Label cleaning type crispness increasing method for fried food

Abstract

The invention discloses a label cleaning type crispness increasing method for fried food, and belongs to the field of fried products. According to the preparation method, firstly, lentinus edodes stem nanocellulose is prepared by combining enzymolysis with a high-pressure homogenization method, and the lentinus edodes stem nanocellulose is compounded with casein, so that stable lentinus edodes stem nanocellulose-casein gel emulsion can be prepared; then the gel-like emulsion is applied to the paste-coated fried product, and the gel-like emulsion is used for forming pores in advance in the paste so as to achieve the crispness increasing effect, reduce the oil content and inhibit grease oxidation. The stable gel emulsion based on a natural formula can replace a commercial leavening agent to realize clean label type crispness enhancement, and the prepared paste can be applied to various paste fried foods and has a good market prospect.

Description

Technical Field

[0001] The present invention relates to a method for increasing crispness with a clean label for fried foods, belonging to the field of fried products. Background Art

[0002] Coated fried products are products obtained by uniformly coating a viscous paste on the surface of pretreated materials and then frying. They are widely popular because of their golden color, crispy exterior and tender interior. The crispness of the outer shell of coated fried products is the key to affecting their taste. Coated fried foods usually use leavening agents to obtain good crisp properties. The main components of leavening agents are sodium bicarbonate, disodium dihydrogen pyrophosphate, sodium dihydrogen phosphate, etc. These leavening agents mainly produce carbon dioxide gas by decomposing when encountering water and heat, creating a pore structure to achieve the effect of increasing crispness. However, in recent years, the awareness of food clean labels has increased rapidly, and various additives involved in leavening agents have been questioned and rejected by consumers. In addition, more importantly, while leavening agents increase the porosity of the outer shell of fried foods, they often lead to an increase in oil absorption and fat oxidation, affecting the product quality and safety. Therefore, developing a new type of natural leavening agent that can reduce the oil content of fried products and inhibit fat oxidation is a difficult problem in the development of fried foods.

[0003] Currently, in the prior art, Patent CN 118077879 A discloses a method for processing and application of mushroom stalks. It uses Mucor indicus JXJQ - 1 to ferment mushroom stalks, combined with a physical treatment method, namely low - temperature frying after freezing, which significantly reduces the hardness and chewiness of mushroom stalks and produces a crispy effect, and can be applied to develop crispy mushroom leisure foods and easily chewable fillings.

[0004] In addition, "Research on the Technology of Mushroom Floss Prepared from Enzymatically Modified Mushroom Stalks" studied the technology of preparing mushroom floss after enzymatically hydrolyzing mushroom stalks with cellulase, and found that the water - holding capacity of mushroom stalks increased by 23.5% after enzymolysis, the swelling force increased by 13.2%, and the oil - holding capacity did not change significantly.

[0005] The above two pieces of prior art have both made certain research on the application of mushroom stalks, but their final products are direct applications of mushroom stalks - fried mushroom stalks and mushroom floss. The product forms are different from those of the present invention, and they do not explain how to apply mushroom stalks to coated fried products to achieve the effect of increasing crispness. Summary of the Invention

[0006] Technical Problem

[0007] When preparing coated fried products, leavening agents are used, but leavening agents will increase the oil absorption of coated fried products while increasing crispness, reducing the health and safety of fried products. Therefore, it is necessary to develop a method with clean raw materials, less oil absorption and capable of increasing the crispness of fried foods.

[0008] Technical content

[0009] To solve the above technical problems, the present invention first efficiently prepares Lentinula edodes stalk nanocellulose-casein hydrogel by enzymatic hydrolysis combined with high-pressure homogenization method, and uses it as the dispersed phase to prepare a gel-like emulsion with 75% oil phase. Then, the gel-like emulsion is added as a pore-forming agent to develop a new natural crispness-enhancing technology for fried foods. The present invention efficiently prepares Lentinula edodes stalk nanocellulose by enzymatic hydrolysis combined with high-pressure homogenization method, and uses it as the dispersed phase to prepare a food-grade gel-like emulsion. The preparation conditions are mild and the operation is simple. The present invention applies the Lentinula edodes stalk nanocellulose-casein gel-like emulsion as a pore-forming agent to fried foods, which can improve the crispness of fried foods, reduce their oil content, and inhibit lipid oxidation, providing a clean-label crispness-enhancing technology for fried foods.

