherein, the oscillating mixer further includes a plurality of adjusting parts, and the placement ring has a plug hole; and the plurality of adjusting parts are arranged in the placement ring.

[0011] Wherein, the adjusting member comprises an adjusting ring, an inserting rod and a soft pad, wherein the adjusting ring is arranged above the placing ring; the inserting rod is fixed below the adjusting ring; and the soft pad is fixed in the adjusting ring.

[0012] The invention discloses a kimchi nitrite color development method and device. The nitrite color development is mainly divided into two parts: pretreatment and color development. The steps before the color development operation are all pretreatment of the kimchi. A small pulverizer is used to pulverize 20g of a vegetable sample. 10mL of saturated sodium borate and 150mL of water are added to the vegetable sample and transferred to a 250mL volumetric flask. NaOH is added to adjust the pH to alkaline to obtain a first solution. A vibration mixer is then used to stir the solution evenly. Finally, a water bath combined with microwave radiation is used for auxiliary heating at a certain temperature for a certain time. When the pH value is 8, it is the most suitable condition for color development. On the basis of the heat treatment of heating in a water bath at 45°C for 10min, a second stage of microwave radiation heating to 80°C is performed for a certain time. 1min long; add 0.3g activated carbon; cool the first solution, then add a certain volume of precipitant potassium ferrocyanide and zinc acetate, the more precipitant is added, the smaller the color solution measurement value is; let it stand for 30min and filter to take 20mL of filtrate to obtain the sample to be tested; perform color development operation on the sample to be tested, fix the volume to 50ml, and measure the absorbance at a wavelength of 538nm, which mainly includes the sample without pretreatment and naphthalene ethylenediamine hydrochloride solution, and make them mix and react; fix the volume to 50ml; measure the absorbance at a wavelength of 538nm; calculate the nitrite content; the principle of this method is: after the sample is pretreated and color developed by two-stage combined heating, sufficient stirring and shaking, the reaction is very sufficient. Liquid, nitrite and p-aminobenzenesulfonic acid diazotization, the diazonium salt produced is coupled with the coupling reagent naphthylethylenediamine hydrochloride to form a purple-red dye. Nitrite and p-aminobenzenesulfonic acid diazotization, the diazonium salt is coupled with the coupling reagent naphthylethylenediamine hydrochloride to form a purple-red dye, and its absorbance is measured at a wavelength of 538nm; activated carbon is used to adsorb natural pigments and eliminate the interference of ascorbic acid, and then placed after the heat treatment to prevent carbonization and other reactions during the heating process; in microwave heating, the alternating electromagnetic field of the microwave electromagnetic field will cause the charged particles in the substance to polarize, such as hydrogen and oxygen atoms in water molecules; and rapidly change the polarization direction. This rapid change in polarization will cause friction between molecules, thereby and generate heat energy; and microwave heating significantly affects the rate at which saturated sodium borate absorbs NO2 decomposed from nitrite in the sample and the ability to release bound nitrite as a nitrite extractant at the molecular level, and adjusts the pH value together with NaOH; the two-stage heating of water bath heating combined with microwave heating enhances the mobility of the non-flowing water in the solid components of the sample compared to the traditional single water bath heating method, thereby promoting the migration and transformation of nitrite, and greatly increasing the extraction efficiency of nitrite in the sample; the recovery rate of nitrite content in kimchi is greater than 99%, thus solving the problems of long detection time, unstable results and low recovery rate when using the naphthylethylenediamine hydrochloride method to detect the nitrite content in kimchi. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 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 are briefly introduced below.

[0014] Figure 1 It is a structural schematic diagram of a kimchi nitrite color development device according to the second embodiment of the present invention.

[0015] Figure 2 It is a front view of a kimchi nitrite color developing device according to a second embodiment of the present invention.

[0016] Figure 3 It is a top view of a kimchi nitrite color developing device according to the second embodiment of the present invention.

[0017] Figure 4 It is a structural schematic diagram of a kimchi nitrite color development device according to the third embodiment of the present invention.

[0018] Figure 5 It is a structural schematic diagram of a kimchi nitrite color development device according to the fourth embodiment of the present invention.

