Low-saturation grease for improving oxidation stability and quality of walnut cakes and application of low-saturation grease

Abstract

The invention relates to low-saturation grease for improving oxidation stability and quality of walnut cakes and application of the low-saturation grease, and belongs to the field of baked food processing. The invention provides a preparation method of low-saturation grease, which comprises the following steps: heating saturated fat and high-oleic acid grease in a water bath, carrying out ultrasonic treatment after high-speed shearing, quenching and kneading to obtain the low-saturation grease; the invention also provides a preparation method of the walnut cake. The preparation method comprises the following steps: adding white granulated sugar into low-saturated grease, stirring and uniformly stirring whole egg liquid; adding baking powder and baking soda, uniformly stirring, adding low-gluten wheat flour, and uniformly stirring to obtain dough; and preparing the dough into walnut cake blanks, and baking to obtain the walnut cakes. The walnut cake prepared from the low-saturated oil has excellent sensory quality, is good in flowering effect, oily and crisp in mouth, fragrant and sweet, rich in flavor and good in oil holding effect; the saturated fatty acid is reduced, the oxidation stability is kept well, and the shelf life is prolonged.

Description

Technical Field

[0001] The invention relates to low-saturated oil for improving the oxidation stability and quality of peach crisps and application thereof, and belongs to the field of baked food processing. Background Art

[0002] Peach pastry is a traditional Chinese pastry made by mixing wheat flour, oil (25% to 35%), white sugar, eggs and other ingredients, and then baking. The oil materials currently available in the market are mostly solid palm oil, lard, etc., which can give peach pastry a crispy and delicious quality, but its saturated fatty acid content is high (45% to 55%), and long-term intake can easily cause obesity and cardiovascular disease. Appropriate intake of unsaturated fatty acids can help lower the level of low-density lipoprotein cholesterol in the blood, which is more beneficial to cardiovascular health. However, oils with high unsaturated fatty acid content are more prone to oxidation reactions. CN104430757A provides a recipe for peach pastry, which uses liquid oil, has a simple recipe and is safe to eat, but does not report any sensory quality issues with the peach pastry made with this recipe; CN115226783A discloses a method for preparing low-saturated fatty acid puff pastry oil, which comprises melting and mixing vegetable oil and animal oil separately, adding a small molecule emulsifier, and finally obtaining a low-fat puff pastry oil that does not contain trans fatty acids and has good plasticity. However, the puff pastry oil contains more water and emulsifiers, and is suitable for puff pastry such as croissants and egg tart crusts. For low-moisture pastry systems such as peach pastry, this type of low-saturated fatty acid puff pastry oil may not be applicable, and is not conducive to the oxidative stability of peach pastry products.

[0003] In order to improve the oxidative stability of peach crisps and extend the shelf life of peach crisps, the current products on the market mainly use the method of adding antioxidants. Artificial synthetic antioxidants such as TBHQ, BHT, BHA and PG are widely used because of their low price and strong antioxidant effect in oils and fats. However, there has been controversy over the safety of synthetic antioxidants, which do not meet people's needs for clean labels and healthy foods. There are also studies on the use of natural antioxidants to extend the shelf life of peach crisps, but the application of natural antioxidants in peach crisps is not as extensive as synthetic antioxidants, which may be due to their relatively high cost and relatively easy degradation during high-temperature baking.

[0004] Therefore, there is an urgent need to develop a natural and green method to reduce the fatty acid saturation of peach crisp products to meet consumers' healthy dietary expectations, and to improve the antioxidant properties and sensory quality of peach crisp products, thereby extending the shelf life. Summary of the invention

[0005]

Technical issues

[0006] The commercially available peach cakes have the problems of high saturated fatty acid content, insufficient oxidative stability, and poor sensory quality. Adding antioxidants to extend the shelf life will increase costs and have questionable safety. It is urgent to develop a natural, green, and safe method to improve the antioxidant properties and sensory quality of peach cakes and reduce the fatty acid saturation of peach cakes.

[0007]

Technical solution

[0008] In view of the above problems, the present invention develops a low-saturated oil and its application for improving the oxidation stability and quality of peach crisps. By optimizing the ultrasonic synergistic quenching crystallization technology of saturated fat and high oleic acid oil, a low-saturated oil for peach crisps with the best antioxidant properties is obtained and used for the production of peach crisps, so that the saturated fatty acids of peach crisps are reduced while the oxidation stability and sensory quality of the product are also improved. The raw materials used in the present invention are more widely available and cheap, which can reduce costs while increasing the nutritional value of the product, and the processing method is simple and easy to operate.