[0010] The present invention provides a Lentinula edodes stalk nanocellulose-casein gel-like emulsion, and the gel-like emulsion is prepared by the following preparation method:

[0011] (1) Preparation of Lentinula edodes stalk nanocellulose: Crush and sieve dried Lentinula edodes stalks to obtain Lentinula edodes stalk powder, mix the powder with edible oil, and perform extraction and degreasing using a carbon dioxide supercritical extraction instrument; then add water to the degreased powder, adjust the pH to 4-6, add cellulase for enzymatic hydrolysis, then add acid protease for enzymatic hydrolysis, and then inactivate the enzyme; add ethanol to the inactivated enzymatic hydrolysis solution and centrifuge to obtain a precipitate, which is crude cellulose; disperse the crude cellulose in an aqueous H2O2 solution, heat it, then add water and stir, and sieve and dry to obtain Lentinula edodes stalk nanocellulose;

[0012] (2) Preparation of Lentinula edodes stalk nanocellulose-casein gel-like emulsion: Take the Lentinula edodes stalk nanocellulose obtained in step (1) to prepare an aqueous solution, then mix it with a casein aqueous solution to obtain a Lentinula edodes stalk nanocellulose-casein complex, and then mix the Lentinula edodes stalk nanocellulose-casein complex with edible oil and disperse it at high speed to obtain a Lentinula edodes stalk nanocellulose-casein gel-like emulsion.

[0013] Further, the mesh number of the sieving of the dried Lentinula edodes stalks in step (1) is 60-100 meshes.

[0014] Further, the edible oil in step (1) includes one or more of soybean oil, corn oil, sunflower oil, rapeseed oil, and peanut oil.

[0015] Further, the mass ratio of the Lentinula edodes stalk powder to the edible oil in step (1) is 1:1-2.

[0016] Further, the parameters of the extraction and degreasing in step (1) are that the pressure of the extraction kettle is 15-20 Pa, the pressure of the separation kettle is 5-6 Pa, and the treatment time is 20-25 min.

[0017] Further, the addition amount of cellulase in step (1) is 1500 - 2500 U / g based on the mass of the substrate.

[0018] Further, the conditions for cellulase hydrolysis in step (1) are hydrolysis at 50 - 55 °C for 1 - 2 h.

[0019] Further, the addition amount of acid protease in step (1) is 1500 - 2500 U / g based on the mass of the substrate.

[0020] Further, the conditions for acid protease hydrolysis in step (1) are hydrolysis at 30 - 35 °C for 1 - 2 h.

[0021] Further, the mass concentration of H2O2 in the H2O2 aqueous solution in step (1) is 20 - 40%.

[0022] Further, the mass ratio of crude cellulose to the H2O2 aqueous solution in step (1) is 1:0.5 - 1.5.

[0023] Further, the heating in step (1) is carried out at 70 - 80 °C for 0.5 - 2 h.

[0024] Further, the concentration of the aqueous solution of Lentinula edodes stalk nanocellulose in step (2) is 20 - 40 mg / mL.

[0025] Further, the concentration of the casein aqueous solution in step (2) is 80 - 120 mg / mL.

[0026] Further, the volume ratio of the aqueous solution of Lentinula edodes stalk nanocellulose to the casein solution in step (2) is 4 - 8:1.

[0027] Further, the edible oil in step (2) includes one or more of soybean oil, corn oil, sunflower oil, rapeseed oil, and peanut oil.

[0028] Further, the volume ratio of the Lentinula edodes stalk nanocellulose - casein complex to the edible oil in step (2) is 1:2 - 4.

[0029] Further, the conditions for high - speed dispersion in step (2) are treatment at 8000 - 10000 g for 1 - 5 min.

[0030] The present invention provides the application of the Lentinula edodes stalk nanocellulose - casein gel - like emulsion in the food field.

[0031] Further, the application in the food field is to mix the Lentinula edodes stalk nanocellulose - casein gel - like emulsion with batter to obtain batter for wrapping food to be fried.

[0032] Further, the food to be fried includes meat and / or vegetables.

[0033] Furthermore, the mixed batter can also be directly fried.

[0034] The present invention also provides a method for frying dough cakes, comprising the following steps:

[0035] Mix corn starch, flour and water to prepare a batter; add the nanocellulose from mushroom stalks-casein gel-like emulsion to the batter, and then fry to obtain fried dough cakes.

[0036] In one embodiment of the present invention, the mass ratio of corn starch to flour is 2:2 to 4.

[0037] In one embodiment of the present invention, the mass ratio of corn starch to water is 2:3 to 7.