[0019] 101-base, 102-connecting seat, 103-hydraulic rod, 104-bracket, 105-sliding seat, 106-first spring, 107-elliptical ring, 108-first telescopic rod, 109-rolling ball, 110-placing ring, 111-rubber pad, 112-second telescopic rod, 113-rotating ball, 114-ball seat, 115-support plate, 201-jack, 202-adjusting ring, 203-insertion rod, 204-cushion, 301-sealing cover, 302-sealing ring, 303-fixing rod. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0021] First embodiment

[0022] The invention provides a kimchi nitrite color development method, comprising the following steps: crushing 20 g of a vegetable sample by a small crusher; adding 10 mL of saturated sodium borate and 150 mL of water into the vegetable sample, transferring the mixture to a 250 mL volumetric flask, adding NaOH to adjust the pH to alkalinity to obtain a first solution, then stirring the mixture evenly by using an oscillating stirrer, and finally bathing the mixture at a certain temperature for a certain time; cooling the first solution, then adding a certain volume of precipitant potassium ferrocyanide and zinc acetate, respectively, keeping the mixture still for 10 minutes, filtering and obtaining 20 mL of filtrate to obtain a sample to be tested; performing a color development operation on the sample to be tested, fixing the volume to 50 mL, and measuring the absorbance by using a wavelength of 538 nm; and calculating the nitrite content.

[0023] In this embodiment, nitrite color development is mainly divided into two parts: pretreatment and color development, wherein the steps before the color development operation are all pretreatment of kimchi; 20g of vegetable sample is crushed by a small grinder; 10mL of saturated sodium borate and 150mL of water are added to the vegetable sample and transferred to a 250mL volumetric flask, NaOH is added to adjust the pH to alkaline to obtain a first solution, and then a shaking mixer is used to stir evenly, and finally a water bath combined with microwave radiation is used for auxiliary heating at a certain temperature for a certain time; a pH value of 8 is the most suitable condition for color development, and a second stage of microwave radiation heating to 80°C for 1m is carried out on the basis of the heat treatment of heating in a water bath at 45°C for 10min. in; cool the first solution, then add 0.5 mL of potassium ferrocyanide and zinc acetate as precipitants; let it stand for 10 minutes and filter to obtain 20 mL of the filtrate to obtain the sample to be tested; perform color development on the sample to be tested, set the volume to 50 mL, and measure the absorbance at a wavelength of 538 nm, which mainly includes the sample without pretreatment and the naphthalene ethylenediamine hydrochloride solution, and mix them for reaction; set the volume to 50 mL; measure the absorbance at a wavelength of 538 nm; calculate the nitrite content; the principle of this method is: after the sample is subjected to two-stage combined heating, fully stirred and shaken pretreatment and color development operation, due to the extremely fully reacted color solution, nitrite and p-aminobenzenesulfonic acid are diazotized to produce Diazonium salt is coupled with coupling reagent naphthylethylenediamine hydrochloride to form purple-red dye. Nitrite is diazotized with p-aminobenzenesulfonic acid to produce diazonium salt. This diazonium salt is then coupled with coupling reagent naphthylethylenediamine hydrochloride to form purple-red dye, and its absorbance is measured at a wavelength of 538nm. Activated carbon is used to adsorb natural pigments and eliminate the interference of ascorbic acid. After the heat treatment, it is placed to prevent carbonization and other reactions during the heating process. In microwave heating, the alternating electromagnetic field of the microwave electromagnetic field will cause the charged particles in the substance to polarize, such as hydrogen and oxygen atoms in water molecules; and the polarization direction will change rapidly. This rapid change in polarization will cause friction between molecules, thereby generating heat energy; and microwave Heating significantly affects the rate at which saturated sodium borate absorbs NO2 decomposed from nitrite in the sample and its ability to release bound nitrite as an extractant for nitrite at a molecular level, and adjusts the pH value together with NaOH; the two-stage heating of water bath heating combined with microwave heating enhances the mobility of the non-flowing water in the solid components of the sample compared to the traditional single water bath heating method, thereby promoting the migration and transformation of nitrite, and greatly increasing the extraction efficiency of nitrite in the sample; the recovery rate of nitrite content in kimchi is greater than 99%, thus solving the problems of long detection time, unstable results and low recovery rate when using the naphthylethylenediamine hydrochloride method to detect the nitrite content in kimchi.

