Compound feed additive for improving flavor of eggs, preparation process and compound feed

Abstract

The invention provides a compound feed additive capable of improving the flavor of eggs, a preparation technology and a compound feed, and relates to the technical field of feed preparation.Main components in shaddock peel are analyzed, the main components influencing the flavor of the eggs are screened out, and chemical components and shaddock peel powder are adopted to prepare the compound feed additive. The grapefruit flavor extract (active ingredients such as limonene, polyphenols and the like) prepared on the basis of the grapefruit peel powder. The preparation method comprises the following steps of: compounding 20-40 parts of linalool, 5-10 parts of linalyl acetate, 2-4 parts of limonene, 1-2 parts of vanillyl alcohol, 0.7-1.4 parts of flavoyl acetate, 5-10 parts of laurel, 80 parts of shaddock peel powder, 150 parts of carrier and 70 parts of shaddock flavor extract; the total addition amount of the shaddock peel powder in the basal feed is reduced from 2% to 0.1%, a good flavor improvement effect can be maintained, and dependence on shaddock peel raw materials is greatly reduced.

Description

Technical Field

[0001] The present application relates to the technical field of feed preparation, and more specifically, to a compound feed additive for improving egg flavor, a preparation process, and a compound feed. Background Art

[0002] Eggs are indispensable nutritious foods in people's daily lives. Raw eggs have an egg odor, which mainly comes from nitrogen-containing heterocyclic compounds such as pyridine, pyrazine, pyrrole, thiazole, and volatile flavor substances such as aldehydes and indenes in eggs. Cooked eggs have a fragrance, and the fragrance of cooked eggs mainly comes from volatile substances such as alkyl aromatics, nitriles, and ketones formed by oxidation or degradation of fatty acids, amino acids, pigments, hydroxy acids (synthetic terpenoids), monosaccharides, and glycosides in eggs. In particular, small molecule substances such as aldehydes, ketones, and alcohols produced by the oxidative decomposition of fatty acids play an important role in egg flavor.

[0003] To improve egg flavor, it is necessary to consider the principle of flavor substance deposition in eggs. Egg flavor is a mixture of various flavor substances in different proportions and concentrations. These flavor substances mainly include volatile flavor substances, fatty acids, phospholipids, amino acids, and small peptides.

[0004] Volatile flavor substances can be divided into eight categories, including aliphatic hydrocarbons, aldehydes, ketones, alcohols, aromatics, furans, sulfides, and terpenoids. Among them, the content of aliphatic hydrocarbons is the highest and is almost ubiquitous in all eggs, but it has little effect on egg flavor. In contrast, aldehydes and aromatics have lower thresholds but play a major role in egg flavor. Nutritional components in eggs, such as proteins and fatty acids, are also important factors affecting egg flavor. Sulfur and nitrogen elements in proteins are respectively converted into hydrogen sulfide and ammonia under the action of bacteria, and these gases have a strong stench.

[0005] To improve egg flavor, it can be achieved by improving feed ingredients or through methods such as egg production and pickling processes. The composition of laying hen diets directly affects egg quality and flavor. For example, if excessive fish meal or fish oil is added to laying hen feed, trimethylamine oxide in fish meal is oxidized to trimethylamine with a fishy odor under the action of intestinal microorganisms in chickens and deposited in eggs, resulting in off-flavors such as moldy, stale, putrid, and fishy smells. In addition, the spoilage of unsaturated fatty acids in fish meal or fish oil is also a factor leading to a decline in egg flavor.

[0006] It has been found through research that there are a large number of volatile active substances in pomelo peel, such as limonene and polyphenols. Most of these substances have antioxidant and anti-inflammatory components, and they have shown significant effects in antioxidant, antibacterial, and inhibiting pancreatic lipase. The flavor of eggs is affected by factors such as the flavor of raw materials, the health of laying hens, immune capacity, and antioxidant capacity. Therefore, we speculate that certain components of pomelo peel can be deposited in eggs, especially in egg yolks, and interact with the components of egg yolks to improve the flavor of eggs. Our previous research found that adding 2% pomelo peel powder to the feed of laying hens can significantly improve the flavor of eggs. However, due to the large addition amount and limited sources of pomelo peel (currently, the amount of natural pomelo peel is small and affected by regions and production areas), it is difficult to meet the production demand. Summary of the Invention

[0007] The purpose of the embodiments of this application is to provide a compound feed additive for improving the flavor of eggs, a preparation process, and a compound feed, so as to significantly reduce the addition amount of pomelo peel powder in the feed of laying hens, and achieve a good effect of improving the flavor of eggs, and be able to meet the production demand of large-scale commercialization.

[0008] To achieve the above purpose, the embodiments of this application are implemented as follows:

[0009] The embodiments of this application provide a compound feed additive for improving the flavor of eggs. The compound feed additive includes the following substances in parts by weight: 20 - 40 parts of linalool, 5 - 10 parts of linalyl acetate, 2 - 4 parts of limonene, 1 - 2 parts of vanillyl alcohol, 0.7 - 1.4 parts of acetic acid flavor ester, 5 - 10 parts of myrcene, 80 parts of pomelo peel powder, 150 parts of carrier, and 70 parts of pomelo flavor extract.

