Low-saturation oil and application thereof for improving oxidation stability and quality of shortbread

Abstract

The present application relates to a kind of low saturated oil and its application for improving the oxidation stability and quality of shortbread, belonging to the field of baked food processing.The present application provides the preparation method of low saturated oil: saturated fat and high oil acid oil are heated in water bath, after high-speed shearing, ultrasonic treatment, quench kneading, and low saturated oil is obtained;It also provides the preparation method of shortbread: low saturated oil is added into white sugar and stirred, whole egg liquid is stirred evenly;Baking powder and baking soda are added and stirred evenly, low-gluten wheat flour is added and stirred evenly, and dough is obtained;Shortbread cake blank is made from dough and baked to obtain shortbread.The shortbread made of low saturated oil has excellent sensory quality: good blooming effect, oiliness and crispness in mouth, rich sweet flavor and good oil retention effect;While reducing saturated fatty acid, the oxidation stability is well maintained, and the shelf life is extended.

Description

Technical Field

[0001] This invention relates to a low-saturated oil that improves the oxidative stability and quality of peach shortbread and its application, belonging to the field of baking food processing. Background Technology

[0002] Peach shortbread is a traditional Chinese pastry made by mixing wheat flour, oil (25%–35%), white sugar, eggs, and other ingredients, and then baking it. Currently, commercially available peach shortbread often uses solid palm oil and lard, which gives it its crumbly and delicious texture, but its saturated fatty acid content is high (45%–55%), and long-term consumption can easily lead to obesity and cardiovascular disease. Appropriate intake of unsaturated fatty acids helps lower the level of low-density lipoprotein cholesterol in the blood, which is more beneficial to cardiovascular health. However, oils high in unsaturated fatty acids are more prone to oxidation. CN104430757A provides a recipe for peach shortbread using liquid oil. The recipe is simple and safe to consume, but no sensory quality issues have been reported with peach shortbread made using this recipe. CN115226783A discloses a method for preparing low-saturated fatty acid shortbread oil, which involves melting and mixing vegetable oil and animal oil separately, adding a small molecule emulsifier, and finally obtaining a low-fat shortbread oil that does not contain trans fatty acids and has good plasticity. However, this shortbread oil contains a lot of water and emulsifier, making it suitable for shortbread pastries such as croissants and egg tarts. For low-moisture pastry systems such as peach shortbread, this type of low-saturated fatty acid shortbread oil may not be suitable and may be detrimental to the oxidative stability of peach shortbread products.

[0003] To improve the oxidative stability of peach shortbread and extend its shelf life, commercially available products mainly use the addition of antioxidants. Synthetic antioxidants such as TBHQ, BHT, BHA, and PG are widely used due to their low cost and strong antioxidant activity in oils. However, the safety of synthetic antioxidants remains controversial, as they do not meet consumer demand for clean labels and healthy foods. Some studies have also explored the use of natural antioxidants to extend the shelf life of peach shortbread, but their application is not as widespread as that of synthetic antioxidants, possibly due to their relatively higher cost and easier 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' expectations for healthy eating, and to improve the antioxidant properties and sensory quality of peach crisp products, thereby extending their shelf life. Summary of the Invention

[0005] [Technical Issues]

[0006] Commercially available peach crisps suffer from high saturated fatty acid content, insufficient oxidative stability, and poor sensory quality. Adding antioxidants to extend shelf life increases costs and raises safety concerns. There is an urgent need to develop a natural, green, and safe method to improve the antioxidant properties and sensory quality of peach crisps, while also reducing their fatty acid saturation.

[0007] [Technical Solution]

[0008] This invention addresses the aforementioned problems by developing a low-saturated oil and its application to improve the oxidative stability and quality of peach shortbread. Through optimized ultrasonic-assisted rapid cooling crystallization technology for saturated fats and high-oleic fats, a low-saturated oil specifically for peach shortbread with optimal antioxidant properties is obtained and used in the production of peach shortbread. This reduces the saturated fatty acid content of the product while simultaneously improving its oxidative stability and sensory quality. This invention utilizes a wider range of inexpensive raw materials, reducing costs while increasing the product's nutritional value, and the processing method is simple and easy to operate.