[0038] In one embodiment of the present invention, the addition amount of the nanocellulose from mushroom stalks-casein gel-like emulsion is 10-30 wt% of the mass of the batter.

[0039] Preferably, the addition amount of the nanocellulose from mushroom stalks-casein gel-like emulsion is 20-25 wt% of the mass of the batter.

[0040] In one embodiment of the present invention, the frying conditions are 160-180 °C and the time is 1-3 min.

[0041] Beneficial effects

[0042] (1) The present invention uses natural-based ingredients from mushroom stalks to prepare a gel emulsion, which can endow batter-fried foods with excellent crispness properties, with better effects than commercial leavening agents, and can also effectively reduce the oil content and degree of oil oxidation of batter-fried foods, improving the health and safety of fried foods.

[0043] (2) The gel emulsion crispness enhancement technology proposed by the present invention can replace commercial leavening agents to achieve clean-label crispness enhancement of fried foods, with high consumer acceptance. Its preparation method is also simple and easy to implement, suitable for production applications at the household, catering, and factory levels, and has broad market prospects. Description of the drawings

[0044] Figure 1 It is a full flow chart of the preparation of the nanocellulose from mushroom stalks-casein gel-like emulsion and its application method in batter-fried products.

[0045] Figure 2 It is a confocal microscope observation diagram of the nanocellulose from mushroom stalks-casein gel-like emulsion in Example 1, Example 2, Example 3, and Example 4.

[0046] Figure 33D printing effect diagrams of the Pleurotus eryngii stalk nanocellulose-casein gel-like emulsion for Examples 1, 2, 3, and 4.

[0047] Figure 4 Thermal stability diagrams of the Pleurotus eryngii stalk nanocellulose-casein gel-like emulsion for Examples 1, 2, 3, and 4.

[0048] Figure 5 Appearance diagrams of fried bread cakes for Examples 5, 6, 7, 8, 9, 10 and Comparative Examples 1, 2, 3.

[0049] Figure 6 Sensory evaluation test results of fried bread cakes for Examples 5, 6, and 7.

[0050] Figure 7 Sensory evaluation test results of fried bread cakes for Examples 8, 9, and 10.

[0051] Figure 8 Sensory evaluation test results of fried bread cakes for Comparative Examples 1, 2, and 3.

[0052] Figure 9 L* chromaticity test results of fried bread cakes for Examples 5, 6, 7, 8, 9, 10, Comparative Examples 1, 2, and 3.

[0053] Figure 10 a* chromaticity test results of fried bread cakes for Examples 5, 6, 7, 8, 9, 10, Comparative Examples 1, 2, and 3.

[0054] Figure 11 b* chromaticity test results of fried bread cakes for Examples 5, 6, 7, 8, 9, 10, Comparative Examples 1, 2, and 3.

[0055] Figure 12 Oil absorption test results of fried bread cakes for Examples 5, 6, 7, 8, 9, 10, Comparative Examples 1, 2, and 3.

[0056] Figure 13 TBARS test results of fried bread cakes for Examples 5, 6, 7, 8, 9, 10, Comparative Examples 1, 2, and 3. Specific implementation manners

[0057] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0058] Testing Method

[0059] 1. Microscopic test: Place the gel-like emulsion on a glass slide, cover it with a coverslip and gently press, and observe using a confocal microscope.

[0060] 2. Self-supporting test: The gel-like emulsion is printed into a cuboid shape. The gel-like emulsion is extruded from a circular nozzle with a diameter of 0.40 mm, and the printing speed is 20 mm s -1 , and the filling density is 15%.

[0061] 3. Thermal stability test: Pour 10 mL of freshly prepared emulsion into a plastic tube, heat it at different temperatures of 80 and 100 °C for 30 min, and balance the sample at room temperature for 12 h before measuring the physical properties of the emulsion.

[0062] 4. Chromaticity test: Use a chromaticity meter to measure the color characteristics of the noodle cake in the reflection mode. The values of brightness (L*), red / green spectrum (a*), and yellow / blue spectrum (b*) are recorded. The whiteness (W) is calculated as follows:

[0063] W = 100 - [(100 - L * ) 2 + a *2 + b *2 1 / 2 (1)

[0064] 5. Oil content test: Weigh 5.00 g of the dried and constant-weight noodle cake into filter paper respectively. The solvent is petroleum ether, and reflux extraction is carried out for 6 - 8 h. Place it in a fume hood to volatilize the petroleum ether and then place it in an oven to dry to constant weight, and convert the crude fat content in the sample.