[0010] Further, the carrier is 50 parts of organic carrier and 100 parts of functional carrier. The organic carrier is defatted rice bran, defatted wheat bran, or a combination of both, and the functional carrier is zeolite powder.

[0011] Further, the linalool is 20 parts, the linalyl acetate is 5 parts, the limonene is 2 parts, the vanillyl alcohol is 1 part, the acetic acid flavor ester is 0.7 part, the myrcene is 5 parts, the pomelo peel powder is 80 parts, the carrier is 150 parts, and the pomelo flavor extract is 70 parts.

[0012] Further, the linalool is 40 parts, the linalyl acetate is 10 parts, the limonene is 4 parts, the vanillyl alcohol is 2 parts, the acetic acid flavor ester is 1.4 parts, the myrcene is 10 parts, the pomelo peel powder is 80 parts, the carrier is 150 parts, and the pomelo flavor extract is 70 parts.

[0013] Further, the linalool is 30 parts, the linalyl acetate is 7.5 parts, the limonene is 3 parts, the vanillyl alcohol is 1.5 parts, the acetic acid flavor ester is 1 part, the myrcene is 7.5 parts, the pomelo peel powder is 80 parts, the carrier is 150 parts, and the pomelo flavor extract is 70 parts.

[0014] Further, the pomelo flavor extract is obtained by subjecting pomelo peel powder to headspace solid-phase microextraction, followed by microencapsulation and mixing with a carrier.

[0015] The embodiment of the present application also provides a preparation process for a compound feed additive for improving the flavor of eggs, including: S1: Select fresh pomelo peel, wash it, dry it at a low temperature, and pulverize it, then pass it through an 80-mesh sieve to obtain pomelo peel powder; S2: Take the pomelo peel powder to prepare a pomelo flavor extract; S3: Mix linalool, linalyl acetate, limonene, vanillyl alcohol, acetic acid flavor ester, and myrcene in proportion to obtain a flavor component mixture; S4: Spray the flavor component mixture in an atomized form onto the activated zeolite powder; S5: Add the zeolite powder adsorbed with flavor components, pomelo peel powder, and defatted rice bran to a double-cone mixer, protect it with nitrogen, and mix at a low speed for 30 minutes; S6: Add the prepared pomelo flavor extract into the double-cone mixer and continue to mix at a low speed for 30 minutes to obtain the prepared compound feed additive for improving the flavor of eggs.

[0016] Further, the preparation method of the pomelo flavor extract is as follows: S21: Perform headspace solid-phase microextraction on the pomelo peel powder to obtain a pomelo flavor extraction solution; S22: Concentrate and recover the solvent of the pomelo flavor extraction solution to obtain a pomelo flavor concentrate; S23: Perform microencapsulation treatment on the pomelo flavor concentrate to form microcapsules, wherein the microcapsule wall material is selected as a 1:1 mixture of β-cyclodextrin and arabic gum; S24: Select expanded corn flour with a particle size of 80 mesh, bake and sterilize it, and mix it with the microcapsules in a ratio of 9:1 to obtain a uniformly mixed pomelo flavor extract.

[0017] The embodiment of the present application also provides a compound feed for improving the flavor of eggs, which is prepared by adding the compound feed additive prepared by the preparation process of the compound feed additive for improving the flavor of eggs to the basic feed.

[0018] Further, the addition ratio of the compound feed additive is 0.1% - 0.3%.

[0019] Beneficial effects:

[0020] 1. In this solution, by analyzing the main components in pomelo peel, the main components affecting the flavor of eggs are screened out, and a compound feed additive for improving the flavor of eggs is prepared by compounding chemical components with pomelo peel powder and a pomelo flavor extract prepared based on pomelo peel powder (the effective components in concentrated pomelo peel such as limonene and polyphenols are prepared by mixing after microencapsulation and expanded corn flour). The total addition amount of pomelo peel powder in the basic feed is reduced from 2% to 0.1%, and a good flavor improvement effect can be maintained, greatly reducing the dependence on pomelo peel raw materials and meeting the production requirements of large-scale commercialization.