[0024] Second embodiment

[0025] See also Figure 1 to Figure 3 , Figure 1 is a schematic structural diagram of a kimchi nitrite color development device according to a second embodiment of the present invention; Figure 2is a front view of a kimchi nitrite color developing device according to a second embodiment of the present invention; Figure 3 It is a top view of a kimchi nitrite color developing device according to the second embodiment of the present invention.

[0026] On the basis of the first embodiment, a kimchi nitrite coloring device of the present invention includes a small crusher, a microwave heater and an oscillating mixer, wherein the oscillating mixer includes a base 101, a connecting seat 102, a plurality of hydraulic rods 103, a bracket 104, a plurality of sliding seats 105, a plurality of first springs 106, an elliptical ring 107, two first telescopic rods 108, two rolling balls 109, a placement ring 110, a rubber pad 111, a second telescopic rod 112, a rotating ball 113, a ball seat 114 and a support plate 115.

[0027] The connecting seat 102 is arranged on the base 101; the plurality of hydraulic rods 103 are fixed on the base 101; the bracket 104 is fixed on the connecting seat 102; the plurality of sliding seats 105 are slidably arranged in the bracket 104; the plurality of the first springs 106 are fixedly connected to the plurality of sliding seats 105, and are fixedly connected to the bracket 104; the elliptical ring 107 is rotatably connected to the plurality of sliding seats 105; the placement ring 110 is arranged in the elliptical ring 107; the two first telescopic rods 108 are fixedly connected to the placement ring 110, and are located on both sides of the placement ring 110; the two rolling balls 109 are rotatably connected to the two first telescopic rods 108, respectively, and are rotatably connected to the elliptical ring 107; the rubber pad 111 is fixed in the placement ring 110; the small crusher can also use a homogenizer or an existing extrusion and filtering device to process kimchi samples and remove impurities; the microwave heating machine is used to use microwave radiation for heating in a combined heating method, It can quickly reach the optimal reaction temperature and shorten the waiting time; in both the pretreatment step and the color development operation, it is necessary to shake and stir evenly. The base 101 is the support of the entire shaking mixer. The connecting seat 102 can rise and fall and swing back and forth with the cooperation of the multiple hydraulic rods 103, and let the sliding seat 105 slidably mounted on the bracket 104 slide up and down, and the elliptical ring 107 rotatably connected to the sliding seat 105 also follows the up and down shaking. The placement ring 110 is used to place test tubes, reaction bottles, etc., and the rubber pad 111 is used to protect the test tube; the placement ring 110 is arranged in the elliptical ring 107 through the first telescopic rods 108 and the rolling balls 109 on both sides. When the elliptical ring 107 swings up and down, the placement ring 110 moves back and forth under the action of the rolling balls 109, and shakes up and down to achieve the effect of shaking and stirring the test tube, and the pretreated solution and the color development solution can be quickly replaced on the placement ring 110, thereby solving the problem that the shaking device cannot effectively shake the test tube solution.

[0028] The second telescopic rod 112 is fixedly connected to the base 101; the rotating ball 113 is fixedly connected to the output end of the second telescopic rod 112 and is located above the second telescopic rod 112; the ball seat 114 is arranged on the outside of the rotating ball 113; the support plate 115 is fixed above the ball seat 114; the second telescopic rod 112 is used to support the rotating ball 113 and cooperate with the extension and retraction of the multiple hydraulic rods 103. The multiple hydraulic rods 103 can control the extension and retraction amount according to the program to make the support plate 115 deflect, and the rotating ball 113 and the ball seat 114 are used to cooperate with the deflection of the support plate 115, so as to make the bracket 104 above the support plate 115 shake up and down.

[0029] Third embodiment

[0030] See also Figure 4 , Figure 4 It is a structural schematic diagram of a kimchi nitrite color development device according to the third embodiment of the present invention.

[0031] On the basis of the second embodiment, a kimchi nitrite coloring device of the present invention further includes a plurality of adjusting parts, wherein the placing ring 110 has a plug hole 201 ; the adjusting parts include an adjusting ring 202 , an inserting rod 203 and a cushion 204 .

[0032] A plurality of the adjusting members are arranged in the placing ring 110 ; the plurality of the adjusting members have different sizes, but can all be installed in the placing ring 110 , so as to achieve the effect of placing test tubes of different sizes.

