Egg yolk shortening with zero trans-fatty acid and preparation method thereof

Abstract

The invention discloses zero trans-fatty acid egg yolk shortening and a preparation method thereof, and belongs to the technical field of food processing. The zero trans-fatty acid yolk shortening is prepared through the steps of enzyme hydrolysis, dry fractionation of yolk oil and recombination of the yolk oil. The egg yolk shortening retains nutritional ingredients such as lipid in egg yolk and is rich in nutritional value, generation of trans-fatty acid in a traditional hydrogenation process is avoided in the preparation process, the requirements of modern healthy diet are met, meanwhile, the egg yolk shortening is quite excellent in plasticity and shortening property, the optimal expansion rate can reach 6.0 or above, and the egg yolk shortening is suitable for being used as a food-grade food-grade food-grade food-grade food-grade food-grade food-grade food-grade food-grade food-grade food-grade food-grade food-grade food. The method is suitable for production of various baked foods.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to zero trans fatty acid egg yolk shortening and a preparation method thereof. Background Art

[0002] Traditional shortening is mainly derived from vegetable oil or animal fat, and is obtained through processes such as hydrogenation or transesterification. However, trans fatty acids may be produced during the hydrogenation process, posing a potential threat to human health. In addition, traditional shortening is relatively simple in flavor and nutritional value. Egg yolk, as an important raw material in the food industry, is rich in nutrients such as lecithin, cholesterol and various unsaturated fatty acids, but there are technical difficulties in using it directly in the preparation of shortening.

[0003] In order to overcome these problems, patent CN114403240B discloses a method for preparing a novel rice bran protein-based shortening substitute, using rice bran protein as a raw material to prepare an edible rice bran protein-based multi-structured oil gel, which contains significantly lower trans fatty acids and saturated fatty acids than commercially available shortening, and contains healthy rice bran protein. Patent CN111357836B discloses a method for preparing a non-palm shortening oil composition, which is prepared by a heating and cooling process to improve the softness and texture stability of baked goods and enhance the flavor. However, there is no technology in the prior art to use egg yolk oil to prepare shortening. Summary of the invention

[0004] Technical issues

[0005] Traditional shortening may contain trans fatty acids, which pose a potential threat to human health. It is necessary to provide a method for preparing zero trans fatty acid shortening.

[0006] Technical content

[0007] The invention provides an egg yolk shortening with zero trans fatty acid. The egg yolk shortening consists of solid egg yolk oil and liquid egg yolk oil.

[0008] Furthermore, the mass ratio of the solid egg yolk oil to the liquid egg yolk oil is 2-6:8-4.

[0009] Preferably, the mass ratio of the solid egg yolk oil to the liquid egg yolk oil is 2-4:8-6.

[0010] Most preferably, the mass ratio of the solid egg yolk oil to the liquid egg yolk oil is 4:6.

[0011] Furthermore, the solid egg yolk oil and the liquid egg yolk oil are prepared by enzymatically hydrolyzing the egg yolk oil and then separating the solid and liquid oils.

[0012] Furthermore, the preparation method of the solid egg yolk oil and the liquid egg yolk oil is specifically as follows:

[0013] The egg yolk oil is mixed with phospholipase, hydrolyzed at 45-55°C and pH 6.5-7.5 for 2-6 hours, and then the enzymatically hydrolyzed egg yolk oil is heated at 70-90°C for 10-50 minutes, and then cooled to 55-65°C, and then cooled to the crystallization temperature of 20-25°C at a cooling rate of 1-5°C / h and grown until the amount of solid no longer increases, and then centrifuged for solid-liquid separation to obtain solid and liquid egg yolk oil, respectively.

[0014] Furthermore, the added amount of the phospholipase is 0.5-2% of the mass of the egg yolk oil.

[0015] Furthermore, the phospholipase is an enzyme that can catalyze the hydrolysis of phospholipids.

[0016] Furthermore, the phospholipase is phospholipase A2 and / or phospholipase A1.

