Emulsified flour product with stable litchi shell cellulose and preparation method of emulsified flour product

Abstract

According to the emulsified flour product with stable litchi shell cellulose and the preparation method of the emulsified flour product, the litchi shells are effectively utilized, the cellulose nanocrystalline emulsion with high emulsifying performance is prepared, a grease emulsifier is replaced, the emulsified flour product is prepared, the fat content of the emulsified flour product is reduced, and the flavor and taste are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of food technology, more particularly, relates to a lychee shell cellulose stabilized emulsified flour product and a preparation method thereof. BACKGROUND

[0002] The emulsified flour product is a flour product formed by uniformly dispersing the water phase (flour, water, salt, etc.) and the oil phase (edible oil) through emulsification technology. Food-grade emulsifiers (such as monoglyceride, sucrose ester, etc.) are usually used to reduce the interfacial tension, combined with mechanical stirring (dough mixer, homogenizer) to form small oil droplets, control the oil droplet size in the range of 1-50 μm, build a stable oil-in-water (O / W) or water-in-oil (W / O) structure in the dough, improve the water retention capacity, maintain the softness of the product, enhance the flavor substance embedding effect, and at the same time make the product texture more uniform and delicate. However, some consumers have health concerns about synthetic emulsifiers, and emulsifiers may interfere with the natural flavor of the flour product.

[0003] In the food industry, cellulose is widely used in food to improve food texture and shelf life. At present, the main source of cellulose is wood, accounting for 90% to 95% of the cellulose raw material. Over-reliance on wood to prepare cellulose is easy to cause over-harvesting problems, and further puts pressure on the ecological environment. In addition, due to the high content and complex structure of lignin in wood, wood is not suitable for preparing cellulose nanocrystals.

[0004] Lychee shell is the main by-product produced during lychee processing and consumption, which contains rich cellulose. At present, lychee shell is mostly discarded or buried as waste, and the comprehensive utilization level is low, which not only causes environmental pollution, but also wastes cellulose resources.

[0005] Therefore, how to effectively extract cellulose from lychee shell, improve the emulsification capacity of cellulose, and apply it to emulsified flour products is of great significance to the food industry. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a preparation method of a lychee shell cellulose stabilized emulsified flour product, comprising the following steps:

[0007] Step S1, preparing lychee shell dry powder: drying, crushing and sieving the lychee shell to prepare lychee shell dry powder A;

[0008] Step S2, removing water-soluble impurities: adding lychee shell dry powder A into water, stirring and washing, collecting the precipitate after filtration and drying to prepare lychee shell dry powder B;

[0009] Step S3, alkali hydrolysis of hemicellulose: adding lychee shell dry powder B into alkali solution, stirring and alkali hydrolysis, collecting the precipitate after filtration, washing and drying to prepare solid C;

[0010] Step S4, removing lignin: solid C is added into bleaching solution, stirring bleaching, after bleaching, filtering, washing, collecting precipitate, drying, crushing into powder D;

[0011] Step S5, sulfuric acid hydrolysis: powder D is added into sulfuric acid aqueous solution, stirring hydrolysis, after bleaching, stopping reaction, obtaining reaction liquid E;

[0012] Step S6, preparing colloidal suspension: centrifuging reaction liquid E, collecting precipitate F and washing;

[0013] adding precipitate F into water, ultrasonic dispersion, preparing dispersion liquid G; centrifuging dispersion liquid G, collecting supernatant H;

[0014] ultrafiltration dialysis supernatant H, obtaining cellulose nanocrystal colloidal suspension I;

[0015] Step S7, preparing emulsion: homogenizing colloidal suspension I into dispersion liquid J;

[0016] adding essential oil into edible oil, shaking mixing, preparing oil phase K;

[0017] mixing and homogenizing oil phase K and dispersion liquid J, ultrasonic treatment, preparing emulsion L;

[0018] Step S8, preparing lipid: mixing emulsion L with butter, preparing lipid;

[0019] Step S9, preparing batter: stirring lipid, sweetener, egg liquid, flour uniformly, preparing batter;

[0020] Step S10, baking: drying after shaping batter, preparing emulsified flour product.