[0065] 6. TBARS test: Add 5 mL of thiobarbituric acid mixture to 0.1 g of the noodle cake and heat it in boiling water for 10 min. After centrifugation, collect the supernatant and measure its absorbance at a wavelength of 532 nm using an enzyme-linked immunosorbent assay reader. Calculate the MDA content in the sample using a standard curve and express it as the thiobarbituric acid reactive substances (TBRAS) value.

[0066] 7. Sensory evaluation: Invite 10 people (5 males and 5 females) who have passed the sensory evaluation training to form a sensory evaluation panel to conduct a sensory evaluation on the fried noodle cake. The sensory evaluation criteria are shown in Table 1.

[0067] Table 1 Sensory Scoring Standard Table

[0068]

[0069] Instrument usage

[0070] The high-pressure homogenizer model is Panda Plus 1000; the CO2 supercritical extraction system model is HA220-50-06-C; the high-speed disperser model is Lichen Technology LC-ES-120SH.

[0071] Raw material usage

[0072] The cellulase activity is 10,000 U / g, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; the acid protease activity is 50,000 U / g, purchased from Shanghai Yizhu Biotechnology Co., Ltd.

[0073] Example 1

[0074] A method for preparing a gel-like emulsion with a hydrogel composed of a complex of lentinula edodes stalk nanocellulose and casein as the dispersed phase, comprising the following steps:

[0075] (1) Extract lentinula edodes stalk cellulose:

[0076] Crush the dried lentinula edodes stalks and pass through an 80-mesh sieve to obtain lentinula edodes stalk powder; mix the powder with soybean oil in a ratio of 1:1.5 and perform extraction and degreasing through a carbon dioxide supercritical extractor (extraction pressure: 20 Pa, separation pressure: 6 Pa, time 25 min); add 20 times the weight of deionized water to the degreased powder, adjust the pH to 3, add cellulase (the addition amount of the enzyme relative to the substrate is 2000 U / g), enzymatically hydrolyze at 55 °C for 2 h, then add acid protease (the addition amount of the enzyme relative to the substrate is 2000 U / g), enzymatically hydrolyze at 30 °C for 2 h, and perform enzyme inactivation treatment after enzymatic hydrolysis; mix the enzyme-hydrolyzed solution after enzyme inactivation with absolute ethanol in a volume ratio of 1:1.5 and centrifuge, and the precipitate obtained after centrifugation is crude cellulose; disperse the crude cellulose in a 30% H2O2 aqueous solution in a mass ratio of 1:1, heat at 80 °C for 1 h, then add 3 times its weight of water and stir at 25 °C for 6 h, and filter the obtained mixture through a 120-mesh sieve and dry to obtain lentinula edodes stalk cellulose;

[0077] (2) Prepare lentinula edodes stalk nanocellulose hydrogel:

[0078] Take the lentinula edodes stalk cellulose obtained in step (1) and mix it with water, and homogenize at 40 MPa for 3 min to obtain lentinula edodes stalk nanocellulose hydrogel (SMNC-40) with a concentration of 30 mg / mL;

[0079] (3) Complex lentinula edodes stalk nanocellulose-casein:

[0080] Take the lentinula edodes stalk nanocellulose hydrogel obtained in step (2) and mix it with a 100 mg / mL casein solution in a volume ratio of 4:1 to obtain a lentinula edodes stalk nanocellulose complexed casein hydrogel;

[0081] (4) Preparation of Lentinula edodes stalk nanocellulose-casein stabilized gel-like emulsion:

[0082] Take the Lentinula edodes stalk nanocellulose-casein hydrogel obtained in step (3) and soybean oil and mix them at a volume ratio of 1:3, and disperse them at a high speed of 8000g for emulsification for 2 min to obtain a Lentinula edodes stalk nanocellulose-casein stabilized gel-like emulsion.

[0083] Example 2

[0084] Adjust the volume ratio of Lentinula edodes stalk nanocellulose (SMNC-40) to casein solution in step (3) of Example 1 to 6:1, and keep the others the same as in Example 1 to obtain a Lentinula edodes stalk nanocellulose-casein stabilized gel-like emulsion.

[0085] Example 3

[0086] Adjust the high-pressure homogenization pressure in step (2) of Example 1 to 60 MPa (SMNC-60), and keep the others the same as in Example 1 to obtain a Lentinula edodes stalk nanocellulose-casein stabilized gel-like emulsion.