[0017] Furthermore, the enzyme activity of the phospholipase is 5000-15000 U / mL.

[0018] Preferably, the enzyme activity of the phospholipase is 8000-12000 U / mL.

[0019] Furthermore, the egg yolk oil is egg yolk oil obtained by supercritical CO2 extraction.

[0020] Further, the preparation method of egg yolk oil is specifically as follows:

[0021] Add egg yolk powder to the extraction kettle of a supercritical CO2 extractor, then adjust the CO2 flow rate to 16-28 L / h, the extraction temperature to 35-55°C, and the extraction pressure to 25-45 MPa to perform supercritical extraction on the egg yolk powder, collect the extracted egg yolk lipids, and obtain egg yolk oil.

[0022] Furthermore, the egg yolk powder has a protein concentration of 20 to 60 wt % and a fat content of 40 to 80 wt %.

[0023] Application of the zero trans fatty acid egg yolk shortening provided by the present invention in the food field.

[0024] The present invention also provides a method for preparing egg yolk shortening with zero trans fatty acid, comprising the following steps:

[0025] (1) Enzymatic hydrolysis process: egg yolk oil is mixed with phospholipase for enzymatic hydrolysis to obtain enzymatically hydrolyzed egg yolk oil;

[0026] (2) Dry fractionation of egg yolk oil: heating the egg yolk oil after enzymatic hydrolysis in step (1) to 70-90° C., then cooling to 55-65° C.; then slowly cooling to a crystallization temperature of 20-25° C. at a certain cooling rate, and growing the crystals until the solid no longer increases, then centrifuging for solid-liquid separation to obtain solid egg yolk oil and liquid egg yolk oil, respectively;

[0027] (3) Egg yolk shortening reconstitution: the solid egg yolk shortening and the liquid egg yolk shortening obtained in step (2) are mixed in a certain proportion, and then heated, melted and stirred to obtain zero trans fatty acid egg yolk shortening.

[0028] In one embodiment of the present invention, the egg yolk oil in step (1) is egg yolk oil obtained by supercritical CO2 extraction.

[0029] In one embodiment of the present invention, the method for preparing egg yolk oil is specifically as follows: egg yolk powder is added to the extraction kettle of a supercritical CO2 extractor, and then the CO2 flow rate is adjusted to 16-28L / h, the extraction temperature is adjusted to 35-55°C, and the extraction pressure is adjusted to 25-45MPa to perform supercritical extraction on the egg yolk powder, and the extracted egg yolk lipids are collected to obtain egg yolk oil.

[0030] In one embodiment of the present invention, the egg yolk powder has a protein concentration of 20 to 60 wt % and a fat content of 40 to 80 wt %.

[0031] In one embodiment of the present invention, the phospholipase in step (1) is an enzyme capable of catalyzing the hydrolysis of phospholipids.

[0032] In one embodiment of the present invention, the phospholipase in step (1) is phospholipase A2 and / or phospholipase A1.

[0033] In one embodiment of the present invention, the enzyme activity of the phospholipase is 5000-15000 U / mL.

[0034] Preferably, the enzyme activity of the phospholipase is 8000-12000 U / mL.

[0035] In one embodiment of the present invention, the amount of phospholipase added in step (1) is 0.5-2% of the mass of egg yolk oil.

[0036] In one embodiment of the present invention, the enzymatic hydrolysis in step (1) is carried out at 45-55° C. and pH 6.5-7.5 for 2-6 hours.

[0037] In one embodiment of the present invention, the cooling rate in step (2) is 1-5°C / h.

[0038] In one embodiment of the present invention, the centrifugal speed in step (2) is 4000-6000 rpm, and the centrifugal time is 5-15 min.

[0039] In one embodiment of the present invention, the mixing mass ratio of the solid egg yolk oil and the liquid egg yolk oil in step (3) is 2-6:8-4.

[0040] Preferably, the mass ratio of the solid egg yolk oil to the liquid egg yolk oil is 2-4:8-6.

[0041] Most preferably, the mass ratio of the solid egg yolk oil to the liquid egg yolk oil is 4:6.

