Low-oil low-fat fruit and vegetable crisp and preparation technology thereof

Abstract

The invention provides low-oil low-fat fruit and vegetable crisps and a preparation technology thereof, and belongs to the technical field of fruit and vegetable crisps. The preparation process comprises the following steps: preparing the low-oil-absorption starch; preparing the calcium cross-linked low-oil-absorption starch; preparing a color fixative; pretreating fruits and vegetables; and preparing the low-oil low-fat fruit and vegetable crisp. The fruit and vegetable slices treated by the color fixative are wrapped by the paste prepared by adopting the calcium cross-linked low-oil-absorption starch as a main principle, and then vacuum frying is performed to prepare the crisp fruit and vegetable which is low in oil and fat, and the nutrition and taste of the fruit and vegetable can be reserved to the maximum extent.

Description

Technical Field

[0001] The invention relates to the technical field of fruit and vegetable crisp preparation, and in particular to low-oil and low-fat fruit and vegetable crisp and a preparation process thereof. Background Art

[0002] As people's health awareness continues to improve, they pay more and more attention to the nutritional and health properties of food. In daily diet, fruits and vegetables are rich in vitamins, minerals, dietary fiber and other nutrients, and are an indispensable food source for maintaining human health. However, fresh fruits and vegetables are easy to perish, inconvenient to store and carry, etc., which limits their consumption in a wider range of scenarios.

[0003] Traditional fruit and vegetable processing methods, such as frying, can give fruits and vegetables a crispy taste and improve their flavor and shelf life, but it will cause the product to have too high an oil content. Excessive intake of high-fat foods can easily lead to health problems such as obesity and cardiovascular disease, which does not meet the current consumer's pursuit of a healthy diet. In addition, although conventional drying methods such as drying can reduce moisture content and extend shelf life, they often make fruits and vegetables hard and cause serious loss of nutrients due to excessive drying, which cannot meet consumers' dual needs for taste and nutrition.

[0004] Therefore, developing a fruit and vegetable crisp that is low in oil and fat and can retain the nutrition and taste of fruits and vegetables and a preparation process thereof has become an urgent problem to be solved in the food field. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a low-oil and low-fat fruit and vegetable crisp and a preparation process thereof.

[0006] A preparation process of low-oil and low-fat fruit and vegetable crisps, comprising the following steps: S1: Preparation of low oil absorption starch The mung bean starch is first ultrasonicated at 120-180W for 20-22 minutes, then frozen at -20--22°C for 20-22 hours, thawed and then frozen again, and after repeated freeze-thaw, low oil absorption starch is obtained; S2: Preparation of calcium cross-linked low oil absorption starch Add low oil absorption starch to the calcium chloride aqueous solution, adjust the pH to 9 after dispersion, and then stir and filter to obtain calcium cross-linked low oil absorption starch; S3: Preparation of color protection agent Lactobacillus is used to prepare a fermentation liquid, and the fermentation liquid, kojic acid, methyl cellulose and soy protein isolate are added into low-temperature plasma activated water, and the mixture is stirred to obtain a color preservative; S4: Pretreatment of fruits and vegetables The fruits and vegetables are washed and blanched, then soaked in a color preservative, and finally dried to obtain pretreated fruit and vegetable slices; S5: Preparation of low-oil and low-fat fruit and vegetable crisps The batter is prepared by taking 10-12 parts by weight of calcium cross-linked low oil absorption starch, 5-8 parts by weight of wheat flour, 1-2 parts by weight of acetate starch, 8-10 parts by weight of egg liquid, 20-30 parts by weight of water, 0.1-0.2 parts by weight of hydroxypropyl methylcellulose and 0.2-0.3 parts by weight of curdlan as raw materials, and then the surfaces of pretreated fruit and vegetable slices are coated with the batter and vacuum fried to prepare low-oil and low-fat fruit and vegetable crisps.

[0007] Furthermore, step S1 of preparing low oil absorption starch specifically comprises the following steps: S1.1: Add 2-3 parts by weight of mung bean starch to 20-22 parts by weight of deionized water, and then mix under magnetic stirring at 200-300 r / min for 20-30 minutes to obtain a starch solution; S1.2: Use a vibrating titanium tip probe of an 1800W ultrasonic crusher to intermittently immerse the starch solution in a 25-26°C water bath, and ultrasonicate at 120-180W for 20-22 minutes, during which the ultrasonic cycle is repeated for 2 seconds and 2 seconds without ultrasonication. After the ultrasonication is completed, an ultrasonic starch solution is obtained; S1.3: Freeze the ultrasonic starch solution at -20--22°C for 20-22h, then thaw at 30-32°C for 2-3h, repeat the freeze-thaw process 2-3 times, dry at 45-46°C for 10-12h after freeze-thaw treatment, and then pass through a 100-120 mesh sieve to obtain low oil absorption starch.

[0008] Furthermore, step S2 of preparing calcium cross-linked low oil absorption starch specifically comprises the following steps: S2.1: Add 20-30 parts by weight of anhydrous calcium chloride to 200-230 parts by weight of deionized water, and stir to obtain a calcium chloride aqueous solution; S2.2: The temperature of the calcium chloride aqueous solution is adjusted to 30-32°C, and then 50-53 parts by weight of low oil absorption starch is added, and ultrasonic dispersion is performed for 20-30 minutes, and then 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution are added to adjust the pH to 9, and then magnetic stirring is performed at 30-32°C and 500-600 r / min for 2-3 hours to obtain a mixed solution; S2.3: The mixed solution is repeatedly filtered with deionized water for 3-5 times to obtain a precipitate, and the precipitate is dried at 40-42°C for 24-28 hours, and then crushed by a grinder and passed through a 100-120 mesh sieve to obtain calcium cross-linked low oil absorption starch.