[0021] As a preferred technical scheme, the litchi shell in step S1 is derived from Litchi chinensis Sonn.

[0022] As a preferred technical scheme, the washing temperature in step S2 is 80-90℃; the washing time is 2-4h; the mass ratio of litchi shell dry powder A to water is 1:(20-30).

[0023] As a preferred technical scheme, the alkaline hydrolysis temperature in step S3 is 90-100℃; the alkaline hydrolysis time is 2-4h; the mass ratio of litchi shell dry powder B to alkali solution is 1:(20-30); the alkaline hydrolysis is repeated 2-4 times; the washing solution is water; the mass-volume ratio of alkali solution is 4%.

[0024] As a preferred technical solution, the bleaching temperature in the step S4 is 80-90 DEG C; the bleaching time is 2-4 hours; the mass ratio of the solid C to the bleaching solution is 1:(20-30); the bleaching is repeated 2-4 times; the washing solution is water; the bleaching solution comprises 1.7% sodium hypochlorite, 2.7% sodium hydroxide and 7.5% glacial acetic acid by mass; the drying temperature is 50-60 DEG C; and the drying time is 10-20 hours.

[0025] As a preferred technical solution, the hydrolysis temperature in the step S5 is 40-50 DEG C; the hydrolysis time is 0.2-1 hour; the mass ratio of the solid D to the sulfuric acid aqueous solution is 1:(10-20); the mass concentration of the sulfuric acid aqueous solution is 60%; the method for terminating the reaction is adding deionized water, the temperature of the deionized water is 2-8 DEG C; and the volume ratio of the deionized water to the sulfuric acid aqueous solution is 10:1.

[0026] As a preferred technical solution, the centrifugal rotation speed in the step S6 is 12000 rpm, and the centrifugal time is 10 minutes; the washing solution is water; and the mass concentration of the colloidal suspension I is 1-2%.

[0027] As a preferred technical solution, the homogenization rotation speed in the step S7 is 10000 rpm; the homogenization time is 2 minutes; the mass ratio of the essential oil to the edible oil is 1:20; the edible oil is food-grade soybean oil; the essential oil is food-grade lemon essential oil; the oscillation time is 2 minutes; the mass ratio of the oil phase K to the dispersion liquid J is 3:7, the homogenization rotation speed is 12000 rpm; the homogenization time is 3 minutes; the ultrasonic power is 800 w; and the ultrasonic time is 2 minutes.

[0028] As a preferred technical solution, the mass ratio of the emulsion to the butter in the step S8 is 1:1.

[0029] As a preferred technical solution, the mass ratio of the lipid, the sweetener, the egg liquid, and the flour in the step S9 is 1:(0.3-0.5):(0.2-0.3):(1.2-1.5).

[0030] As a preferred technical solution, the drying temperature in the step S10 is 175-185 DEG C; and the drying time is 20-30 minutes.

[0031] In the second aspect of the present application, an emulsified pastry is provided, which is prepared by the method described above.

[0032] In the third aspect of the present application, a method for reducing the oiliness of an emulsified pastry is provided, which adopts the method for preparing the emulsified pastry described above.

[0033] Through the above technical solutions, the present application has the following technical effects:

[0034] (1) The litchi shell is effectively utilized, and a high-quality cellulose nanocrystal emulsion with emulsifying performance is prepared, and compared with wood sources, the emulsifying performance and stability of the emulsion are improved.

[0035] (2) The cellulose nanocrystal emulsion is used to replace the oil emulsifier to prepare an emulsified surface product, the fat content of the emulsified surface product is reduced, and the flavor and taste are improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The micro-morphology of cellulose nanocrystals and cellulose nanofibers is shown in the figure; (a) is the cellulose nanocrystals in the colloidal suspension I obtained in Example 1; (b) is the cellulose nanocrystals in the colloidal suspension I obtained in Comparative Example 1; (c) is the cellulose nanofibers of Comparative Example 2.