[0042] In one embodiment of the present invention, the heating temperature in step (3) is 80-90° C. and the heating time is 10-20 min.

[0043] Beneficial effects of the present invention:

[0044] (1) Improving nutritional value: The present invention utilizes natural lipid resources in egg yolk to prepare shortening, thereby retaining nutritional components such as lipids in egg yolk and improving the nutritional value of shortening. In addition, the egg yolk shortening of the present invention also avoids the generation of trans fatty acids in the traditional hydrogenation process, which meets the needs of modern healthy diet.

[0045] (2) Improved baking performance: By optimizing the hydrolysis and esterification reaction conditions, the prepared egg yolk shortening has excellent plasticity and shortening properties, and the optimal expansion rate can reach above 6.0, which is suitable for the production of various baked foods.

[0046] (3) Enriching the dimension of resource utilization: The present invention innovatively makes egg yolk oil into shortening, which expands the application scope of egg yolk oil and enriches the utilization scope of egg yolk resources; and the method of the present invention is simple in process, easy to operate, and the obtained product has high nutritional value and good baking performance, has a very good market promotion prospect, and can benefit the egg yolk and egg yolk oil processing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is the expansion rate of the baked product obtained in the products obtained in each embodiment and each comparative example.

[0048] Figure 2 It is a macroscopic picture of the baked products prepared in the products obtained in Example 3 and each comparative example. DETAILED DESCRIPTION

[0049] The technical solutions described in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Source of raw materials

[0051] The phospholipase A2 used in the present invention was purchased from Changse (China) Co., Ltd., and the lipase (porcine pancreas) was purchased from Sinopharm Wokai, and the activities of both enzymes were 10000 U / mL.

[0052] The egg yolk oil is obtained from common egg yolk powder through supercritical CO2 extraction, specifically, 100.0g of egg yolk powder is added into an extraction kettle of supercritical equipment, and then the CO2 flow rate (16-28L / h), extraction temperature (35-55°C) and extraction pressure (25-45MPa) are selected to extract the egg yolk powder, and the extracted egg yolk lipids are collected once every 30 minutes, and the collection is carried out five times in total to obtain the egg yolk oil; the egg yolk powder is prepared by spray drying fresh egg yolk, wherein the protein concentration is 32wt% and the fat content is 65wt% as detected.

[0053] Test Method

[0054] 1. Determination of fatty acid content of egg yolk oil:

[0055] GB5009.168-2016 was used to determine the fatty acid content of egg yolk shortening.

[0056] 1. Saponification of fats and methyl esterification of fatty acids

[0057] Add 8 mL of 2% sodium hydroxide methanol solution to the fat extract, connect a reflux condenser, and reflux in a water bath at 80°C ± 1°C until the oil droplets disappear. Add 7 mL of 15% boron trifluoride methanol solution from the top of the reflux condenser, and continue to reflux in a water bath at 80°C ± 1°C for 2 minutes. Rinse the reflux condenser with a small amount of water. Stop heating, remove the flask from the water bath, and quickly cool to room temperature. Accurately add 10 mL to 30 mL of n-heptane, shake for 2 minutes, then add saturated sodium chloride aqueous solution, and let stand to separate. Pipette about 5 mL of the upper n-heptane extraction solution into a 25 mL test tube, add about 3 g to 5 g of anhydrous sodium sulfate, shake for 1 minute, let stand for 5 minutes, and pipette the upper solution into the injection bottle for determination.

[0058] 2. Gas chromatography conditions for fatty acid determination

[0059] Chromatographic column DB-WAX (30m×0.32mm, Agilent, USA); injection port temperature 230℃; hydrogen flame ionization detector FID temperature 240℃; carrier gas N2, flow rate 2mL / min, hydrogen flow rate 35mL / min, air flow rate 400mL / min. Split injection was used with a split ratio of 15:1; heating program: initial temperature 120℃, hold for 3min, heat to 190℃ at 5℃ / min, then heat to 210℃ at 1℃ / min, hold for 3min. The injection volume was 2μL. The fatty acid methyl esters were qualitatively analyzed according to the retention time, and the peak area normalization method was used for quantification.

