CN115804406A - Micro-freezing color-protecting fresh-keeping process for litchi - Google Patents
Micro-freezing color-protecting fresh-keeping process for litchi Download PDFInfo
- Publication number
- CN115804406A CN115804406A CN202211201814.2A CN202211201814A CN115804406A CN 115804406 A CN115804406 A CN 115804406A CN 202211201814 A CN202211201814 A CN 202211201814A CN 115804406 A CN115804406 A CN 115804406A
- Authority
- CN
- China
- Prior art keywords
- litchi
- temperature
- color
- refrigerator
- fresh
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The application relates to a slightly-freezing color-protecting fresh-keeping process for litchi. The process comprises the following steps: picking fresh litchis; putting the selected litchi fruits into clear water for cleaning; soaking the cleaned litchi fruits in a disinfectant for surface disinfection, and airing the surface moisture; placing the litchi in a refrigerator at 3-5 ℃ for cooling until the temperature of the core of the litchi is reduced to the temperature of the refrigerator; placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes; removing the litchi out of the freezer, and quickly soaking the litchi in a color-protecting mixed solution of 1-4% of edible hydrochloric acid, 2-8% of oxalic acid, 0.1-0.5% of isoascorbic acid and 0.1-0.5 g/L of natamycin for 1-5 minutes; taking out, airing and packaging the surface water with a polyethylene bag with the thickness of 0.01-0.03 mm; and (4) putting the dried litchi into an ice-temperature refrigerator at the temperature of-1 ℃ for refrigeration. The scheme provided by the application can effectively prolong the storage time of the litchi to 40-60 days, and keep the color of the peel and the taste and flavor of pulp of the litchi.
Description
Technical Field
The application relates to the technical field of food freezing and preservation, in particular to a slightly-frozen color-protecting and preserving process for litchi.
Background
Litchi (lichcichinesesooson.) is a subtropical fruit with high nutritive value and unique taste and flavor, enjoys the reputation of "king of fruit" and is popular with consumers at home and abroad. The litchi is mainly produced in the fresh market, the maturation period is generally concentrated in the high-temperature and humid season of 5-7 months, the litchi is easy to be infected by microorganisms or mechanically damaged after being picked to cause quality deterioration, the loss after being picked is serious, the litchi is naturally subjected to color change in one day and flavor change in three days, the browning of the peel and the change of the pulp flavor are key reasons for extremely intolerance of storage and transportation of the litchi, even if the litchi is stored in a low-temperature environment by using a modern preservation technology, the shelf life is still not long enough for 30 days, the additional value of the litchi is severely limited, the industrial economic benefit is reduced, and the long-distance remote transportation and long-term storage of the litchi are influenced.
Freezing is an effective fruit preservation mode, however, pretreatment conditions, pretreatment time and quick-freezing temperature before quick-freezing can influence quick-freezing efficiency and effect to a great extent, and the quick-freezing method for quick-freezing and fresh-keeping of litchi at present has been disclosed, such as a litchi freezing and fresh-keeping process (Chinese patent CN 201110001447.7) which carries out short-time blanching treatment on litchi and adopts 5% citric acid and 2% salt mixed color protection liquid to carry out color protection treatment on litchi; the IQF is frozen in a quick freezing chamber at the temperature of minus 25 to 30 ℃ for 5 minutes, and then the IQF is slowly frozen in a refrigeration house at the temperature of minus 18 ℃; the above-mentioned patent techniques have the following drawbacks: the whole fruit can be frozen in a slow freezing mode in a refrigeration house at the temperature of 18 ℃ below zero, so that the pulp cell tissue is damaged, the pulp is not alive, and the original taste and nutrition of the litchi are not lost.
For the reasons, the litchi quick-freezing technology in the prior art needs to be improved urgently, and a new technology which can effectively improve the litchi preservation quality and overcome the defects of the prior art is provided. The technology combines the technical principles of freezing and sulfur treatment, destroys the structure of litchi peel by a micro-freezing technology without affecting the structure and flavor of litchi pulp, utilizes the color-protecting preservative solution to treat the litchi peel to keep the color of the litchi peel, stores the litchi peel at the ice temperature of-1 to 1 ℃ to inhibit the metabolism of the litchi fruit to the maximum extent, and does not cause the color change of the peel due to cold damage, thereby keeping the appearance and the edible quality of the litchi fruit to the maximum extent and meeting the requirements of long-time storage and long-distance transportation. The technology has the advantages of operability, safety, reliability and obvious effect, and is suitable for processing most litchi varieties.