[0037] Figure 2 The contact angle detection results are shown in the figure; from left to right, the contact angle detection results of Example 1, Comparative Example 1, and Comparative Example 2 are shown in the figure;

[0038] Figure 3 The cellulose and oil droplet distribution results in the emulsion are shown in the figure; from top to bottom, the first row, the second row, and the third row in the figure are Example 1, Comparative Example 1, and Comparative Example 2; from left to right, the first column, the second column, and the third column in the figure are the cellulose and oil droplet dyeing distribution superimposition, the cellulose distribution dyed by Calcofluor white, and the oil droplet distribution dyed by Nile red;

[0039] Figure 4 The emulsion stability results are shown in the figure; from left to right, the emulsion stability results of Example 1, Comparative Example 1, and Comparative Example 2 are shown in the figure. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0041] Example 1

[0042] Step S1, preparing litchi shell dry powder: drying, crushing, and sieving litchi shells to prepare litchi shell dry powder A; the litchi shells are derived from Litchi chinensis Sonn; the aperture of the sieve is 80 mesh;

[0043] Step S2, removing water-soluble impurities: adding the dry litchi shell powder A into water, stirring and washing, collecting the precipitate after filtration and drying to prepare dry litchi shell powder B; the washing temperature is 80℃; the washing time is 2h; the mass ratio of the dry litchi shell powder A to water is 1:20;

[0044] Step S3, alkali hydrolysis of hemicellulose: adding the dry litchi shell powder B into alkali solution, stirring and alkali hydrolysis, collecting the precipitate after filtration, washing and drying to prepare solid C; the alkali hydrolysis temperature is 90℃; the alkali hydrolysis time is 2h; the mass ratio of the dry litchi shell powder B to alkali solution is 1:20; the alkali hydrolysis is repeated twice; the washing solution is water; the mass-volume ratio of the alkali solution is 4%;

[0045] Step S4, removing lignin: adding the solid C into bleaching solution, stirring and bleaching, collecting the precipitate after filtration, washing, drying and crushing to prepare powder D; the bleaching temperature is 80℃; the bleaching time is 2h; the mass ratio of the solid C to bleaching solution is 1:20; the bleaching is repeated twice; the washing solution is water; the bleaching solution contains 1.7% sodium hypochlorite, 2.7% sodium hydroxide and 7.5% glacial acetic acid by mass-volume ratio; the drying temperature is 50℃; the drying time is 10h;

[0046] Step S5, sulfuric acid hydrolysis: adding the powder D into sulfuric acid aqueous solution, stirring and hydrolysis, stopping the reaction after bleaching to obtain reaction liquid E; the hydrolysis temperature is 40℃; the hydrolysis time is 0.2h; the mass ratio of the solid D to sulfuric acid aqueous solution is 1:10; the mass concentration of the sulfuric acid aqueous solution is 60%; the method for stopping the reaction is adding deionized water, and the temperature of the deionized water is 2℃; the volume ratio of the deionized water to sulfuric acid aqueous solution is 10:1;

[0047] Step S6, preparing colloidal suspension: centrifuging the reaction liquid E to collect the precipitate F and washing; the centrifugation speed is 12000rpm, and the centrifugation time is 10min; the washing solution is water;

[0048] adding the precipitate F into water, ultrasonic dispersion to prepare dispersion liquid G; centrifuging the dispersion liquid G to collect supernatant H; the centrifugation speed is 12000rpm, and the centrifugation time is 10min;

[0049] ultrafiltration and dialysis of the supernatant H to obtain cellulose nanocrystal colloidal suspension I; the mass concentration of the colloidal suspension I is 1%;

[0050] Step S7, preparing emulsion: homogenizing the colloidal suspension I to prepare dispersion liquid J; the homogenization speed is 10000rpm; the homogenization time is 2min;

[0051] The edible oil is added with the essential oil, and the oil phase K is prepared by mixing and oscillation; the mass ratio of the essential oil to the edible oil is 1:20; the edible oil is food-grade soybean oil; the essential oil is food-grade lemon essential oil; and the oscillation time is 2 minutes;

