Process for preparing shredded papaya pickles

Abstract

The invention provides a process for preparing shredded papaya pickles. A radio frequency drying technology is matched with a compounding agent, a pulsed electric field technology and an ultrasonic technology are used for pickling the shredded papaya pickles, the obtained shredded papaya pickles are rich in nutrition and crisp and tasty in taste, pickling raw materials of the used pickles are low in salt content, the pickling time is short, the product quality is stable, and used fermentation liquor is safe, green and healthy; the preparation process is simple, easy to implement and suitable for large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of food, and in particular relates to a process for preparing shredded papaya pickles. Background Art

[0002] Pickled vegetables are a traditional food processing method, which mainly involves pickling vegetables with salt, soy sauce, vinegar, sugar and other seasonings, and then fermenting them for a period of time. Pickled vegetables have a sweet and sour taste, a unique salty and fresh taste, and also retain the nutrients of vegetables. Pickled vegetables are a general term for various vegetable and fruit products made from fresh vegetables and fruits using different pickling processes, mainly pickled papaya, cucumber, radish, kohlrabi, etc., and the pickling methods include soy sauce, vinegar, brine, sugar, etc., which have a long history in my country. Among them, pickling with soy sauce is easy to taste, simple to operate, short pickling time, unique fragrance and certain nutritional value. It has become the preferred form of several pickled vegetables and is one of the indispensable and popular seasoning side dishes in daily life. Papaya is rich in nutrients and easy to pickle, and is the most common pickling raw material in southern my country.

[0003] The traditional method of making papaya shreds pickled vegetables is mainly to use the water seal method in the fermentation tank. This method is not easy to control the fermentation process, the product quality is unstable, and there are also disadvantages such as serious loss of nutrients during the pickling process, short storage time, and large waste of raw materials. In recent years, the emerging compaction pickling method and low-temperature fermentation method have obvious effects on improving the quality of pickled vegetables, but they are expensive and difficult to operate. In addition, the salt content in the pickled vegetables made by the traditional method is relatively high, which does not meet the modern food health standards. Traditional preservatives are mainly mixed by tumbling by physical methods. Physical methods are prone to uneven distribution of preservatives, and are not easy to diffuse into the liquid pickling solution, causing the pickling solution to spoil. Summary of the invention

[0004] The purpose of the present invention is to provide a process for preparing pickled papaya shreds in sauce in view of the defects and shortcomings of the prior art, shorten the pickling time, ensure stable product quality, reduce the use of preservatives and reduce the salt content. The pickled papaya shreds prepared by the present invention are rich in nutrition and have a crisp taste. The fermentation liquid used is safe, green and healthy. The preparation process is simple, easy to implement and suitable for large-scale production.

[0005] The present invention utilizes radio frequency drying technology, a compounding agent, pulse electric field technology, and ultrasonic technology to pickle papaya shreds and pickles, so that the crispness of the papaya shreds and pickles reaches more than 1020g. The papaya shreds and pickles are pickled with low-salt ingredients, which helps to control the sodium level in the body, thereby lowering blood pressure, and can also reduce the risk of cardiovascular diseases, protect the health of the cardiovascular and cerebrovascular systems, reduce the burden of kidney metabolism, maintain kidney function, and reduce the risk of water retention in the body, which helps to alleviate edema symptoms, can enhance the smooth taste, and make the fragrance fresh and lasting.

[0006] In one aspect, the present invention provides a method for preparing shredded papaya pickles, comprising the steps of:

[0007] S1, drying: drying the shredded papaya to obtain shredded papaya raw materials;

[0008] S2, sterilization: mix and stir the raw materials of papaya shreds and seasonings, put them in a pickling container, and sterilize them;

[0009] S3, adding a compounding agent: adding a compounding agent into the pickling container, wherein the compounding agent includes whey fermentation powder and nisin;

[0010] S4, pickled and canned.

[0011] In some embodiments, the water content of the shredded papaya material is 5-10%.

[0012] In some embodiments, the water content of the shredded papaya material is 7%.