[0009] Furthermore, the preparation of the color retaining agent in step S3 specifically comprises the following steps: S3.1: Dissolve 20 g of whey powder, 10 g of glucose, 1 g of magnesium sulfate, 2 g of dipotassium hydrogen phosphate, and 0.5 g of manganese sulfate in 200 mL of water, then make up to 1 L, and sterilize to obtain a fermentation medium; S3.2: 10 8 -10 9 CFU / g of lactic acid bacillus powder is inoculated into the fermentation medium, and then fermented in a shaker at 200-230r / min and 37°C for 10-12h, and then filtered to obtain a fermentation liquid; S3.3: 300-320 parts by weight of distilled water are placed in a beaker, and the nozzle of the low-temperature plasma jet device is placed 15 mm below the liquid surface of the distilled water, and then treated for 60-80 seconds to obtain low-temperature plasma activated water; S3.4: Add 10-12 parts by weight of fermentation liquid, 1-2 parts by weight of kojic acid, 2-3 parts by weight of methylcellulose and 2-3 parts by weight of soy protein isolate to 200-230 parts by weight of low-temperature plasma activated water, stir and mix for 20-30 minutes, and then adjust the pH to 4.5 to obtain a color protection agent.

[0010] Furthermore, step S4 of pre-processing fruits and vegetables specifically includes the following steps: S4.1: Take fresh fruits and vegetables, remove the diseased and insect-infested and rotten parts, then rinse them with clean water for 2-3 times, slice them after washing, blanch the fruit and vegetable slices in a 98-100°C blanching solution for 2-3 minutes, drain and cool them to obtain blanched fruit and vegetable slices; S4.2: Soak the blanched fruit and vegetable slices in water for 40-50 minutes, with the mass ratio of the blanched fruit and vegetable slices to the color preservative being 1:10-12. After the soaking is completed, drain the water to obtain the color-protected fruit and vegetable slices; S4.3: Place the color-protected fruit and vegetable slices in a hot air drying oven at a temperature of 60-65° C. for 30-40 minutes to obtain pretreated fruit and vegetable slices.

[0011] Furthermore, step S5 of preparing low-oil and low-fat fruit and vegetable crisps specifically comprises the following steps: S5.1: 10-12 parts by weight of calcium cross-linked low oil absorption starch, 5-8 parts by weight of wheat flour, 1-2 parts by weight of acetate starch and 8-10 parts by weight of egg liquid, then slowly add 20-30 parts by weight of water, stirring and mixing during the process, then add 0.1-0.2 parts by weight of hydroxypropyl methylcellulose and 0.2-0.3 parts by weight of curdlan, stirring and mixing for 20-30 minutes to obtain a batter; S5.2: Place 10-20 parts by weight of pretreated fruit and vegetable slices in 30-50 parts by weight of batter, so that the surface of the pretreated fruit and vegetable slices is coated with the batter, and then put them into a vacuum fryer for frying. After frying, spin dry to remove oil, cool, sterilize, and vacuum pack to obtain low-oil and low-fat fruit and vegetable crisps.

[0012] Furthermore, the inoculation amount of the lactic acid Bacillus powder in step S3.2 is 0.1% by weight of the fermentation medium.

[0013] Furthermore, the parameters of the low-temperature plasma jet device in step S3.3 are: working carrier gas: air; gas flow rate: 22.5L / min; gas source pressure: 4-6kg; input voltage: AC220V; output voltage: 19kV; output current: 0.024mA; working frequency: 20kHz; spray gun processing speed: 30-90m / min.

[0014] Furthermore, the frying conditions in step S5.2 are as follows: edible oil temperature 70-75° C., vacuum 75-80 kPa, and frying for 5-10 minutes.

[0015] A low-oil and low-fat fruit and vegetable crisp is prepared by any of the preparation processes for low-oil and low-fat fruit and vegetable crisp.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention uses ultrasound-assisted freeze-thaw treatment of mung bean starch, followed by calcium cross-linking, to prepare starch with low oil absorption. During the freezing process, the starch forms ice crystals, which physically damage the gel structure, expose the hydroxyl groups, and enhance the ability to bind water. At the same time, the cavitation effect of ultrasound shortens the starch molecular chain, generates free radicals, reduces hydrogen bonds, weakens the interaction force between starch molecules, increases the distance between straight-chain starch, and forms a sponge-like structure that can absorb more water, resulting in an increase in water absorption. The enhanced hydrophilicity reduces its lipophilicity during heat transfer, reduces the permeability of oil in the starch matrix, and thus reduces oil absorption. During calcium cross-linking, Ca 2+ It can form a coordination complex with the COC of starch molecules to improve the thermal stability of starch. The high thermal stability of calcium-cross-linked low-oil-absorption starch enables it to maintain a relatively complete particle structure and network structure under high-temperature frying conditions, providing a solid support framework for fruit and vegetable crisps, allowing them to maintain good crispness after frying, thereby achieving a crispy taste while being low in oil and fat.