[0052] The oil phase K and the dispersion liquid J are mixed and homogenized to prepare the emulsion L; the mass ratio of the oil phase K to the dispersion liquid J is 3:7, the homogenization speed is 12000 rpm, the homogenization time is 3 minutes, the ultrasonic power is 800 w, and the ultrasonic time is 2 minutes;

[0053] Step S8, preparing the lipid: the emulsion is mixed with the butter to prepare the lipid; the mass ratio of the emulsion to the butter is 1:1;

[0054] Step S9, preparing the batter: the lipid, the sweetener, the egg liquid and the flour are stirred uniformly to prepare the batter; the sweetener is icing sugar; and the mass ratio of the lipid, the sweetener, the egg liquid and the flour is 1:0.3:0.2:1.2;

[0055] Step S10, baking: the batter is shaped and dried to prepare the emulsified flour product; the drying temperature is 175 ℃, and the drying time is 20 minutes.

[0056] Example 2

[0057] Step S1, preparing the dried lychee shell powder: the lychee shell is dried, crushed and sieved to prepare the dried lychee shell powder A; the lychee shell is derived from the lychee shell of Feizixiao; and the aperture of the sieve is 80 mesh;

[0058] Step S2, removing the water-soluble impurities: the dried lychee shell powder A is added into water, stirred and washed, and the precipitate is collected by filtration and dried to prepare the dried lychee shell powder B; the washing temperature is 85 ℃, the washing time is 3 hours, and the mass ratio of the dried lychee shell powder A to the water is 1:25;

[0059] Step S3, alkaline hydrolysis of hemicellulose: the dried lychee shell powder B is added into an alkali solution, stirred and alkaline-hydrolyzed, and the solid C is prepared by filtering, washing, collecting the precipitate and drying after the alkaline hydrolysis; the alkaline hydrolysis temperature is 95 ℃, the alkaline hydrolysis time is 3 hours, the mass ratio of the dried lychee shell powder B to the alkali solution is 1:25, the alkaline hydrolysis is repeated for 3 times, the washing solution is water, and the mass-volume ratio of the alkali solution is 4%;

[0060] Step S4, removing lignin: solid C is added into bleaching solution, stirring bleaching, after bleaching, filtering, washing, collecting precipitate, drying, crushing into powder D; the bleaching temperature is 85℃; the bleaching time is 3h; the mass ratio of solid C to bleaching solution is 1:25; the bleaching is repeated for 3 times; the washing solution is water; the bleaching solution contains 1.7% sodium hypochlorite, 2.7% sodium hydroxide and 7.5% glacial acetic acid by mass volume ratio; the drying temperature is 55℃; the drying time is 15h;

[0061] Step S5, sulfuric acid hydrolysis: powder D is added into sulfuric acid aqueous solution, stirring hydrolysis, after bleaching, the reaction is terminated to obtain reaction liquid E; the hydrolysis temperature is 45℃; the hydrolysis time is 0.3h; the mass ratio of solid D to sulfuric acid aqueous solution is 1:15; the mass concentration of sulfuric acid aqueous solution is 60%; the method for terminating the reaction is adding deionized water, the temperature of deionized water is 4℃; the volume ratio of deionized water to sulfuric acid aqueous solution is 10:1;

[0062] Step S6, preparing colloidal suspension: centrifuging reaction liquid E, collecting precipitate F and washing; the centrifugal speed is 12000rpm, the centrifugal time is 10min; the washing solution is water;

[0063] adding precipitate F into water, ultrasonic dispersion, preparing dispersion liquid G; centrifuging dispersion liquid G, collecting supernatant H; the centrifugal speed is 12000rpm, the centrifugal time is 10min;

[0064] ultrafiltration dialysis supernatant H, obtaining cellulose nanocrystal colloidal suspension I; the mass concentration of colloidal suspension I is 1%~2%;

[0065] Step S7, preparing Pickering emulsion: homogenizing colloidal suspension I to prepare dispersion liquid J; the homogenization speed is 10000rpm; the homogenization time is 2min;

[0066] adding essential oil into edible oil, shaking mixing, preparing oil phase K; the mass ratio of essential oil to edible oil is 1:20; the edible oil is food grade soybean oil; the essential oil is food grade lemon essential oil; the shaking time is 2min;