[0009] The first object of the present invention is to provide a method for preparing low-saturated fat, comprising the steps of:

[0010] S1, heating saturated fat and high oleic acid oil in a water bath to obtain an oil composition;

[0011] S2, subjecting the oil composition to high-speed shearing and then ultrasonic treatment;

[0012] S3, rapidly cooling and kneading the product of step S2 to obtain low-saturated fat.

[0013] In one embodiment of the present invention, saturated fat is selected from one or more of palm oil and palm stearin; high oleic oil is selected from one or more of high oleic rapeseed oil, high oleic peanut oil, camellia oil, and olive oil; the mass ratio of saturated fat to high oleic oil is 2-3:1-2; high oleic oil is an oil with an oleic acid content ≥75%.

[0014] In one embodiment of the present invention, the palm oil is preferably medium melting point palm oil.

[0015] The medium melting point palm oil is palm oil with a melting point of 30 to 35°C.

[0016] In one embodiment of the present invention, in step S1, the water bath heating temperature is 70-80°C, the water bath heating time is 20-30 minutes, and the stirring speed of the water bath heating is 400-500 rpm. The water bath heating is used to melt the saturated fat and high oleic acid oil and remove the crystal memory.

[0017] In one embodiment of the present invention, in step S2, the rotation speed of the high-speed shearing is 8000-10000 rpm, and the time of the high-speed shearing is 5-10 min.

[0018] In one embodiment of the present invention, in step S2, the power of the ultrasonic treatment is 450-500 W; and the time of the ultrasonic treatment is 1-3 min.

[0019] In one embodiment of the present invention, in step S2, the pulse width of the ultrasonic treatment is: 20 to 40 seconds per ultrasonic treatment, and 5 to 15 seconds for pause.

[0020] In one embodiment of the present invention, in step S3, the temperature of the cooling medium is -7 to -5°C, the cooling time is 5 to 10 seconds, the kneading speed is 100 to 120 rpm, and the kneading time is 10 to 20 minutes.

[0021] The second object of the present invention is to provide low-saturated fat prepared by the above preparation method.

[0022] In one embodiment of the present invention, the unsaturated fatty acid mass content of the low-saturated oil is 60% to 71%, and the oxidation induction time is 15.61 to 16.67 hours.

[0023] The third object of the present invention is to provide the application of the low-saturated fat in the food field.

[0024] In one embodiment of the present invention, the application in the food field includes application in peach crisps, almond crisps, butterfly crisps, tile crisps, biscuits and cookies.

[0025] In one embodiment of the present invention, the application in the food field includes application in improving the oxidation stability, unsaturated fatty acid content or sensory quality of baked food.

[0026] The fourth object of the present invention is to provide a peach cake made with the above-mentioned low-saturated fat; its raw materials include low-saturated fat, white granulated sugar, whole egg liquid, baking powder, baking soda and low-gluten wheat flour; the mass proportion of each raw material is: 150-170 parts of low-saturated fat, 100-120 parts of white granulated sugar, 20-30 parts of whole egg liquid, 5-6 parts of baking powder, 4-5 parts of baking soda, and 250-270 parts of low-gluten wheat flour.

[0027] In one embodiment of the present invention, the weight proportions of the raw materials for peach crisps are preferably 160 parts of low-saturated fats and oils, 110 parts of white sugar, 25 parts of whole egg liquid, 5 parts of baking powder, 5 parts of baking soda, and 260 parts of low-gluten wheat flour.

[0028] In one embodiment of the present invention, the mass ratio of saturated fat to high oleic acid oil in the low saturated oil used in the peach crisp raw material is preferably 3:1-2.

[0029] A fifth object of the present invention is to provide a method for preparing the above-mentioned peach crisp, comprising the steps of:

[0030] S1. Stir 150-170 parts of low-saturated fat, add 100-120 parts of white sugar and mix well, add 20-30 parts of whole egg liquid and mix well;

[0031] S2, adding 5-6 parts of baking powder and 4-5 parts of baking soda to the product of step S1, stirring evenly, adding 250-270 parts of low-gluten wheat flour, stirring evenly, and obtaining a dough;

[0032] S3, divide the dough into small portions, put them into molds to make peach shortbread bases;

[0033] S4. Bake the cake dough in an oven to obtain peach pastry.