Disclosure of Invention
In order to overcome the problems in the related art, the application provides a litchi slightly-freezing color-protecting and fresh-keeping process, which can ensure the fresh-keeping effect of litchi by slightly-freezing treatment and ice-temperature storage, and meanwhile, litchi fruits cannot be frozen until pulp cells are damaged to make litchi pulp lose life.
The application provides in a first aspect a litchi slightly-freezing color-protecting and fresh-keeping process, which comprises the following steps:
picking fresh litchis;
putting the selected litchi fruits into clear water for cleaning;
soaking the cleaned litchi fruits in a disinfectant for surface disinfection, and airing the surface moisture;
placing the litchis into a refrigerator at 3-5 ℃ for cooling until the temperature of the litchis is reduced to the temperature of the refrigerator;
placing the litchis into a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes;
soaking litchi in color protecting mixture at room temperature for 1-5 min; taking out and airing the surface water, and packaging by using a polyethylene bag with the thickness of 0.01-0.03 mm;
and (3) putting the bagged litchis into a refrigerator at the temperature of-1 ℃ for refrigeration.
In one embodiment, the color-protecting mixed solution is prepared by mixing 1 to 4% of edible hydrochloric acid, 2 to 8% of oxalic acid, 0.1 to 0.5% of isoascorbic acid and 0.1 to 0.5g/L natamycin.
In one embodiment, the time from harvesting to the time the litchi is placed in a 3 ℃ to 5 ℃ freezer for cooling is less than 6 hours.
In one embodiment, the step of cooling the litchi to the freezer temperature is performed until the core temperature of the litchi is cooled to the freezer temperature.
In one embodiment, the disinfecting solution is a chlorine-containing disinfecting solution.
In one embodiment, the slightly freezing color-protecting and fresh-keeping process for litchi comprises the following steps:
picking fresh litchis;
putting the selected litchi fruits into clear water for cleaning;
soaking the cleaned litchi fruits in a disinfectant for surface disinfection, and airing the surface moisture;
placing the litchi in a refrigerator at 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator;
placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes;
soaking litchi in color protecting mixture of 1-4% concentration edible hydrochloric acid, 2-8% concentration citric acid, 0.1-0.5% concentration isoascorbic acid and 0.1-0.5 g/L natamycin at room temperature for 1-5 min; taking out, airing the surface water, and packaging by using a 0.01-0.03 mm polyethylene bag;
and (3) putting the bagged litchis into a-1 ℃ ice-temperature refrigerator for refrigeration.
The technical scheme provided by the application can comprise the following beneficial effects: the litchi surface disinfectant is used for surface disinfection after being soaked in the disinfectant, so that the growth of pathogenic microorganisms of litchi can be reduced, and decay caused by a large amount of microorganisms in the subsequent storage process is avoided.
The method comprises the steps of putting the disinfected litchi into a refrigerator with the temperature of 3-5 ℃ for cooling until the litchi is cooled to the temperature of the refrigerator;
placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes; then, the litchi is immediately soaked in the color protection mixed solution for 1 to 5 minutes for color protection treatment.
The litchi chinensis Sonn is cooled to 3-5 ℃ at normal temperature and then is frozen at the temperature of-18 ℃ to-30 ℃, so that the freezing time can be effectively controlled, and the litchi chinensis Sonn does not have cold damage at the temperature of 3-5 ℃; if the refrigerator is directly placed in a freezer from normal temperature, the freezing time is longer and the freezing time and the freezing effect are difficult to control due to overlarge temperature difference.
The litchi is put into a freezer with the temperature of-18 ℃ to-30 ℃ for 15-50 minutes, the processed litchi peel is frozen, and the flesh of the litchi is not frozen (namely the flesh is not frozen into hard blocks) under the freezing temperature and the freezing time, so that the fresh-keeping effect that the litchi peel is frozen and the litchi fruit is still fresh is met. The specific freezing time depends on the thickness of the peel of different varieties of litchis and the size of the fruit.