[0067] mixing and homogenizing oil phase K and dispersion liquid J, ultrasonic treatment, preparing Pickering emulsion L; the mass ratio of oil phase K to dispersion liquid J is 3:7, the homogenization speed is 12000rpm; the homogenization time is 3min; the ultrasonic power is 800w; the ultrasonic time is 2min;

[0068] Step S8, preparing lipid: mixing emulsified liquid with butter to prepare lipid; the mass ratio of emulsified liquid to butter is 1:1;

[0069] Step S9, preparing batter: stirring the lipid, sweetener, egg liquid, flour to prepare batter; the sweetener is icing sugar; the mass ratio of the lipid, sweetener, egg liquid, flour is 1:0.4:0.25:1.3;

[0070] Step S10, baking: baking the batter to prepare emulsified flour product; the baking temperature is 180℃; the baking time is 25 minutes.

[0071] Example 3

[0072] Step S1, preparing dry lychee shell powder: drying, crushing and sieving lychee shell to prepare dry lychee shell powder A; the lychee shell is from Feizixiao lychee shell; the aperture of the sieve is 80 mesh;

[0073] Step S2, removing water-soluble impurities: adding dry lychee shell powder A into water, stirring and washing, collecting the precipitate after filtration and drying to prepare dry lychee shell powder B; the washing temperature is 90℃; the washing time is 4h; the mass ratio of the dry lychee shell powder A to water is 1:30;

[0074] Step S3, alkali hydrolysis of hemicellulose: adding dry lychee shell powder B into alkali solution, stirring and alkali hydrolysis, collecting the precipitate after filtration, washing and drying to prepare solid C; the alkali hydrolysis temperature is 100℃; the alkali hydrolysis time is 4h; the mass ratio of the dry lychee shell powder B to alkali solution is 1:30; the alkali hydrolysis is repeated for 4 times; the washing solution is water; the mass / volume ratio of the alkali solution is 4%;

[0075] Step S4, removing lignin: adding solid C into bleaching solution, stirring and bleaching, collecting the precipitate after filtration, washing and drying, crushing to prepare powder D; the bleaching temperature is 90℃; the bleaching time is 4h; the mass ratio of the solid C to bleaching solution is 1:30; the bleaching is repeated for 4 times; the washing solution is water; the bleaching solution contains 1.7% sodium hypochlorite, 2.7% sodium hydroxide and 7.5% glacial acetic acid; the drying temperature is 60℃; the drying time is 20h;

[0076] Step S5, sulfuric acid hydrolysis: adding powder D into sulfuric acid aqueous solution, stirring and hydrolyzing, stopping the reaction after bleaching to obtain reaction liquid E; the hydrolysis temperature is 50℃; the hydrolysis time is 1h; the mass ratio of the solid D to sulfuric acid aqueous solution is 1:20; the mass concentration of the sulfuric acid aqueous solution is 60%; the method for stopping the reaction is adding deionized water, the temperature of the deionized water is 8℃; the volume ratio of the deionized water to sulfuric acid aqueous solution is 10:1;

[0077] Step S6, preparing the colloidal suspension: centrifuging the reaction solution E to collect the precipitate F and washing; the centrifugal speed is 12000 rpm, and the centrifugal time is 10 min; the washing solution is water;

[0078] The precipitate F is added into water and dispersed by ultrasonic to prepare the dispersion G; the dispersion G is centrifuged to collect the supernatant H; the centrifugal speed is 12000 rpm, and the centrifugal time is 10 min;

[0079] The supernatant H is ultrafiltrated and dialyzed to obtain the cellulose nanocrystal colloidal suspension I; the mass concentration of the colloidal suspension I is 2%;

[0080] Step S7, preparing the emulsion: homogenizing the colloidal suspension I to prepare the dispersion J; the homogenization speed is 10000 rpm, and the homogenization time is 2 min;