[0034] In one embodiment of the present invention, in step S1, the stirring speed is 500-600 rpm.

[0035] In one embodiment of the present invention, in step S2, the stirring speed is 100-200 rpm.

[0036] In one embodiment of the present invention, in step S1, the low-saturated fat is stirred for 1 to 4 minutes, then white sugar is added and stirred for 1 to 4 minutes, and then the whole egg liquid is added and stirred for 1 to 4 minutes.

[0037] In one embodiment of the present invention, in step S2, baking powder and baking soda are added to the product of step S1, stirred for 1 to 4 minutes, and then low-gluten wheat flour is added and stirred for 10 to 25 seconds to obtain dough.

[0038] In one embodiment of the present invention, in step S3, the size of the small dose is 26 to 34 g.

[0039] In one embodiment of the present invention, in step S4, the baking temperature is 150-200° C., and the baking time is 10-30 minutes.

[0040] Beneficial effects:

[0041] The invention uses ultrasound-assisted rapid cooling crystallization technology to prepare low-saturated oil for peach crisps, with an unsaturated fatty acid mass content of 60% to 71% and an oxidation induction time of 15.61 to 16.67 hours. It has excellent antioxidant properties while reducing the saturation of oil. It is applied to peach crisps to reduce the saturated fatty acid content of peach crisps, while maintaining good oxidation stability of peach crisps and extending the shelf life, which is in line with the contemporary people's concept of healthy diet.

[0042] The low-saturated oil has a certain ductility. When applied to peach cakes, the oil is distributed in layers between the protein and starch when the raw materials are mixed, which enhances the sliding property between the protein and starch. The low-saturated oil has a low solid fat content and weak fluidity, which is conducive to increasing the internal porosity of the peach cake, reducing the hardness of the peach cake, and making it crispy and delicious. Compared with commercially available peach cakes, the peach cake products have excellent sensory quality: good flowering effect, oily and crispy in the mouth, richer baking-specific sweet flavor, and higher oil retention effect than commercially available peach cakes.

[0043] The peach cakes prepared by the method of the present invention can well meet the needs of consumers for delicious, convenient and healthy new Chinese-style cakes. The method is highly operable, convenient for family production, and can be expanded to industrial production and control, thus bringing considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The microstructure diagrams of the defatted peach crisp powders obtained in Examples 4 to 6 and Comparative Examples 5, 6, and 10 are as follows: a. Comparative Example 5; b. Example 4; c. Example 5; d. Example 6; e. Comparative Example 6; f. Comparative Example 10.

[0045] Figure 2 A is the acid value determination result of the accelerated experiment for predicting the shelf life of peach crisps obtained in Examples 4 to 6 and Comparative Examples 5, 6, and 10; Figure 2 B is the peroxide value measurement result of the accelerated shelf life prediction experiment of the peach crisps obtained in Examples 4 to 6 and Comparative Examples 5, 6, and 10. DETAILED DESCRIPTION

[0046] The following examples are used to illustrate the present invention, but do not limit the scope of the present invention. Unless otherwise specified, the experimental materials, reagents and instruments used in the embodiments and comparative examples of the present invention are all commercially available, and the technical means used in the embodiments and comparative examples are conventional means well known to those skilled in the art.

[0047] The medium melting point palm oil used in the following examples and comparative examples has a melting point of 32° C., and the high oleic rapeseed oil used has an oleic acid content of ≥75%.

[0048] Test method:

[0049] (1) Determination of fatty acid composition: Take 20 mg of oil sample, add 2 mL of 0.5 mol / L KOH-CH3OH solution, and place in a 65℃ constant temperature water bath for 30 min saponification. Then add 2 mL of BF3-CH3OH (1:3, v / v) solution, place in a 70℃ constant temperature water bath and heat for 10 min, and cool to room temperature. Add 2 mL of chromatographic grade n-hexane and shake vigorously for 1-2 min. After standing and stratification, take the supernatant and perform gas phase analysis after passing through the membrane. Gas chromatography conditions: Thermo Fisher Trace TR-FAME column, 60m×0.25mm×0.25μm, temperature program: 0 min, 130℃, hold for 3 min; 5℃ / min to 200℃, hold for 10 min; 2℃ / min to 220℃, hold for 5 min; injection volume: 1μL; split ratio 20; column flow rate: 1.8mL / min. A mixed standard of 52 fatty acid methyl esters was used for the qualitative and relative quantification of fatty acids.