[0009] The first objective of this invention is to provide a method for preparing low-saturated oils, comprising the steps of:

[0010] S1. Saturated fat and high oleic acid oil are heated in a water bath to obtain an oil composition;

[0011] S2. The oil composition is subjected to high-speed shearing followed by ultrasonic treatment;

[0012] S3. Quickly cool and knead the product from step S2 to obtain low-saturation oil.

[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, tea seed oil, and olive oil; the mass ratio of saturated fat to high oleic oil is 2-3:1-2; and 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 30-35℃.

[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. Water bath heating melts saturated fats and high-oleic oils and removes their 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 high-speed shearing time is 5-10 min.

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

[0019] In one embodiment of the present invention, in step S2, the pulse width of the ultrasonic treatment is: 20-40 seconds for each ultrasonic treatment, followed by a 5-15 second pause.

[0020] In one embodiment of the present invention, in step S3, the temperature of the refrigerant used for rapid cooling is -7 to -5°C, the rapid 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] A second objective of this invention is to provide a low-saturation oil prepared by the above-described preparation method.

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

[0023] A third objective of this invention is to provide the application of the aforementioned low-saturated oils in the food industry.

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

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

[0026] The fourth objective of this invention is to provide a peach shortbread made with the aforementioned low-saturated fat; the raw materials include low-saturated fat, white sugar, whole egg liquid, baking powder, baking soda and low-gluten wheat flour; the mass parts of each raw material 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.

[0027] In one embodiment of the present invention, the preferred mass proportions of the ingredients for peach crisp are: 160 parts of low-saturated oil, 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 fat in the low saturated oil used in the peach crisp raw material is preferably 3:1 to 2.

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

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

[0031] S2. Add 5-6 parts baking powder and 4-5 parts baking soda to the product of step S1, mix well, add 250-270 parts low-gluten wheat flour, mix well, and obtain dough.

[0032] S3. Divide the dough into small portions and place them in the mold to make peach shortbread dough;

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

[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 oil is stirred for 1 to 4 minutes, then 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.

[0037] In one embodiment of the present invention, in step S2, baking powder and baking soda are added to the product of step S1, and the mixture is stirred for 1 to 4 minutes. Then, low-gluten wheat flour is added and the mixture is 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 26-34g.

[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] This invention utilizes ultrasonic-assisted rapid cooling crystallization technology to produce a low-saturated oil specifically for peach crisps. The oil contains 60%–71% unsaturated fatty acids and has an oxidation induction time of 15.61–16.67 hours, exhibiting excellent antioxidant properties while reducing oil saturation. Applying this oil to peach crisps reduces the saturated fatty acid content while maintaining good oxidative stability and extending shelf life, aligning with modern healthy eating habits.

[0042] The prepared low-saturated oil possesses a certain degree of extensibility. When applied to peach shortbread, it is distributed in layers between the protein and starch during ingredient mixing, enhancing the sliding properties between these components. The prepared low-saturated oil has a low solid fat content and low fluidity, which helps increase the internal porosity of the peach shortbread, reducing its hardness and making it crisp and delicious. Compared to commercially available peach shortbread, the resulting product has superior sensory qualities: better blooming effect, a richer and crispier texture, a more intense and sweet roasted flavor, and better oil retention.

[0043] The method of this invention can well meet consumers' demand for delicious, convenient and healthy new Chinese-style pastries. Moreover, this method is highly operable, which is not only easy to produce at home, but can also be expanded to industrial production and control, which can bring considerable economic benefits. Attached Figure Description

[0044] Figure 1 Microstructure diagrams of the defatted peach crisp powders obtained in Examples 4-6 and Comparative Examples 5, 6, and 10: 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 represents the acid value determination results of the accelerated shelf-life prediction experiment for the peach crisps obtained in Examples 4-6 and Comparative Examples 5, 6, and 10; Figure 2 B represents the peroxide value determination results of the accelerated shelf-life prediction experiment for the peach crisps obtained in Examples 4-6 and Comparative Examples 5, 6, and 10. Detailed Implementation