[0087] Example 4

[0088] Adjust the high-pressure homogenization pressure in step (2) of Example 1 to 60 MPa (SMNC-60), and adjust the volume ratio of Lentinula edodes stalk nanocellulose to casein solution in step (3) to 6:1, and keep the others the same as in Example 1 to obtain a Lentinula edodes stalk nanocellulose-casein stabilized gel-like emulsion.

[0089] Figure 2 are the confocal laser scanning microscopy images of Example 1, Example 2, Example 3, and Example 4. It can be seen from Figure 2 that: In Example 1 and Example 2, gel-like emulsions can be formed under the mixing conditions of SMNC-40 and casein at a ratio of 4:1 or 6:1, and their droplet sizes are relatively large (63.93 μm, 56.79 μm) and are in a closely arranged state. In Example 3 and Example 4, the compounding of SMNC-60 and casein at 4:1 or 6:1 can prepare gel-like emulsions with small sizes (34.74 μm, 28.07 μm), and the droplets show a state of high-density packing and mutual connection.

[0090] Figure 3 are the 3D printing appearance images of Example 1, Example 2, Example 3, and Example 4. It can be seen from Figure 3 that: The cube-shaped gel-like emulsions printed by Examples 1-4 have regular and smooth shapes, clear surface patterns, and no obvious collapse phenomenon.

[0091] Figure 4Appearance diagrams of Examples 1 - 4 after heating at 80 and 100 °C for 10 min respectively. From Figure 3 It can be seen that: after heating at 80 °C, no oil phase separated out in Examples 1, 2, 3, and 4; while when the heating temperature was higher than 100 °C, partial oil phase separated out in Examples 1, 2, 3, and 4, showing demulsification. The results indicate that the lentinus edodes stalk nanocellulose - casein gel - like emulsion prepared by the method of the present invention has good self - supporting performance and suitable thermal stability, which enables it to maintain good emulsion stability in the early stage of frying, while in the later stage of frying, it can achieve bursting and pore formation, realizing increased crispness, meeting the special requirements of frying processing, and can be applied in batter - fried foods.

[0092] Example 5

[0093] A method for applying a lentinus edodes stalk nanocellulose - casein gel - like emulsion in batter - fried foods, comprising the following steps:

[0094] (1) Extracting lentinus edodes stalk cellulose:

[0095] Crush dry lentinus edodes stalks and sieve through an 80 - mesh sieve to obtain lentinus edodes stalk powder; mix the powder with soybean oil in a ratio of 1:1.5, and perform extraction and defatting through a carbon dioxide supercritical extractor (extraction pressure: 20 Pa, separation pressure: 6 Pa, time 25 min); add 20 times the weight of deionized water to the defatted powder, adjust the pH to 3, add cellulase (the addition amount of the enzyme relative to the substrate is 2000 U / g), enzymatically hydrolyze at 55 °C for 2 h, then add acidic protease (the addition amount of the enzyme relative to the substrate is 2000 U / g), enzymatically hydrolyze at 30 °C for 2 h, and perform enzyme inactivation treatment after enzymatic hydrolysis; mix the enzyme - inactivated enzymatic hydrolysate with absolute ethanol in a volume ratio of 1:1.5 and centrifuge, and the obtained precipitate is crude cellulose; disperse the crude cellulose in a 30% H2O2 aqueous solution in a mass ratio of 1:1, heat at 80 °C for 1 h, then add 3 times its weight of water and stir at 25 °C for 6 h, filter the obtained mixture through a 120 - mesh sieve and dry to obtain lentinus edodes stalk cellulose;

[0096] (2) Preparing lentinus edodes stalk nanocellulose:

[0097] Take the lentinus edodes stalk cellulose obtained in step (1) and mix it with water, and perform high - pressure homogenization at 40 MPa for 3 min to obtain a lentinus edodes stalk nanocellulose hydrogel with a concentration of 30 mg / mL;

[0098] (3) Compound lentinus edodes stalk nanocellulose - casein:

[0099] Take the lentinus edodes stalk nanocellulose hydrogel obtained in step (2) and mix it with a 100 mg / mL casein solution in a volume ratio of 6:1 to obtain a lentinus edodes stalk nanocellulose compound casein hydrogel;

[0100] (4) Mix the mushroom stalk nanocellulose-casein hydrogel obtained in step (3) and soybean oil at a volume ratio of 1:3, and disperse them at a high speed of 8000g for emulsification for 2 minutes to obtain a gel-like emulsion (GE-40) stabilized by mushroom stalk nanocellulose-casein;

[0101] (5) Mix corn starch, flour and water in a mass ratio of 2:3:7 to obtain a batter;

[0102] (6) Add 10wt% of the gel-like emulsion to the batter and disperse it evenly;

[0103] (7) Fry the batter at 160°C for 3 minutes to obtain a fried dough cake.