[0021] 2. In the compound feed additive formula for improving egg flavor, pomelo peel extract is combined with various terpenes and esters (such as linalyl acetate and myrcene), and through synergistic effects, it masks the fishy smell of eggs (such as pyridine and trimethylamine), while promoting the formation of flavor substances such as aldehydes and ketones in cooked eggs. Low-threshold components (such as aromatics and aldehydes) directly dominate the flavor, and high-content aliphatic hydrocarbons act as carriers without interfering with the overall flavor. When preparing the pomelo flavor extract, β-cyclodextrin and arabic gum (mixed at a ratio of 1:1) are used as wall materials to protect volatile substances (such as limonene) in the concentrated solution from oxidation and degradation, extend the action time, and ensure the slow release and deposition of active ingredients in the intestinal tract of laying hens into the egg yolk. Zeolite powder adsorbs odor substances such as trimethylamine and hydrogen sulfide in the intestinal tract, and defatted rice bran provides a physically uniform dispersion carrier to reduce the loss of active ingredients. Moreover, since pomelo peel powder contains pectin and cellulose, it can synergistically form a multi-level "adsorption network" with zeolite powder and organic carriers (rich in cellulose) to further fix volatile components and reduce the loss of flavor substances: the activated zeolite powder, due to its porous structure with pore sizes of 0.4 - 1.2 nm, can strongly adsorb small-molecule terpenes such as linalool and limonene to achieve molecular-level locking; the gel network can wrap zeolite particles, and cellulose fibers can penetrate between zeolite particles to prevent zeolite agglomeration, fill its macropores (>2 nm) and gaps, and reduce aroma loss during processing and storage; while rice bran fibers cover the surface and adsorb non-polar molecules such as myrcene through hydrophobic interactions to form an outer slow-release layer. The polyphenols in pomelo peel can enhance the immunity of laying hens, reduce the spoilage of fatty acids caused by oxidative stress, and reduce the generation of odor substances (such as ammonia) in eggs. Zeolite powder can also adsorb harmful metabolites, improve the intestinal microecology, and indirectly enhance the egg flavor.

[0022] 3. An admixture plan of natural flavor extraction (pomelo flavor extract prepared based on pomelo peel powder) + chemical components (such as linalool, linalyl acetate, limonene, vanillyl alcohol, acetate flavor ester, myrcene, etc.) + natural pomelo peel powder (pomelo peel powder ground through an 80-mesh sieve) is adopted. Even when significantly reducing the dosage of pomelo peel powder (from 2% to about 0.1%), it can still better improve the flavor of eggs. Verified by experiments, the improvement of egg flavor is reflected in appearance (mainly the egg yolk and egg white: compared with the control group, the color of the egg yolk in all flavor-added groups is much brighter and more vivid, presenting a golden yellow color, which gives a sense of warmth and appetite visually, while the color of the cooked egg white is whiter than that of the control group, forming a contrast with the egg yolk and increasing the visual appeal), aroma (the control group has an obvious fishy smell unique to raw eggs, the fishy smell in all flavor-added groups is significantly reduced, and in some flavor-added groups, it is even slightly or not significantly fishy, and presents a pleasant fragrance, enhancing the layering of egg flavor), taste (compared with the control group, after the eggs in the flavor-added group are cooked, both the egg yolk and egg white have a better taste, the egg yolk feels smoother in the mouth, and the egg white has better elasticity), and flavor (compared with the control group, the eggs in the flavor-added group have a more sufficient fresh flavor overall).

[0023] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specific preferred embodiments are given for detailed description as follows. Detailed implementation manners

[0024] It should be noted that the test methods in the following embodiments are all conventional methods unless otherwise specified, and the test materials used in the following embodiments are all commercially available. The features and properties of the present invention will be further described in detail below in combination with the embodiments.

[0025] Embodiment 1

[0026] A compound feed additive for improving the flavor of eggs, comprising the following substances in parts by weight: 20 - 40 parts of linalool, 5 - 10 parts of linalyl acetate, 2 - 4 parts of limonene, 1 - 2 parts of vanillyl alcohol, 0.7 - 1.4 parts of acetate flavor ester, 5 - 10 parts of myrcene, 80 parts of pomelo peel powder, 150 parts of carrier, and 70 parts of pomelo flavor extract.

[0027] Among them, the pomelo flavor extract is obtained by performing headspace solid-phase microextraction, concentration, microencapsulation, carrier mixing, etc. on pomelo peel powder, and the specific preparation process will be introduced in detail later.

[0028] The carrier is 50 parts of organic carrier and 100 parts of functional carrier. The organic carrier is defatted rice bran, defatted wheat bran, or a combination of both (for example, only using defatted rice bran, or only using defatted wheat bran, or using an equal amount of defatted rice bran and defatted wheat bran), and the functional carrier is zeolite powder.

[0029] The preparation process of the compound feed additive for improving egg flavor is as follows:

[0030] S1: Select fresh pomelo peels, wash them, dry them at low temperature, crush them, and sieve them through an 80-mesh sieve to obtain pomelo peel powder.

[0031] Here, the obtained pomelo peel powder has two uses and needs to be allocated according to weight. One is 80 parts of pomelo peel powder required for compounding, and the other is 120 parts of pomelo peel powder required for preparing pomelo flavor extract.

[0032] S2: Take the pomelo peel powder to prepare pomelo flavor extract.

[0033] Here, 120 parts of pomelo peel powder need to be taken, and the following preparation process is used to prepare pomelo flavor extract:

[0034] S21: Perform headspace solid-phase microextraction on the pomelo peel powder to obtain pomelo flavor extraction solution.

[0035] Specifically, place the pomelo peel powder in a headspace vial, preheat it at 60°C for 10 minutes, insert a DVB / CAR / PDMS fiber head, and extract for 40 minutes. Here, 60°C can balance and activate volatile substances, avoiding the destruction of the terpene structure at too high a temperature. Other approximate parameters during the extraction process are also acceptable (for example, parameter settings with a 10% range of fluctuations), and it should not be regarded as a limitation to this application. Then, desorb at 250°C in the GC injection port for 5 minutes to collect volatile components.