[0046] The following examples are used to illustrate the present invention, but do not limit the scope of the 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 all 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) Fatty acid composition determination: Take 20 mg of oil sample, add 2 mL of 0.5 mol / L KOH-CH3OH solution, and saponify in a 65℃ constant temperature water bath for 30 min. Then add 2 mL of BF3-CH3OH (1:3, v / v) solution, and heat in a 70℃ constant temperature water bath for 10 min, then cool to room temperature. Add 2 mL of chromatographic grade n-hexane and shake vigorously for 1-2 min. After standing and separating the layers, take the supernatant, filter through a membrane, and perform gas chromatography analysis. Gas chromatography conditions: Thermo Fisher Trace TR-FAME column, 60 m × 0.25 mm × 0.25 μm, 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: 1 μL; split ratio: 20; column flow rate: 1.8 mL / min. The qualitative and relative quantification of fatty acids were performed using a mixed standard of 52 fatty acid methyl esters.

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

[0051] (3) The content of vitamin E in oils and fats was determined by reversed-phase high-performance liquid chromatography in GB / T 5009.82-2016.

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

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

[0054] (6) Extraction of oil from peach crisp and determination of oil oxidation: The oil in peach crisp was extracted using the Soxhlet extraction method as described in GB5009.6-2016 "Determination of Fat in Food". The acid value, peroxide value, and anisidine value of the oil extracted from peach crisp were determined according to GB5009.229-2016 "National Food Safety Standard - Determination of Acid Value in Food", GB5009.227-2016 "National Food Safety Standard - Determination of Peroxide Value in Food", and GB / T24304-2009 "Determination of Anisidine Value in Animal and Vegetable Oils". The total oxidation value was calculated using the formula: Total Oxidation Value = 4 × Peroxide Value + Anisidine Value.

[0055] (7) Accelerated shelf-life prediction test: The accelerated shelf-life test (ASLT) model was used to predict the shelf life. Specifically, the peach crisps were stored at 60°C and 60% humidity to accelerate the generation of acid value and peroxide value of oil in the peach crisps. The acid value and peroxide value of each group of samples were measured every 5 days. When the acid value or peroxide value of the peach crisps exceeded the national standard requirements, it was the end of the shelf life.

[0056] (8) Color measurement: The color of the sample was measured using an SC-10 colorimeter (Shenzhen Sanenshi Technology Co., Ltd.). The sample was packaged in a transparent self-sealing bag. The color of the sample was represented by L*, a*, and b*. Three points were selected for measurement, and the measurement was repeated three times.

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

[0058] (10) Oil holding capacity determination: Take five sheets of dried filter paper and record their mass as W1. Weigh 7±0.5g of peach crisp (cut the peach crisp 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 crisp and record it as W2. After the peach crisp has been 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 capacity of the peach crisp according to the following formula.

[0059]

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

[0061] (12) Scanning electron microscopy observation: The shape and distribution of protein and starch in the defatted peach crisp powder were observed using a SU8220 cold field emission scanning electron microscope (Hitachi, Japan). A small amount of dry defatted peach crisp powder was coated onto a silicon dioxide chip substrate, and then sputtered with gold for scanning observation. The voltage was 3.0 kV and the magnification was 1.2 k.

[0062] Table 1

[0063]

[0064]

[0065] Example 1

[0066] A low-saturated fat specifically for peach shortbread, with a predicted unsaturated fatty acid content of 64.5%, is prepared using the following steps:

[0067] S1. Place medium-melting-point (32℃) palm oil and high-oleic rapeseed oil in a clean and dry beaker with a mass ratio of 3:1, heat in a 75℃ water bath to melt, and stir at 450 rpm for 20 min to remove crystal memory and obtain an oil composition.

[0068] S2. The oil composition was sheared at 9000 rpm for 8 min, and then ultrasonically treated at 470W power for 2 min with a pulse width of , with a 30s ultrasonic treatment followed by a 10s pause.

[0069] S3. The product from step S2 is rapidly cooled and kneaded. The temperature of the refrigerant for rapid cooling is -5℃, and the cooling time is 7s. The kneading speed is 100rpm, and the kneading time is 15min to obtain low-saturation oil.

[0070] Example 2

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

[0072] Example 3

[0073] A low-saturated oil specifically for peach crisps, with a predicted unsaturated fatty acid content of 74%, is prepared in a method that differs from Example 1 in that the mass ratio of medium-melting-point palm oil to high-oleic rapeseed oil is 1:1.

[0074] Comparative Example 1

[0075] Purchase a popular peach shortbread product and extract its oil.