[0050] (2) Determination of oil oxidation induction time: Rancimat method (GB / T 21121-2007) was used. 3.00 g of the extracted oil sample was weighed in a test tube. The test conditions were: air flow rate 20 L / min, oxidation temperature 120°C.

[0051] (3) Determine the VE content in oils and fats by reversed-phase high performance liquid chromatography according to GB / T 5009.82-2016.

[0052] (4) Determine the sterol content in oils and fats by gas chromatography according to GB / T 25223-2010.

[0053] (5) Determine the squalene content in oils and fats with reference to GB / T 43732-2024.

[0054] (6) Extraction of fats and determination of fat oxidation in peach pastry: The fats of peach pastry were extracted by Soxhlet extraction method in GB5009.6-2016 "Determination of fats in food". The acid value, peroxide value and anisidine value of the fats extracted from peach pastry were determined in accordance with GB5009.229-2016 "Determination of acid value in food of national food safety standard", GB5009.227-2016 "Determination of peroxide value in food of national food safety standard" and GB / T24304-2009 "Determination of anisidine value in animal and plant fats". The total oxidation value was calculated by the formula: total oxidation value = 4 × peroxide value + anisidine value.

[0055] (7) Accelerated experiment for shelf life prediction: The accelerated shelf-life test (ASLT) model is used for accelerated shelf life prediction. Specifically, the peach cakes are stored at 60°C and 60% humidity to accelerate the generation of fat acid value and peroxide value in the peach cakes. The acid value and peroxide value of each group of samples are measured every 5 days. When the acid value or peroxide value of the peach cake exceeds the national standard requirements, the shelf life ends.

[0056] (8) Color measurement: The SC-10 colorimeter (Shenzhen Sanenshi Technology Co., Ltd.) was used to measure the color of the samples. The samples were packaged in transparent ziplock bags. The sample color was expressed by L*, a*, and b*. Three points were selected for measurement and the measurement was repeated three times.

[0057] (9) Hardness measurement: The hardness characteristics of the peach crisp samples were tested using a TA.XTPlus texture analyzer (SMS, UK). The test conditions were: single press, pre-test speed 2 mm / s, test speed 1 mm / s, post-test speed 2 mm / s, probe model P / 2, press displacement 8 mm, trigger force 5 g, and repeated measurement 8 times.

[0058] (10) Determination of oil holding rate: Take five dried filter papers and record the mass as W1. Weigh 7±0.5g of peach cake (cut the peach cake into four equal parts and take one part) and place it on the five layers of filter paper. Measure the total weight of the filter paper and peach cake and record it as W2. After the peach cake is placed for 24 hours, remove it from the filter paper and place the filter paper in a 60℃ oven to constant weight to remove moisture. Measure the weight of the filter paper after constant weight and record it as W3. Calculate the oil holding rate of peach cake according to the following formula.

[0059]

[0060] (11) Sensory evaluation of peach pastry: This experiment evaluated peach pastry from five aspects: shape, color, smell, texture, and taste. Ten male and ten female students majoring in food were selected to conduct sensory evaluation on the quality of peach pastry. The full score was 100 points, and the final score was the average of the 20 people. The sensory evaluation table of peach pastry is shown in Table 1.

[0061] (12) Scanning electron microscope observation: A SU8220 cold field emission scanning electron microscope (Hitachi, Japan) was used to observe the shape and distribution of defatted peach crisp powder protein and starch. A small amount of dry defatted peach crisp powder was applied to a silicon dioxide chip substrate, and then gold was sprayed for scanning observation at a voltage of 3.0 kV and a magnification of 1.2k.

[0062] Table 1

[0063]

[0064]

[0065] Example 1

[0066] A low-saturated fat specially used for peach cake, wherein the unsaturated fatty acid content is predicted to be 64.5%, and the preparation method comprises the following steps:

[0067] S1. Place medium melting point (32°C) palm oil and high oleic rapeseed oil in a mass ratio of 3:1 in a clean and dry beaker, heat and melt in a 75°C water bath, and stir at a speed of 450 rpm for 20 min to remove crystallization memory, thereby obtaining a fat composition;

[0068] S2, the oil composition was sheared at 9000 rpm for 8 min, and then ultrasonically treated at 470 W power for 2 min, with a pulse width of 30 s per ultrasonic treatment and 10 s rest;

[0069] S3. Rapidly cool and knead the product of step S2. The temperature of the refrigerant for rapid cooling is -5°C and the rapid cooling time is 7s. The kneading speed is 100rpm and the kneading time is 15min to obtain low saturated oil.