[0017] 2. The present invention also adds hydroxypropyl methylcellulose and curdlan to the batter, which have thickening properties and can increase the viscosity of the batter. Curdlan forms a gel structure when heated. This gel structure can build a three-dimensional network in the batter, enhance the adhesion between the batter and fruits and vegetables, and make the batter better adhere to the surface of fruits and vegetables. The interaction between hydroxypropyl methylcellulose and curdlan can form a uniform protective film on the surface of fruits and vegetables. During the frying process, this film helps to maintain the shape of fruits and vegetables and prevent them from excessive shrinkage or deformation, so that the final fruit and vegetable crisps have better integrity and crisp taste. In addition, the continuous film structure can reduce the direct contact area between oil and fruits and vegetables, thereby reducing the absorption of oil by fruits and vegetables during frying, thereby realizing the preparation of low-oil and low-fat fruit and vegetable crisps.

[0018] 3. The present invention also uses a color preservative to pretreat fruits and vegetables to protect their color. After the fruits and vegetables are sliced, PPO will catalyze the oxidation of phenolic substances into quinones, which will then polymerize to form brown substances. Low-temperature plasma activated water can change the active center structure or amino acid residues of PPO through physical and chemical effects, reduce the activity of PPO or even inactivate it, thereby reducing the generation of quinone substances and effectively inhibiting enzymatic browning. The lactic acid Bacillus fermentation broth contains acidic substances such as lactic acid, which can reduce the pH value of the environment around the fruit and vegetable slices and create an acidic environment. Most enzymes related to fruit and vegetable browning, such as polyphenol oxidase and peroxidase, are more active under neutral or alkaline conditions, but their activity will be inhibited in an acidic environment. Therefore, Lactobacillus fermentation broth reduces the degree of non-enzymatic browning in fruit and vegetable slices by lowering the pH value, which helps to maintain their original color. The synergistic effect of low-temperature plasma activated water and lactobacillus fermentation broth can significantly improve the color protection effect. In addition, lactobacillus fermentation broth can produce antibacterial substances such as bacteriocins and hydrogen peroxide. Bacteriocins can destroy the cell membrane of microorganisms and leak the cell contents, thereby inhibiting the growth and reproduction of microorganisms. Hydrogen peroxide has strong oxidizing properties and can interfere with the metabolic process of microorganisms and play a bactericidal role. These antibacterial substances can reduce the number of microorganisms on the surface of fruit and vegetable slices, reduce the influence of enzymes secreted by microorganisms on the color of fruits and vegetables, and prevent discoloration caused by microbial contamination.

[0019] 4. Methylcellulose and soy protein isolate are further added to the color protector of the present invention. Since the lactic acid bacillus fermentation broth in the color protector contains acidic substances such as lactic acid, an acidic environment can be created. A large number of polar groups such as hydroxyl groups exist on the added methylcellulose molecular chains. These groups can interact with each other through forces such as hydrogen bonds, so that the molecular chains are interconnected to form a stable membrane structure. The isoelectric point of soy protein isolate is generally around pH 4.5. Under acidic conditions, especially when close to the isoelectric point, the net charge on the surface of protein molecules decreases, the electrostatic repulsion between molecules weakens, and aggregation and cross-linking reactions are more likely to occur. Such aggregation and cross-linking are conducive to forming a tighter protein network structure, thereby promoting the formation of a membrane. Therefore, the basic framework of the membrane is provided by methylcellulose, and the soy protein isolate fills and strengthens this framework through aggregation and cross-linking, thereby forming a denser and more stable protective film on the surface of the fruit and vegetable slices, which can effectively reduce the oxidation and nutrient loss of the fruit and vegetable slices, and at the same time can reduce the oil absorption of the fruit and vegetable crisps during the subsequent frying process, thereby achieving a low-oil and low-fat effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, further serve to explain the principles of the invention and to enable those skilled in the relevant art to make and use the invention.