The litchi which is frozen at the temperature of between 18 ℃ below zero and 30 ℃ below zero after being cooled to 3 ℃ to 5 ℃ is soaked in the color protection mixed solution for color protection, because the peel of the litchi is frozen, the purpose of freezing the peel is to destroy the structure of the peel cells, the color protection mixed solution can enter the peel cells during color protection, the color of the peel can be fixed, the color of the peel is ensured not to change in subsequent storage and transportation, and browning caused by the temperature of less than 3 ℃ is avoided, so that the storage and transportation time of the litchi is prolonged, and the color of the peel is maintained.
After the processing, the air-dried litchi is placed in an ice temperature refrigerator with the temperature of-1 ℃ for refrigeration storage, the suitable refrigeration temperature of the litchi is 3-5 ℃, but the litchi is placed in the refrigerator with the temperature of 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator; the litchi is put into a freezer with the temperature of-18 to-30 ℃ for 15 to 50 minutes and then is treated by color protection liquid, the color of the peel is fixed, and the pulp can bear the temperature above the freezing point, so that the litchi has lower metabolism, less consumption and better inhibition effect on microorganisms at the ice temperature of-1 to 1 ℃ compared with the suitable refrigeration temperature of 3 to 5 ℃, the fruit metabolism is lower, the consumption is lower, and the flavor of the litchi fruit can be better maintained.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application, as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.
FIG. 1 is a schematic flow chart of a litchi partial-freezing color-protecting fresh-keeping process in an embodiment of the present application;
fig. 2 is a schematic flow chart of a litchi slightly-freezing color-protecting fresh-keeping process in the third embodiment of the present application.
Detailed Description
Preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
Example one
Litchi (lichcichinesesooson.) is a subtropical fruit with high nutritive value and unique taste and flavor, enjoys the reputation of "king of fruit" and is popular with consumers at home and abroad. The litchi is mainly produced in the fresh market, the maturation period is generally concentrated in the high-temperature and humid season of 5-7 months, the litchi is easy to be infected by microorganisms or mechanically damaged after being picked to cause quality deterioration, the loss after being picked is serious, the litchi is naturally subjected to color change in one day and flavor change in three days, the browning of the peel and the change of the pulp flavor are key reasons for extremely intolerance of storage and transportation of the litchi, even if the litchi is stored in a low-temperature environment by using a modern preservation technology, the shelf life is still not long enough for 30 days, the additional value of the litchi is severely limited, the industrial economic benefit is reduced, and the long-distance remote transportation and long-term storage of the litchi are influenced.
Freezing is an effective fruit preservation mode, however, pretreatment conditions, pretreatment time and quick-freezing temperature before quick-freezing can influence quick-freezing efficiency and effect to a great extent, and the quick-freezing method for quick-freezing and fresh-keeping of litchi at present has been disclosed, such as a litchi freezing and fresh-keeping process (Chinese patent CN 201110001447.7) which carries out short-time blanching treatment on litchi and adopts 5% citric acid and 2% salt mixed color protection liquid to carry out color protection treatment on litchi; the IQF quick freezing chamber is frozen at the freezing temperature of minus 25 to 30 ℃ for 5 minutes, and then the slow freezing mode is adopted in a cold storage at the temperature of minus 18 ℃; the above-mentioned patent techniques have the following drawbacks: the whole fruit can be frozen in a slow freezing mode in a refrigeration house at the temperature of 18 ℃ below zero, the pulp cell tissue is damaged, the pulp loses life, and the original taste and nutrition of the litchi are lost.
For the reasons, the litchi quick-freezing technology in the prior art needs to be improved urgently, and a new technology which can effectively improve the litchi preservation quality and overcome the defects of the prior art is provided. The technology combines the technical principles of freezing and sulfur treatment, destroys the structure of litchi peel by a micro-freezing technology without affecting the structure and flavor of litchi pulp, utilizes the color-protecting preservative solution to treat the litchi peel to keep the color of the litchi peel, stores the litchi peel at the ice temperature of-1 to 1 ℃ to inhibit the metabolism of the litchi fruit to the maximum extent, and does not cause the color change of the peel due to cold damage, thereby keeping the appearance and the edible quality of the litchi fruit to the maximum extent and meeting the requirements of long-time storage and long-distance transportation. The technology has the advantages of operability, safety, reliability and obvious effect, and is suitable for processing most litchi varieties.