[0070] Example 2

[0071] A low-saturated oil specially used for peach cakes, wherein the unsaturated fatty acid content is predicted to be 70.2%. The difference between the preparation method and that of Example 1 lies in that the mass ratio of medium melting point palm oil to high oleic rapeseed oil is 3:2.

[0072] Example 3

[0073] A low-saturated oil specially used for peach crisps, wherein the unsaturated fatty acid content is predicted to be 74%. The difference between the preparation method and that of Example 1 lies in that the mass ratio of medium melting point palm oil to high oleic rapeseed oil is 1:1.

[0074] Comparative Example 1

[0075] Buy a peach cake that is popular in the market and extract the oil.

[0076] Comparative Example 2

[0077] A low-saturated fat, the preparation method of which is different from that of Example 1 in that the ultrasonic treatment in step S2 is not performed.

[0078] Comparative Example 3

[0079] A low-saturated oil, the preparation method of which is different from that of comparative example 2 in that the mass ratio of medium melting point palm oil to high oleic rapeseed oil is 3:2.

[0080] Comparative Example 4

[0081] A low-saturated oil, the preparation method of which is different from that of comparative example 2 in that the mass ratio of medium melting point palm oil to high oleic rapeseed oil is 1:1.

[0082] The fatty acid composition and oxidation induction time of the prepared low-saturated oil, medium-melting point palm oil, high-oleic rapeseed oil, commercial rapeseed oil and commercial peach cake were determined, and the V E The results are shown in Tables 2, 3 and 4.

[0083] Table 2

[0084]

[0085] Table 3

[0086]

[0087]

[0088] Table 4

[0089]

[0090] From Tables 2 to 4, we can see that:

[0091] (1) The unsaturated fatty acid (UFA) content of Example 1 is 59.59%; the unsaturated fatty acid content of Example 2 is 66.57%; and the unsaturated fatty acid content of Example 3 is 70.73%, which is 6% to 17% higher than the unsaturated fatty acid content of commercially available peach cakes.

[0092] (2) The main difference in fatty acid composition between high oleic oil and ordinary commercial oil is due to the oleic acid (C18:1) content and polyunsaturated fatty acid (PUFA) content. The oleic acid content of high oleic rapeseed oil in the table is 18.41% higher than that of ordinary commercial rapeseed oil, and the polyunsaturated fatty acid is 16.41% less. VE, sterols, and squalene have certain antioxidant properties, and the content of these trace antioxidant active ingredients in the two is also different. The oxidation induction time of high oleic rapeseed oil is 1.82 times that of ordinary commercial rapeseed oil. It can be seen that increasing the oleic acid content helps to improve the oxidative stability of oils.

[0093] (3) The oxidation induction time of Examples 1 to 3 is 15.61 to 16.67 h, which is slightly different from the oxidation induction time of commercially available peach oil. The proportion of high oleic rapeseed oil in Examples 1 to 3 increases successively. As the proportion of high oleic rapeseed oil increases, the content of monounsaturated fatty acids (MUFA) in the oil from Example 1 to Example 2 increases by 6.76%, which is significantly higher than the increase in the content of monounsaturated fatty acids in the oil from Example 2 to Example 3; the increase in the content of polyunsaturated fatty acids in the oil from Example 1 to Example 2 is not significant, while the content of polyunsaturated fatty acids in the oil from Example 2 to Example 3 increases significantly by 1.32%. And as can be seen from Table 3, high oleic rapeseed oil is rich in sterols, and the sterol content is 774 mg / 100 g higher than that of medium melting point palm oil. Therefore, when the proportion of high oleic rapeseed oil is increased, the phenomenon that the oxidation induction time of the oil in the present invention first increases and then decreases occurs, which may be caused by the synergistic antioxidant effect of oleic acid and sterols. Due to the presence of unsaturated bonds, oils with high unsaturated fatty acid content are usually more susceptible to oxidation, while the low-saturated oils prepared by the present invention have a higher oxidation induction time while reducing the saturation.