[0076] Comparative Example 2

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

[0078] Comparative Example 3

[0079] A low-saturated oil, the preparation method of which differs from that of Comparative Example 2, is 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 differs from that of Comparative Example 2, is that the mass ratio of medium-melting-point palm oil and 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, commercially available rapeseed oil, and oil extracted from commercially available peach crisp were determined. The vitamin C content of medium-melting-point palm oil, high-oleic rapeseed oil, and commercially available rapeseed oil was also determined. E The contents of sterols and squalene are shown in Tables 2, 3 and 4.

[0083] Table 2

[0084]

[0085] Table 3

[0086]

[0087]

[0088] Table 4

[0089]

[0090] As can be seen from Tables 2-4:

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

[0092] (2) The main difference in fatty acid composition between high-oleic rapeseed oils and ordinary commercially available oils lies in the content of oleic acid (C18:1) and polyunsaturated fatty acids (PUFAs). The table shows that high-oleic rapeseed oil has 18.41% more oleic acid and 16.41% less polyunsaturated fatty acids than ordinary commercially available rapeseed oil. Vitamin E, sterols, and squalene possess certain antioxidant properties, but the content of these trace antioxidant active ingredients differs between the two. Furthermore, the oxidation induction time of high-oleic rapeseed oil is 1.82 times that of ordinary commercially available rapeseed oil, indicating that increasing the oleic acid content helps improve the oxidative stability of the oil.

[0093] (3) The oxidation induction time of Examples 1-3 was 15.61-16.67 h, which was not significantly different from the oxidation induction time of commercially available peach crisp oil. The proportion of high-oleic rapeseed oil in Examples 1-3 increased sequentially. With the increase of the proportion of high-oleic rapeseed oil, the content of monounsaturated fatty acids (MUFA) in the oils of Examples 1-2 increased by 6.76%, which was significantly greater than the increase in the content of monounsaturated fatty acids in the oils of Examples 2-3; the increase in the content of polyunsaturated fatty acids in the oils of Examples 1-2 was not significant, while the content of polyunsaturated fatty acids in the oils of Examples 2-3 increased significantly by 1.32%. Furthermore, as shown in Table 3, high-oleic rapeseed oil is rich in sterols, with a sterol content 774 mg / 100 g higher than that of medium-melting-point palm oil. Therefore, when the proportion of high-oleic rapeseed oil was increased, the phenomenon of the oil oxidation induction time first increasing and then decreasing in this invention occurred, 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 prone to oxidation. However, the low-saturated oils prepared by this invention have a higher oxidation induction time while reducing saturation.

[0094] Example 4

[0095] A type of peach shortbread, the preparation method includes the following steps:

[0096] S1. Adjust the mixer speed to 550 rpm, mix 160g of the low-saturated oil prepared in Example 1 for 2 minutes, add 110g of white sugar and mix for 2 minutes, add 25g of whole egg liquid and mix for 2 minutes;

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

[0098] S3. Divide the dough into small portions of 30±0.1g and place them in the mold to make peach shortbread dough;

[0099] S4. Bake the dough in a preheated oven at 180℃ for 20 minutes, then cool to room temperature to obtain peach shortbread.

[0100] Example 5

[0101] A type of peach shortbread, the preparation method of which differs from that of Example 4, is that the low-saturated oil prepared in Example 1 is replaced with the low-saturated oil prepared in Example 2.

[0102] Example 6

[0103] A type of peach shortbread, the preparation method of which differs from that of Example 4, is that the low-saturated oil prepared in Example 1 is replaced with the low-saturated oil prepared in Example 3.

[0104] Comparative Example 5

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

[0106] Comparative Example 6

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

[0108] Comparative Example 7

[0109] A type of peach shortbread, the preparation method of which differs from that of Example 4, is that the low-saturated oil prepared in Example 1 is replaced with the low-saturated oil prepared in Comparative Example 2.

[0110] Comparative Example 8

[0111] A type of peach shortbread, the preparation method of which differs from that of Example 4, is that the low-saturated oil prepared in Example 1 is replaced with the low-saturated oil prepared in Comparative Example 3.

[0112] Comparative Example 9

[0113] A type of peach shortbread, the preparation method of which differs from that of Example 4, is that the low-saturated oil prepared in Example 1 is replaced with the low-saturated oil prepared in Comparative Example 4.