Referring to fig. 1, the slightly-freezing color-protecting and fresh-keeping process for litchi in the embodiment of the application comprises the following steps:
s101, picking fresh litchis;
the step plays a very critical role in the storage of subsequent litchis, if fresh litchis are not picked, the litchis picked from the litchis can have the condition of bad fruits, and the mould carried in the bad fruits can pollute the whole litchis, so that greater loss is caused.
S102, putting the selected litchi fruits into clear water for cleaning; the method can clean impurities on the surfaces of litchi peels, improve the cleanliness of litchi and facilitate subsequent storage and transportation.
S103, soaking the cleaned litchis in disinfectant to sterilize the surfaces, and airing the surface moisture; the purpose of the step is to disinfect the surface of litchi, reduce the growth of pathogenic microorganisms of litchi and avoid litchi rot caused by the existence of a large amount of microorganisms in the subsequent storage process.
S104, placing the litchi in a refrigerator at 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator;
s105, placing the litchi in a freezer at a temperature of between 18 ℃ below zero and 30 ℃ below zero for 15 to 50 minutes;
s106, soaking the litchi in the color-protecting mixed solution for 1-5 minutes at room temperature; taking out, airing and packaging the surface water with a polyethylene bag with the thickness of 0.01-0.03 mm;
according to the embodiment of the application, the litchi is placed in a refrigerator at 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator; placing the litchis into a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes; this process is referred to as a partial freeze process.
The litchi is cooled to 3-5 ℃ at normal temperature and then is frozen at the temperature of-18 ℃ to-30 ℃, so that the freezing time can be effectively controlled, and the litchi cannot be subjected to cold damage at the temperature of 3-5 ℃; if the refrigerator is directly placed in the freezer from the normal temperature, the freezing time is longer and the freezing time is difficult to control due to overlarge temperature difference.
The litchi is put into a freezer at the temperature of-18 ℃ to-30 ℃ for 15-50 minutes, and the experimental results in the embodiment of the application prove that under the freezing condition of the temperature and the time, the litchi peel is frozen, and the litchi pulp is not frozen (namely the litchi pulp is not frozen into hard blocks). The peel of the litchi after the micro-freezing treatment process is frozen, but the litchi fruit is still fresh.
The litchi after being treated by the micro-freezing treatment process has the advantages that litchi pericarp is frozen, the color protection treatment is carried out by soaking the litchi pericarp for 1-5 minutes by using the color protection mixed solution, the structure of litchi pericarp cells is damaged by freezing the litchi pericarp, the color protection mixed solution can enter the litchi pericarp cells during color protection, the color of the pericarp can be fixed, and the litchi cannot become brown due to the fact that the temperature is lower than 3 ℃ in the subsequent storage and transportation process, so that the storage and transportation time of the litchi can be greatly prolonged, and the color of the pericarp can be kept. If the fruit is not frozen, the color protection liquid is difficult to enter the fruit peel tissue, and the color protection effect is not ideal.
S107, placing the dried litchi in a refrigerator at the temperature of-1 ℃ for refrigeration and storage.
The suitable refrigeration temperature of the litchi is 3-5 ℃, but the litchi fruits can endure the low temperature of-1 ℃ after the litchi is processed by the micro-freezing treatment process, and compared with the condition that the storage temperature is lower and the fruits cannot be damaged by cold and discolored, the litchi refrigeration and transportation time can be obviously prolonged, and the flavor of the litchi fruits can be better maintained.
The beneficial effects of the embodiment of the application are as follows: the litchi surface disinfectant is used for surface disinfection after being soaked in the disinfectant, so that the growth of pathogenic microorganisms of litchi can be reduced, and decay caused by a large amount of microorganisms in the subsequent storage process is avoided.
The method comprises the steps of putting the disinfected litchi into a refrigerator with the temperature of 3-5 ℃ for cooling until the litchi is cooled to the temperature of the refrigerator;
placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes; then, the litchi is immediately soaked in the color protection mixed solution for 1 to 5 minutes for color protection treatment.
The litchi chinensis Sonn is cooled to 3-5 ℃ at normal temperature and then is frozen at the temperature of-18 ℃ to-30 ℃, so that the freezing time can be effectively controlled, and the litchi chinensis Sonn does not have cold damage at the temperature of 3-5 ℃; if the refrigerator is directly placed in a freezer from normal temperature, the freezing time is longer and the freezing time and the freezing effect are difficult to control due to overlarge temperature difference.
