CN112335856A - Processing method of quick-frozen vegetables - Google Patents

Processing method of quick-frozen vegetables Download PDF

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CN112335856A
CN112335856A CN202011096647.0A CN202011096647A CN112335856A CN 112335856 A CN112335856 A CN 112335856A CN 202011096647 A CN202011096647 A CN 202011096647A CN 112335856 A CN112335856 A CN 112335856A
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vegetables
blanching
vegetable
seconds
liquid nitrogen
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戴长征
张晓鹏
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Qingdao Jilong Agricultural Products Co ltd
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Qingdao Jilong Agricultural Products Co ltd
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    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
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    • A23L19/01—Instant products; Powders; Flakes; Granules
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/02—Dehydrating; Subsequent reconstitution
    • A23B7/024—Freeze-drying, i.e. cryodessication or lyophilisation
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/04—Freezing; Subsequent thawing; Cooling
    • A23B7/045—Thawing subsequent to freezing
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/04—Freezing; Subsequent thawing; Cooling
    • A23B7/05—Freezing; Subsequent thawing; Cooling with addition of chemicals or treatment with chemicals other than cryogenics, before or during cooling, e.g. in the form of an ice coating or frozen block
    • A23B7/055—Freezing; Subsequent thawing; Cooling with addition of chemicals or treatment with chemicals other than cryogenics, before or during cooling, e.g. in the form of an ice coating or frozen block with direct contact between the food and the chemical, e.g. liquid nitrogen, at cryogenic temperature
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/14—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10
    • A23B7/153—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of liquids or solids
    • A23B7/154—Organic compounds; Microorganisms; Enzymes
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/14—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10
    • A23B7/153—Preserving or ripening with chemicals not covered by groups A23B7/08 or A23B7/10 in the form of liquids or solids
    • A23B7/157—Inorganic compounds
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
    • A23L19/03—Products from fruits or vegetables; Preparation or treatment thereof consisting of whole pieces or fragments without mashing the original pieces
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
    • A23L5/20—Removal of unwanted matter, e.g. deodorisation or detoxification
    • A23L5/21—Removal of unwanted matter, e.g. deodorisation or detoxification by heating without chemical treatment, e.g. steam treatment, cooking
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
    • A23L5/40—Colouring or decolouring of foods
    • A23L5/41—Retaining or modifying natural colour by use of additives, e.g. optical brighteners
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
    • A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs

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Abstract

The invention provides a processing method of quick-frozen vegetables. The processing method of the quick-frozen vegetables comprises the following steps: the method comprises the steps of raw material selection, vegetable cleaning, blanching and enzyme deactivation, alkaline blanching treatment, sugar adding and infiltration, draining and drying treatment and freeze drying treatment. The invention can provide quick-frozen vegetables which keep the appearance of the frozen vegetables and have good taste.

Description

Processing method of quick-frozen vegetables
Technical Field
The invention relates to the technical field of vegetable processing, in particular to a processing method of quick-frozen vegetables.
Background
Nowadays, the catering industry in China continuously develops towards the production direction of industrialized, intensified, standardized, automated and specialized central kitchens, and the method is an important embodiment of the transformation of the catering industry in China. Fast food and group meal have large proportion, large demand and high development speed in the total income of the catering industry, and the quality of the food in the fast food and group meal is not ignored. The green vegetables are an indispensable food material in catering food such as Chinese fast food, ball meal and the like produced in a central kitchen, are generally cooked and processed in a high-temperature blanching way, and then are preserved and transported in a hot storage or refrigeration way. In the processing and preservation processes, due to the effects of cutting, high temperature and the like of vegetables, the damage of tissue structures and the loss of nutrient components can be caused, the color and luster are seriously yellow, the texture is softened, the product quality is seriously influenced, the appetite of consumers is reduced, and the resource waste of a large amount of vegetables is also caused. The study on crispness and green protection of green vegetables in catering foods is not available at home and abroad, so that the method has great significance for solving the problem that the green vegetables turn yellow and soft in the processing and preservation processes in catering, can improve the quality of the catering foods and reduce the resource waste, and has substantial applicability.