[0033] The adjustment ring 202 is arranged above the placement ring 110; the insertion rod 203 is fixed below the adjustment ring 202; the soft pad 204 is fixed in the adjustment ring 202; the size of the adjustment ring 202 is smaller than the placement ring 110, and the insertion rod 203 can be inserted into the socket 201 of the placement ring 110 and fixed, thereby achieving the effect of placing test tubes of different sizes.

[0034] Fourth embodiment

[0035] See also Figure 5 , Figure 5 It is a structural schematic diagram of a kimchi nitrite color development device according to the fourth embodiment of the present invention.

[0036] On the basis of the third embodiment, a kimchi nitrite coloring device of the present invention further includes a sealing cover 301 , a sealing ring 302 and a fixing rod 303 .

[0037] The sealing cover 301 is arranged above the placing ring 110; the fixing rod 303 is fixed below the sealing cover 301; the sealing cover 301 is inserted into the insertion hole 201 of the placing ring 110 through the fixing rod 303, and is used to seal the top of the test tube in some special situations, such as when it is shaken violently, to avoid splashing inside.

[0038] The sealing ring 302 is arranged on the inner side of the sealing cover 301; the sealing ring 302 can be changed in size to directly cover the mouth of the closed test tube to prevent overflow to the outside during shaking.

[0039] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A kimchi nitrite color development device, used in a kimchi nitrite color development method, comprising: Crush 20 g of the vegetable sample using a small grinder; Add 10 mL of saturated sodium borate and 150 mL of water to the vegetable sample and transfer to a 250 mL volumetric flask, add NaOH to adjust the pH to 8; conduct a second stage of microwave radiation heating to 80 ° C for 1 min on the basis of the heat treatment of heating in a water bath at 45 ° C for 10 min; add 0.3 g of activated carbon after the heat treatment to obtain a first solution, then stir evenly with a vibration mixer, and finally heat at a certain temperature for a certain time by a water bath combined with microwave combined heating method; Add 0.3 g of activated carbon; Cool the first solution, then add 0.5 mL of precipitant potassium ferrocyanide and zinc acetate, let it stand for 10 minutes, filter and take 20 mL of the filtrate to obtain the sample to be tested; Take multiple tubes of 20.0 mL of the sample to be tested, add 2.5 mL of p-aminobenzenesulfonic acid solution to each tube, mix well with a vibration mixer, let stand for 2 to 3 minutes, then add 1.5 mL of naphthalene ethylenediamine hydrochloride solution, add water to the scale of 50 mL, mix well with a vibration mixer, let stand for 10 minutes to prepare a color solution, and measure the absorbance at a wavelength of 538 nm; Calculating nitrite content, characterized in that, It comprises a small pulverizer, a microwave heating machine and an oscillating mixer, wherein the oscillating mixer comprises a base, a connecting seat, a plurality of hydraulic rods, a bracket, a plurality of sliding seats, a plurality of first springs, an elliptical ring, two first telescopic rods, two rolling balls, a placement ring and a rubber pad, wherein the connecting seat is arranged on the base; a plurality of the hydraulic rods are fixed on the base; the bracket is fixed on the connecting seat; a plurality of the sliding seats are slidably arranged in the bracket; a plurality of the first springs are fixedly connected to a plurality of the sliding seats and are fixedly connected to the bracket; the elliptical ring is rotatably connected to a plurality of the sliding seats; the placement ring is arranged in the elliptical ring; two of the first telescopic rods are fixedly connected to the placement ring and are located on both sides of the placement ring; two of the rolling balls are rotatably connected to the two first telescopic rods respectively and are rotatably connected to the elliptical ring; the rubber pad is fixed in the placement ring; The connecting seat includes a second telescopic rod, a rotating ball, a ball seat and a support plate, the second telescopic rod is fixedly connected to the base; the rotating ball is fixedly connected to the output end of the second telescopic rod and is located above the second telescopic rod; the ball seat is arranged on the outside of the rotating ball; and the support plate is fixed above the ball seat.

2. The kimchi nitrite color developing device according to claim 1, characterized in that: The oscillating mixer also includes a plurality of adjusting members, and the placement ring has a plug hole; the plurality of adjusting members are arranged in the placement ring.

3. A kimchi nitrite color developing device as claimed in claim 2, characterized in that: The adjusting member comprises an adjusting ring, an inserting rod and a soft pad. The adjusting ring is arranged above the placing ring; the inserting rod is fixed below the adjusting ring; and the soft pad is fixed in the adjusting ring.

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