The litchi is put into a freezer with the temperature of-18 ℃ to-30 ℃ for 15-50 minutes, the litchi peel is frozen after the treatment, and the flesh of the litchi is not frozen (namely the flesh is not frozen into hard blocks) under the freezing temperature and the freezing time, so that the fresh-keeping effect that the litchi peel is frozen and the litchi fruit is still fresh is met. The specific freezing time depends on the thickness of the peel of different varieties of litchis and the size of the fruit.
The litchi which is frozen at the temperature of between 18 ℃ below zero and 30 ℃ below zero after being cooled to 3 ℃ to 5 ℃ is soaked in the color protection mixed solution for color protection, because the peel of the litchi is frozen, the purpose of freezing the peel is to destroy the structure of the peel cells, the color protection mixed solution can enter the peel cells during color protection, the color of the peel can be fixed, the color of the peel is ensured not to change in subsequent storage and transportation, and browning caused by the temperature of less than 3 ℃ is avoided, so that the storage and transportation time of the litchi is prolonged, and the color of the peel is maintained.
After the processing, the air-dried litchi is placed in an ice temperature refrigerator with the temperature of-1 ℃ for refrigeration storage, the suitable refrigeration temperature of the litchi is 3-5 ℃, but the litchi is placed in the refrigerator with the temperature of 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator; the litchi is placed in a freezer with the temperature of-18 ℃ to-30 ℃ for 15-50 minutes, and then is treated by color protection liquid, the color of peel is fixed, and the pulp can bear the temperature above the freezing point, so that the litchi has lower metabolism, less consumption and better inhibition effect on microorganisms at the ice temperature of-1 ℃ to 1 ℃ compared with the suitable refrigeration temperature of 3-5 ℃, the metabolism of the fruit is lower, the consumption is lower, and the flavor of the litchi fruit can be better maintained.
Example two
The first embodiment introduces a slightly-freezing color-protecting and fresh-keeping process for litchi, and at present, cold treatment and steaming heat treatment are adopted as quarantine treatment measures at the litchi outlet, but rapid color change of litchi peels is caused. Therefore, in order to solve the problem, the color of the litchi pericarp is fixed in production by adopting a sulfur treatment mode, the litchi pericarp can be kept red for a long time, but the problems of unnatural color, residual sulfur and the like exist. Aiming at the problems, the slightly-frozen color-protecting and fresh-keeping process for litchi is further invented and designed for color-protecting mixed liquid, so that the litchi peel can be kept natural for a long time and has no sulfur residue.
The embodiment of the application is further invented and designed by combining the situation in practical application.
The slightly-freezing color-protecting and fresh-keeping process for the litchi provided by the embodiment of the application comprises the following steps of:
picking fresh litchis;
putting the selected litchi fruits into clear water for cleaning;
soaking the cleaned litchi fruits in a disinfectant for surface disinfection, and airing the surface moisture;
further, the above embodiments do not limit the kind of the disinfectant, and all the disinfectant that can be used for food disinfection is within the protection scope of the present application, for example, the disinfectant solution is a chlorine-containing disinfectant, and further, the chlorine-containing disinfectant used in the present application is a 0.2% to 0.4% bleaching powder solution, the concentration of the bleaching powder solution can ensure the disinfection effect of the litchi, and the 0.2% to 0.4% bleaching powder solution is within the safe use concentration range of the bleaching powder.
Furthermore, other chlorine-containing disinfection solutions applied to the litchi surface disinfectant belong to the protection scope of the invention of the application.
Placing the litchi in a refrigerator at 3-5 ℃ for cooling until the litchi is cooled to the temperature of the refrigerator; in the step, the temperature of the litchi is reduced to the temperature of the refrigerator, the temperature of the litchi refers to the temperature of the core of the litchi, the temperature of the core of the litchi can be measured by using a thermometer, and the temperature can be measured by inserting a probe into the litchi fruit. Furthermore, the temperature of the core of the litchi can be reduced to the temperature of the refrigerator within 24 hours when the litchi is placed in the refrigerator at the temperature of 3-5 ℃.