[0094] Example 4

[0095] A peach pastry, the preparation method comprising the steps of:

[0096] S1, adjust the mixer speed to 550rpm, stir 160g of low-saturated fat prepared in Example 1 for 2min, add 110g of white sugar and stir for 2min, add 25g of whole egg liquid and stir for 2min;

[0097] S2, add 5g baking powder and 5g baking soda to the product of step S1, adjust the mixer speed to 150rpm, stir for 2min, add 260g low-gluten wheat flour, stir for 15s, and obtain dough;

[0098] S3, divide the dough into small portions of 30±0.1g, and put them into a mold to make peach shortbread base;

[0099] S4. Bake the cake in a preheated oven at 180°C for 20 minutes, cool to room temperature, and obtain peach pastry.

[0100] Example 5

[0101] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated oil prepared in Example 1 is replaced by the low-saturated oil prepared in Example 2.

[0102] Example 6

[0103] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated oil prepared in Example 1 is replaced by the low-saturated oil prepared in Example 3.

[0104] Comparative Example 5

[0105] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated fat prepared in Example 1 is replaced with medium-melting point palm oil.

[0106] Comparative Example 6

[0107] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated oil prepared in Example 1 is replaced with high-oleic rapeseed oil.

[0108] Comparative Example 7

[0109] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated fat prepared in Example 1 is replaced by the low-saturated fat prepared in Comparative Example 2.

[0110] Comparative Example 8

[0111] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated oil prepared in Example 1 is replaced by the low-saturated oil prepared in Comparative Example 3.

[0112] Comparative Example 9

[0113] A peach pastry, the preparation method of which is different from that of Example 4 in that the low-saturated oil prepared in Example 1 is replaced by the low-saturated oil prepared in Comparative Example 4.

[0114] Comparative Example 10

[0115] The peach cakes have good sales in the market, and the production date of the purchased peach cakes is guaranteed to be consistent with Examples 4 to 6 and Comparative Examples 5 to 9.

[0116] The peach crisps of Examples 4 to 6, Comparative Examples 5 to 6 and Comparative Example 10 were subjected to sensory evaluation, color, hardness, and oil retention were measured, and oil was extracted to measure acid value, peroxide value, anisidine value, and total oxidation value, and then a peach crisp shelf life prediction experiment was conducted; Comparative Examples 7 to 9 were subjected to sensory evaluation, and color, hardness, and oil retention were measured. The index analysis results of different peach crisps are shown in Table 4, and the sensory evaluation results of different peach crisps are shown in Table 5.

[0117] Table 5

[0118]

[0119]

[0120] Table 6

[0121] form Color Flavor organize Taste Overall Rating Example 4 17.78 17.39 17.14 16.18 17.06 85.55 Example 5 17.04 17.9 18.9 17.77 17.09 88.70 Example 6 16.00 17.78 18.88 15.88 17.46 86.00 Comparative Example 5 18.65 18.20 13.17 16.88 14.16 81.06 Comparative Example 6 12.55 17.30 18.69 11.64 13.75 73.93 Comparative Example 7 16.82 17.21 15.19 15.04 15.20 79.46 Comparative Example 8 15.01 17.14 18.20 14.37 15.58 80.30 Comparative Example 9 14.50 16.52 18.90 13.19 13.61 76.72 Comparative Example 10 17.86 17.57 18.04 17.11 15.97 86.55

[0122] From Tables 5 and 6, we can see that:

[0123] (1) The brightness values ​​of the peach cakes of Examples 4 to 6 and Comparative Examples 5 to 10 are 66.3 to 67.9, the red-green values ​​are 5.0 to 5.8, and the yellow-blue values ​​are 21.2 to 22.7, indicating that different compound oils have little effect on the color of the peach cakes. According to the color sensory score, the color of the peach cakes (Examples 4 to 6) made with the low-saturated oils of Examples 1 to 3 is within an acceptable range.