[0081] The essential oil is added into the edible oil, and the mixture is shaken to prepare the oil phase K; the mass ratio of the essential oil to the edible oil is 1:20; the edible oil is food-grade soybean oil; the essential oil is food-grade lemon essential oil; and the shaking time is 2 min;

[0082] The oil phase K and the dispersion J are mixed and homogenized, and then treated by ultrasonic to prepare the emulsion L; the mass ratio of the oil phase K to the dispersion J is 3:7, the homogenization speed is 12000 rpm, the homogenization time is 3 min, the ultrasonic power is 800 w, and the ultrasonic time is 2 min;

[0083] Step S8, preparing the lipid: mixing the emulsion and butter to prepare the lipid; the mass ratio of the emulsion to the butter is 1:1;

[0084] Step S9, preparing the batter: stirring the lipid, sweetener, egg liquid and flour uniformly to prepare the batter; the sweetener is icing sugar; and the mass ratio of the lipid, sweetener, egg liquid and flour is 1:0.5:0.3:1.5;

[0085] Step S10, baking: baking the shaped batter to prepare the emulsified flour product; the baking temperature is 185℃, and the baking time is 30 min.

[0086] Comparative Example 1

[0087] Wood is used instead of litchi shell, and other parameters are consistent with those in Example 1.

[0088] Comparative Example 2

[0089] Commercially available cellulose nanofiber is purchased, and the emulsion is prepared according to Step 7.

[0090] Comparative Example 3

[0091] In step S8, the emulsion prepared from the lychee shell is no longer used, and butter is used to prepare the emulsified surface product.

[0092] The microstructure of the cellulose nanocrystals in the colloidal suspension I obtained in Example 1 and Comparative Example 1, and the cellulose nanofiber of Comparative Example 2 was observed by transmission electron microscopy; the aspect ratio of the cellulose nanocrystals and nanofibers was determined by ImageJ software combined with the transmission electron microscopy images. The microstructure comparison is shown in Figure 1 , and the test results are shown in Table 1.

[0093] The cellulose nanocrystals obtained in Example 1 exhibit a needle-like structure, with an average diameter of 6 nm and an average length of 355 nm, and have a large aspect ratio, with an aspect ratio of 59. The cellulose nanocrystals obtained in Comparative Example 1 exhibit a short rod-like structure, with an average diameter of 13 nm and an average length of 145 nm, and an aspect ratio of 11. The commercially available nanocellulose filaments of Comparative Example 2 exhibit a typical filamentous structure, with a length of about 3 μm and an average diameter of 5 nm, and are intertwined into a three-dimensional network structure.

[0094] Table 1: Cellulose aspect ratio and contact angle test results

[0095] Detection item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Average diameter (nm) 6 6 6 13 5 Average length (nm) 355 327 314 145 3261 Aspect ratio 59 55 52 11 652 Contact angle (°) 56.20 58.50 59.90 48.00 38.27

[0096] The contact angle of the cellulose nanocrystals in the colloidal suspension I obtained in Example 1 and Comparative Example 1, and the cellulose nanofiber of Comparative Example 2 was determined. The contact angle test results are shown in Figure 2 and Table 1. The cellulose nanocrystals obtained in Example 1 have an average contact angle of 56.20° to 59.90°, which is stronger than the cellulose nanocrystals of Comparative Example 1 (48.00°) and the cellulose nanofiber of Comparative Example 2 (38.27°), showing stronger amphiphilicity and stronger surface activity. By precisely controlling the degree of sulfuric acid hydrolysis, cellulose nanocrystals with a specific aspect ratio are obtained from lychee shells, improving the surface activity and thermal stability of the emulsion.

[0097] The cellulose was stained with Calcofluor White fluorescence, and the oil droplets were stained with Nile Red; the distribution of cellulose and oil droplets in the emulsions obtained in Example 1, Comparative Example 1 and Comparative Example 2 was observed by laser confocal microscopy; the stability of the emulsions obtained in Example 1, Comparative Example 1 and Comparative Example 2 was determined by centrifugation at 2000 r / min for 30 min using a LUMifuge full-function stability analyzer.