[0036] S22: Concentrate the pomelo flavor extraction solution and recover the solvent to obtain pomelo flavor concentrated solution.

[0037] After obtaining the pomelo flavor extraction solution, transfer the extraction solution to a rotary evaporator, concentrate it under reduced pressure at 40°C to 1 / 10 of the original volume, recover the ethanol solvent, and concentrate it under reduced pressure at low temperature to prevent the oxidation of heat-sensitive substances (such as polyphenols and terpenoids).

[0038] It should be noted that the obtained pomelo flavor concentrated solution can be further compounded, but this embodiment does not perform compounding in this process, and it should not be regarded as a limitation.

[0039] S23: Perform microencapsulation treatment on the pomelo flavor concentrated solution to form microcapsules. Among them, the microcapsule wall material is selected as a 1:1 mixture of β-cyclodextrin and arabic gum.

[0040] Here, a 1:1 mixture of β-cyclodextrin and gum arabic is selected as the wall material. The limonene in the concentrated pomelo flavor can be included in the hydrophobic cavity of β-cyclodextrin to reduce volatilization loss. Specifically, the concentrated pomelo flavor is mixed with the wall material (a 1:1 mixture of β-cyclodextrin and gum arabic) at a mass ratio of 1:3, homogenized and emulsified at 50 °C for 30 minutes, and then spray-dried (inlet air temperature 160 °C, outlet air temperature 80 °C) to complete the microencapsulation process.

[0041] S24: After roasting and sterilizing the expanded corn flour with a particle size of 80 mesh, it is mixed with the microcapsules at a ratio of 9:1 to obtain a uniformly mixed pomelo flavor extract.

[0042] Select the expanded corn flour with a particle size of 80 mesh (80 - 100 mesh) as the carrier, roast it at 120 °C for 20 minutes for sterilization, cool it to room temperature, and then uniformly mix the microcapsules and the carrier at a ratio of 1:9 to obtain a uniformly mixed pomelo flavor extract. The mixing here can adopt a multi-stage mixing scheme. For example, the microcapsules and the carrier are put into a V-type mixer at a ratio of 1:3, and mixed at a low speed for 20 minutes (for example, 15 revolutions per minute), then the remaining part of the carrier is added for secondary mixing, and mixed at a low speed for 30 minutes (for example, 20 revolutions per minute) to ensure uniform mixing.

[0043] Thus, the preparation of the pomelo flavor extract can be completed. From 120 parts of pomelo peel powder, about 70 parts can be obtained. In actual experiments, due to the differences in the types of pomelo peels (such as Shatian pomelo, Wenzhou pomelo, grapefruit, honey pomelo, pomelo, etc., preferably grapefruit and pomelo, whose flavor component contents are relatively high) and the extraction efficiency of flavor components, this fluctuation will be relatively large (mainly caused by the types and qualities of seed peels). If formulated strictly according to the ingredients, the floating range can reach 45 - 120. However, by controlling the variety and quality of pomelo peels, the fluctuation range can be effectively reduced. In this example, the empirical value of the pomelo flavor extract from the pomelo peel powder of a certain variety (such as grapefruit) is taken as 70 parts, which should not be regarded as a limitation to this application. Of course, for subsequent large-scale production, strict quality control is required. For specific factors such as the type and quality of pomelo peel powder, and how much pomelo flavor extract can be produced, it will not cause a large fluctuation in the preparation quality of the compound feed additive for improving the egg flavor. If less pomelo flavor extract is obtained per unit mass of pomelo peel powder, more pomelo peel powder can be consumed.

[0044] S3: Linalool, linalyl acetate, limonene, vanillyl alcohol, acetate flavor ester, and myrcene are mixed in proportion to obtain a flavor component mixture.

[0045] Acetic acid flavor esters and myrcene are generally stored refrigerated in the dark (4°C). Before use, they need to be rewarmed to 25°C to reduce viscosity and ensure the uniformity of spray mixing. Then, linalool (20 - 40 parts), linalyl acetate (5 - 10 parts), limonene (2 - 4 parts), vanillyl alcohol (1 - 2 parts), acetic acid flavor esters (0.7 - 1.4 parts), and myrcene (5 - 10 parts) are mixed in proportion to obtain a flavor component mixture. Of course, a small amount of natural antioxidants (such as vitamin E or rosemary extract) can also be added, with a proportion not exceeding 0.015%.

[0046] S4: Spray the flavor component mixture in an atomized form onto the activated zeolite powder.

[0047] Zeolite powder (sieved through 200 mesh) needs to be activated before use. It is calcined at 400°C for 2 hours (the activation treatment can open the pores of the zeolite powder and improve the adsorption capacity), and then stored in a sealed manner after cooling. When in use, the flavor component mixture can be sprayed in an atomized form onto the activated zeolite powder (75 - 100 parts). For balanced absorption, sealed aging (12 - 24 hours) can also be carried out.