[0060] 2. Determination of shortening ability

[0061] 1. Preparation of puff pastry

[0062] (1) Mix 250g of all-purpose flour, 40g of shortening and 125g of water and knead into dough. After kneading the dough into a smooth surface, wrap it with plastic wrap and place it in the refrigerator to relax for 1 hour before use.

[0063] (2) Press 180 g of shortening into a square sheet with a thickness of 13 mm (for wrapping).

[0064] (3) Wrap the shortening flakes inside the dough using the quilt-folding method. Perform three rounds of four-folding. Wrap each round with plastic wrap and place in the refrigerator to relax for about 15 minutes.

[0065] (4) Press the dough sheet that has been folded three times into a rectangle with a thickness of 5 mm.

[0066] (5) Cut into small rectangles of 0.4 cm × 0.4 cm and spread them neatly on a baking tray. The upper and lower oven temperatures are 170°C and 170°C, respectively, and the baking time is about 20 minutes.

[0067] 2. Determination of puff pastry expansion rate

[0068] The height of the puff pastry and the height of the dough before baking can be measured with a vernier caliper to calculate the expansion rate of the puff pastry: expansion rate = puff pastry height (mm) / height before baking (mm).

[0069] Example 1

[0070] (1) Enzymatic hydrolysis process: The egg yolk oil was mixed with phospholipase A2 (added at 1% of the egg yolk oil mass) and hydrolyzed at 50°C and pH 7.0 for 4 h to increase the fat release rate.

[0071] (2) Dry fractionation of egg yolk oil: Heat the enzymatically hydrolyzed egg yolk oil at 80°C for 30 min to completely melt the egg yolk oil, and then quickly cool it to 60°C; then slowly cool it at 2°C / h to the crystallization temperature of 25°C; grow the crystals at this temperature for a period of time, and use low-speed centrifugation at 5000 rpm for 10 min to separate the solid and liquid oils, respectively.

[0072] (3) Egg yolk shortening reconstitution: solid and liquid egg yolk shortening are mixed in a ratio of 0% and 100%, heated to melt and stirred, and then placed in a refrigerator at 4°C overnight to form reconstituted egg yolk shortening.

[0073] Example 2

[0074] (1) Enzymatic hydrolysis process: The egg yolk oil was mixed with phospholipase A2 (added at 1% of the egg yolk oil mass) and hydrolyzed at 50°C and pH 7.0 for 4 h to increase the fat release rate.

[0075] (2) Dry fractionation of egg yolk oil: Heat the enzymatically hydrolyzed egg yolk oil at 80°C for 30 min to completely melt the egg yolk oil, and then quickly cool it to 60°C; then slowly cool it at 2°C / h to the crystallization temperature of 25°C; grow the crystals at this temperature for a period of time, and use low-speed centrifugation at 5000 rpm for 10 min to separate the solid and liquid oils, respectively.

[0076] (3) Egg yolk shortening reconstitution: The separated solid and liquid egg yolk shortenings are mixed in a ratio of 20% and 80%, heated to melt and stirred, and then placed in a refrigerator at 4°C overnight to form reconstituted egg yolk shortening.

[0077] Example 3

[0078] (1) Enzymatic hydrolysis process: The egg yolk oil was mixed with phospholipase A2 (added at 1% of the egg yolk oil mass) and hydrolyzed at 50°C and pH 7.0 for 4 h to increase the fat release rate.

[0079] (2) Dry fractionation of egg yolk oil: Heat the enzymatically hydrolyzed egg yolk oil at 80°C for 30 min to completely melt the egg yolk oil, and then quickly cool it to 60°C; then slowly cool it at 2°C / h to the crystallization temperature of 25°C; grow the crystals at this temperature for a period of time, and use low-speed centrifugation at 5000 rpm for 10 min to separate the solid and liquid oils, respectively.