The vegetables are fresh and tender, contain rich Vc, carotene, minerals, cellulose and carbohydrates, and are one of the essential important foods in the life of people. The production season of the vegetables is strong, and the vegetables are difficult to store due to the fact that the vegetables are rich in water content, fresh, tender, easy to wither and easy to decay, and the quick-frozen vegetables can better solve the problems of freshness and liveness and supply regulation. At present, vegetable demand in foreign markets is increasing day by day, and quick-frozen vegetables are one of important agricultural products for earning foreign exchange by virtue of low cost and high added value, so that the prospect is very wide. However, the quick-frozen vegetables have some problems, such as unstable product quality, so that the improvement of the product quality to adapt to the international market change is urgent.
At present, frozen vegetables are a kind of frozen food, which is a small package food made by freezing fresh vegetables after processing at as low temperature as possible and as fast as possible. The processing method can make the water in the vegetable quickly form regular and fine ice crystals which are uniformly dispersed in cells, so that the vegetable tissue can not be damaged, and the biochemical process in the vegetable can not be carried out, so that bacteria and mould can not be developed. The quick-frozen vegetables are very convenient to eat, do not need to be washed and cut when being taken into a room, are slightly unfrozen, most of frozen vegetable products are steamed and boiled, and seasoning such as salt and the like can be added, so that the quick-frozen vegetables are cooked by sharp fire and are instantly cooked, the taste, color, vitamin content and the like of the quick-frozen vegetables are almost the same as those of fresh vegetables, but the process of the frozen vegetables still has the following problems: firstly, the frozen vegetables and the fresh vegetables are still different in appearance and slightly dull; secondly, frozen vegetables are less tasty than fresh vegetables, and therefore, it is necessary to provide a method for processing quick-frozen vegetables which can effectively maintain the appearance of frozen vegetables and have good taste.
Disclosure of Invention
The invention provides a processing method of quick-frozen vegetables, which has reasonable process, can provide the quick-frozen vegetables with good taste and the appearance of the frozen vegetables, and solves the technical problems that the appearance of the frozen vegetables and the appearance of fresh vegetables are still different and slightly dim in the current market.
In order to achieve the purpose, the invention provides a processing method of quick-frozen vegetables, which comprises the following steps:
selecting fresh vegetables without damage on surfaces as raw materials;
a vegetable cleaning step, wherein the vegetables are collected and then are shaped, soaked and cleaned;
blanching and enzyme deactivation, namely placing the vegetables in blanching liquid for blanching in boiling water, wherein the blanching liquid contains 0.08-0.25 mass percent of sodium chloride and 0.5-2.5 mass percent of calcium chloride, and the blanching time in the boiling water is 60-80 seconds, so that peroxidase in the vegetables is negative after blanching;
an alkaline blanching treatment step, wherein sodium bicarbonate and L-calcium ascorbate are added into the blanching liquid, the pH value of the blanching liquid is adjusted to be 7.5-8.2, the temperature is 85-90 ℃, and the blanching time is 30-40 seconds;
surface acid mist treatment, namely fishing out the vegetables, putting the vegetables into citric acid spray containing 0.01-0.02%, and keeping for 70-160 seconds;
a sugar adding and permeating step, namely putting the vegetables into a sugar medium which accounts for 20 to 40 percent of the weight of the vegetables for permeation treatment under the conditions of normal temperature of 20 ℃ and time of 0.5 to 1.5 hours, wherein the sugar medium contains one or more of glucose, lactose and high maltose syrup;
a draining and drying treatment step, namely draining vegetables, wrapping the vegetables with tinfoil, spraying ethanol on the surface of the vegetables, blowing cold air at low temperature for half an hour, and spraying ethanol on the surface of the vegetables again;
and a freeze drying step, namely conveying the dried vegetables to a liquid nitrogen instant freezer for fast freezing, conveying the vegetables to a freeze dryer for freeze drying, and then spreading and ventilating the vegetables for 4-5 hours.
Further, in the step of blanching and enzyme deactivation, the mass percentage concentration of sodium chloride is 0.08-0.25%, and the mass percentage concentration of calcium chloride is 0.5-2.5%.
Further, in the sugar adding and permeating step, the sugar medium comprises 14% -18% of glucose, 3% -5% of lactose and 3% -5% of high maltose syrup by weight of vegetables; or the sugar medium contains 14 to 18 percent of glucose and 7 to 10 percent of lactose based on the weight of the vegetables.