[0021] Figure 1 The present invention is a flow chart of a process for preparing low-oil and low-fat fruit and vegetable crisps adopted in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following is a detailed description of a preparation process of low-oil and low-fat fruit and vegetable crisps provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0023] Example 1 A preparation process of low-oil and low-fat fruit and vegetable crisps, such as Figure 1 As shown, the following steps are included: S1: Preparation of low oil absorption starch S1.1: 2 parts by weight of mung bean starch was added to 20 parts by weight of deionized water, and then mixed under magnetic stirring at 200 r / min for 20 minutes to obtain a starch solution; S1.2: Use a vibrating titanium tip probe of an 1800W ultrasonic crusher in a 25°C water bath to intermittently immerse the starch solution and ultrasonicate at 120W for 20 minutes, during which the ultrasonic cycle is repeated for 2 seconds and 2 seconds without ultrasonication. After the ultrasonication is completed, an ultrasonic starch solution is obtained; S1.3: Freeze the ultrasonic starch solution at -20°C for 20 h, then thaw at 30°C for 2 h, repeat the freeze-thaw process twice, dry at 45°C for 10 h after freeze-thaw treatment, and then pass through a 100-mesh sieve to obtain low oil absorption starch; S2: Preparation of calcium cross-linked low oil absorption starch S2.1: Add 20 parts by weight of anhydrous calcium chloride to 200 parts by weight of deionized water, and stir to obtain a calcium chloride aqueous solution; S2.2: The temperature of the calcium chloride aqueous solution was adjusted to 30°C, and then 50 parts by weight of low oil absorption starch was added, and ultrasonic dispersion was performed for 20 minutes. Then, 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution were added to adjust the pH to 9, and then magnetic stirring was performed at 30°C and 500 r / min for 2 hours to obtain a mixed solution; S2.3: The mixed solution was repeatedly filtered with deionized water for 3 times to obtain a precipitate, and the precipitate was dried at 40°C for 24 hours, and then crushed by a grinder and passed through a 100-mesh sieve to obtain calcium cross-linked low oil absorption starch; S3: Preparation of color protection agent S3.1: Dissolve 20 g of whey powder, 10 g of glucose, 1 g of magnesium sulfate, 2 g of dipotassium hydrogen phosphate, and 0.5 g of manganese sulfate in 200 mL of water, then make up to 1 L, and sterilize to obtain a fermentation medium; S3.2: 10 8 CFU / g of lactic acid Bacillus powder was inoculated into the fermentation medium, and the inoculation amount was 0.1% by weight of the fermentation medium, and then fermented in a shaking incubator at 200 r / min and 37°C for 10 h, and then filtered to obtain a fermentation liquid; S3.3: 300 parts by weight of distilled water are placed in a beaker, and the nozzle of the low-temperature plasma jet device is placed 15 mm below the distilled water surface, and then treated for 60 seconds to obtain low-temperature plasma activated water; S3.4: Add 10 parts by weight of fermentation broth, 1 part by weight of kojic acid, 2 parts by weight of methylcellulose and 2 parts by weight of soy protein isolate to 200 parts by weight of low-temperature plasma activated water, stir and mix for 20 minutes, and then adjust the pH to 4.5 to obtain a color protection agent; The parameters of the low-temperature plasma jet device are as follows: working carrier gas: air; gas flow rate: 22.5L / min; gas source pressure: 4kg; input voltage: AC220V; output voltage: 19kV; output current: 0.024mA; working frequency: 20kHz; spray gun processing speed: 30m / min; S4: Pretreatment of fruits and vegetables S4.1: Take fresh fruits and vegetables, remove those with diseases, insect pests and rotten parts, then rinse them with clean water twice, slice them after washing, blanch the fruit and vegetable slices in 98℃ blanching liquid for 2 minutes, drain and cool them to obtain blanched fruit and vegetable slices; S4.2: Soak the blanched fruit and vegetable slices in water for 40 minutes, with the mass ratio of the blanched fruit and vegetable slices to the color preservative being 1:10. After the soaking is completed, drain the water to obtain the color-protected fruit and vegetable slices; S4.3: placing the color-protected fruit and vegetable slices in a hot air drying oven at a temperature of 60° C. for 30 minutes to obtain pretreated fruit and vegetable slices; S5: Preparation of low-oil and low-fat fruit and vegetable crisps S5.1: 10 parts by weight of calcium cross-linked low oil absorption starch, 5 parts by weight of wheat flour, 1 part by weight of acetate starch and 8 parts by weight of egg liquid, then slowly add 20 parts by weight of water, stirring and mixing during the process, then add 0.1 parts by weight of hydroxypropyl methylcellulose and 0.2 parts by weight of curdlan, stirring and mixing for 20 minutes to obtain a batter; S5.2: Place 10 parts by weight of pretreated fruit and vegetable slices in 30 parts by weight of batter so that the surface of the pretreated fruit and vegetable slices is coated with the batter, and then fry them in a vacuum fryer. The frying conditions are as follows: edible oil temperature of 70°C, vacuum of 75 kPa, and frying for 5 minutes. After frying, spin dry to remove oil, cool, sterilize, and vacuum pack to obtain low-oil and low-fat fruit and vegetable crisps.