[0013] The compound agent used in the invention is composed of whey fermentation powder and nisin, has the advantages of simple and rapid synthesis, green and pollution-free, biodegradable, and free of harmful residues. The pickled papaya shreds pickled with the compound agent can not only inhibit the growth of harmful microorganisms in the pickled vegetables, but also inhibit the production of nitrite, so that the nitrate content can be maintained at an extremely low level of 2.5 mg / kg for a long time, and the product shelf life can be as long as 16 months.

[0014] Compared with other beneficial bacteria and single beneficial bacteria, the compound agent of the present invention is a combination of whey fermentation powder and nisin, which have a synergistic effect and can control the nitrite content in the finished papaya pickled vegetable to an extremely low level, thereby further extending the shelf life.

[0015] Specifically, the introduction of whey fermentation powder and nisin causes the microbial activity in papaya pickles to advance from the early aerobic fermentation stage where various bacteria simultaneously produce carbon dioxide and water as the main products to the middle fermentation stage dominated by lactic acid bacteria. At this time, the main function is to produce lactic acid through homolactic fermentation, and the pH is quickly lowered to inhibit the growth of miscellaneous bacteria. Nisin mainly inhibits various Gram-positive bacteria that cause food spoilage, such as Leuconostoc and Staphylococcus aureus, which threaten the preservation of pickles. Nisin also has an inhibitory effect on spores in food. By adding nisin in combination with Lactobacillus plantarum, the inhibitory While controlling various kinds of miscellaneous bacteria, it provides a favorable environment for the required target bacteria, allowing them to become dominant strains in advance, reducing the production of non-target impurities, avoiding affecting the final nutrition and safety of the product, while also maintaining the acid-base environment in the pickle environment and controlling the growth and reproduction direction of microorganisms. Nisin is mainly based on those on the market, and whey fermentation powder is a new type of food preservative that is harmless to the five toxins. It has the effect of inhibiting unexpected strains in the pickling process, such as Bacillus subtilis, Escherichia coli, Aspergillus niger, and yeast. It can play a better role in the presence of nisin, and inhibit the above-mentioned strains through mechanisms such as energy competition and permeabilization of the bacterial outer membrane.

[0016] In some embodiments, in step S3, the mass ratio of whey fermentation powder to nisin in the compound is 1:0.1-1:10.

[0017] Preferably, in step S3, the mass ratio of whey fermentation powder to nisin in the compound is 1:1.

[0018] The mass ratio of the compounding agent to the papaya shreds raw material can refer to the relevant food process standards. In some methods, the mass ratio of the compounding agent to the papaya shreds raw material is 1:20.

[0019] Furthermore, in step S1, the drying is performed by using a radio frequency device.

[0020] The present invention utilizes radio frequency drying technology to pretreat papaya shreds raw materials. Radio frequency technology applies a high-frequency electric field between electrodes to make water molecules and other polar molecules in food vibrate rapidly to generate heat, thereby achieving rapid and uniform heating. This technology can heat papaya shreds uniformly in a short time. Compared with traditional heating methods (such as hot air drying), radio frequency technology avoids the problem of uneven heat distribution in traditional heating methods, and the heating treatment time is shorter, the energy consumption is lower, and the production efficiency is higher. At the same time, radio frequency technology can effectively kill microorganisms and pathogens in papaya shreds. Processing pathogenic microorganisms at the raw material stage helps to improve the yield rate, extend the shelf life of the product, and improve food safety. Due to the fast heating speed of radio frequency technology, the loss of heat-sensitive nutrients (such as vitamin C) in papaya shreds can be reduced, its nutritional value can be maintained, and the color, texture and flavor of papaya shreds can be maintained, making the final product more attractive in the market.

[0021] Furthermore, in step S2, sterilization is performed using a pulsed electric field.