Further, in the draining and drying treatment step, the mass fraction of the ethanol is 80-90%, and the amount of the ethanol sprayed twice is 25-35 ml per kg of vegetables.
Further, in the freeze-drying treatment step, the temperature in the liquid nitrogen instant freezer is set to be in the range of-170 ℃ to-130 ℃, and the freezing time is 3 minutes to 6 minutes.
Further, in the freeze-drying treatment step, the temperature in the freeze-dryer is set to be in the range of-30 ℃ to-20 ℃ and the drying time is 5 hours to 10 hours; the freeze dryer has a vacuum of 0.25-0.3 kPa.
Further, the alkaline blanching treatment step and the sugar-adding infiltration step further comprise the following steps: surface acid mist treatment, namely fishing out the vegetables, putting the vegetables into citric acid spray containing 0.01-0.02%, and keeping for 70-160 seconds.
Further, in the surface acid mist treatment step, the citric acid spray is used for ensuring that the pH value of the surface of the vegetable is in the range of 6-7.
Further, the freeze drying treatment step further comprises: and vacuum packaging, namely putting the vegetables into a sterilizing chamber for sterilization, and vacuum packaging the sterilized vegetables.
Further, the sterilization condition of the sterilization chamber is 113 +/-2 ℃, the time is 30 +/-5 minutes, the back pressure is 0.1-0.15 MPa, and then the sterilization chamber is cooled to be below minus 30 ℃.
Further, after the vacuum packaging step, the method further comprises: a step of segmented thawing, in which a three-segment combined dielectric power port hot thawing method is adopted to thaw the quick-frozen side dishes, and the process is that 25MHz-50MHz radio frequency treatment is adopted for 40 seconds-50 seconds, 915MHz low-frequency microwave treatment is adopted for 45 seconds-70 seconds, and 2450MHz high-frequency microwave treatment is adopted for 60 seconds-80 seconds; the side dish with uniform quality guarantee and thawing can be obtained.
The invention has the beneficial effects that: the invention provides a processing method of quick-frozen vegetables, which can provide the quick-frozen vegetables with good taste and the appearance of the frozen vegetables. On one hand, the calcium chloride is used as a color fixative to prevent the green leaf vegetables of the vegetables from browning in the preservation period; in addition, sodium chloride and calcium chloride form a crispness keeping agent, and the hardness and chewiness of the vegetables can be kept well at high temperature. On the other hand, sodium bicarbonate and L-calcium ascorbate are used as green-protecting agents to brown green leafy vegetables of the vegetables in a preservation period, and citric acid is used as a color-protecting agent to keep the surfaces of the vegetables green. In yet another aspect, the sugaring osmotic treatment significantly prolongs the sugar return time of the dehydrated vegetables. On the other hand, the materials are unfrozen by combining the variable power radio frequency with the low-frequency ultrasonic mode, so that local high temperature generated inside the materials can be avoided, the materials are unfrozen quickly and stably, the loss of vegetable juice is reduced, and the taste and the nutritional quality of vegetables are kept.
Drawings
The invention is further explained below with reference to the figures and examples.
FIG. 1 is a flow chart of a processing method of quick-frozen vegetables according to an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The present invention may, however, be embodied in many different forms of embodiment, and the scope of the present invention should not be construed as limited to the embodiment set forth herein, but rather construed as being limited only by the following description of the embodiment.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
The embodiment of the invention provides a processing method of quick-frozen vegetables, which comprises the steps of S1-S10.
S1, selecting raw materials, namely selecting fresh vegetables without damage to the surface as the raw materials. Which may also include cutting operations.
And S2, vegetable cleaning, namely, after the vegetables are collected, shaping, soaking and cleaning.
S3, blanching and enzyme deactivation, namely placing the vegetables in a blanching liquid for blanching in boiling water, wherein the blanching liquid contains 0.08-0.25 mass percent of sodium chloride and 0.5-2.5 mass percent of calcium chloride, and the blanching time in the boiling water is 60-80 seconds, so that peroxidase in the vegetables is negative after blanching.