[0024] Example 2 A preparation process of low-oil and low-fat fruit and vegetable crisps, such as Figure 1 As shown, the following steps are included: S1: Preparation of low oil absorption starch S1.1: 3 parts by weight of mung bean starch was added to 22 parts by weight of deionized water, and then mixed under magnetic stirring at 200 r / min for 20 minutes to obtain a starch solution; S1.2: Use a vibrating titanium tip probe of an 1800W ultrasonic crusher in a 25°C water bath to intermittently immerse the starch solution and ultrasonicate at 120W for 20 minutes, during which the ultrasonic cycle is repeated for 2 seconds and 2 seconds without ultrasonication. After the ultrasonication is completed, an ultrasonic starch solution is obtained; S1.3: Freeze the ultrasonic starch solution at -20°C for 20 h, then thaw at 30°C for 2 h, repeat the freeze-thaw process twice, dry at 45°C for 10 h after freeze-thaw treatment, and then pass through a 100-mesh sieve to obtain low oil absorption starch; S2: Preparation of calcium cross-linked low oil absorption starch S2.1: Add 30 parts by weight of anhydrous calcium chloride to 230 parts by weight of deionized water, stir and mix, and obtain a calcium chloride aqueous solution; S2.2: The temperature of the calcium chloride aqueous solution was adjusted to 30°C, and then 53 parts by weight of low oil absorption starch was added, and ultrasonic dispersion was performed for 20 minutes. Then, 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution were added to adjust the pH to 9, and then magnetic stirring was performed at 30°C and 500 r / min for 2 hours to obtain a mixed solution; S2.3: The mixed solution was repeatedly filtered with deionized water for 3 times to obtain a precipitate, and the precipitate was dried at 40°C for 24 hours, and then crushed by a grinder and passed through a 100-mesh sieve to obtain calcium cross-linked low oil absorption starch; S3: Preparation of color protection agent S3.1: Dissolve 20 g of whey powder, 10 g of glucose, 1 g of magnesium sulfate, 2 g of dipotassium hydrogen phosphate, and 0.5 g of manganese sulfate in 200 mL of water, then make up to 1 L, and sterilize to obtain a fermentation medium; S3.2: 10 9 CFU / g of lactic acid Bacillus powder was inoculated into the fermentation medium, and the inoculation amount was 0.1% by weight of the fermentation medium, and then fermented in a shaking incubator at 200 r / min and 37°C for 10 h, and then filtered to obtain a fermentation liquid; S3.3: 320 parts by weight of distilled water are placed in a beaker, and the nozzle of the low-temperature plasma jet device is placed 15 mm below the liquid surface of the distilled water, and then treated for 60 seconds to obtain low-temperature plasma activated water; S3.4: Add 12 parts by weight of fermentation broth, 2 parts by weight of kojic acid, 3 parts by weight of methylcellulose and 3 parts by weight of soy protein isolate to 230 parts by weight of low-temperature plasma activated water, stir and mix for 20 minutes, and then adjust the pH to 4.5 to obtain a color protection agent; The parameters of the low-temperature plasma jet device are as follows: working carrier gas: air; gas flow rate: 22.5L / min; gas source pressure: 4kg; input voltage: AC220V; output voltage: 19kV; output current: 0.024mA; working frequency: 20kHz; spray gun processing speed: 30m / min; S4: Pretreatment of fruits and vegetables S4.1: Take fresh fruits and vegetables, remove those with diseases, insect pests and rotten parts, then rinse them with clean water twice, slice them after washing, blanch the fruit and vegetable slices in 98℃ blanching liquid for 2 minutes, drain and cool them to obtain blanched fruit and vegetable slices; S4.2: Soak the blanched fruit and vegetable slices in water for 40 minutes, with the mass ratio of the blanched fruit and vegetable slices to the color preservative being 1:12. After the soaking, drain the water to obtain the color-protected fruit and vegetable slices; S4.3: placing the color-protected fruit and vegetable slices in a hot air drying oven at a temperature of 60° C. for 30-40 minutes to obtain pretreated fruit and vegetable slices; S5: Preparation of low-oil and low-fat fruit and vegetable crisps S5.1: 12 parts by weight of calcium cross-linked low oil absorption starch, 8 parts by weight of wheat flour, 2 parts by weight of acetate starch and 10 parts by weight of egg liquid, then slowly add 30 parts by weight of water, stirring and mixing during the process, then add 0.2 parts by weight of hydroxypropyl methylcellulose and 0.3 parts by weight of curdlan, stirring and mixing for 20-30 minutes to obtain a batter; S5.2: Place 20 parts by weight of pretreated fruit and vegetable slices in 50 parts by weight of batter so that the surface of the pretreated fruit and vegetable slices is coated with the batter, and then fry them in a vacuum fryer. The frying conditions are as follows: edible oil temperature of 70°C, vacuum of 75 kPa, and frying for 5 minutes. After frying, spin dry to remove oil, cool, sterilize, and vacuum pack to obtain low-oil and low-fat fruit and vegetable crisps.

[0025] Example 3 A preparation process of low-oil and low-fat fruit and vegetable crisps, such as Figure 1 As shown, the following steps are included: S1: Preparation of low oil absorption starch S1.1: 2 parts by weight of mung bean starch was added to 20 parts by weight of deionized water, and then mixed under magnetic stirring at 300 r / min for 30 minutes to obtain a starch solution; S1.2: Use a vibrating titanium tip probe of an 1800W ultrasonic crusher in a 26°C water bath to intermittently immerse the starch solution, and ultrasonicate at 180W for 22 minutes, during which the ultrasonic cycle is repeated for 2 seconds and no ultrasonication for 2 seconds. After the ultrasonication is completed, an ultrasonic starch solution is obtained; S1.3: Freeze the ultrasonic starch solution at -22°C for 22 hours, then thaw at 32°C for 3 hours, repeat the freeze-thaw process 3 times, dry at 46°C for 12 hours after freeze-thaw treatment, and then pass through a 120-mesh sieve to obtain low oil absorption starch; S2: Preparation of calcium cross-linked low oil absorption starch S2.1: Add 20 parts by weight of anhydrous calcium chloride to 200 parts by weight of deionized water, and stir to obtain a calcium chloride aqueous solution; S2.2: The temperature of the calcium chloride aqueous solution was adjusted to 32°C, and then 50 parts by weight of low oil absorption starch was added, and ultrasonic dispersion was performed for 30 minutes. Then, 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution were added to adjust the pH to 9, and then magnetic stirring was performed at 600 r / min at 32°C for 3 hours to obtain a mixed solution; S2.3: The mixed solution was repeatedly filtered with deionized water for 5 times to obtain a precipitate, and the precipitate was dried at 42°C for 28 hours, and then crushed by a grinder and passed through a 120-mesh sieve to obtain calcium cross-linked low oil absorption starch; S3: Preparation of color protection agent S3.1: Dissolve 20 g of whey powder, 10 g of glucose, 1 g of magnesium sulfate, 2 g of dipotassium hydrogen phosphate, and 0.5 g of manganese sulfate in 200 mL of water, then make up to 1 L, and sterilize to obtain a fermentation medium; S3.2: 10 8 CFU / g of lactic acid Bacillus powder was inoculated into the fermentation medium, and the inoculation amount was 0.1% by weight of the fermentation medium, and then fermented in a shaking incubator at 230 r / min and 37°C for 12 h, and then filtered to obtain a fermentation liquid; S3.3: 300 parts by weight of distilled water are placed in a beaker, and the nozzle of the low-temperature plasma jet device is placed 15 mm below the distilled water surface, and then treated for 80 seconds to obtain low-temperature plasma activated water; S3.4: Add 10 parts by weight of fermentation broth, 1 part by weight of kojic acid, 2 parts by weight of methylcellulose and 2 parts by weight of soy protein isolate to 200 parts by weight of low-temperature plasma activated water, stir and mix for 30 minutes, and then adjust the pH to 4.5 to obtain a color protection agent; The parameters of the low-temperature plasma jet device are as follows: working carrier gas: air; gas flow rate: 22.5L / min; gas source pressure: 6kg; input voltage: AC220V; output voltage: 19kV; output current: 0.024mA; working frequency: 20kHz; spray gun processing speed: 90m / min; S4: Pretreatment of fruits and vegetables S4.1: Take fresh fruits and vegetables, remove the diseased and insect-infested and rotten parts, then rinse them with clean water for 3 times, slice them after washing, blanch the fruit and vegetable slices in a 100°C blanching solution for 3 minutes, drain and cool them to obtain blanched fruit and vegetable slices; S4.2: Soak the blanched fruit and vegetable slices in water for 50 minutes, with the mass ratio of the blanched fruit and vegetable slices to the color preservative being 1:10. After the soaking is completed, drain the water to obtain the color-protected fruit and vegetable slices; S4.3: placing the color-protected fruit and vegetable slices in a hot air drying oven at a temperature of 60-65° C. for 40 minutes to obtain pretreated fruit and vegetable slices; S5: Preparation of low-oil and low-fat fruit and vegetable crisps S5.1: 10 parts by weight of calcium cross-linked low oil absorption starch, 5 parts by weight of wheat flour, 1 part by weight of acetate starch and 8 parts by weight of egg liquid, then slowly add 20 parts by weight of water, stirring and mixing during the process, then add 0.1 parts by weight of hydroxypropyl methylcellulose and 0.2 parts by weight of curdlan, stirring and mixing for 30 minutes to obtain a batter; S5.2: Place 10 parts by weight of pretreated fruit and vegetable slices in 30 parts by weight of batter so that the surface of the pretreated fruit and vegetable slices are coated with the batter, and then fry them in a vacuum fryer. The frying conditions are as follows: edible oil temperature of 75°C, vacuum of 80 kPa, and frying for 10 minutes. After frying, spin dry to remove oil, cool, sterilize, and vacuum pack to obtain low-oil and low-fat fruit and vegetable crisps.