[0104] Example 6

[0105] Adjust the addition amount of the gel-like emulsion (GE-40) in step (6) of Example 5 to 20wt%, and keep the others the same as in Example 5 to obtain a fried dough cake.

[0106] Example 7

[0107] Adjust the addition amount of the gel-like emulsion (GE-40) in step (6) of Example 5 to 30wt%, and keep the others the same as in Example 5 to obtain a fried dough cake.

[0108] Example 8

[0109] Adjust the high-pressure homogenization pressure in step (2) of Example 5 to 60MPa, keep the others the same as in Example 5, prepare a gel-like emulsion (GE-60) and obtain a fried dough cake.

[0110] Example 9

[0111] Adjust the addition amount of the gel-like emulsion (GE-60) in step (7) of Example 8 to 20wt%, and keep the others the same as in Example 8 to obtain a fried dough cake.

[0112] Example 10

[0113] Adjust the addition amount of the gel-like emulsion (GE-60) in step (7) of Example 8 to 30wt%, and keep the others the same as in Example 8 to obtain a fried dough cake.

[0114] Comparative Example 1

[0115] (1) Mix corn starch, flour and water in a mass ratio of 2:3:5 to obtain a batter;

[0116] (2) Fry the batter at 160°C for 3 minutes to obtain a fried dough cake.

[0117] Comparative Example 2

[0118] (1) Mix corn starch, flour, and water in a mass ratio of 2:3:5 to obtain a batter.

[0119] (2) Add 4% of a compound leavening agent (sodium bicarbonate (≤26%), disodium dihydrogen pyrophosphate (≤10%), mono- and diglycerol fatty acid esters (≤8%), sodium dihydrogen phosphate, citric acid, DL-malic acid) to the batter.

[0120] (3) Fry the batter at 160 °C for 3 min to obtain a fried dough cake.

[0121] Comparative Example 3

[0122] (1) Extract lentinus edodes stalk cellulose:

[0123] Crush dried lentinus edodes stalks and pass through an 80-mesh sieve to obtain lentinus edodes stalk powder; mix the powder with soybean oil in a ratio of 1:1.5 and perform extraction and degreasing through a supercritical carbon dioxide extractor (extraction pressure: 20 Pa, separation pressure: 6 Pa, time: 25 min); add 20 times the weight of deionized water to the degreased powder, adjust the pH to 3, add cellulase (the addition amount of the enzyme relative to the substrate is 2000 U / g), enzymatically hydrolyze at 55 °C for 2 h, then add acid protease (the addition amount of the enzyme relative to the substrate is 2000 U / g), enzymatically hydrolyze at 30 °C for 2 h, and perform enzyme inactivation treatment after enzymatic hydrolysis; mix the enzyme hydrolysis solution after enzyme inactivation with absolute ethanol in a volume ratio of 1:1.5 and centrifuge, and the precipitate obtained after centrifugation is crude cellulose; disperse the crude cellulose in 30% H2O2 in a mass ratio of 1:1, heat at 80 °C for 1 h, then add 3 times its weight of water and stir at 25 °C for 6 h, and filter the obtained mixture through a 120-mesh sieve and dry to obtain lentinus edodes stalk cellulose;

[0124] (2) Mix corn starch, flour, and water in a mass ratio of 2:3:7 to obtain a batter.

[0125] (3) Add 4.28 wt% of lentinus edodes stalk cellulose, 0.71 wt% of casein, and 15 wt% of soybean oil to the batter.

[0126] (4) Fry the batter at 160 °C for 3 min to obtain a fried dough cake.