[0048] S5: Add the zeolite powder adsorbed with flavor components, pomelo peel powder, and defatted rice bran to a double-cone mixer, protect with nitrogen, and mix at low speed for 30 minutes.

[0049] Specifically, add the zeolite powder adsorbed with flavor components, pomelo peel powder, and defatted rice bran to a double-cone mixer, protect with nitrogen, and mix at a low speed (such as 20 revolutions per minute) for 30 minutes.

[0050] S6: Add the prepared pomelo flavor extract into the double-cone mixer, and continue to mix at low speed for 30 minutes to obtain the prepared compound feed additive for improving egg flavor.

[0051] Add the prepared pomelo flavor extract (taking 70 parts as an example) into the double-cone mixer, continue to mix at a low speed (20 revolutions per minute) for 30 minutes, and then sieve (such as through a 20-mesh sieve) to remove lumps, and the compound feed additive for improving egg flavor can be obtained.

[0052] After obtaining the compound feed additive for improving egg flavor, it can be applied to the preparation of chicken feed. Add the compound feed additive for improving egg flavor prepared in this example to the basic feed, and the addition ratio can be 0.1% - 0.3%.

[0053] Generally speaking, consuming about 200 parts of pomelo peel powder can produce 330 - 360 parts of the compound feed additive for improving egg flavor. If added to the basic feed at an addition ratio of 0.1%, the comprehensive consumption of pomelo peel powder is less than 0.1%. If added at a ratio of 0.3%, the comprehensive consumption of pomelo peel powder does not exceed 0.2% either.

[0054] Example 2

[0055] A compound feed additive for improving the flavor of eggs, comprising the following substances in parts by weight: 20 parts of linalool, 5 parts of linalyl acetate, 2 parts of limonene, 1 part of vanillyl alcohol, 0.7 part of acetic acid flavor ester, 5 parts of myrcene, 80 parts of pomelo peel powder, 150 parts of carrier (50 parts of organic carrier, selected from defatted rice bran, defatted wheat bran or a combination of the two, and the differences among the three types of organic carriers in this solution are not significant; 100 parts of functional carrier, selected from zeolite powder), and 70 parts of pomelo flavor extract. The compound feed additive for improving the flavor of eggs prepared according to this formula ratio is denoted as compound feed additive A; compound feed additive A is added to the basal feed at the addition ratios of 0.1%, 0.2%, and 0.3% respectively to obtain compound feeds 1, 2, and 3.

[0056] Example 3

[0057] A compound feed additive for improving the flavor of eggs, comprising the following substances in parts by weight: 30 parts of linalool, 7.5 parts of linalyl acetate, 3 parts of limonene, 1.5 parts of vanillyl alcohol, 1 part of acetic acid flavor ester, 7.5 parts of myrcene, 80 parts of pomelo peel powder, 150 parts of carrier (50 parts of organic carrier, selected from defatted rice bran, defatted wheat bran or a combination of the two, and the differences among the three types of organic carriers in this solution are not significant; 100 parts of functional carrier, selected from zeolite powder), and 70 parts of pomelo flavor extract. The compound feed additive for improving the flavor of eggs prepared according to this formula ratio is denoted as compound feed additive B; compound feed additive B is added to the basal feed at the addition ratios of 0.1%, 0.2%, and 0.3% respectively to obtain compound feeds 4, 5, and 6.

[0058] Example 4

[0059] A compound feed additive for improving the flavor of eggs, comprising the following substances in parts by weight: 40 parts of linalool, 10 parts of linalyl acetate, 4 parts of limonene, 2 parts of vanillyl alcohol, 1.4 parts of acetic acid flavor ester, 10 parts of myrcene, 80 parts of pomelo peel powder, 150 parts of carrier (50 parts of organic carrier, selected from defatted rice bran, defatted wheat bran or a combination of the two, and the differences among the three types of organic carriers in this solution are not significant; 100 parts of functional carrier, selected from zeolite powder), and 70 parts of pomelo flavor extract. The compound feed additive for improving the flavor of eggs prepared according to this formula ratio is denoted as compound feed additive C; compound feed additive C is added to the basal feed at the addition ratios of 0.1%, 0.2%, and 0.3% respectively to obtain compound feeds 7, 8, and 9.

[0060] Based on the introduction of the above embodiments, an experiment was designed in this solution:

[0061] Laying hen breeds: Select laying hens of the same batch with similar health status, 30 hens in each group, a total of 11 groups, namely: Experimental group 1 (control group, fed with basal diet during the experimental period), Experimental group 2 (fed with compound feed supplemented with 2% pomelo peel powder during the experimental period), Experimental group 3 (fed with compound feed 1 during the experimental period), Experimental group 4 (fed with compound feed 2 during the experimental period), Experimental group 5 (fed with compound feed 3 during the experimental period), Experimental group 6 (fed with compound feed 4 during the experimental period), Experimental group 7 (fed with compound feed 5 during the experimental period), Experimental group 8 (fed with compound feed 6 during the experimental period), Experimental group 9 (fed with compound feed 7 during the experimental period), Experimental group 10 (fed with compound feed 8 during the experimental period), Experimental group 11 (fed with compound feed 9 during the experimental period).