[0022] The present invention utilizes pulse electric field technology to process pickles. The pulse electric field destroys the microbial cell membrane by applying a high electric field strength instantaneously, making it inactive, thereby preventing the possibility of food corruption and deterioration. The method can effectively kill microorganisms, extend the shelf life, promote the penetration of seasonings, and improve the quality and taste of food. At the same time, this treatment method belongs to non-thermal processing, so the natural color, taste and nutritional components of papaya shreds can be retained, making it more delicious and healthy. At the same time, the pulse electric field can also promote the penetration of seasonings, making them evenly distributed in papaya shreds, thereby improving the taste and flavor of food. In summary, the pulse electric field treatment of papaya shreds can not only ensure the safety and stability of food, but also improve the quality and taste of food, and meet people's demand for healthy and delicious food.

[0023] In some embodiments, in step S2, the pulse electric field voltage is set to 20-30 kV, the energy per pulse is between 1-100 J, and the frequency is set to 1-5 kHz.

[0024] Furthermore, in step S4, citral solution is added during the pickling process and ultrasonic treatment is performed at the same time; the preparation method of the citral solution is: soaking the dried citrus peel in alcohol and distilling to obtain the citral solution.

[0025] Citral is a natural lemon-flavored seasoning. The lemon aroma can give papaya pickles a fresh fragrance, which can cover up bad odors while improving sensory quality and enhance the overall flavor. It also has significant antibacterial properties and can be used as a natural preservative to inhibit the growth of a variety of microorganisms and prevent food from spoiling. The oil component in the citral emulsion can increase the lubricity of pickles and make them taste more delicate. Combined with ultrasonic technology, the penetration effect of citral can be further enhanced, making its distribution in pickles more uniform, thereby greatly extending the shelf life of the product. Ultrasonic treatment can generate tiny bubbles in the ingredients and pickling liquid through high-frequency sound waves. These bubbles burst instantly and release energy, forming the so-called "cavitation effect". This process helps to increase the temperature and pressure of the liquid, making it easier for the seasoning to penetrate into the papaya shreds and evenly distribute them, making the ingredients more tender and delicious, effectively promoting the penetration and dispersion of the seasoning, and improving the quality and taste of the food. Compared with traditional pickling methods, the mechanical action of ultrasound can make the texture of papaya pickles more uniform, reduce air bubbles in the tissue, and enhance the taste. It can also shorten the pickling time and speed up the absorption of seasonings, thereby improving production efficiency. Citral emulsion combined with ultrasonic technology is an innovative food processing method that aims to improve the flavor, quality and shelf life of papaya pickles. In this method, an emulsion containing citral is first prepared, then mixed with papaya pickles, and then ultrasonic treatment is applied. Ultrasonic waves help to improve the distribution uniformity and penetration of citral emulsion in pickles through its strong mechanical force and cavitation effect, thereby greatly enhancing its antibacterial, fresh-keeping and flavor-enhancing effects. Extend the shelf life of the product, improve the nutritional value, and ensure the safety of the product. This treatment method provides an efficient, green and innovative solution for the processing of traditional pickles.

[0026] In some embodiments, in step S4, the frequency of the ultrasonic treatment device is 20-40 kHz and the power is 20-500w.

[0027] In some embodiments, in step S4, the pickling is performed at 4° C. for 4 hours, at 20° C. for 6 hours, or at 25° C. for 4 hours.

[0028] In another aspect, the present invention provides a method for preparing shredded papaya pickles, comprising the steps of:

[0029] S1, drying, sterilization;

[0030] S2, pickling: citral solution is added during the pickling process, and ultrasonic treatment is performed at the same time; the preparation method of the citral solution is: alcohol is soaked in dried citrus peels, and the citral solution is obtained by distillation;

[0031] S3, canned.

[0032] On the other hand, the present invention provides pickled papaya shreds prepared by any of the above-mentioned preparation methods.

[0033] The beneficial effects of the present invention include:

[0034] 1. For the first time, a method for preparing papaya shreds pickled vegetables combining radio frequency drying technology, compounding agent, pulsed electric field technology and ultrasonic technology was proposed, and good results were achieved. The papaya shreds pickled vegetables are rich in nutrition and have a crisp taste. The pickled vegetables pickling raw materials used have low salt content, short pickling time, stable product quality, and the fermentation liquid used is safe, green and healthy. The preparation process is simple, easy to implement, and suitable for large-scale production.