[0127] The parameter settings of Examples 1-9 and Comparative Examples 1-2 are shown in Table 2 below:

[0128] Table 2

[0129]

[0130] Perform performance tests on the obtained fried dough cakes, and the test results are as follows:

[0131] Figure 5 Appearance pictures of the batter-fried products of Examples 5-10 and Comparative Examples 1, 2, and 3. No obvious pore structure was seen after frying in Comparative Example 1. In Comparative Example 2, a large amount of gas was decomposed from the leavening agent upon heating, causing relatively large pores to bulge in the noodle cake. In Comparative Example 3, large pores with relatively thick pore walls were visible on the surface. Compared with Comparative Examples 2 and 3, a large number of small-sized pores were formed inside the noodle cakes of Examples 5-9, and with the increase in the addition amount of the gel-like emulsion, the pore structure of the fried noodle cake increased. Compared with Examples 5-7 with GE-40 added, Examples 8, 9, and 10 with GE-60 added showed more dense pore structures. In particular, Example 10 had more large pores and thinner pore walls. The results indicate that the gel-like emulsion can significantly increase the pore structure of the fried noodle cake, and the nano-cellulose-stabilized gel-like emulsion treated at a higher pressure increases the density of the pore structure of the fried noodle cake.

[0132] Figures 6 - 8 Sensory evaluation pictures of Examples 5-7, Examples 8-10, and Comparative Examples 1, 2, and 3 respectively. From Figures 6 - 8 It can be seen that: the batter prepared in the above Examples 5-10 was wrapped around the food and batter-fried, and the obtained finished products were compared with the finished products of Comparative Example I, Comparative Example 2, and Comparative Example 3 after the same batter-frying. The overall acceptability of the finished products fried with the batter formula of Examples 5-10 was high, with a golden color, strong aroma, and crispy crust. In particular, the finished products of the food fried with the batter formula in Example 9 had the best sensory properties. The crusts of Comparative Example 1 and Comparative Example 2 were not crispy and were slightly sticky to the teeth, with a poor taste. The results indicate that adding the gel-like emulsion to the batter can significantly improve the sensory evaluation value of the fried products, and the batter with 20% GE-60 added had the best sensory properties after frying.

[0133] Figure 9 、 10 、11 are the test results of L*, a*, and b* of Examples 5–10 and Comparative Examples 1, 2, and 3 respectively. From Figures 9 - 11 It can be seen that: Comparative Example 1 had the highest L* value, the lowest a* and b* values, resulting in a relatively white color; Comparative Example 3 showed the lowest L* value, presenting a dark brown color. The L* values of Examples 5, 6, 8, and 9 were similar to those of Comparative Example 2, but their a* and b* values were significantly higher than those of Comparative Example 2. Therefore, Examples 5, 6, 8, and 9 presented a more acceptable golden yellow color. The lower L* values of Example 7 and Example 10 made their appearance colors slightly darker. The results indicate that adding the gel-like emulsion can effectively control the color of the fried products.

[0134] Figure 12 Test results of the oil content of Examples 5-10, Comparative Example 1, Comparative Example 2, and Comparative Example 3. From Figure 13It can be seen that Examples 5, 8 and 9 showed the lowest oil content, which were 19.01%, 18.17% and 20.80% respectively. The oil contents of Examples 6, 7 and 10 were 23.01%, 27.21% and 26.03% respectively, higher than 22.01% of Comparative Example 1, but lower than 30.30% of Comparative Example 2 and 33.17% of Comparative Example 3. This indicates that compared with commercial leavening agents, adding the gel-like emulsion can significantly reduce the oil absorption of the batter for fried foods, and the oil reduction effect of the nano-cellulose-stabilized gel-like emulsion prepared at a higher pressure is more significant.

[0135] Figure 13 are the test results of the lipid oxidation of Examples 5-10, Comparative Example 1, Comparative Example 2 and Comparative Example 3. From Figure 13 It can be seen that the TBARs values of Comparative Example 1, Comparative Example 2 and Comparative Example 3 were 4.02 mg / kg, 7.02 mg / kg and 7.79 mg / kg respectively. The TBARs values of Examples 5-10 (≤3 mg / kg) were all lower than those of Comparative Example 1 and Comparative Example 2. The TBARs values of Examples 8, 9 and 10 were 2.28 mg / kg, 1.80 mg / kg and 1.85 mg / kg respectively, which were lower than those of Examples 5, 6 and 7 (2.97 mg / kg, 1.85 mg / kg and 2.42 mg / kg). This result indicates that adding the gel-like emulsion can significantly reduce the lipid oxidation of the fried dough cake, and the nano-cellulose-stabilized gel-like emulsion prepared at a higher pressure has a better effect on inhibiting lipid oxidation. When the frying temperature is higher than 80 °C, the gel-like emulsion will demulsify, and the internal phase oil will escape. At the same time, a nano-cellulose-casein shell will be left on the surface of the pores. The shell layer prevents part of the oxygen from directly contacting the dough cake, and can reduce the lipid oxidation value of the fried product.