[0062] Feeding environment: Standardized chicken house, temperature (20 - 25 °C), humidity (50 - 70%), light cycle (16 hours of light / 8 hours of darkness).

[0063] Adaptation period: Pre-feed with basal diet for 2 weeks to eliminate the influence of previous feed. Experimental period: Each group was fed with the corresponding feed for 6 weeks, and the feed intake, egg production rate, and egg weight were recorded daily.

[0064] Experimental period: Each group was fed with the corresponding feed for 6 weeks, and the feed intake, egg production rate, and egg weight were recorded daily. The average data during the experimental period are shown in Table 1 below: Table 1. Mean and standard deviation of experimental period data

[0065] It can be seen that in Experimental group 2 (supplemented with 2% pomelo peel powder), the feed intake of laying hens decreased due to high fiber, but the feed intake of the compound feed groups (including Experimental groups 3 - 11) was generally close to or slightly higher than that of the control group. The egg production rates of the compound feed groups (including Experimental groups 3 - 11) were slightly higher than that of the control group, which may be related to the antioxidant properties of high - active ingredients (linalool, limonene) and the improvement of intestinal health. The egg weights of Experimental group 2 and the compound feed groups (including Experimental groups 3 - 11) were slightly higher than that of the control group. Moreover, the feed intake, egg production rate, and egg weight of Experimental groups 4, 7, and 10 (i.e., compound feed with 0.2% addition) were slightly better than those of Experimental group 2 (i.e., supplemented with 2% pomelo peel powder).

[0066] In addition, to verify the improvement in egg flavor, egg samples were collected once each in the 3rd week and the 6th week of the experimental period. Each time, 20 eggs were randomly selected from each group. The reviewers evaluated raw eggs and hard-boiled eggs (boiled in boiling water for 10 minutes) respectively. The evaluation dimensions included four major dimensions: appearance, aroma, taste, and flavor. The appearance included four sub-indicators: transparency of raw egg white (scored from 1 to 5, 1 = turbid, 5 = clear), color of raw egg yolk (Roche score, 1 - 15 points), whiteness of cooked egg white (scored from 1 to 5, 5 = pure white), and color of cooked egg yolk (Roche score, 1 - 15 points); the aroma included two sub-indicators: raw egg fishiness (1 = no egg fishiness, 5 = obvious egg fishiness) and cooked egg fragrance (scored from 1 to 5, 1 = almost no egg fragrance, 5 = obvious egg fragrance); the taste included two sub-indicators: elasticity of cooked egg white (scored from 1 to 5, 1 = almost no elasticity, 5 = full elasticity) and smoothness of cooked egg yolk (scored from 1 to 5, 1 = rough, 5 = smooth); the flavor was measured by the freshness of cooked eggs (scored from 1 to 5, 1 = not fresh, 5 = fresh). The evaluation data are shown in Table 2 below:

[0067] In addition, to verify the improvement in egg flavor, egg samples were collected once each in the 3rd week and the 6th week of the experimental period. Each time, 20 eggs were randomly selected from each group. The reviewers evaluated raw eggs and hard-boiled eggs (boiled in boiling water for 10 minutes) respectively. The evaluation dimensions included four major dimensions: appearance, aroma, taste, and flavor. The appearance included four sub-indicators: transparency of raw egg white (scored from 1 to 5, 1 = turbid, 5 = clear), color of raw egg yolk (Roche score, 1 - 15 points), whiteness of cooked egg white (scored from 1 to 5, 5 = pure white), and color of cooked egg yolk (Roche score, 1 - 15 points); the aroma included two sub-indicators: raw egg fishiness (1 = no egg fishiness, 5 = obvious egg fishiness) and cooked egg fragrance (scored from 1 to 5, 1 = almost no egg fragrance, 5 = obvious egg fragrance); the taste included two sub-indicators: elasticity of cooked egg white (scored from 1 to 5, 1 = almost no elasticity, 5 = full elasticity) and smoothness of cooked egg yolk (scored from 1 to 5, 1 = rough, 5 = smooth); the flavor was measured by the freshness of cooked eggs (scored from 1 to 5, 1 = not fresh, 5 = fresh). The evaluation data are shown in Table 2 below: and cooked egg fragrance (scored from 1 to 5, 1 = almost no egg fragrance, 5 = obvious egg fragrance) two sub-indicators; the taste included elasticity of cooked egg white (scored from 1 to 5, 1 = almost no elasticity, 5 = full elasticity), smoothness of cooked egg yolk (scored from 1 to 5, 1 = rough, 5 = smooth) two sub-indicators; the flavor was measured by the freshness of cooked eggs (scored from 1 to 5, 1 = not fresh, 5 = fresh). The evaluation data are shown in Table 2 below: Table 2. Mean values of sample evaluation data in the 3rd week and the 6th week