[0035] 2. Use radio frequency technology to process papaya shreds raw materials, which can not only quickly dry the papaya shreds, shorten the raw material processing time and improve production efficiency, but also effectively kill the microorganisms and pathogens in the papaya shreds to ensure product quality control.

[0036] 3. The use of pulsed electric field technology can sterilize pickled vegetables under low temperature conditions, which not only maintains the original flavor and taste of the pickled vegetables, but also achieves the purpose of efficient sterilization.

[0037] 4. The use of citral emulsion combined with ultrasonic technology can effectively reduce the pickling time and realize the preservation of liquid materials by diffusing into the liquid pickling liquid. At the same time, the aroma substances are absorbed by the solid material of papaya shreds, which effectively preserves and forms a good flavor while improving the absorption capacity of papaya shreds for seasonings, making the pickling more complete and improving the flavor of papaya shreds pickled vegetables.

[0038] 5. Combining compounding agents with radio frequency technology and pulsed electric field technology, dominant bacteria are introduced after sterilization to inhibit the growth of miscellaneous bacteria, including the growth of bacteria that cause food spoilage. On the one hand, the use of preservatives is reduced, and on the other hand, the content of nitrites and other substances in food is reduced, thereby improving the flavor while ensuring food safety. The ingredients of the compounding agents have also been strictly screened, and whey fermentation powder and nisin have a synergistic effect. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings and specific examples, which are only used to explain the present invention and are not intended to limit the scope of the present invention. The materials, reagents, etc. used in the following examples are reagents and materials available from commercial sources unless otherwise specified.

[0040] Figure 1 The present invention provides a process flow chart for preparing shredded papaya pickles, which integrates radio frequency drying, pulsed electric field sterilization, compounding agent and citral with ultrasound. These four process steps can provide good flavor for shredded papaya pickles or ensure stable quality. Several or all of the steps can be selected to form a process for preparing shredded papaya pickles.

[0041] Example 1

[0042] 1) Raw material processing: Take fresh papaya, wash and peel it, and then use a grater to shred it into strips, and send it into a radio frequency dryer for radio frequency drying. The obtained dried papaya strips have a water content of 7% and a mass fraction of 20 parts.

[0043] 2) Mixing and stirring: Mix the dried papaya shreds and pickling soy sauce in a pickling container, wherein the pickling soy sauce comprises the following ingredients: 12 parts of 5% low-salt soy sauce, 5 parts of cooking wine, 6 parts of crystal sugar, 5 parts of chili pepper, 5 parts of crushed garlic, 2 parts of monosodium glutamate, and 1 part of vinegar.

[0044] 3) Pulse electric field sterilization: The pulse electric field voltage is set at 20-30kV, the energy of each pulse is between 1 and 100J, and the frequency is set at 1-5kHz. The machine pushes the mixed papaya pickles through the pulse electric field, and the sterilized materials are placed in a bucket. PE plastic wrap is used to cover the surface of the materials, and a heavy object is pressed on the surface to fully compact the materials.

[0045] 4) Adding a compounding agent: quantitatively weigh whey fermentation powder and nisin in a ratio of 1:1, prepare 1 portion of the compounding agent (0.05% of the mass of the dried papaya shreds), add it to the pickling container, mix well, and seal.

[0046] 5) Pickling: Pickling is divided into four steps. The first step is to pickle for 4 hours at a temperature of 4°C and a humidity of 60%; the second step is to add citral solution and treat in an ultrasonic device for 1 hour; the third step is to pickle for 6 hours at 20°C; the fourth step is to pickle for 4 hours at a temperature of 25°C. The preparation method of citral solution is: alcohol is soaked in sun-dried citrus peels, and citral solution is obtained by distillation.

[0047] 6) Canning: pasteurize the prepared papaya shreds, can them, and seal them to obtain papaya shreds pickled vegetables.