Wherein, calcium chloride is used as a color fixative to prevent the green leaf vegetables of the vegetables from browning in the preservation period; in addition, sodium chloride and calcium chloride constitute crisping agent, calcium chloride as component of crisping agent, and Ca ionized during soaking of cut vegetables2+The vegetable cell wall is penetrated by osmotic pressure, and the pectate acid is converted into pectic acid by activating pectate methylase activity and forms insoluble with pectic acidThe calcium pectate gel is high temperature resistant and alkali resistant, can better protect the texture of vegetable tissues during high-temperature blanching and storage, and improves the taste of consumers during taste. The crisp-keeping agent contains sodium chloride, and Na ionized when soaking cut vegetables2+Bica (b.c.)2+The protein can enter the cells of the vegetables more easily and even enter vacuoles for accumulation, and has a remarkable influence on the osmotic pressure of the vegetable cells, so that the activity of related oxidases is inhibited.
Cell walls and intercellular substances are important substances for maintaining the chewiness of vegetable tissue structures, such as cellulose, pectin, hemicellulose, and lignin. Wherein cellulose forms the main skeleton of cell walls, and pectin is an intercellular binder besides constituting cell walls, and is particularly important for supporting the vegetable morphology. Pectin is an important substance for regulating the size of cell wall pores and firm adhesion between cells, and determines the chewiness and relaxation degree of vegetable tissues. The pectin substances are classified into protopectin, pectic acid and pectic acid, enzymes such as protopectinase and pectin methylesterase can be released from cells damaged and broken by cutting or heating vegetables, under the action of enzyme, acid, alkali or high temperature, water-insoluble protopectin can be hydrolyzed into water-soluble pectic acid, so that the cross-linking effect of maintaining the texture of the vegetables is lost, and the texture and the mouthfeel of the vegetables are deteriorated. But if there are enough polyvalent metal ions such as Ca2+、Mg2 +The calcium pectate gel exists and is combined with free carboxyl of pectic acid to form water-insoluble calcium pectate gel with firm structure, so that the hardness and chewiness of the vegetable can be well maintained at high temperature.
S4, alkaline blanching treatment, namely adding sodium bicarbonate and L-calcium ascorbate into the blanching liquid, adjusting the pH value of the blanching liquid to be 7.5-8.2, controlling the temperature to be 85-90 ℃, and controlling the blanching time to be 30-40 seconds. Sodium bicarbonate and L-calcium ascorbate are used as green protecting agent to brown the green leaf vegetables of the vegetables in the preservation period, and sodium bicarbonate as a component in the green protecting agent is hydrolyzed in water to make the aqueous solution in alkalescence, so that organic acid released by damaged vegetable cells during cutting, blanching and preservation can be effectively neutralized, the inside of the vegetables can be kept alkalescence, and hydrogen ions are prevented from being generatedMagnesium ions in the chlorophyll porphyrin ring are replaced, thereby interrupting the degradation process of chlorophyll. The green-protecting agent contains L-ascorbic acid and Ca as its components2+The generated calcium complex is stable in high-temperature and alkaline environments, so that the oxidation resistance of the L-ascorbic acid can be effectively maintained at high temperature, the oxidation browning of the non-inactivated oxidases of the hot-soup vegetables in the subsequent preservation process due to the contact with oxygen is prevented, and the food quality is ensured.
S5, surface acid mist treatment, fishing out the vegetables, and placing the vegetables in citric acid mist containing 0.01-0.02% for 70-160 seconds. Citric acid as color fixative can keep the vegetable green, and neutralize alkalinity to make the pH value of the vegetable surface in the range of 6-7. It is noted that this step may be omitted, not affecting the green-keeping properties of the vegetables, but may be provided to further enhance the green-keeping properties of the vegetables.
S6, adding sugar and penetrating, namely putting the vegetables into a sugar medium which accounts for 20-40% of the weight of the vegetables for penetrating treatment under the conditions of normal temperature of 20 ℃ and time of 0.5-1.5 hours, wherein the sugar medium contains one or more of glucose, lactose and high maltose syrup. Preferably, the sugar medium comprises 14 to 18 percent of glucose, 3 to 5 percent of lactose and 3 to 5 percent of high maltose syrup by weight of vegetables; or the sugar medium contains 14 to 18 percent of glucose and 7 to 10 percent of lactose based on the weight of the vegetables.