[0098] The results of the distribution of cellulose and oil droplets in the emulsion are shown in Figure 3 , and the results of the stability of the emulsion are shown in Figure 4 . From Figure 3It can be seen that the Calcofluor fluorescent white labeled (blue) nanocellulose is wrapped around the Nile red labeled (red) oil phase, indicating that the three nanocellulose emulsions are all O / W type emulsions. Compared with the cellulose nanocrystal emulsion of Comparative Example 1 and Comparative Example 1, the small aspect ratio of Comparative Example 1 is irreversibly adsorbed on the surface of the oil droplets, forming a dense interfacial film; Example 1 not only forms an interfacial film on the surface of the droplets, but also has a long size and a large aspect ratio, and a bridging phenomenon occurs between the droplets, further preventing the aggregation between the droplets, and improving the stability of the emulsion. Comparative Example 2 only wraps the oil droplets by forming a crosslinked network structure by mutual entanglement to prevent the collision and aggregation of the droplets.

[0099] The emulsion stability test results of the three nanocellulose emulsions are shown in Figure 4 Example 1 and Comparative Example 2 emulsions have no change in appearance after centrifugation at 2000 r / min for 30 min, and the transmission curve of the emulsion always maintains a low transmittance, and the instability index is less than 0.001, indicating that the emulsions of Example 1 and Comparative Example 2 have good centrifugal stability. The average instability index of the emulsion of Comparative Example 1 is 0.23, and the transmittance of the sample increases rapidly above 120 mm, indicating that the emulsion of Comparative Example 1 has obvious layering instability after centrifugation.

[0100] The cellulose nanocrystal (CNC) prepared in the example has a specific aspect ratio, which can uniformly adsorb on the oil-water interface in the aqueous phase due to its excellent dispersibility, and form a dense Pickering interfacial film. The rich -SO3 - groups on the surface of the nanocrystal effectively inhibit the coalescence of oil droplets through electrostatic repulsion, and the high aspect ratio of the nanocrystal forms a three-dimensional network skeleton in the continuous phase, which can physically limit the movement of the oil droplets, further preventing the aggregation between the oil droplets, and even in high concentration emulsion, it can also maintain good stability. In addition, the three-dimensional network structure can also significantly improve the mechanical stability of the emulsion, which is suitable for emulsion systems that require high strength and high stability. This dual stabilization mechanism of "interfacial adsorption + spatial barrier" improves the surface activity and thermal stability of the emulsion.

[0101] The sensory evaluation of the emulsified face product was carried out by a team of 15 evaluators, all of whom were trained to evaluate the quality of biscuits. Referring to the standards in Table 2, the quality rating test was used to evaluate the color, appearance, aroma, taste and mouthfeel of the biscuits on a 100-point scale. From the above five aspects, there is no obvious difference between Example 1 and Comparative Example 3 (butter); in terms of color and appearance, the biscuit product obtained by Example 1 has a higher score than Comparative Example 3. The above results show that there is no significant difference between Example 1 and Comparative Example 3 in terms of overall acceptance, and the sensory properties of the emulsified face product prepared by replacing traditional butter with the technical solution of the present application can be accepted by the public, and it is feasible.

[0102] Table 2: Sensory Evaluation Criteria

[0103]

[0104] Table 3: Sensory Evaluation Results of Emulsified Noodle Products

[0105]

[0106]

[0107] Note: The same lowercase letter indicates that there is no significant difference between the two samples.

[0108] On the one hand, cellulose nanocrystals typically possess high crystallinity, good dispersibility, and excellent thermal stability, but they are difficult to form effective network structures through bridging in flour products. On the other hand, cellulose nanofibers exhibit high mechanical strength and modulus, enabling the construction of more efficient network structures; however, their dispersibility is relatively poor, and some cellulose nanofibers have poor biocompatibility, potentially triggering immune responses after entering the body. The technical solution of this invention integrates the advantages of both and compensates for their respective shortcomings through cellulose nanocrystals with a specific aspect ratio.

[0109] This invention obtains cellulose nanocrystals with a specific aspect ratio from lychee shells by precisely controlling the degree of sulfuric acid hydrolysis, thereby improving the texture and mouthfeel of emulsified noodle products.