[0026] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that Comparative Example 1 removes steps S1-S2, replaces the calcium-cross-linked low oil absorption starch in S5.2 with mung bean starch, and prepares low-oil and low-fat fruit and vegetable crisps without changing the other steps, which is recorded as Comparative Example 1.

[0027] Comparative Example 2 Compared with Example 1, the difference of Comparative Example 2 is that Comparative Example 2 removes step S2, replaces the calcium-cross-linked low oil absorption starch in step S5.2 with low oil absorption starch, and prepares low-oil and low-fat fruit and vegetable crisps without changing the other steps, which is recorded as Comparative Example 2.

[0028] Comparative Example 3 Compared with Example 1, the difference of Comparative Example 3 is that the fermentation liquid in steps S3.1-S3.2 and S3.4 is removed in Comparative Example 3, and the remaining steps remain unchanged to prepare low-oil and low-fat fruit and vegetable crisps, which is recorded as Comparative Example 3.

[0029] Comparative Example 4 Compared with Example 1, the difference of Comparative Example 4 is that Comparative Example 4 removes step S3.3, replaces the low-temperature plasma activated water in S3.4 with pure water, and prepares low-oil and low-fat fruit and vegetable crisps without changing the other steps, which is recorded as Comparative Example 4.

[0030] Comparative Example 5 Compared with Example 1, the difference of Comparative Example 5 is that the methyl cellulose and soy protein isolate in step S3.4 are removed in Comparative Example 5, and the other steps remain unchanged to prepare low-oil and low-fat fruit and vegetable crisps, which is recorded as Comparative Example 5.

[0031] Comparative Example 6 Compared with Example 1, the difference of Comparative Example 6 is that the fermentation liquid and kojic acid in step S3.4 are removed in Comparative Example 6, and the other steps remain unchanged to prepare low-oil and low-fat fruit and vegetable crisps, which is recorded as Comparative Example 6.

[0032] Comparative Example 7 Compared with Example 1, the difference of Comparative Example 6 is that, in Comparative Example 6, hydroxypropyl methylcellulose and curdlan in step S5.1 are removed, and the remaining steps remain unchanged to prepare low-oil and low-fat fruit and vegetable crisps, which is recorded as Comparative Example 7.

[0033] Oil absorption determination: The oil absorption of low-oil and low-fat fruit and vegetable crisps was measured using a low-field nuclear magnetic resonance analyzer. The low-oil and low-fat fruit and vegetable crisps were weighed and wrapped with plastic wrap, and the wrapped low-oil and low-fat fruit and vegetable crisps were placed in a glass test tube with a diameter of 25 mm, and their spin-spin relaxation characteristics were measured using LF-NMR at a constant temperature of 32°C. The instrument was calibrated using the free induction decay signal (FID) mode, and the test was performed using the CPMG pulse sequence mode. The test parameters were: repeated sampling waiting time (TW): 1500; repeated sampling times (NS): 32; echo time (TE): 0.3ms; number of echoes (NECH): 8000. A standard curve was drawn using edible soybean oil as the standard sample.

[0034] The oil absorption of the low-oil and low-fat fruit and vegetable crisps prepared in Examples 1-3 and Comparative Examples 1 and 5-7 was measured. The measurement results are shown in Table 1.