[0124] (2) Oil plays an important role in baked products and can change the structure and texture of peach cakes. Figure 1 As shown, about Comparative Example 5 ( Figure 1 a), because the solid fat content of medium melting point palm oil is high, it lacks fat spreading ability. During the raw material mixing process, the oil will be broken down into small pieces and distributed between the protein and starch. Therefore, many small pores can be seen in the microstructure of defatted peach crisp powder after baking, which indicates that the distribution of fat particles in the peach crisp matrix is ​​discontinuous. Comparative Example 6 ( Figure 1 e) It can be seen that the protein and starch are arranged compactly. This may be because high oleic rapeseed oil is a pure liquid oil with strong fluidity. When baked, it is easy to penetrate into the surface of the peach crisp along with the water vapor inside the peach crisp, which reduces the porosity inside the peach crisp. Example 5 ( Figure 1 c) and Comparative Example 10 ( Figure 1 f) The microstructure is relatively similar, with flaky protein-starch aggregates. This may be because the appropriate fatty acid composition gives the oil a certain degree of ductility. When the raw materials are mixed, the oil is distributed in layers between the protein and starch, which enhances the sliding properties between the protein and starch, avoiding the rough taste of the final product.

[0125] (3) The physical property index of hardness is more related to the texture and taste of peach crisps. The medium melting point palm oil peach crisp (Comparative Example 5) has a higher hardness than the commercial peach crisp (Comparative Example 10), which may be due to its high solid fat content. After the baked peach crisp is cooled, the fat filled between the protein and the starch crystallizes, the hardness increases, and the peach crisp is not easy to melt in the mouth, and it is easy to get stuck, which affects the taste of the peach crisp. The high oleic rapeseed oil peach crisp (Comparative Example 6) has a higher hardness than the commercial peach crisp (Comparative Example 10), which may be due to the fact that high oleic rapeseed oil is a pure liquid oil with strong fluidity. When baked, it is easy to penetrate into the surface of the peach crisp with the water vapor in the peach crisp, which reduces the porosity in the peach crisp, and the protein and starch are closely arranged, which is hard and rough in taste. However, the low saturated oil peach crisp prepared in Examples 4 to 6 gradually decreases in hardness as the proportion of high oleic rapeseed oil increases, and is significantly lower than the peach crisp made from low saturated oil raw materials (Comparative Examples 5 and 6). The reason may be that with the addition of liquid high-oleic rapeseed oil, the solid fat content of low-saturated oil gradually decreases, the fluidity of oil also weakens, and the two oils work synergistically to increase the internal porosity of peach crisps, and the peach crisps appear to be low in hardness and crisp and delicious in macroscopic terms. Therefore, the peach crisps made with low-saturated oils of the present invention have better flowering effect, loose texture, crisp taste, good mouth-melting properties, and higher sensory scores.

[0126] (4) Compared with the peach cakes made from medium-melting point palm oil (Comparative Example 5), the peach cakes made from the low-saturated fats of Examples 1 to 3 (Examples 4 to 6) had higher flavor sensory scores. The flavor sensory scores were close to or even higher than that of Comparative Example 10 (commercially available peach cakes) using only simple natural ingredients, indicating that the peach cakes made from the low-saturated fats of the present invention had a richer sweet flavor that was unique to baking.

[0127] (5) Compared with the peach crisps made with high oleic rapeseed oil (Comparative Example 6) and commercially available peach crisps (Comparative Example 10), the peach crisps made with low saturated fats (Examples 4 to 6) have lower acid values ​​and total oxidation values ​​and higher oil retention rates, indicating that the peach crisps made with low saturated fats of the present invention have high oil retention rates and better oxidative stability.

[0128] (6) By comparing Examples 4 to 6 with Comparative Examples 7 to 9, it can be seen that the hardness and oil permeability of peach crisps made with low-saturated oils treated with ultrasound-assisted rapid cooling and crystallization are greatly reduced, and the sensory score of peach crisps is higher than that of peach crisps not treated with ultrasound-assisted rapid cooling and crystallization, indicating that low-saturated oils produced with ultrasound-assisted rapid cooling and crystallization technology are more conducive to improving the sensory quality of peach crisps.

[0129] (7) In low-moisture baked goods, oxidation is usually the main reason for the deterioration of product quality during the shelf life. The optimal taste and flavor of the product will also be affected by oil oxidation. Acid value can be used as an indicator of oil quality deterioration, determining the content of free fatty acids produced by triglyceride hydrolysis; peroxide value can indicate the amount of hydroperoxides contained in the oil, thereby judging the degree of oil oxidation. The national standard stipulates that the acid value of baked products should be ≤5mg / g and the peroxide value should be ≤0.25g / 100g. Figure 2 The acid value and peroxide value measurement results of the accelerated experiment for predicting the shelf life of the peach crisps prepared in Examples 4 to 6 and Comparative Examples 5, 6, and 10 are shown.