[0110] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a litchi peel cellulose-stabilized emulsified noodle product, characterized in that, Includes the following steps: Step S1, Prepare lychee peel powder: Dry, crush, and sieve the lychee peels to make lychee peel powder A; Step S2, removing water-soluble impurities: Add lychee shell powder A to water, stir and wash, filter and collect the sediment, then dry to make lychee shell powder B. Step S3, Alkaline hydrolysis of hemicellulose: Add lychee peel powder B to alkaline solution, stir and hydrolyze, then filter, wash, collect the precipitate and dry to make solid C; Step S4, removing lignin: Solid C is added to bleaching solution, stirred and bleached, then filtered, washed, and the precipitate is collected, dried, and pulverized to make powder D; Step S5, sulfuric acid hydrolysis: Add powder D to sulfuric acid aqueous solution, stir to hydrolyze, bleach and then terminate the reaction to obtain reaction solution E; Step S6, prepare colloidal suspension: centrifuge reaction solution E, collect precipitate F and wash it; Precipitate F was added to water and ultrasonically dispersed to prepare dispersion G; Centrifuge the dispersion G and collect the supernatant H; Ultrafiltration dialysis supernatant H yields cellulose nanocrystal colloidal suspension I; Step S7, preparing the emulsion: homogenize the colloidal suspension I to prepare the dispersion J; Add essential oil to edible oil, shake and mix to obtain oil phase K; The oil phase K and dispersion J were mixed and homogenized, and then ultrasonically treated to prepare emulsion L; Step S8, lipid preparation: Mix emulsion L with butter to prepare lipids; Step S9, Prepare the batter: Mix the lipids, sweetener, egg liquid, and flour evenly to make a batter; Step S10, Baking: After the batter is shaped, it is dried to produce emulsified dough products.

2. The preparation method according to claim 1, characterized in that, In step S1, the lychee shells are derived from the shells of the Fei Zi Xiao lychee; the sieve has an aperture of 80 mesh.

3. The preparation method according to claim 2, characterized in that, In step S2, the washing temperature is 80℃~90℃; the washing time is 2h~4h; and the mass ratio of the lychee peel powder A to water is 1:(20~30).

4. The preparation method according to claim 3, characterized in that, In step S3, the alkaline hydrolysis temperature is 90℃~100℃; the alkaline hydrolysis time is 2h~4h; the mass ratio of the lychee peel powder B to the alkaline solution is 1:(20~30); the alkaline hydrolysis is repeated 2 to 4 times; the washing solution is water; and the mass-volume ratio of the alkaline solution is 4%.

5. The preparation method according to claim 4, characterized in that, In step S4, the bleaching temperature is 80℃~90℃; the bleaching time is 2h~4h; the mass ratio of solid C to bleaching liquid is 1:(20~30); the bleaching is repeated 2 to 4 times; the washing solution is water; the bleaching liquid contains 1.7% sodium hypochlorite, 2.7% sodium hydroxide, and 7.5% glacial acetic acid by mass / volume ratio; the drying temperature is 50℃~60℃; and the drying time is 10h~20h.

6. The preparation method according to claim 5, characterized in that, In step S5, the hydrolysis temperature is 40℃~50℃; the hydrolysis time is 0.2h~1h; the mass ratio of solid D to sulfuric acid aqueous solution is 1:(10~20); the mass concentration of sulfuric acid aqueous solution is 60%; the method for terminating the reaction is to add deionized water, the temperature of the deionized water is 2℃~8℃; the volume ratio of deionized water to sulfuric acid aqueous solution is 10:

1.

7. The preparation method according to claim 6, characterized in that, In step S6, the centrifugation speed is 12000 rpm and the centrifugation time is 10 min; the washing liquid is water; and the mass concentration of the colloidal suspension I is 1% to 2%.

8. A method for reducing the oil content in emulsified flour products, characterized in that, The method employs any one of the preparation methods described in claims 1-7.

9. An emulsified noodle product, characterized in that, The emulsified noodle product is made by any one of the preparation methods described in claims 1 to 7.

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