[0136] Based on the comprehensive research results of each example and comparative example, the technology of the present invention can endow the batter-fried products with good crispness, effectively improve the color characteristics of the fried products, reduce the oil content and lipid oxidation degree of the batter shell. Using this set of technologies, various batter-fried foods with clean labels can be produced, which have good market prospects.

[0137] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. An oyster mushroom stalk nanocellulose-casein gel-like emulsion, characterized in that, The gel-like emulsion is prepared by the following method: (1) Preparation of Lentinula edodes stalk nanocellulose: The dried Lentinula edodes stalks are crushed and sieved to obtain Lentinula edodes stalk powder. The powder is mixed with edible oil, and supercritical carbon dioxide extraction is carried out to remove the oil. After that, water is added to the defatted powder, the pH is adjusted to 4-6, cellulase is added for enzymatic hydrolysis, then acid protease is added for enzymatic hydrolysis, and then the enzyme is inactivated. Ethanol is added to the inactivated enzymatic hydrolysate, and the precipitate is obtained by centrifugation as crude cellulose. The crude cellulose is dispersed in an aqueous H2O2 solution and heated, then water is added and stirred, and after sieving and drying, Lentinula edodes stalk nanocellulose is obtained; (2) Preparation of Lentinula edodes stalk nanocellulose-casein gel-like emulsion: An aqueous solution of the Lentinula edodes stalk nanocellulose obtained in step (1) is prepared, and then mixed with an aqueous casein solution to obtain a Lentinula edodes stalk nanocellulose-casein complex. Then the Lentinula edodes stalk nanocellulose-casein complex is mixed with edible oil and dispersed at high speed to obtain a Lentinula edodes stalk nanocellulose-casein gel-like emulsion; The concentration of the aqueous solution of Lentinula edodes stalk nanocellulose is 20-40 mg / mL; the concentration of the aqueous casein solution is 80-120 mg / mL; the volume ratio of the aqueous solution of Lentinula edodes stalk nanocellulose to the casein solution is 4-8:1; the volume ratio of the Lentinula edodes stalk nanocellulose-casein complex to the edible oil is 1:2-4.

2. According to the preparation method described in claim 1, characterized in that, In step (1), the edible oil includes one or more of soybean oil, corn oil, sunflower oil, rapeseed oil, and peanut oil; the mass ratio of the Lentinula edodes stalk powder to the edible oil is 1:1-2.

3. According to the preparation method described in claim 1, characterized in that, In step (1), the parameters for extraction and oil removal are that the pressure in the extraction kettle is 15-20 Pa, the pressure in the separation kettle is 5-6 Pa, and the treatment time is 20-25 min.

4. According to the preparation method described in claim 1, characterized in that, In step (1), the addition amount of cellulase is 1500-2500 U / g based on the mass of the substrate; the conditions for cellulase enzymatic hydrolysis are enzymatic hydrolysis at 50-55 °C for 1-2 h.

5. According to the preparation method described in claim 1, characterized in that, In step (1), the addition amount of acid protease is 1500-2500 U / g based on the mass of the substrate; the conditions for acid protease enzymatic hydrolysis are enzymatic hydrolysis at 30-35 °C for 1-2 h.

6. According to the preparation method described in claim 1, characterized in that, In step (1), the mass concentration of H2O2 in the aqueous H2O2 solution is 20-40%; the mass ratio of the crude cellulose to the aqueous H2O2 solution is 1:0.5-1.5; the heating is carried out at 70-80 °C for 0.5-2 h.

7. According to the preparation method described in claim 1, characterized in that, In step (2), the edible oil includes one or more of soybean oil, corn oil, sunflower oil, rapeseed oil, and peanut oil.

8. According to the preparation method described in claim 1, characterized in that, In step (2), the conditions for high-speed dispersion are treatment at 8000-10000 g for 1-5 min.

9. Application of the Lentinula edodes stalk nanocellulose-casein gel-like emulsion according to any one of claims 1-8 in the food field.

10. A method for frying dough cakes, characterized in that, It includes the following steps: Corn starch, flour and water are mixed to prepare a batter. The Lentinula edodes stalk nanocellulose-casein gel-like emulsion according to any one of claims 1-8 is added to the batter, and then fried to obtain a fried bread cake. The addition amount of the Lentinula edodes stalk nanocellulose-casein gel-like emulsion is 20-25 wt% of the mass of the batter.

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