The phenomenon of sugar return of dehydrated vegetables is due to the fact that glucose has various isomers and has strong hygroscopicity. There are three forms of isomers of glucose crystals: alpha-D-hexacyclic glucose monohydrate, alpha-D-hexacyclic glucose anhydrate and beta-D-hexacyclic glucose anhydrate. The glucose is present in the form of anhydrous alpha-D-hexacyclic glucose at the end of the dehydration process and drying of the vegetable. When the dried product is stored under cooling in a dry environment (i.e., Relative Humidity (RH). ltoreq.30 soil 5%), the glucose in the dehydrated vegetable is still present in the form of anhydrous alpha-D-hexacyclic glucose. When the ambient temperature is higher than the humidity in the dried product, the anhydrous glucose absorbs the water and is converted to the monohydrate glucose, and the crystals gradually migrate from the inside of the dried vegetable product to the surface of the dried product and are gathered together.
Lactose is chemically stable. Lactose (alpha-lactose) is relatively stable in the processing and storage processes of dehydrated vegetables, has low solubility and is not influenced by environmental moisture. The mechanism of inhibition of glucose migration by lactose may be due to the presence of alpha-lactose hydrate which hinders glucose migration. During the treatment, the dehydrated vegetables mixed and permeated by sugar medium with the mass of 20-40% of that of the vegetables are stored under the conditions that the temperature is 20 ℃ and the relative humidity is 80 ℃ and 5%, and the number of sugar returning days can be prolonged to 30-50 days.
The high maltose syrup contains glucose, maltose, maltotriose and maltotetraose, wherein maltose content is above 50%. Maltose has two kinds of isomorphous alpha and beta crystal, i.e. beta-hydrous crystal, alpha-hydrous crystal and alpha, beta-complex crystal. The complex crystal of maltose and the aqueous crystal of β -maltose have no hygroscopicity and are in a stable state at relative humidities of 71% and 84%, respectively. The mechanism of inhibition of glucose transport by maltose may be similar to that of lactose, since maltose is relatively stable at air relative humidity below 84%, does not absorb moisture, and has no change in crystal form. In addition, high maltose syrup has high viscosity, contains small amount of trisaccharide and tetrasaccharide with large molecules, and also has effect of inhibiting glucose migration. Therefore, the high maltose syrup, glucose and lactose are mixed for osmotic treatment, and the sugar returning time of the dehydrated vegetables is obviously prolonged.
And S7, a draining and drying treatment step, namely draining the vegetables, wrapping the vegetables with tinfoil, spraying ethanol on the surface, blowing cold air at low temperature for half an hour, and spraying the ethanol on the surface again. The step can be replaced by spin-drying treatment by a spin dryer. Wherein the mass fraction of the ethanol is 80-90%, and the amount of the ethanol sprayed twice is 25-35 ml per kg of vegetables.
And S8, freeze-drying, namely conveying the dried vegetables to a liquid nitrogen instant freezer for fast freezing, conveying the vegetables to a freeze dryer for freeze-drying, and spreading and ventilating the vegetables for 4-5 hours. The temperature in the liquid nitrogen instant freezer is set to be in the range of-170 ℃ to-130 ℃, and the freezing time is 3 minutes to 6 minutes. The temperature in the freeze dryer is set to be in the range of-30 ℃ to-20 ℃, and the drying time is 5 hours to 10 hours; the freeze dryer has a vacuum of 0.25-0.3 kPa.
S9, a vacuum packaging step, namely, putting the vegetables into a sterilizing chamber for sterilization, and vacuum packaging the sterilized vegetables. The sterilization condition of the sterilization chamber is 113 +/-2 ℃, the time is 30 +/-5 minutes, the back pressure is 0.1-0.15 MPa, and then the sterilization chamber is cooled to the temperature below minus 30 ℃.