[0114] Comparative Example 10

[0115] Choose peach shortbread with good market sales, and ensure that the production date of the purchased peach shortbread is consistent with that of Examples 4-6 and Comparative Examples 5-9.

[0116] Sensory evaluations were conducted on the peach crisps from Examples 4-6, Comparative Examples 5-6, and Comparative Example 10, measuring their color, hardness, and oil retention. Oil was extracted to determine acid value, peroxide value, anisidine value, and total oxidation value. A shelf-life prediction experiment was then performed on the peach crisps. Sensory evaluations were also conducted on Comparative Examples 7-9, measuring their color, hardness, and oil retention. The analytical results of the different peach crisps are shown in Table 4, and the sensory evaluation results are shown in Table 5.

[0117] Table 5

[0118]

[0119]

[0120] Table 6

[0121] 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] As can be seen from Tables 5 and 6:

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

[0124] (2) Fats play an important role in baked goods, altering the structure and texture of peach shortbread. For example... Figure 1 As shown, regarding Comparative Example 5 ( Figure 1 a) Due to the high solid fat content of medium-melting-point palm oil, it lacks fat spreading ability. During the mixing process, the oil is broken down into small fragments distributed between the protein and starch. Therefore, after baking, the microstructure of the defatted peach shortbread powder shows many small pores, indicating that the distribution of fat particles in the peach shortbread matrix is ​​discontinuous. Comparative Example 6 ( Figure 1 e) It can be seen that the protein and starch are tightly arranged, which may be because high-oleic rapeseed oil is a pure liquid oil with high fluidity. During baking, it is easy for water vapor inside the peach crisp to penetrate to the surface of the peach crisp, thus reducing the porosity inside the peach crisp. Example 5 ( Figure 1 c) and Comparative Example 10 Figure 1 f) The microstructures are quite similar, with the appearance of sheet-like protein-starch aggregates. This may be because the appropriate fatty acid composition gives the oil a certain degree of extensibility. When the raw materials are mixed, the oil is distributed in layers between the protein and starch, which enhances the sliding property between the protein and starch and avoids a rough texture in the final product.

[0125] (3) Hardness is a physical property that is closely related to the texture and taste of peach crisps. The peach crisp made with medium melting point palm oil (Comparative Example 5) is harder than that made with commercially available peach crisps (Comparative Example 10). This may be because of its high solid fat content. After baking and cooling, the fat filling the spaces between the protein and starch crystals, increasing the hardness. Furthermore, the peach crisp does not melt easily in the mouth and tends to stick, thus affecting its taste. The peach crisp made with high oleic rapeseed oil (Comparative Example 6) is harder than that made with commercially available peach crisps (Comparative Example 10). This may be because high oleic rapeseed oil is a pure liquid oil with high fluidity. During baking, it easily penetrates to the surface of the peach crisp with the water vapor inside, reducing the porosity inside the peach crisp. The protein and starch are tightly packed together, resulting in a hard texture and a rough mouthfeel. However, the peach crisps made with low saturated oil in Examples 4-6 show a gradual decrease in hardness as the proportion of high oleic rapeseed oil increases, and the hardness is significantly lower than that made with 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 the low-saturated oil gradually decreases, and the fluidity of the oil also weakens. The synergistic effect of the two oils increases the porosity inside the peach crisp, resulting in a peach crisp that is low in hardness and crumbly and delicious. Therefore, the peach crisp made with the low-saturated oil of this invention has a better blooming effect, a loose texture, a crisp taste, good melt-in-your-mouth properties, and a higher sensory score.

[0126] (4) Compared with peach crisps made with medium melting point palm oil (Comparative Example 5), peach crisps made with low saturated oils in Examples 1-3 (Examples 4-6) have higher flavor sensory scores. Using only simple natural ingredients, the flavor sensory scores can be close to or even higher than those in Comparative Example 10 (commercially available peach crisps), indicating that the peach crisps made with low saturated oils of the present invention have a richer, sweeter flavor.

[0127] (5) Compared with peach crisps made from high-oleic rapeseed oil (Comparative Example 6) and commercially available peach crisps (Comparative Example 10), peach crisps made from low-saturated oils (Examples 4-6) have lower acid value and total oxidation value and higher oil holding capacity, indicating that the peach crisps made from low-saturated oils of the present invention have high oil holding capacity and good oxidative stability.