[0068] From the above evaluation results, it can be seen that the improvement of egg flavor is manifested in appearance (mainly the egg yolk and egg white: compared with the control group, the color of the egg yolk in all flavor-added groups (i.e., experimental groups 2-11) is much brighter and more vivid, showing a golden yellow color, which gives people a sense of warmth and appetite visually, and the color of the cooked egg white is whiter than that of the control group, forming a contrast with the egg yolk and increasing the visual appeal), aroma (the control group has an obvious raw-egg-specific fishy smell, and the fishy smell in all flavor-added groups (i.e., experimental groups 2-11) is significantly reduced, and in some flavor-added groups, it is even slightly or not significantly fishy, and a pleasant fragrance is presented, enhancing the layering of the egg flavor), taste (compared with the control group, after the eggs in the flavor-added groups are cooked, both the egg yolk and egg white have better taste. The egg yolk feels smoother in the mouth, and the egg white has better elasticity), and flavor (compared with the control group, the eggs in the flavor-added groups have a more sufficient fresh flavor overall).

[0069] Generally speaking, the 0.2% addition amount of the compound feed additive (corresponding to experimental groups 4, 7, and 10) has better overall flavor improvement effect. And the overall performance of compound feed additive B (corresponding to experimental groups 6, 7, and 8) comprehensively exceeds that of compound feed additive A (corresponding to experimental groups 3, 4, and 5), and is almost not inferior to compound feed additive C (corresponding to experimental groups 9, 10, and 11). Moreover, the overall dosage of pomelo peel powder is directly reduced from the original 2% addition amount to about 0.1%, and it can maintain a good flavor improvement effect, greatly reducing the dependence on pomelo peel raw materials and meeting the production requirements of large-scale commercialization.

[0070] In summary, the embodiments of the present application provide a compound feed additive, a preparation process, and a compound feed for improving egg flavor. By analyzing the main components in pomelo peel, the main components affecting egg flavor are screened out, and a compound feed additive for improving egg flavor is prepared by compounding chemical components with pomelo peel powder and a pomelo flavor extract prepared based on pomelo peel powder (the effective components in concentrated pomelo peel such as limonene and polyphenols are prepared by mixing after microencapsulation and expanded corn flour). The total addition amount of pomelo peel powder in the basic feed is reduced from 2% to 0.1%, and it can maintain a good flavor improvement effect, greatly reducing the dependence on pomelo peel raw materials and meeting the production requirements of large-scale commercialization.

[0071] In the compound feed additive formula for improving egg flavor, pomelo peel extract is combined with various terpenes and esters (such as linalyl acetate and myrcene), and through synergistic effects, it masks the fishy smell of eggs (such as pyridine and trimethylamine), while promoting the formation of flavor substances such as aldehydes and ketones in cooked eggs. Low-threshold components (such as aromatics and aldehydes) directly dominate the flavor, and high-content aliphatic hydrocarbons act as carriers without interfering with the overall flavor. When preparing the pomelo flavor extract, β-cyclodextrin and arabic gum (mixed at a ratio of 1:1) are used as wall materials to protect volatile substances (such as limonene) in the concentrated solution from oxidation and degradation, extend the action time, and ensure the slow release and deposition of active ingredients in the intestinal tract of laying hens into the egg yolk. Zeolite powder adsorbs odor substances such as trimethylamine and hydrogen sulfide in the intestinal tract, and defatted rice bran provides a physically uniform dispersion carrier to reduce the loss of active ingredients. Moreover, since pomelo peel powder contains pectin and cellulose, it can synergistically form a multi-level "adsorption network" with zeolite powder and organic carriers (rich in cellulose) to further fix volatile components and reduce the loss of flavor substances: the activated zeolite powder, due to its porous structure with pore sizes of 0.4 - 1.2 nm, can strongly adsorb small molecule terpenes such as linalool and limonene to achieve molecular-level locking; the gel network can wrap the zeolite particles, and cellulose fibers can penetrate between the zeolite particles to prevent zeolite aggregation, fill its macropores (>2 nm) and gaps, and reduce the aroma loss during processing and storage; while rice bran fibers cover the surface and adsorb non-polar molecules such as myrcene through hydrophobic interactions to form an outer slow-release layer. The polyphenols in pomelo peel can enhance the immunity of laying hens, reduce the fatty acid spoilage caused by oxidative stress, and reduce the generation of odor substances (such as ammonia) in eggs. Zeolite powder can also adsorb harmful metabolites, improve the intestinal microecology, and indirectly enhance the egg flavor.