[0080] (3) Egg yolk shortening reconstitution: The separated solid and liquid egg yolk shortenings are mixed in a ratio of 40% and 60%, heated to melt and stirred, and then placed in a refrigerator at 4°C overnight to form reconstituted egg yolk shortening.

[0081] Example 4

[0082] (1) Enzymatic hydrolysis process: The egg yolk oil was mixed with phospholipase A2 (added at 1% of the egg yolk oil mass) and hydrolyzed at 50°C and pH 7.0 for 4 h to increase the fat release rate.

[0083] (2) Dry fractionation of egg yolk oil: Heat the enzymatically hydrolyzed egg yolk oil at 80°C for 30 min to completely melt the egg yolk oil, and then quickly cool it to 60°C; then slowly cool it at 2°C / h to the crystallization temperature of 25°C; grow the crystals at this temperature for a period of time, and use low-speed centrifugation at 5000 rpm for 10 min to separate the solid and liquid oils, respectively.

[0084] (3) Egg yolk shortening reconstitution: The separated solid and liquid egg yolk shortenings are mixed in a ratio of 60% and 40%, heated to melt and stirred, and then placed in a refrigerator at 4°C overnight to form reconstituted egg yolk shortening.

[0085] Example 5

[0086] (1) Enzymatic hydrolysis process: The egg yolk oil was mixed with phospholipase A2 (added at 1% of the egg yolk oil mass) and hydrolyzed at 50°C and pH 7.0 for 4 h to increase the fat release rate.

[0087] (2) Dry fractionation of egg yolk oil: Heat the enzymatically hydrolyzed egg yolk oil at 80°C for 30 min to completely melt the egg yolk oil, and then quickly cool it to 60°C; then slowly cool it at 2°C / h to the crystallization temperature of 25°C; grow the crystals at this temperature for a period of time, and use low-speed centrifugation at 5000 rpm for 10 min to separate the solid and liquid oils, respectively.

[0088] (3) Egg yolk shortening reconstitution: The separated solid and liquid egg yolk shortenings are mixed in a ratio of 80% and 20%, heated to melt and stirred, and then placed in a refrigerator at 4°C overnight to form reconstituted egg yolk shortening.

[0089] Example 6

[0090] (1) Enzymatic hydrolysis process: The egg yolk oil was mixed with phospholipase A2 (added at 1% of the egg yolk oil mass) and hydrolyzed at 50°C and pH 7.0 for 4 h to increase the fat release rate.

[0091] (2) Dry fractionation of egg yolk oil: Heat the enzymatically hydrolyzed egg yolk oil at 80°C for 30 min to completely melt the egg yolk oil, and then quickly cool it to 60°C; then slowly cool it at 2°C / h to the crystallization temperature of 25°C; grow the crystals at this temperature for a period of time, and use low-speed centrifugation at 5000 rpm for 10 min to separate the solid and liquid oils, respectively.

[0092] (3) Egg yolk shortening reconstitution: The separated solid and liquid egg yolk shortenings are mixed in a ratio of 100% and 0%, heated to melt and stirred, and then placed in a refrigerator at 4°C overnight to form reconstituted egg yolk shortening.

[0093] Comparative Example 1

[0094] A method for preparing zero trans fatty acid egg yolk shortening, referring to Example 3, differs only in that:

[0095] The enzymatic hydrolysis in step (1) is omitted, and the other steps and parameters remain unchanged to obtain egg yolk shortening.

[0096] Comparative Example 2

[0097] A method for preparing zero trans fatty acid egg yolk shortening, referring to Example 3, differs only in that:

[0098] The enzyme added in step (1) is replaced by lipase (porcine pancreas), and the other steps and parameters remain unchanged to obtain egg yolk shortening.

[0099] The shortenings obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were tested for the fatty acid content of egg yolk oil, and the results are shown in Table 1. It can be seen that the egg yolk oil reconstituted after extraction does not contain trans fatty acids, thus avoiding the generation of trans fatty acids in the traditional hydrogenation process.