[0128] (6) Comparing Examples 4-6 with Comparative Examples 7-9, it can be seen that the low-saturated oils treated with ultrasonic synergistic rapid cooling crystallization resulted in a significant reduction in the hardness and oil penetration rate of the peach crisps. Furthermore, the sensory scores of the peach crisps were higher than those of the group that had not undergone ultrasonic synergistic rapid cooling crystallization treatment. This indicates that the low-saturated oils produced by ultrasonic synergistic rapid cooling 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 cause of product quality decline during shelf life, and the best taste and flavor of the product are also affected by oil oxidation. Acid value can be used as an indicator of oil quality deterioration, which determines the content of free fatty acids produced by triglyceride hydrolysis; peroxide value can indicate the amount of hydroperoxide contained in oil, thereby judging the degree of oil oxidation. The national standard stipulates that the acid value of baked goods is ≤5mg / g and the peroxide value is ≤0.25g / 100g. Figure 2 The results of the accelerated shelf-life prediction experiment for peach crisps prepared in Examples 4-6 and Comparative Examples 5, 6, and 10 are the determination results of acid value and peroxide value.

[0130] It can be seen that the acid value of the peach crisp in Comparative Example 6 exceeded 5 mg KOH / g after 25 days of storage, indicating that the shelf life of this sample under storage conditions of 60°C and 60% humidity was only 25 days; the peroxide value of commercially available peach crisp (Comparative Example 10) exceeded 0.25 g / 100g after 35 days of storage, and the shelf life of this sample was 35 days; while the shelf life of 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 peach crisps during storage, thereby extending the shelf life of peach crisps.

[0131] (8) In a comprehensive comparison, the peach crisps made in Examples 4 and 5 had higher overall sensory scores, higher oil holding rate, lower total oxidation value, and longer shelf life. This indicates that the peach crisps made with low saturated oils of the present invention can improve product quality while reducing saturated fatty acids, making the overall sensory acceptance greater, and maintaining good product oxidative stability, thus extending the shelf life.

Claims

1. A method for preparing low-saturated oils to improve the oxidative stability and quality of peach crisps, characterized in that, Including the following steps: S1. Saturated fat and high oleic acid oil are heated in a water bath to obtain an oil composition; the water bath heating temperature is 70~80℃ and the water bath heating time is 20~30 min. S2. The oil composition is subjected to high-speed shearing followed by 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. The product from step S2 is rapidly cooled and kneaded to obtain low-saturated oil; the refrigerant temperature for rapid cooling is -7~-5℃, the rapid cooling time is 5~10 s; the kneading time is 10~20 min. 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, tea seed 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%; The low-saturated oil has an unsaturated fatty acid content of 60%~71% and an oxidation induction time of 15.61~16.67h.

2. The low-saturation oil prepared by the method of claim 1.

3. Peach shortbread made using the low-saturated oil described in claim 2.

4. The peach shortbread according to claim 3, characterized in that, The ingredients and their weight proportions are as follows: 150-170 parts of low-saturated oil, 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.

5. The method for preparing peach shortbread according to claim 4, characterized in that, Including the following steps: S1. Stir 150-170 parts of low-saturated oil, add 100-120 parts of white sugar and stir well, then add 20-30 parts of whole egg liquid and stir well. S2. Add 5-6 parts baking powder and 4-5 parts baking soda to the product of step S1, mix well, add 250-270 parts low-gluten wheat flour, mix well, and obtain dough. S3. Divide the dough into small portions and place them in the mold to make peach shortbread dough; S4. Bake the dough in an oven to obtain peach shortbread.

6. The preparation method according to claim 5, characterized in that, In step S4, the baking temperature is 150~200℃ and the baking time is 10~30 min.

7. The preparation method according to claim 5, characterized in that, In step S1, stir the low-saturated fat for 1-4 minutes, then add the white sugar and stir for 1-4 minutes, then add the whole egg liquid and stir for 1-4 minutes; in step S2, add baking powder and baking soda to the product of step S1, stir for 1-4 minutes, then add low-gluten wheat flour and stir for 10-25 seconds to obtain dough.

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