[0035] Table 1. Oil absorption measurement results of Examples 1-3 and Comparative Examples 1 and 5-7

[0036] It can be seen from the data in Table 1 that the low-oil and low-fat fruit and vegetable crisps prepared in the embodiment have lower oil absorption, and the oil absorption of comparative example 1 is significantly improved compared with that of the embodiment, indicating that the oil absorption can be reduced by ultrasonic synergistic freeze-thaw treatment of mung bean starch, thereby achieving the preparation of low-oil and low-fat fruit and vegetable crisps; it can be seen from the data of comparative examples 5 and 6 that the methylcellulose and soy protein isolate added to the color preservative can also reduce the oil absorption of the fruit and vegetable crisps during the subsequent frying process, and the presence of lactic acid bacillus fermentation broth and kojic acid in the color preservative can also reduce the oil absorption, indicating that the acidic environment in the color preservative is conducive to the formation of a tighter protein network structure, thereby promoting the formation of a denser and more stable membrane, thereby effectively preventing the absorption of oil; it can be seen from the data of comparative example 7 that the addition of hydroxypropyl methylcellulose and curdlan to the batter can reduce the absorption of oil by fruits and vegetables during frying, thereby achieving the preparation of low-oil and low-fat fruit and vegetable crisps.

[0037] Sensory evaluation: The sensory evaluation method was used to perform sensory testing on the low-oil and low-fat fruit and vegetable crisps prepared in Examples 1-3, Comparative Examples 2-4, and Comparative Example 7. A total of 10 volunteers aged between 20 and 45 years old were selected to form a sensory evaluation panel, and the sensory evaluation panel scored the samples. The sensory score value of each indicator was set between 0 and 25 points, with a total of 100 points. The sensory evaluation criteria are shown in Table 2, and the sensory evaluation results are shown in Table 3: Table 2. Sensory scoring criteria

[0038] Table 3. Sensory scores of crispness of low-oil and low-fat fruits and vegetables

[0039] From the data of Comparative Example 2 in Table 3, it can be seen that the use of calcium cross-linked low oil absorption starch can enable the fruit and vegetable crisps to maintain good crispness and shape after frying. From the data of Comparative Examples 3-4, it can be seen that the color preservative containing low-temperature plasma activated water and lactic acid Bacillus fermentation liquid can help fruits and vegetables maintain their original color. From the data of Comparative Example 7, it can be seen that the addition of hydroxypropyl methylcellulose and curdlan can make the final fruit and vegetable crisps have better integrity and crisp taste.

[0040] The thermal properties of the calcium cross-linked low oil absorption starches of Examples 1-3 and the low oil absorption starch of Comparative Example 2 were measured. The results are shown in Table 4. 30% , T 50% , T 70% and T d Represent the temperatures when the sample loses 30%, 50%, 70% of its mass and the maximum mass loss rate respectively.

[0041] Table 4. Thermogravimetric analysis parameters of Examples 1-3 and Comparative Example 2

[0042] It can be seen from the data in Table 4 that the main degradation temperature range of Comparative Example 2 is 314.12-329.12°C, which is significantly lower than that of the embodiment, indicating that the calcium-crosslinked low oil absorption starch after calcium crosslinking in the present invention has higher thermal stability.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A preparation process for low-oil and low-fat fruit and vegetable crisps, characterized in that: The steps include: S1: Preparation of low oil absorption starch The mung bean starch is first ultrasonicated at 120-180W for 20-22 minutes, then frozen at -20--22°C for 20-22 hours, thawed and then frozen again, and after repeated freeze-thaw, low oil absorption starch is obtained; S2: Preparation of calcium cross-linked low oil absorption starch Add low oil absorption starch to the calcium chloride aqueous solution, adjust the pH to 9 after dispersion, and then stir and filter to obtain calcium cross-linked low oil absorption starch; S3: Preparation of color protection agent Lactobacillus is used to prepare a fermentation liquid, and the fermentation liquid, kojic acid, methyl cellulose and soy protein isolate are added into low-temperature plasma activated water, and the mixture is stirred to obtain a color preservative; S4: Pretreatment of fruits and vegetables The fruits and vegetables are washed and blanched, then soaked in a color preservative, and finally dried to obtain pretreated fruit and vegetable slices; S5: Preparation of low-oil and low-fat fruit and vegetable crisps The batter is prepared by taking 10-12 parts by weight of calcium cross-linked low oil absorption starch, 5-8 parts by weight of wheat flour, 1-2 parts by weight of acetate starch, 8-10 parts by weight of egg liquid, 20-30 parts by weight of water, 0.1-0.2 parts by weight of hydroxypropyl methylcellulose and 0.2-0.3 parts by weight of curdlan as raw materials, and then the surfaces of pretreated fruit and vegetable slices are coated with the batter and vacuum fried to prepare low-oil and low-fat fruit and vegetable crisps.

2. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 1, characterized in that: Step S1: Preparation of low oil absorption starch, specifically comprising the following steps: S1.1: Add 2-3 parts by weight of mung bean starch to 20-22 parts by weight of deionized water, and then mix under magnetic stirring at 200-300 r / min for 20-30 minutes to obtain a starch solution; S1.2: Use a vibrating titanium tip probe of an 1800W ultrasonic crusher to intermittently immerse the starch solution in a 25-26°C water bath, and ultrasonicate at 120-180W for 20-22 minutes, during which the ultrasonic cycle is repeated for 2 seconds and 2 seconds without ultrasonication. After the ultrasonication is completed, an ultrasonic starch solution is obtained; S1.3: Freeze the ultrasonic starch solution at -20--22°C for 20-22h, then thaw at 30-32°C for 2-3h, repeat the freeze-thaw process 2-3 times, dry at 45-46°C for 10-12h after freeze-thaw treatment, and then pass through a 100-120 mesh sieve to obtain low oil absorption starch.