[0100] Table 1 Fatty acid composition of egg yolk oil

[0101]

[0102]

[0103] The shortening ability of the shortenings obtained in Examples 1 to 6 and Comparative Examples 1 to 2 was tested. The test results are as follows: Figure 1 As shown, the expansion ratios of the shortenings prepared in Examples 1 to 6 and Comparative Examples 1 to 2 are 4.78, 6.00, 6.53, 5.78, 5.23, 4.14, 5.12, and 4.98, respectively.

[0104] Comparative Example 1 removes the enzymatic hydrolysis step in Example 3, which reduces the shortening ability of the egg yolk oil, while Comparative Example 2 replaces the enzyme in the enzymatic hydrolysis process with lipase, which also reduces the shortening ability of the egg yolk oil.

[0105] In summary, the present invention uses phospholipase A2 to enzymatically hydrolyze the egg yolk oil so that the phosphatidylcholine in the egg yolk oil is hydrolyzed, thereby enhancing the plasticity of the egg yolk oil and improving the shortening ability of the egg yolk oil; at the same time, the mixing ratio of saturated fatty acids and unsaturated fatty acids in the reorganization of the egg yolk oil also determines the shortening ability of the egg yolk oil.

[0106] Although the present invention has been disclosed as above in the form of a preferred embodiment, 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 scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing egg yolk shortening with zero trans fatty acids, characterized in that: The following steps are involved: (1) Enzymatic hydrolysis process: egg yolk oil is mixed with phospholipase for enzymatic hydrolysis to obtain enzymatically hydrolyzed egg yolk oil; (2) Dry fractionation of egg yolk oil: heating the egg yolk oil after enzymatic hydrolysis in step (1) to 70-90° C., then cooling to 55-65° C.; then slowly cooling to a crystallization temperature of 20-25° C. at a certain cooling rate, and growing the crystals until the solid no longer increases, then centrifuging for solid-liquid separation to obtain solid egg yolk oil and liquid egg yolk oil, respectively; (3) egg yolk shortening reconstitution: the solid egg yolk shortening and the liquid egg yolk shortening obtained in step (2) are mixed in a certain proportion, and then heated, melted and stirred to obtain zero trans fatty acid egg yolk shortening; The phospholipase in step (1) is an enzyme that can catalyze the hydrolysis of phospholipids; the amount of the phospholipase added is 0.5-2% of the mass of the egg yolk oil; The mixing mass ratio of the solid egg yolk oil and the liquid egg yolk oil in step (3) is 2-6:8-4.

2. The preparation method according to claim 1, characterized in that: The egg yolk oil in step (1) is prepared by the following preparation method: adding egg yolk powder to the extraction kettle of a supercritical CO2 extractor, then adjusting the CO2 flow rate to 16-28L / h, the extraction temperature to 35-55°C, and the extraction pressure to 25-45MPa to perform supercritical extraction on the egg yolk powder, and collecting the extracted egg yolk lipids to obtain egg yolk oil.

3. The preparation method according to claim 2, characterized in that: The egg yolk powder has a protein concentration of 20-60 wt % and a fat content of 40-80 wt %.

4. The preparation method according to claim 2, characterized in that: The phospholipase in step (1) is phospholipase A2 and / or phospholipase A1.

5. The preparation method according to claim 2, characterized in that: The enzymatic activity of the phospholipase in step (1) is 5000-15000 U / mL.

6. The preparation method according to claim 2, characterized in that: The enzymatic hydrolysis in step (1) is carried out at 45-55°C and pH 6.5-7.5 for 2-6 hours.

7. The preparation method according to claim 2, characterized in that: The mass ratio of the solid egg yolk oil to the liquid egg yolk oil in step (3) is 2-4:8-6.

8. The preparation method according to claim 2, characterized in that: The heating temperature in step (3) is 80-90° C. and the heating time is 10-20 min.

9. An egg yolk shortening with zero trans fatty acids, characterized in that: The egg yolk shortening with zero trans fatty acid is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the zero trans fatty acid egg yolk shortening according to claim 9 in the food field.

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