S10, a step of segmented thawing, namely thawing the quick-frozen side dishes by adopting a three-segment combined dielectric power port hot thawing method, wherein the process comprises the steps of treating the quick-frozen side dishes for 40-50 seconds by adopting 25-50 MHz radio frequency, treating the quick-frozen side dishes for 45-70 seconds by 915MHz low-frequency microwave and treating the quick-frozen side dishes for 60-80 seconds by adopting 2450MHz high-frequency microwave; the side dish with uniform quality guarantee and thawing can be obtained. The method comprises the following steps of firstly quickly thawing frozen vegetables to-5 ℃ by using radio frequency equipment with the frequency of 25MHz-50MHz, preferably 27.12 MHz, then adjusting the radio frequency to 915MHz, thawing the vegetables to 0 ℃, and finally performing thawing treatment by using 2450MHz high-frequency microwave, and stopping thawing when the central temperature of the vegetables reaches 5 ℃. According to the invention, the materials are unfrozen by combining a variable power radio frequency with low frequency ultrasonic wave, so that local high temperature generated in the materials can be avoided, the materials can be unfrozen quickly and stably, the loss of vegetable juice is reduced, and the taste and the nutritional quality of vegetables are maintained.
The invention has the beneficial effects that: the invention provides a processing method of quick-frozen vegetables, which can provide the quick-frozen vegetables with good taste and the appearance of the frozen vegetables. On one hand, the calcium chloride is used as a color fixative to prevent the green leaf vegetables of the vegetables from browning in the preservation period; in addition, sodium chloride and calcium chloride form a crispness keeping agent, and the hardness and chewiness of the vegetables can be kept well at high temperature. On the other hand, sodium bicarbonate and L-calcium ascorbate are used as green-protecting agents to brown green leafy vegetables of the vegetables in a preservation period, and citric acid is used as a color-protecting agent to keep the surfaces of the vegetables green. In yet another aspect, the sugaring osmotic treatment significantly prolongs the sugar return time of the dehydrated vegetables. On the other hand, the materials are unfrozen by combining the variable power radio frequency with the low-frequency ultrasonic mode, so that local high temperature generated inside the materials can be avoided, the materials are unfrozen quickly and stably, the loss of vegetable juice is reduced, and the taste and the nutritional quality of vegetables are kept.
The processing method of the quick-frozen vegetables provided by the embodiment of the application is described in detail, a specific example is applied in the method to explain the principle and the implementation mode of the application, and the description of the embodiment is only used for helping to understand the method and the core idea of the application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims (10)

1. A processing method of quick-frozen vegetables is characterized by comprising the following steps:
selecting fresh vegetables without damage on surfaces as raw materials;
a vegetable cleaning step, wherein the vegetables are collected and then are shaped, soaked and cleaned;
blanching and enzyme deactivation, namely placing the vegetables in blanching liquid for blanching in boiling water, wherein the blanching liquid contains 0.08-0.25 mass percent of sodium chloride and 0.5-2.5 mass percent of calcium chloride, and the blanching time in the boiling water is 60-80 seconds, so that peroxidase in the vegetables is negative after blanching;
an alkaline blanching treatment step, wherein sodium bicarbonate and L-calcium ascorbate are added into the blanching liquid, the pH value of the blanching liquid is adjusted to be 7.5-8.2, the temperature is 85-90 ℃, and the blanching time is 30-40 seconds;
a sugar adding and permeating step, namely putting the vegetables into a sugar medium which accounts for 20 to 40 percent of the weight of the vegetables for permeation treatment under the conditions of normal temperature of 20 ℃ and time of 0.5 to 1.5 hours, wherein the sugar medium contains one or more of glucose, lactose and high maltose syrup;
a draining and drying treatment step, namely draining vegetables, wrapping the vegetables with tinfoil, spraying ethanol on the surface of the vegetables, blowing cold air at low temperature for half an hour, and spraying ethanol on the surface of the vegetables again;
and a freeze drying step, namely conveying the dried vegetables to a liquid nitrogen instant freezer for fast freezing, conveying the vegetables to a freeze dryer for freeze drying, and then spreading and ventilating the vegetables for 4-5 hours.
2. The liquid nitrogen vegetable drying method of claim 1, wherein in the sugar-adding infiltration step, the sugar medium comprises 14% -18% of glucose, 3% -5% of lactose and 3% -5% of high maltose syrup by weight of the vegetable; or the sugar medium contains 14 to 18 percent of glucose and 7 to 10 percent of lactose based on the weight of the vegetables.