3. The preparation process of low-oil and low-fat fruit and vegetable crisps according to claim 2, characterized in that: Step S2 is the preparation of calcium cross-linked low oil absorption starch, which specifically comprises the following steps: S2.1: Add 20-30 parts by weight of anhydrous calcium chloride to 200-230 parts by weight of deionized water, and stir to obtain a calcium chloride aqueous solution; S2.2: The temperature of the calcium chloride aqueous solution is adjusted to 30-32°C, and then 50-53 parts by weight of low oil absorption starch is added, and ultrasonic dispersion is performed for 20-30 minutes, and then 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution are added to adjust the pH to 9, and then magnetic stirring is performed at 30-32°C and 500-600 r / min for 2-3 hours to obtain a mixed solution; S2.3: The mixed solution is repeatedly filtered with deionized water for 3-5 times to obtain a precipitate, and the precipitate is dried at 40-42°C for 24-28 hours, and then crushed by a grinder and passed through a 100-120 mesh sieve to obtain calcium cross-linked low oil absorption starch.

4. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 3, characterized in that: Step S3: preparation of color retaining agent, specifically comprising the following steps: S3.1: Dissolve 20 g of whey powder, 10 g of glucose, 1 g of magnesium sulfate, 2 g of dipotassium hydrogen phosphate, and 0.5 g of manganese sulfate in 200 mL of water, then make up to 1 L, and sterilize to obtain a fermentation medium; S3.2: 10 8 -10 9 CFU / g of lactic acid bacillus powder is inoculated into the fermentation medium, and then fermented in a shaker at 200-230r / min and 37°C for 10-12h, and then filtered to obtain a fermentation liquid; S3.3: 300-320 parts by weight of distilled water are placed in a beaker, and the nozzle of the low-temperature plasma jet device is placed 15 mm below the liquid surface of the distilled water, and then treated for 60-80 seconds to obtain low-temperature plasma activated water; S3.4: Add 10-12 parts by weight of fermentation liquid, 1-2 parts by weight of kojic acid, 2-3 parts by weight of methylcellulose and 2-3 parts by weight of soy protein isolate to 200-230 parts by weight of low-temperature plasma activated water, stir and mix for 20-30 minutes, and then adjust the pH to 4.5 to obtain a color protection agent.

5. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 4, characterized in that: Step S4: pre-processing of fruits and vegetables, specifically comprising the following steps: S4.1: Take fresh fruits and vegetables, remove the diseased and insect-infested and rotten parts, then rinse them with clean water for 2-3 times, slice them after washing, blanch the fruit and vegetable slices in a 98-100°C blanching solution for 2-3 minutes, drain and cool them to obtain blanched fruit and vegetable slices; S4.2: Soak the blanched fruit and vegetable slices in water for 40-50 minutes, with the mass ratio of the blanched fruit and vegetable slices to the color preservative being 1:10-12. After the soaking is completed, drain the water to obtain the color-protected fruit and vegetable slices; S4.3: Place the color-protected fruit and vegetable slices in a hot air drying oven at a temperature of 60-65° C. for 30-40 minutes to obtain pretreated fruit and vegetable slices.

6. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 5, characterized in that: Step S5 is the preparation of low-oil and low-fat fruit and vegetable crisps, which specifically comprises the following steps: S5.1: 10-12 parts by weight of calcium cross-linked low oil absorption starch, 5-8 parts by weight of wheat flour, 1-2 parts by weight of acetate starch and 8-10 parts by weight of egg liquid, then slowly add 20-30 parts by weight of water, stirring and mixing during the process, then add 0.1-0.2 parts by weight of hydroxypropyl methylcellulose and 0.2-0.3 parts by weight of curdlan, stirring and mixing for 20-30 minutes to obtain a batter; S5.2: Place 10-20 parts by weight of pretreated fruit and vegetable slices in 30-50 parts by weight of batter, so that the surface of the pretreated fruit and vegetable slices is coated with the batter, and then put them into a vacuum fryer for frying. After frying, spin dry to remove oil, cool, sterilize, and vacuum pack to obtain low-oil and low-fat fruit and vegetable crisps.

7. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 4, characterized in that: The inoculation amount of the lactic acid Bacillus powder in step S3.2 is 0.1% by weight of the fermentation medium.

8. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 4, characterized in that: The parameters of the low-temperature plasma jet device in step S3.3 are: working carrier gas: air; gas flow rate: 22.5L / min; gas source pressure: 4-6kg; input voltage: AC220V; output voltage: 19kV; output current: 0.024mA; working frequency: 20kHz; spray gun processing speed: 30-90m / min.

9. The process for preparing low-oil and low-fat fruit and vegetable crisps according to claim 6, characterized in that: The frying conditions in step S5.2 are as follows: edible oil temperature of 70-75° C., vacuum of 75-80 kPa, and frying for 5-10 minutes.

10. A low-oil and low-fat fruit and vegetable crisp, characterized in that: The low-oil and low-fat fruit and vegetable crisps are prepared by the preparation process of the low-oil and low-fat fruit and vegetable crisps described in any one of claims 1 to 9.

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