The method comprises the steps of putting litchi in a freezer at-18 ℃ to-30 ℃ for 15-50 minutes, wherein the specific time for putting the litchi in the freezer at-18 ℃ to-30 ℃ is not limited in the step in the embodiment, the specific time for putting the litchi in the freezer at-18 ℃ to-30 ℃ is set according to the variety of the litchi, the size of the litchi fruit is different, the thickness of the peel is different, and the temperature of the freezer is different when the litchi is put in the freezer at-18 ℃ to-30 ℃. For example, a thin peel, such as cinnamon, may be left at-20 ℃ for 15 minutes, while a thicker peel, such as seedless litchi, may be left at-20 ℃ for 35 minutes.
Then soaking the litchi in the color-protecting mixed solution for 1-5 minutes at room temperature; taking out and airing the surface water; furthermore, the color protection mixed solution of the embodiment of the application is prepared by mixing 1-4% of edible hydrochloric acid, 2-8% of oxalic acid, 0.1-0.5% of isoascorbic acid and 0.1-0.5 g/L natamycin, can keep the color of the litchi to be the original color, namely the natural fruit color without becoming bright red or other colors, and does not generate the problem of sulfur residue.
And (4) putting the dried litchi into a refrigerator for refrigerating and storing at the temperature of-1 ℃.
The beneficial effects of the embodiment of the application are as follows: the embodiment of the application further reduces the temperature of the litchi in a refrigerator at 3-5 ℃ until the temperature of the litchi is reduced to the temperature of the refrigerator, wherein the temperature reduction time is less than 24 hours, and the setting of the time can reduce the temperature of the core of the litchi to the temperature of the refrigerator.
The disinfectant adopted by the application is 0.2% -0.4% of bleaching powder liquid, the bleaching powder liquid with the concentration can ensure the disinfection effect of the litchi, and the 0.2% -0.4% bleaching powder liquid is in the safe use concentration range of the bleaching powder.
The embodiment of the application combines the micro-freezing treatment process and the technical principle of color-protecting mixed liquid, the structure of litchi peels is damaged through the micro-freezing technology, the structure and the flavor of litchi pulp are not influenced, the color of the litchi peels is maintained through the treatment of the color-protecting fresh-keeping liquid, the metabolism of the litchi fruits is inhibited to the maximum extent through storage at the ice temperature of-1 ℃, the color of the peels is not changed due to cold damage, the appearance and the edible quality of the litchi fruits are maintained to the maximum extent, and the requirements of long-time storage and long-distance transportation are met. The technology has the advantages of operability, safety, reliability and obvious effect, and is suitable for processing most litchi varieties.
EXAMPLE III
Referring to fig. 2, the slightly-freezing color-protecting and fresh-keeping process for litchi in the embodiment of the application comprises the following steps:
s301, picking fresh litchis;
s302, putting the selected litchi fruits into clear water for cleaning;
s303, soaking the cleaned litchi in a disinfectant to sterilize the surface, and airing the surface moisture;
s304, placing the litchi in a refrigerator at 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator;
s305, placing the litchi in a freezer at a temperature of between 18 ℃ below zero and 30 ℃ below zero for 15 to 50 minutes;
s306, soaking litchi in color-protecting mixed solution of 1-4% of edible hydrochloric acid, 2-8% of citric acid, 0.1-0.5% of isoascorbic acid and 0.1-0.5 g/L natamycin for 1-5 minutes at room temperature; taking out, airing and packaging the surface water with a polyethylene bag with the thickness of 0.01-0.03 mm;
the embodiment of the application is different from the second embodiment in that 2-8% of oxalic acid is replaced by 2-8% of citric acid.
S307, putting the bagged litchis into a refrigerator for refrigerating and storing at the temperature of-1 ℃.
The beneficial effects of the embodiment of the application are as follows: the litchi surface disinfectant is used for surface disinfection after being soaked in the disinfectant, so that the growth of pathogenic microorganisms of litchi can be reduced, and decay caused by a large amount of microorganisms in the subsequent storage process is avoided.
The method comprises the following steps of putting litchi in a refrigerator with the temperature of 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator;
placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes; then, the litchi is soaked in a color protection mixed solution of 1 to 4 percent of edible hydrochloric acid, 2 to 8 percent of citric acid, 0.1 to 0.5 percent of isoascorbic acid and 0.1 to 0.5g/L of natamycin for 1 to 5 minutes at room temperature for color protection treatment.