[0048] Example 2

[0049] The method of Example 1 is followed, except that step 1 is changed to:

[0050] 1) Raw material processing: Take fresh papaya, wash and peel it, then use a grater to shred it, and dry it in a dryer. The obtained dried papaya shreds have a water content of 7% and a mass percentage of 20 parts.

[0051] Example 3

[0052] The method of Example 1 is followed, except that steps 2 and 3 are changed to:

[0053] 2) Sterilization: Take 20 parts of dried papaya shreds by weight, spray the surface with 70% alcohol by volume, and place them in a sterile room to air for 10 minutes after spraying, so that the water content of the dried papaya shreds is 0.5% higher than that before soaking in alcohol, thereby obtaining sterilized shreds.

[0054] 3) Mixing and stirring: Mix the dried papaya shreds and pickling soy sauce in a pickling container, wherein the pickling soy sauce comprises the following ingredients: 12 parts of 5% low-salt soy sauce, 5 parts of cooking wine, 6 parts of crystal sugar, 5 parts of chili pepper, 5 parts of crushed garlic, 2 parts of monosodium glutamate, and 1 part of vinegar.

[0055] Example 4

[0056] The method of Example 1 is followed, except that step 5 is changed to:

[0057] 5) Marinating: Marinating is carried out in three steps. The first step is to marinate at a temperature of 4°C and a humidity of 60% for 4 hours; the second step is to marinate at 20°C for 6 hours; and the third step is to marinate at a temperature of 25°C for 4 hours.

[0058] Example 5

[0059] 1) Raw material processing: Take fresh papaya, wash and peel it, then use a grater to shred it, and dry it in a dryer. The obtained dried papaya shreds have a water content of 7% and a mass percentage of 20 parts.

[0060] 2) Sterilization: Take 20 parts of dried papaya shreds by weight, spray the surface with 70% alcohol by volume, and place them in a sterile room to air for 10 minutes after spraying, so that the water content of the dried papaya shreds is 0.5% higher than that before soaking in alcohol, thereby obtaining sterilized shreds.

[0061] 3) Mixing and stirring: Mix the dried papaya shreds and pickling soy sauce in a pickling container, wherein the pickling soy sauce comprises the following ingredients: 12 parts of 5% low-salt soy sauce, 5 parts of cooking wine, 6 parts of crystal sugar, 5 parts of chili pepper, 5 parts of crushed garlic, 2 parts of monosodium glutamate, and 1 part of vinegar.

[0062] 4) Pickling: add citral solution, seal the pickling container, and treat in an ultrasonic device for 1 hour; pickle at 20°C for 6 hours.

[0063] 5) Canning: pasteurize the prepared papaya shreds, can them, and seal them to obtain papaya shreds pickled vegetables.

[0064] Example 6

[0065] The method of Example 1 was followed, except that no citral was added during pickling;

[0066] Comparative Example 1

[0067] 1) Raw material processing: Take fresh papaya, wash and peel it, then use a grater to shred it, and dry it in a dryer. The obtained dried papaya shreds have a water content of 7% and a mass percentage of 20 parts.

[0068] 2) Sterilization: Take 20 parts of dried papaya shreds by weight, spray the surface with 70% alcohol by volume, and place them in a sterile room to air for 10 minutes after spraying, so that the water content of the dried papaya shreds is 0.5% higher than that before soaking in alcohol, thereby obtaining sterilized shreds.

[0069] 3) Mixing and stirring: Mix the dried papaya shreds and pickling soy sauce in a pickling container, wherein the pickling soy sauce comprises the following ingredients: 12 parts of 5% low-salt soy sauce, 5 parts of cooking wine, 6 parts of crystal sugar, 5 parts of chili pepper, 5 parts of crushed garlic, 2 parts of monosodium glutamate, and 1 part of vinegar.

[0070] 4) Marinating: Seal the marinating container and marinate at 20°C for 6 hours.

[0071] 5) Canning: pasteurize the prepared papaya shreds, can them, and seal them to obtain papaya shreds pickled vegetables.

[0072] Comparative Example 2

[0073] The commercially available papaya shreds pickled vegetables were purchased from Guangxi Hengxian Yunshang Network Technology Co., Ltd. The brand name is Yixiangpo, the product name is spicy papaya shreds, and the specification is 500 grams per bag / slightly spicy.

[0074] The physical and chemical indicators and taste and flavor of the papaya pickles obtained in Examples 1 to 5 and Comparative Examples 1 to 2 are tested and evaluated below.

[0075] 1. Nutritional content and appearance

[0076] After testing, the amino acid content and the content of nutrients such as vitamin C in Examples 1 to 5 are higher than those in Comparative Example 1 and Comparative Example 2, wherein the amino acid and vitamin C content of nutrients such as Examples 1, 3, and 4 are higher, because radio frequency drying technology is used. Radio frequency technology applies a high-frequency electric field between electrodes to make water molecules and other polar molecules in food vibrate rapidly to generate heat, thereby achieving rapid and uniform heating. This technology can heat papaya shreds uniformly in a short time. Compared with traditional heating methods (such as hot air drying), radio frequency technology avoids the problem of uneven heat distribution in traditional heating methods, and the heating treatment time is shorter, the energy consumption is lower, and the production efficiency is higher. At the same time, radio frequency technology can effectively kill microorganisms and pathogens in papaya shreds. Processing pathogenic microorganisms at the raw material stage helps to improve the yield rate, extend the shelf life of the product, and improve food safety. Due to the fast heating speed of radio frequency technology, the loss of heat-sensitive nutrients (such as vitamin C) in papaya shreds can be reduced, its nutritional value can be maintained, and the color, texture and flavor of papaya shreds can be maintained, making the final product more attractive in the market.

[0077] 2. Determination of salt content and nitrite content

[0078] Salt content: indirect precipitation titration

[0079] Nitrite content: GB 5009.33-2016 National Food Safety Standard Determination of Nitrite and Nitrate in Food

[0080] Table 2: Determination of salt and nitrite content in papaya pickles

[0081]

[0082] The salt content of Examples 1 to 5 and Comparative Example 1 is significantly lower than that of Comparative Example 2. This is because Examples 1 to 5 and Comparative Example 1 are pickled with low-salt ingredients, while Comparative Example 2 is commercially available and has a high salt content. This shows that the papaya pickles prepared by the present invention are beneficial to the health of the cardiovascular system and kidney organs, and at the same time, the low salt content is more conducive to improving the smooth taste and the aroma is more refreshing.

[0083] The nitrite content of Examples 1 to 6 is significantly lower than that of Comparative Examples 1 to 2. This is because radio frequency drying, pulsed electric field, compounding agent and citral ultrasound can inhibit the production of nitrite. Among them, the nitrite content of Examples 1 to 4 and 6 is lower. This is because the compounding agent has a particularly good effect in inhibiting the production of nitrite. The compounding agent is composed of whey fermentation powder and nisin, which can inhibit the growth of harmful microorganisms, thereby inhibiting the production of nitrite.

[0084] In the preliminary research of the present invention, the following groups of experiments were also conducted, namely, adding only whey fermentation powder, only adding nisin, only adding bifidobacterium powder, and in the form of a composite agent, whey fermentation powder: nisin = 1:0.1 and 1:10, and the nitrite content was measured, as shown in Table 3.

[0085] Table 3: Nitrite content of pickled food with different ingredients

[0086] Beneficial bacteria Nitrite content (mg / kg) Whey fermented powder 18.0 Nisin 19.6 Bifidobacterium powder 17.2 Whey fermentation powder: Nisin = 1:0.1 3.3 Whey fermentation powder: Nisin = 1:10 3.4

[0087] Combining the contents of Table 2 and Table 3, it can be found that when only one beneficial bacteria is added, the nitrite content is reduced compared with Comparative Example 1, but there is no significant effect. When two beneficial bacteria (whey fermentation powder and nisin) are used in combination, the nitrite content is significantly reduced. It may be that the simultaneous presence of the two bacteria has a synergistic effect on inhibiting harmful bacteria. The compatibility ratio is between 1:0.1 and 1:10, and the best effect is achieved at 1:1.