[0130] It can be obtained that the acid value of the peach crisps in Comparative Example 6 exceeded 5 mg KOH / g when stored for 25 days, indicating that the shelf life of the sample under the storage conditions of temperature 60°C and humidity 60% is only 25 days; the peroxide value of the commercially available peach crisps (Comparative Example 10) exceeded 0.25 g / 100 g when stored for 35 days, and the shelf life of the sample was 35 days; and the shelf life of the peach crisps in Examples 4, 5 and Comparative Example 5 all reached more than 40 days, indicating that the low-saturated oil produced by the present invention can significantly improve the oxidative stability of the peach crisps during storage, thereby extending the shelf life of the peach crisps.

[0131] (8) Comprehensive comparison shows that the peach cakes prepared in Examples 4 and 5 have higher comprehensive sensory scores, higher oil retention rates, lower total oxidation values, and longer shelf lives, indicating that the peach cakes prepared with low-saturated oils and fats of the present invention can improve product quality while reducing saturated fatty acids, making the overall sensory acceptance greater, and maintaining better oxidative stability of the product, thereby extending the shelf life.

Claims

1. A method for preparing low-saturated fat, characterized in that: Includes steps: S1. Heating saturated fat and high oleic acid oil in a water bath to obtain an oil composition; the water bath heating temperature is 70-80° C., and the water bath heating time is 20-30 min; S2, subjecting the oil composition to high-speed shearing and then ultrasonic treatment; the high-speed shearing speed is 8000-10000 rpm, the high-speed shearing time is 5-10 min; the ultrasonic treatment time is 1-3 min; S3, quenching and kneading the product of step S2 to obtain low saturated fat; the temperature of the refrigerant for quenching is -7 to -5°C, the quenching time is 5 to 10 seconds, and the kneading time is 10 to 20 minutes; Among them, saturated fat is selected from one or more of palm oil and palm stearin; high oleic oil is selected from one or more of high oleic rapeseed oil, high oleic peanut oil, camellia oil, and olive oil; the mass ratio of saturated fat to high oleic oil is 2-3:1-2; high oleic oil is oil with an oleic acid content ≥75%.

2. The low-saturated fat prepared by the preparation method according to claim 1.

3. The low-saturated fat according to claim 2, characterized in that: The mass content of unsaturated fatty acids is 60% to 71%, and the oxidation induction time is 15.61 to 16.67 hours.

4. Use of the low-saturated fat according to claim 2 or 3 in the food field.

5. The use according to claim 4, characterized in that: Including applications in peach crisps, almond crisps, butterfly crisps, tile crisps, biscuits and cookies.

6. Peach cake made from the low-saturated oil according to claim 2.

7. The peach cake according to claim 6, characterized in that: The raw materials and their mass proportions are: 150-170 parts of low-saturated fat, 100-120 parts of white sugar, 20-30 parts of whole egg liquid, 5-6 parts of baking powder, 4-5 parts of baking soda, and 250-270 parts of low-gluten wheat flour.

8. The method for preparing peach crisp according to claim 7, characterized in that: Includes steps: S1. Stir 150-170 parts of low-saturated fat, add 100-120 parts of white sugar and mix well, add 20-30 parts of whole egg liquid and mix well; S2, adding 5-6 parts of baking powder and 4-5 parts of baking soda to the product of step S1, stirring evenly, adding 250-270 parts of low-gluten wheat flour, stirring evenly, and obtaining a dough; S3, divide the dough into small portions, put them into molds to make peach shortbread bases; S4. Bake the cake dough in an oven to obtain peach pastry.

9. The preparation method according to claim 8, characterized in that: In step S4, the baking temperature is 150-200° C., and the baking time is 10-30 minutes.

10. The preparation method according to claim 8, characterized in that: In step S1, low saturated fat is stirred for 1 to 4 minutes, white sugar is added and stirred for 1 to 4 minutes, and then whole egg liquid is added and stirred for 1 to 4 minutes; in step S2, baking powder and baking soda are added to the product of step S1, stirred for 1 to 4 minutes, and low-gluten wheat flour is added and stirred for 10 to 25 seconds to obtain dough.

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