The litchi chinensis Sonn is cooled to 3-5 ℃ at normal temperature and then is frozen at the temperature of-18 ℃ to-30 ℃, so that the freezing time can be effectively controlled, and the litchi chinensis Sonn does not have cold damage at the temperature of 3-5 ℃; if the refrigerator is directly placed in a freezer from normal temperature, the freezing time is longer and the freezing time and the freezing effect are difficult to control due to overlarge temperature difference.
The litchi is put into a freezer with the temperature of-18 ℃ to-30 ℃ for 15-50 minutes, the processed litchi peel is frozen, and the flesh of the litchi is not frozen (namely the flesh is not frozen into hard blocks) under the freezing temperature and the freezing time, so that the fresh-keeping effect that the litchi peel is frozen and the litchi fruit is still fresh is met.
The litchi which is frozen at the temperature of between 18 ℃ below zero and 30 ℃ below zero after being cooled to 3 ℃ to 5 ℃ is soaked in the color protection mixed solution for color protection, because the peel of the litchi is frozen, the purpose of freezing the peel is to destroy the structure of the peel cells, the color protection mixed solution can enter the peel cells during color protection, the color of the peel can be fixed, the color of the peel is ensured not to change in subsequent storage and transportation, and browning caused by the temperature of less than 3 ℃ is avoided, so that the storage and transportation time of the litchi is prolonged, and the color of the peel is maintained.
After the processing, the air-dried litchi is placed in a refrigerator at the temperature of-1 ℃ for refrigeration storage, the suitable refrigeration temperature of the litchi is 3-5 ℃, but the litchi is placed in the refrigerator at the temperature of 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator; the litchi is put into a freezer with the temperature of-18 ℃ to-30 ℃ for 15-50 minutes, so that the litchi can endure the temperature of-1 ℃ to 1 ℃, and compared with the suitable refrigeration temperature of 3-5 ℃, the temperature for refrigeration is lower, the storage and transportation time is obviously prolonged, and the flavor of the litchi fruits can be better maintained.
In summary, the method combines the technical principle of micro-freezing and color protection mixed liquid, destroys the structure of the litchi peel by the micro-freezing technology without affecting the structure and the flavor of the litchi pulp, utilizes the color protection and preservation liquid to treat the litchi peel to keep the color of the litchi peel, and stores the litchi peel at the ice temperature of-1 to 1 ℃ to inhibit the metabolism of the litchi fruit to the maximum extent and avoid the color change of the peel due to cold damage, thereby keeping the appearance and the edible quality of the litchi fruit to the maximum extent and meeting the requirements of long-time storage and long-distance transportation. The technology has the advantages of operability, safety, reliability and obvious effect, and is suitable for processing most litchi varieties.
Having described embodiments of the present application, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (6)
1. A slightly frozen color-protecting and fresh-keeping process for litchi is characterized in that: the method comprises the following steps:
picking fresh litchis;
putting the selected litchi fruits into clear water for cleaning;
soaking the cleaned litchi fruits in a disinfectant for surface disinfection, and airing the surface moisture;
placing the litchi in a refrigerator at 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator;
placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes;
soaking litchi in color protecting mixture at room temperature for 1-5 min; taking out, airing the surface water, and packaging by using a 0.01-0.03 mm polyethylene bag;
and (3) putting the bagged litchis into a refrigerator at the temperature of-1 ℃ for refrigeration.
2. The slightly-frozen color-protecting and fresh-keeping process for litchi fruits according to claim 1, which is characterized in that:
the color protection mixed solution is prepared by mixing 1 to 4 percent of edible hydrochloric acid, 2 to 8 percent of oxalic acid, 0.1 to 0.5 percent of isoascorbic acid and 0.1 to 0.5g/L of natamycin.
3. The slightly-frozen color-protecting and fresh-keeping process for litchi fruits according to claim 1, which is characterized in that:
the time from the harvest to the temperature reduction of the litchi in a refrigerator at 3-5 ℃ is less than 6 hours.
4. The slightly-frozen color-protecting and fresh-keeping process for litchi fruits according to claim 1, which is characterized in that:
and the temperature of the litchi is reduced to the temperature of the refrigerator until the temperature of the core of the litchi is reduced to the temperature of the refrigerator.
5. The slightly-frozen color-protecting and fresh-keeping process for litchi fruits according to claim 1, which is characterized in that:
the disinfectant is a chlorine-containing disinfectant.