[0088] In addition, the amount of compounding agent added can refer to relevant food standards. In some embodiments of the present invention, the amount of compounding agent added is 0.05% of the mass of papaya shreds raw material. Since the function of the compounding agent is to introduce dominant bacteria and inhibit harmful bacteria after sterilization, this is not strongly correlated with the amount added, but is strongly correlated with the ingredients in the compounding agent. As long as the appropriate amount is added, this purpose can be achieved. Therefore, the amount of compounding agent added is not limited.

[0089] 3. Yield and shelf life

[0090] First, the yield rate is determined. Ignoring comparative example 2, 50 batches of embodiments 1 to 5 and comparative example 1 are respectively produced to obtain 50 batches of products. Among them, those with uneven color, black appearance, or odor are directly marked as waste products, and the rest are marked as good products. The yield rate = number of good products / 50.

[0091] Table 4: Yield of papaya pickles

[0092] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Yield rate (%) 100 100 100 100 98 64

[0093] It can be seen that the method for preparing shredded papaya pickles provided by the present invention can achieve an extremely high yield rate, which is much higher than the existing method for preparing shredded papaya pickles.

[0094] The shelf life of the pickled papaya shreds of Examples 1 to 5 and Comparative Examples 1 to 2 was further measured.

[0095] Table 5: Shelf life of papaya pickles

[0096]

[0097] It can be seen that the papaya shreds pickled vegetables of the present invention have a shelf life of 9 to 10 months without adding preservatives. The comparative example is the existing method for preparing papaya shreds pickled vegetables, which has a shelf life of only 1 month. The commercially available papaya shreds pickled vegetables have a shelf life of only 6 months when preservatives are added. It is not ruled out that some commercially available products have a longer shelf life, but the corresponding preservatives added are also more, which seriously affects the flavor of the papaya shreds pickled vegetables.

[0098] Pulsed electric field technology is used to treat pickles. The pulsed electric field destroys the cell membrane of microorganisms and makes them inactive by applying high electric field strength instantly, thereby preventing the possibility of food corruption and deterioration. This method can effectively kill microorganisms, extend the shelf life, promote the penetration of seasonings, and improve the quality and taste of food. At the same time, this treatment method belongs to non-thermal processing, so it can retain the natural color, taste and nutritional components of papaya shreds, making it more delicious and healthy. At the same time, the pulsed electric field can also promote the penetration of seasonings, making them evenly distributed in the papaya shreds, thereby improving the taste and flavor of the food. In summary, the treatment of papaya shreds with pulsed electric fields can not only ensure the safety and stability of food, but also improve the quality and taste of food, meeting people's demand for healthy and delicious food.

[0099] Of course, radio frequency drying, pulsed electric field, and compound agents have a synergistic effect. This may be because radio frequency drying can effectively kill microorganisms and pathogens in papaya shreds, and the pulsed electric field further kills microorganisms. The introduction of compound agents directly makes beneficial bacteria become the dominant flora, inhibiting the growth of harmful bacteria and significantly extending the shelf life.

[0100] 4. Taste and flavor test

[0101] Organize the subjects to taste the pickled papaya shreds of Examples 1 to 5 and Comparative Examples 1 to 2 at random, and score the taste and flavor. Each item is 15 points, with a total score of 60 points. The specific scoring is based on the following table:

[0102] Table 6: Details of the scoring items for taste and flavor test

[0103]

[0104] The scores obtained are:

[0105] Table 7: Taste and flavor rating results of papaya shreds pickled vegetables

[0106]

[0107]

[0108] Therefore, the papaya pickles prepared in Examples 1 to 6 have better taste and flavor, and are significantly better than the papaya pickles prepared by the existing preparation process and those purchased commercially in terms of appearance, aroma, taste and flavor.

[0109] Especially in terms of taste, through testing, the crispness of the papaya pickles of Examples 1 to 6 is all above 1020g, with a smooth and crisp taste. In terms of aroma and taste, Examples 1, 2, 3, and 5 are better because citral is used in combination with ultrasonic treatment.