[0072] Adopt a compounding scheme of natural flavor extraction (pomelo flavor extract prepared based on pomelo peel powder) + chemical components (such as linalool, linalyl acetate, limonene, vanillyl alcohol, acetate fragrance ester, myrcene, etc.) + natural pomelo peel powder (pomelo peel powder crushed and sieved through 80 mesh). Even when significantly reducing the dosage of pomelo peel powder (from 2% to about 0.1%), it can also better improve the flavor of eggs. Verified by experiments, the improvement of egg flavor is reflected in appearance (mainly the egg yolk and egg white: compared with the control group, the color of the egg yolk in all flavored groups is much brighter and more vivid, showing a golden yellow color, which gives a sense of warmth and appetite visually, and the color of the cooked egg white is whiter than that of the control group, forming a contrast with the egg yolk and increasing the visual appeal), aroma (the control group has an obvious fishy smell unique to raw eggs, the fishy smell in all flavored groups is significantly reduced, and in some flavored groups, it is even slightly to almost non-existent, and a pleasant fragrance is presented, enhancing the layering of egg flavor), taste (compared with the control group, after the eggs in the flavored group are cooked, both the egg yolk and egg white have a better taste, the egg yolk feels more delicate in the mouth, and the egg white has better elasticity), and flavor (compared with the control group, the eggs in the flavored group have a more sufficient and delicious flavor overall).

[0073] The above are only examples of this application and are not used to limit the protection scope of this application. For those skilled in the art, various changes and modifications can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A compound feed additive for improving the flavor of eggs, characterized in that: The compound feed additive includes the following substances in parts by weight: 20-40 parts of linalool, 5-10 parts of linalyl acetate, 2-4 parts of limonene, 1-2 parts of vanillyl alcohol, 0.7-1.4 parts of acetic acid ester, 5-10 parts of myrcene, 80 parts of grapefruit peel powder, 150 parts of carrier, and 70 parts of grapefruit flavor extract.

2. The compound feed additive for improving egg flavor according to claim 1, characterized in that: The carrier comprises 50 parts of an organic carrier and 100 parts of a functional carrier, wherein the organic carrier is defatted rice bran, defatted bran or a combination of the two, and the functional carrier is zeolite powder.

3. The compound feed additive for improving egg flavor according to claim 1, characterized in that: The composition includes 20 parts of linalool, 5 parts of linalyl acetate, 2 parts of limonene, 1 part of vanillyl alcohol, 0.7 parts of acetic acid ester, 5 parts of myrcene, 80 parts of grapefruit peel powder, 150 parts of carrier, and 70 parts of grapefruit flavor extract.

4. The compound feed additive for improving egg flavor according to claim 1, characterized in that: 40 parts of linalool, 10 parts of linalyl acetate, 4 parts of limonene, 2 parts of vanillyl alcohol, 1.4 parts of acetic acid fragrance ester, 10 parts of myrcene, 80 parts of grapefruit peel powder, 150 parts of carrier, and 70 parts of grapefruit flavor extract.

5. The compound feed additive for improving egg flavor according to claim 1, characterized in that: 30 parts of linalool, 7.5 parts of linalyl acetate, 3 parts of limonene, 1.5 parts of vanillyl alcohol, 1 part of acetic acid ester, 7.5 parts of myrcene, 80 parts of grapefruit peel powder, 150 parts of carrier, and 70 parts of grapefruit flavor extract.

6. The compound feed additive for improving egg flavor according to any one of claims 1 to 5, characterized in that: The grapefruit flavor extract is obtained by subjecting grapefruit peel powder to headspace solid phase microextraction, followed by microencapsulation and carrier mixing.

7. A process for preparing a compound feed additive for improving egg flavor as claimed in any one of claims 1 to 6, characterized in that: include: S1: fresh grapefruit peel is selected, washed, dried at low temperature, crushed, and passed through an 80-mesh sieve to obtain grapefruit peel powder; S2: preparing grapefruit flavor extract by taking grapefruit peel powder; S3: mixing linalool, linalyl acetate, limonene, vanillyl alcohol, aromatic acetate, and myrcene in proportion to obtain a flavor component mixture; S4: spraying the flavor component mixture into the activated zeolite powder in an atomized form; S5: adding the zeolite powder after the flavor components are absorbed, the grapefruit peel powder and the defatted rice bran into a double cone mixer, filling with nitrogen for protection, and mixing at a low speed for 30 minutes; S6: adding the prepared grapefruit flavor extract into the double cone mixer, and continuing to mix at a low speed for 30 minutes to obtain the prepared compound feed additive for improving egg flavor.

8. The preparation process of the compound feed additive for improving egg flavor according to claim 7, characterized in that: The grapefruit flavor extract is prepared as follows: S21: performing headspace solid phase microextraction on grapefruit peel powder to obtain a grapefruit flavor extract; S22: concentrating the grapefruit flavor extract and recovering the solvent to obtain a grapefruit flavor concentrate; S23: performing microencapsulation treatment on the grapefruit flavor concentrate to form microcapsules, wherein the microcapsule wall material is a mixture of β-cyclodextrin and gum arabic in a ratio of 1:1; S24: Select puffed corn flour with a particle size of 80 mesh, bake and sterilize it, and then mix it with microcapsules in a ratio of 9:1 to obtain a uniformly mixed grapefruit flavor extract.

9. A compound feed for improving the flavor of eggs, characterized in that: The compound feed additive is prepared by adding the compound feed additive for improving egg flavor according to claim 7 to the basic feed.

10. The compound feed for improving egg flavor according to claim 9, characterized in that: The addition ratio of compound feed additives is 0.1%-0.3%.

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