3. The liquid nitrogen vegetable drying method as claimed in claim 1, wherein in the draining and drying step, the ethanol mass fraction is 80% -90%, and the amount of the ethanol sprayed twice is 25ml-35ml per kg of vegetable.
4. The liquid nitrogen vegetable drying method as claimed in claim 1, wherein in the freeze-drying process, the temperature in the liquid nitrogen instant freezer is set to be in the range of-170 ℃ to-130 ℃, and the freezing time is 3 minutes to 6 minutes.
5. The liquid nitrogen vegetable drying method as claimed in claim 1, wherein in the freeze-drying process step, the temperature in the freeze-dryer is set to be in the range of-30 ℃ to-20 ℃ and the drying time is 5 hours to 10 hours; the freeze dryer has a vacuum of 0.25-0.3 kPa.
6. The liquid nitrogen vegetable drying method of claim 1, further comprising between the alkaline blanching step and the sugar-adding infiltration step:
surface acid mist treatment, namely fishing out the vegetables, putting the vegetables into citric acid spray containing 0.01-0.02%, and keeping for 70-160 seconds.
7. The liquid nitrogen vegetable drying method of claim 6, wherein in the surface acid mist treatment step, the citric acid spray is performed to make the pH value of the surface of the vegetable in the range of 6-7.
8. The liquid nitrogen vegetable drying method of claim 1, further comprising, after the freeze-drying step:
and vacuum packaging, namely putting the vegetables into a sterilizing chamber for sterilization, and vacuum packaging the sterilized vegetables.
9. The liquid nitrogen vegetable drying method of claim 5, wherein the sterilizing chamber is sterilized at 113 ± 2 ℃ for 30 ± 5 minutes, is back-pressed to 0.1-0.15 MPa, and is cooled to-30 ℃ or lower.
10. The liquid nitrogen vegetable drying method of claim 5, further comprising, after the vacuum packaging step:
a step of segmented thawing, in which a three-segment combined dielectric power port hot thawing method is adopted to thaw the quick-frozen side dishes, and the process is that 25MHz-50MHz radio frequency treatment is adopted for 40 seconds-50 seconds, 915MHz low-frequency microwave treatment is adopted for 45 seconds-70 seconds, and 2450MHz high-frequency microwave treatment is adopted for 60 seconds-80 seconds; the side dish with uniform quality guarantee and thawing can be obtained.
CN202011096647.0A 2020-10-14 2020-10-14 Processing method of quick-frozen vegetables Pending CN112335856A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113273677A (en) * 2021-05-26 2021-08-20 昆山菜篮子农副产品集团有限公司 Quick-frozen vegetable processing method capable of effectively keeping vegetable raw material brittleness

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1672532A (en) * 2005-04-15 2005-09-28 海通食品集团股份有限公司 Low-cost pre-treating process for prolonging sugar returning time of dewatered vegetable
CN101715807A (en) * 2009-11-06 2010-06-02 海通食品集团股份有限公司 Method for preserving and evenly thawing fast-frozen side dishes
CN106857802A (en) * 2017-02-21 2017-06-20 江南大学 A kind of method that texture improves after freezing conditioning tuberous vegetable re-heat
CN109769923A (en) * 2017-11-11 2019-05-21 四川海盛杰低温科技有限公司 A kind of liquid nitrogen vegetable drying method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1672532A (en) * 2005-04-15 2005-09-28 海通食品集团股份有限公司 Low-cost pre-treating process for prolonging sugar returning time of dewatered vegetable
CN101715807A (en) * 2009-11-06 2010-06-02 海通食品集团股份有限公司 Method for preserving and evenly thawing fast-frozen side dishes
CN106857802A (en) * 2017-02-21 2017-06-20 江南大学 A kind of method that texture improves after freezing conditioning tuberous vegetable re-heat
CN109769923A (en) * 2017-11-11 2019-05-21 四川海盛杰低温科技有限公司 A kind of liquid nitrogen vegetable drying method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113273677A (en) * 2021-05-26 2021-08-20 昆山菜篮子农副产品集团有限公司 Quick-frozen vegetable processing method capable of effectively keeping vegetable raw material brittleness

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Application publication date: 20210209