[0110] Citral is a natural lemon-flavored seasoning. The lemon aroma can give papaya pickles a fresh fragrance, which can cover up bad odors while improving sensory quality and enhance the overall flavor. It also has significant antibacterial properties and can be used as a natural preservative to inhibit the growth of a variety of microorganisms and prevent food from spoiling. The oil component in the citral emulsion can increase the lubricity of pickles and make them taste more delicate. Combined with ultrasonic technology, the penetration effect of citral can be further enhanced, making its distribution in pickles more uniform, thereby greatly extending the shelf life of the product. Ultrasonic treatment can generate tiny bubbles in the ingredients and pickling liquid through high-frequency sound waves. These bubbles burst instantly and release energy, forming the so-called "cavitation effect". This process helps to increase the temperature and pressure of the liquid, making it easier for the seasoning to penetrate into the papaya shreds and evenly distribute them, making the ingredients more tender and delicious, effectively promoting the penetration and dispersion of the seasoning, and improving the quality and taste of the food. Compared with traditional pickling methods, the mechanical action of ultrasound can make the texture of papaya pickles more uniform, reduce air bubbles in the tissue, and enhance the taste. It can also shorten the pickling time and speed up the absorption of seasonings, thereby improving production efficiency. Citral emulsion combined with ultrasonic technology is an innovative food processing method that aims to improve the flavor, quality and shelf life of papaya pickles. In this method, an emulsion containing citral is first prepared, then mixed with papaya pickles, and then ultrasonic treatment is applied. Ultrasonic waves help to improve the distribution uniformity and penetration of citral emulsion in pickles through its strong mechanical force and cavitation effect, thereby greatly enhancing its antibacterial, fresh-keeping and flavor-enhancing effects. Extend the shelf life of the product, improve the nutritional value, and ensure the safety of the product. This treatment method provides an efficient, green and innovative solution for the processing of traditional pickles.

[0111] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto, and any equivalent modifications or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing papaya shreds pickled vegetables, characterized in that: Includes steps: S1, drying: drying the shredded papaya to obtain shredded papaya raw materials; S2, sterilization: mix and stir the raw materials of papaya shreds and seasonings, put them in a pickling container, and sterilize them; S3, adding a compounding agent: adding a compounding agent into the pickling container, wherein the compounding agent includes whey fermentation powder and nisin; S4, pickled and canned.

2. The method according to claim 1, characterized in that: In step S3, the mass ratio of whey fermentation powder to nisin in the compound is 1:0.1-1:

10.

3. The method according to claim 1, characterized in that: In the step S1, the drying is performed by using a radio frequency device to perform radio frequency drying.

4. The method according to claim 1, characterized in that: In step S2, sterilization is performed using a pulsed electric field.

5. The method according to claim 4, characterized in that: In step S2, the pulse electric field voltage is set to 20-30 kV, the energy of each pulse is between 1-100 J, and the frequency is set to 1-5 kHz.

6. The method according to claim 1, characterized in that: In step S4, citral solution is added during the pickling process and ultrasonic treatment is performed at the same time; the preparation method of the citral solution is: immersing the dried citrus peel in alcohol and distilling to obtain the citral solution.

7. The method according to claim 6, characterized in that In the step S4, the frequency of the ultrasonic treatment equipment is 20-40kHz and the power is 20-500w.

8. The method according to claim 1, characterized in that: In step S4, the pickling is performed for 4 hours at 4° C., for 6 hours at 20° C., and for 4 hours at 25° C.

9. A method for preparing papaya shreds pickled vegetables, characterized in that: Includes steps: S1, drying, sterilization; S2, pickling: citral solution is added during the pickling process, and ultrasonic treatment is performed at the same time; the preparation method of the citral solution is: alcohol is soaked in dried citrus peels, and the citral solution is obtained by distillation; S3, canned.

10. Pickled papaya shreds prepared by the method according to any one of claims 1 to 9.

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