6. A slightly frozen color-protecting and fresh-keeping process for litchi is characterized in that: the method comprises the following steps:
picking fresh litchis;
putting the selected litchi fruits into clear water for cleaning;
soaking the cleaned litchi fruits in a disinfectant for surface disinfection, and airing the surface moisture;
placing the litchi in a refrigerator at 3-5 ℃ for cooling until the temperature of the litchi is reduced to the temperature of the refrigerator;
placing the litchis in a freezer at the temperature of-18 to-30 ℃ for 15 to 50 minutes;
soaking litchi in color protecting mixture of 1-4% concentration edible hydrochloric acid, 2-8% concentration citric acid, 0.1-0.5% concentration isoascorbic acid and 0.1-0.5 g/L natamycin at room temperature for 1-5 min; taking out, airing the surface water, and packaging by using a 0.01-0.03 mm polyethylene bag;
and (3) putting the bagged litchis into a-1 ℃ ice-temperature refrigerator for refrigeration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211201814.2A CN115804406A (en) | 2022-09-29 | 2022-09-29 | Micro-freezing color-protecting fresh-keeping process for litchi |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211201814.2A CN115804406A (en) | 2022-09-29 | 2022-09-29 | Micro-freezing color-protecting fresh-keeping process for litchi |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115804406A true CN115804406A (en) | 2023-03-17 |
Family
ID=85482696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211201814.2A Pending CN115804406A (en) | 2022-09-29 | 2022-09-29 | Micro-freezing color-protecting fresh-keeping process for litchi |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115804406A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117663646A (en) * | 2023-11-08 | 2024-03-08 | 广州市从化华隆果菜保鲜有限公司 | Litchi quick-freezing system and method based on ultralow-temperature antifreeze solution |
-
2022
- 2022-09-29 CN CN202211201814.2A patent/CN115804406A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117663646A (en) * | 2023-11-08 | 2024-03-08 | 广州市从化华隆果菜保鲜有限公司 | Litchi quick-freezing system and method based on ultralow-temperature antifreeze solution |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102499276B (en) | Complex preservation method of cold fresh chicken | |
| CN101507447B (en) | Fresh water fish cold-storage preservation method | |
| CN102106568B (en) | Processing method for keeping tenderness of canned crab meat | |
| MXPA04011795A (en) | Methods for preserving fresh produce. | |
| KR910001888B1 (en) | Food preservative compositions | |
| CN106417568A (en) | Storage, preservation and drying method of fresh abelmoschus esculentus fruits | |
| CN115804406A (en) | Micro-freezing color-protecting fresh-keeping process for litchi | |
| CN103431030A (en) | Non-living body preservation method of bamboo shoot | |
| CN109527333B (en) | Preservation process of Jinyang green pepper | |
| CN108522640B (en) | Fresh-cut avocado preservation method based on envelope and liquid nitrogen quick freezing | |
| CN104920752A (en) | An original flavored dried fruit processing method and low-temperature sugar soaking method | |
| JP3610487B2 (en) | Food preservation method and apparatus | |
| CN104982501B (en) | A kind of method that Penaeus Vannmei liquid nitrogen glassy state freezes preservation | |
| CN102870867B (en) | Lychee fresh-preservation method | |
| CN107996694A (en) | A kind of preservation method of Chinese toon bud | |
| KR102035482B1 (en) | Method for manufacturing the chilled red snow crab meat | |
| CN111903746A (en) | Freezing, fresh-keeping and storing method for instant fish | |
| CN114557381B (en) | Quick-freezing fresh-keeping method for large yellow croaker | |
| CN110604269A (en) | Processing method of SVC prefabricated sturgeon meat product based on vacuum low-heat technology | |
| CN113424864B (en) | Method for killing microorganisms on surface of cold-chain food by using low-temperature carbon dioxide | |
| CN111374176A (en) | Fresh-keeping production method for inhibiting bamboo shoot respiration | |
| KR102106277B1 (en) | Method for manufacturing the chilled processed food of red snow crab including crab-shells | |
| CN107279272A (en) | A kind of fresh-cut potato preservation method | |
| CN103622078A (en) | Processing method for ready-to-eat squilla | |
| CN111887292A (en) | Primary processing and storage method of stropharia rugoso-annulata |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |