Active peptide anti-freezing cake and processing method thereof

Abstract

The invention relates to an active peptide anti-freezing cake and a processing method thereof. The active peptide is prepared from the red yeast rice dregs, and the active peptide microfibril capsule is prepared by surface deposition through electrostatic adsorption, so that the bitter taste of the active peptide is improved. The active peptide microfibril capsule is applied to preparation of the cake, so that the freezing resistance of the product is improved, the bad taste of the cake product caused by the bitter taste of the active peptide is well masked, and the frozen storage quality of the cake is improved; the hardness, elasticity, cohesiveness, chewiness and resilience of the frozen cake are kept close to corresponding indexes of a freshly prepared cake, and the frozen cake has no obvious taste difference from the freshly prepared cake.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and more specifically relates to an active peptide antifreeze cake and a processing method thereof. Background Art

[0002] Cakes are fluffy and have a moist and soft taste, making them popular among consumers. However, cakes have a short shelf life when stored at room temperature or in cold conditions. During the frozen storage process, cakes undergo complex physical and chemical changes, such as starch recrystallization, internal water migration and redistribution, and ice crystal formation, which lead to starch aging, dry cake core, and destruction of starch and gluten structures, affecting product quality. How to effectively control the quality deterioration of frozen cakes is an urgent problem that needs to be solved in the baking industry.

[0003] Active peptides have multiple physiological functions such as antibacterial and antifreeze, but the exposure of hydrophobic residues produces a certain bitterness when interacting with taste cells, resulting in poor flavor and taste of active peptides, limiting their scope of application. At present, antifreeze peptides are mostly used in fish paste and dough products. For example, patent document CN113897409B discloses the preparation of antifreeze active peptides from large yellow croaker and their application in fish paste, and patent document CN109943612B discloses the preparation of antifreeze peptides from silver carp scales and their application in frozen fish paste. These antifreeze peptides have the fishy smell of the raw materials themselves, so they can only be applied to similar marine fish products. Patent document CN115896218A discloses the application of a highly active plant-derived antifreeze peptide in frozen dough, and patent document CN118489831A discloses a method for preparing cowhide gelatin antifreeze peptides to improve frozen dough steamed buns, but these antifreeze peptides only improve the texture of the product, and the flavor of the product is not evaluated. It can be seen that the current application of active peptides in food processing technology has problems such as poor flavor and taste. At the same time, there are no reports on the improvement of the freezing quality of frozen cake products by antifreeze peptides. Therefore, how to improve the bitterness of peptides and improve the frozen storage quality of cakes while improving the antifreeze properties of cake products is the main problem facing the current technology. Summary of the invention

[0004] To this end, the present invention provides an active peptide antifreeze cake and a processing method thereof, in order to achieve the following purposes: 1) effectively controlling the quality deterioration of frozen cakes and improving product texture; 2) the active peptides inhibit the growth of ice crystals in frozen cakes, weaken the damage of ice crystals to the internal structure of frozen cakes, and increase the freeze-thaw stability of frozen cakes; 3) improving the bitterness of the active peptides and reducing their impact on the taste of the product.

[0005] To achieve the above object, in a first aspect, the present invention provides a method for processing an active peptide antifreeze cake, comprising the following steps:

[0006] preparing active peptides;

[0007] Preparation of acid-etched oat microfibrils;

[0008] The active peptide is adsorbed on the acid-etched oat microfibril through electrostatic adsorption for surface deposition to prepare active peptide microfibril capsules; the active peptide microfibril capsules are added to cake batter and baked to obtain active peptide antifreeze cakes.

[0009] Different from the existing technology, the above technical scheme adopts acid etching of oat dietary fiber to prepare a microfibril carbon-based skeleton support loaded with active peptides, and prepares active peptide microfibril capsules by electrostatic adsorption during the spray drying process, thereby improving the gastrointestinal tolerance of the active peptides and masking the bitterness of the active peptides. The capsules are applied to the preparation process of cakes, which greatly reduces the bitterness of the peptides while improving the frost resistance of frozen cake products, thereby improving the defect of the active peptides causing a bad taste to the product and improving the frozen storage quality of the cakes.

[0010] In some preferred embodiments of the present invention, the active peptide is a red yeast rice active peptide, and the processing method thereof comprises the following steps: weighing red yeast rice, adding water and mixing evenly in a ratio of lees: water = 1:8-1:12 according to the mass fraction; adding papain for enzymolysis, wherein the amount of papain added is 5000-7000U / g, the enzymolysis time is 1.5-2h, the enzymolysis temperature is 45-50°C, and the pH value is 5.5-6; after inactivating the enzyme, centrifuging and collecting the supernatant, ultrafiltration, collecting the dialyzed fraction with a molecular weight less than 1kDa, and obtaining the active peptide. In these embodiments, the active peptide is prepared by enzymolysis of red yeast rice, and the nutrients in red yeast rice are fully recycled and utilized, and the processing method of the active peptide is efficient and environmentally friendly, which effectively expands the application of red yeast rice resources.

[0011] In some preferred embodiments of the present invention, the steps of preparing the acid-etched oat microfibrils include the following:

[0012] The oat dietary fiber is ultra-finely crushed at low temperature to obtain ultra-fine oat dietary fiber;

[0013] The superfine oat dietary fiber is prepared into a superfine oat dietary fiber suspension with a mass concentration of 8-12 g / L by using citric acid;

[0014] The ultrafine oat dietary fiber suspension is subjected to an ultrasonic-autoclave treatment, wherein the autoclave temperature is 120° C., the time is 50-60 min, and the ultrasonic power is 800 W, and further subjected to a wet ball milling treatment to obtain the acid-etched oat microfibrils.

[0015] These embodiments improve the dispersibility of oat dietary fiber by low-temperature ultrafine grinding, prepare ultrafine oat dietary fiber suspension with citric acid and treat with ultrasonic-autoclave reactor to help loosen the fiber structure and regulate the fiber pore structure to prepare a carbon-based skeleton, and wet ball milling further refines the fiber, making its support easier to load active peptides.

[0016] In a more preferred embodiment, the molar concentration of the citric acid is 1-1.2 mol / L. Citric acid at this concentration can effectively etch oat dietary fiber.

[0017] In some preferred embodiments of the present invention, the grinding speed during the wet ball milling treatment is 5000 r / min and the grinding time is 90-100 min. This can ensure that the oat dietary fiber is fully refined to obtain evenly distributed acid-etched oat microfibrils, thereby improving its dispersibility and stability in the cake.

[0018] In some preferred embodiments of the present invention, in the preparation step of the active peptide microfibril capsule, the mixing mass ratio of the active peptide and the acid-etched oat microfibril is 5:1, the pH is adjusted to 7.0, and the active peptide microfibril capsule is prepared by surface deposition through electrostatic adsorption during the spray drying process, wherein the inlet temperature is 180°C, the outlet temperature is 90°C, and the flow rate is 600 mL / h. This mixing ratio, pH and spray drying conditions can ensure that the active peptide and the acid-etched oat microfibril are fully electrostatically adsorbed to produce surface deposition, forming a stable active peptide microfibril capsule. It has been verified by experiments that the inlet temperature, outlet temperature and flow rate of the spray drying are set in this way, which can dry faster and efficiently prepare active peptide microfibril capsules.

[0019] In some preferred embodiments of the present invention, when the active peptide microfibril capsule is added to the cake batter, the amount of the active peptide microfibril capsule added is 1‰ to 2‰ of the total weight of the cake batter. This amount of addition can ensure that the cake introduces sufficient active peptides and fiber components while maintaining the original taste and texture. The addition amount is moderate and will not affect the overall flavor and taste of the cake.

[0020] In some preferred embodiments of the present invention, the baking step comprises:

[0021] Pour the batter of the active peptide antifreeze cake into the mold and shake out the bubbles;

[0022] Put it in the preheated oven, top fire 200℃, bottom fire 150℃, bake for 16 minutes;

[0023] After taking it out, turn it upside down and let it cool before demoulding.

[0024] This baking step can ensure that the cake is evenly heated, and the baked cake is golden in color and soft in taste. Turning the cake upside down to cool and removing it from the mold can prevent the cake from deforming and collapsing, and maintain its complete shape and taste.

[0025] In a second aspect, the present invention provides an active peptide antifreeze cake obtained by the processing method described in the first aspect of the present invention.

[0026] Preferably, the bitterness response value of the active peptide antifreeze cake is 1.12 to 1.76, and the relative crystallinity of starch is less than 15%. In the prior art, the bitterness response value of cakes prepared with active peptides is between 3.4 and 4.1, and the relative crystallinity of starch is more than 16%; the bitterness response value of cakes prepared with active peptide microfibril capsules is between 1.12 and 1.76, which shows that the active peptide microfibril capsules significantly mask the bitterness of the active peptides, increase the viscosity of the cake, lock in moisture, and hinder the recrystallization of starch particles, thereby reducing the crystallinity of the cake during frozen storage and reducing the deterioration of cake quality.

[0027] Preferably, after the active peptide antifreeze cake is frozen at -18°C for 14 days, the hardness, elasticity, cohesion, chewiness and recovery after thawing are close to those of the fresh active peptide antifreeze cake. It can be seen that the active peptide microfibril capsule has a significant inhibitory effect on the recrystallization of ice crystals in the cake, slowing down the formation and growth of ice crystals, thereby weakening the damage of ice crystals to the internal structure of the frozen cake, increasing the freeze-thaw stability of the frozen cake, and allowing the cake to maintain a good texture after thawing. This is of great significance for extending the shelf life of cakes and expanding their sales range.

[0028] Different from the prior art, the above technical solution uses acid-etched oat dietary fiber to prepare micron-level loose and porous micron-level oat microfibrils, mixes active peptides with acid-etched oat microfibrils, and prepares active peptide microfibril capsules through electrostatic adsorption during the spray drying process to improve the bitterness of active peptides. The active peptide microfibril capsules are applied to the preparation of cakes, which not only improves the product's antifreeze property, but also masks the unpleasant taste of the cake product caused by the bitterness of the active peptides, and improves the frozen storage quality of the cake, so that the hardness, elasticity, cohesion, chewiness, and recovery of the frozen active peptide antifreeze cake after thawing are close to those of freshly prepared cakes.

[0029] The above-mentioned records related to the invention content are only an overview of the technical solution of the present application. In order to enable ordinary technicians in the field to more clearly understand the technical solution of the present application, and then implement it according to the text of the specification and the contents recorded in the drawings, and to make the above-mentioned purpose and other purposes, features and advantages of the present application easier to understand, the following is an explanation in combination with the specific implementation mode and drawings of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings are only used to illustrate the principles, implementation methods, applications, characteristics and effects of the specific embodiments of the present application and other related contents, and shall not be considered as limitations of the present application.

[0031] In the drawings of the specification:

[0032] Figure 1 The bitter taste response value test results of the active peptides and active peptide microfibril capsules in the specific embodiments of the present invention;

[0033] Figure 2 The bitterness response value measurement results of cakes prepared by adding different amounts of active peptides and active peptide microfibril capsules according to a specific embodiment of the present invention (active peptides and active peptide microfibril capsules are configured to have a mass concentration of 1‰, 2‰, 4‰, and 6‰, respectively);

[0034] Figure 3 The peptide deposition rate of oat dietary fiber (oat fiber for short), ultrafine oat dietary fiber obtained by low-temperature ultrafine grinding (oat microfibrils for short), and acid-etched oat microfibrils obtained by ultrasonic-autoclaving treatment with citric acid solution and wet ball milling treatment were measured.

[0035] Figure 4 The hardness test results of freshly prepared cakes, frozen cakes without active peptides or active peptide microfibril capsules, and frozen cake samples prepared in Examples 1-4 of the present invention;

[0036] Figure 5 The elasticity test results of freshly prepared cakes, frozen cakes without active peptides or active peptide microfibril capsules, and frozen cake samples prepared in Examples 1-4 of the present invention;

[0037] Figure 6 The cohesion test results of freshly prepared cakes, frozen cakes without active peptides or active peptide microfibril capsules, and frozen cake samples prepared in Examples 1-4 of the present invention;

[0038] Figure 7 The chewiness test results of freshly prepared cakes, frozen cakes without active peptides or active peptide microfibril capsules, and frozen cake samples prepared in Examples 1-4 of the present invention;

[0039] Figure 8 The recovery test results of freshly prepared cakes, frozen cakes without active peptides or active peptide microfibril capsules, and frozen cake samples prepared in Examples 1-4 of the present invention;

[0040] Fig. 9 Ice crystal structure of frozen cakes with inactive peptide or active peptide microfibril capsules added;

[0041] Fig.10The ice crystal structure of the frozen cake of Example 1 of the present invention;

[0042] Fig.11 The ice crystal structure of the frozen cake of Example 2 of the present invention;

[0043] Fig.12 The ice crystal structure of the frozen cake of Example 3 of the present invention;

[0044] Fig.13 The ice crystal structure of the frozen cake of Example 4 of the present invention;

[0045] Fig.14 These are the evaluation results of in vitro digestion stability (ACE inhibition rate) of the active peptides and active peptide microfibril capsules according to the specific embodiments of the present invention. DETAILED DESCRIPTION

[0046] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0047] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0048] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0049] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0050] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0051] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0052] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0053] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0054] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0055] Unless otherwise specified, the raw materials used in the present invention, such as oats, citric acid, enzymes, flour, sugar, eggs, oil and other raw materials for preparing cakes are all from common market commodities, and it is necessary to ensure that the raw materials are fresh, pollution-free and meet food safety standards.

[0056] Unless otherwise specified, the low-temperature ultrafine pulverizer, ultrasonic-autoclave reactor, wet ball mill, spray dryer, oven, electronic balance, centrifuge, pH meter, etc. used in the present invention are all commonly used instruments and equipment in the field.

[0057] Unless otherwise specified, the operations used in the present invention are all conventional operations of the method in this technical field.

[0058] Red yeast rice is rich in various amino acids, peptide substances and beneficial microbial metabolites, and has various physiological functions such as anti-oxidation and anti-fatigue. The red yeast rice used in the present invention is purchased from Fujian Lanxi Red Wine Co., Ltd.

[0059] The relevant indicators and test methods involved in the present invention are as follows:

[0060] Peptide deposition rate analysis: The peptide deposition rate can be used to examine the electrostatic adsorption degree of active peptides by acid-etched oat microfibrils after spray drying. The spray-dried powder was taken and dissolved in water. The supernatant was the undeposited active peptides and the precipitate was the microfibril capsule. The total amount of peptides in the supernatant and the total amount of peptides in the precipitated microfibril capsule were measured respectively. The peptide deposition rate % = the total amount of active peptides in the active peptide microfibril capsule / (the total amount of peptides in the supernatant + the total amount of peptides in the precipitated microfibril capsule) * 100. Among them, the active peptide content was determined according to GBT22492-2008. The results showed that the peptide deposition rate of active peptide oat fiber was 15.43%. The peptide deposition rate can be increased to 28.42% by preparing oat microfibrils by ultrafine processing. The peptide deposition rate of acid-etched oat microfibrils was 73.64%. Compared with oat fiber, the peptide deposition rate can be significantly increased by 3.8 times by preparing oat microfibrils by acid etching.

[0061] Bitterness response value determination: The TZ-5000Z electronic tongue system (insent, Japan) was equipped with a COO bitterness sensor and data was collected at 25°C. The electronic tongue used 30 mM KCl and 0.3 mM tartaric acid as the reference solution, the sample test time was 120 s, repeated 4 times, and the last 3 sensor response values ​​were taken as sample data for analysis. The bitterness response value of the cake was determined to evaluate the effect of the active peptide microfibril capsule ingredients on the taste of the cake.

[0062] Texture analysis: The texture profile analysis (TPA) of the cake was performed using a TA-XT Express texture analyzer (Stable Micro Systems, UK). The cake was cut into 8 mm thick slices and placed flat on the texture analyzer test bench. The test parameters of the texture analyzer were: probe P / 36R, trigger force 5 g, pre-test speed 1 mm / s, test speed 5 mm / s, post-test speed 5 mm / s, displacement 10 mm, time 5s. Texture analysis includes hardness, elasticity, cohesion, chewiness, and resilience. Hardness is the maximum force value on the first peak when the sample is compressed for the first time. Elasticity is the ratio of the sample recovery height detected by the second compression to the first compression type variable. Cohesion is the ratio of the work done by the second compression to the work done by the first compression. Chewability refers to the energy required to chew a food to a swallowable level, which is the product of hardness, cohesion, and elasticity. Resilience is the ratio of the energy consumed during the first peak compression to the elastic energy after release. The texture characteristics of the cake are evaluated by measuring its hardness, elasticity, cohesion, chewiness and resilience.

[0063] Electron microscope observation: Place the frozen cake under an ultra-depth-of-field electron microscope to observe the ice crystal structure.

[0064] Example 1 An active peptide antifreeze cake and its processing method

[0065] 1) Step 1: Preparation of active peptides

[0066] Enzymatic hydrolysis: Weigh 500g of high-quality red yeast rice, add 5L of deionized water, stir evenly, add 0.5% of complex enzyme (including protease, cellulase, etc.), enzyme addition amount 6000U / g, enzymatic hydrolysis time 90min, temperature 45℃, pH 5.7. After the enzymatic hydrolysis is completed, heat to 90℃ to inactivate the enzyme. After the enzyme is inactivated, centrifuge at 10000 g / min for 15 min and take the supernatant.

[0067] Ultrafiltration and collection: The supernatant is ultrafiltered using an ultrafiltration membrane with a molecular weight cutoff of 1 kDa, and the dialyzed components smaller than 1 kDa are collected, which are the red yeast rice active peptides.

[0068] 2) Step 2: Preparation of acid-etched oat microfibrils

[0069] Ultrafine grinding: Take 100g of oat dietary fiber and use a low-temperature ultrafine grinder to grind it for about 5 hours until the particle size is less than 10μm to obtain ultrafine oat dietary fiber.

[0070] Preparation of suspension: Add superfine oat dietary fiber into 10L of citric acid solution with a molar concentration of 1mol / L, stir evenly to make the mass concentration of the suspension reach 10g / L.

[0071] Ultrasonic-autoclave treatment: The suspension was placed in an ultrasonic-autoclave reactor, the autoclave temperature was set to 120°C, the time was 50 min, and the ultrasonic power was 800 W. The oat dietary fiber filaments were further added to a zirconia ball mill and ball milled at a speed of 5000 r / min for 90 min to obtain micron-level acid-etched oat dietary fiber filaments, i.e., acid-etched oat microfibrils.

[0072] 3) Step 3: Preparation of active peptide microfibril capsules

[0073] Mixing: The active peptide (supernatant) obtained in step 1 and the acid-etched oat microfibrils (suspension) obtained in step 2 are fully mixed at a mass ratio of 5:1, and the pH value is adjusted to 7.0 with NaOH solution.

[0074] Spray drying: The mixture was spray dried, and the inlet temperature was set to 180°C, the outlet temperature was set to 90°C, and the flow rate was set to 600 mL / h. The active peptide microfibril capsule was obtained by surface deposition through electrostatic adsorption during the spray drying process. The degree of electrostatic adsorption of oat fiber to peptides was investigated by peptide deposition rate, and peptide deposition rate % = total amount of peptides in microfibril capsules / (total amount of peptides in supernatant + total amount of peptides in precipitated microfibril capsules) * 100. Among them, the peptide content was determined in accordance with GB / T 22492-2008.

[0075] 4) Step 4: Preparation of the Cake:

[0076] Active peptide antifreeze cake batter formula: 110g butter, 170g milk, 104g low-gluten flour, 43g high-gluten flour, 5g baking powder, 165g egg yolk, 100g whole egg liquid, 385g egg white, 190g sugar, 5g salt, 5g tartar powder, active peptide microfibril capsule is 1‰ of the total weight of the batter.

[0077] Preparation of batter: First, melt 110g butter with warm water and mix it with 170g milk, stir evenly until emulsified, sift in 104g low-gluten flour and 43g high-gluten flour, add 5g baking powder, make a Z-shaped stir evenly, add 165g egg yolk, 100g whole egg liquid and active peptide microfibril capsules to the batter, the amount of active peptide microfibril capsules added is 1‰ of the total weight of the batter, continue to stir evenly, and prepare egg yolk paste. Add 190g sugar, 5g salt and 5g tartar powder to 385g egg whites, and beat at high speed until the egg white hook is firm. Add the whipped egg whites to the egg yolk paste three times, stir evenly, and get the batter.

[0078] Baking: Pour the batter into the mold and shake it slightly to remove bubbles. Preheat the oven to 150℃, put the mold with batter in, set the top fire to 200℃ and the bottom fire to 150℃, bake for 20 minutes, take it out, turn it upside down and let it cool, remove it from the mold, and evenly cut it into 8mm cake slices. Frozen cakes are frozen at -18℃ for 14 days, and various tests are performed after thawing in the refrigerator.

[0079] Example 2 A kind of active peptide antifreeze cake and its processing method (the addition amount of active peptide microfibril capsule is adjusted to 2‰)

[0080] The method is basically the same as Example 1, but the addition amount of the active peptide microfibril capsule is adjusted to 2‰ of the total weight of the cake batter to investigate the effects of different addition amounts on the bitterness and texture of the cake.

[0081] Example 3 A kind of active peptide antifreeze cake and its processing method (the addition amount of active peptide microfibril capsule is adjusted to 4‰) Active peptide

[0082] The method is basically the same as Example 1, but the addition amount of the active peptide microfibril capsule is adjusted to 4‰ of the total weight of the cake batter to investigate the effects of different addition amounts on the bitterness and texture of the cake.

[0083] Example 4 A kind of active peptide antifreeze cake and its processing method (the addition amount of active peptide microfibril capsule is adjusted to 6‰) Active peptide

[0084] The method is basically the same as Example 1, but the addition amount of the active peptide microfibril capsule is adjusted to 6‰ of the total weight of the cake batter to investigate the effects of different addition amounts on the bitterness and texture of the cake.

[0085] Example 5 Preparation of control group cake

[0086] Step 4 of Example 1 was repeated, except that the common active peptide prepared in Step 1 of Example 1 was added.

[0087] Example 6 Bitterness response value of active peptide and active peptide microfibril capsule detected by electronic tongue

[0088] The active peptide and active peptide microfibril capsule prepared in Example 1 were respectively prepared into solutions with mass concentrations of 1‰, 2‰, 4‰, and 6‰. The bitter taste response values ​​detected by electronic tongue were as follows: Figure 1 As shown. Figure 1 It can be seen that the bitter response values ​​of active peptides at different concentrations are between 5.24 and 5.81, while the bitter response values ​​of active peptide microfibril capsules at different concentrations are between 1.84 and 2.67, which are significantly lower than the bitter response values ​​of active peptides. This shows that the active peptide microfibril capsules significantly mask the bitterness of the active peptides.

[0089] Example 7 Bitterness response value of cake detected by electronic tongue

[0090] Sample preparation:

[0091] 100 g of cake samples prepared with different addition amounts of active peptides and active peptide microfibril capsules in Examples 1-4 were taken respectively, crushed, added with 300 mL of pure water, homogenized for 10 min, and centrifuged at 6000 G / min for 15 min to obtain samples to be tested.

[0092] Electronic tongue test: Take the supernatant and use the electronic tongue to perform the bitterness test described in the bitterness response value determination method above. Take the last three sensor response values ​​as sample data for analysis. The analysis results are as follows: Figure 2 shown.

[0093] Result analysis: From Figure 2 It can be clearly seen that the bitterness response value of the cake prepared with ordinary active peptides is between 3.4 and 4.1; while the bitterness response value of the cake prepared with the active peptide microfibril capsules of the present invention is between 1.12 and 1.76. The microfibril capsules significantly reduce the bitterness of the active peptides.

[0094] Example 8 Crystallinity Analysis

[0095] The relative crystallinity of starch in frozen cakes was determined by X-ray diffractometer. The powder of the frozen cake core after freeze-drying and grinding was placed in the lead sheet hole for determination. Determination parameters: voltage 45kV, current 40mA. Scanning range 5°~45°, scanning rate 0.02°, continuous scanning, using MDI Jade 6.0 software for analysis, the results are shown in Table 1.

[0096] Table 1 Relative crystallinity of starch in cakes of Examples 1-4 of the present invention and the control group

[0097] Active peptide microfibril capsule addition amount (‰) Relative crystallinity (%) Comparison 16.64 1 14.61 2 13.42 4 12.94 6 11.95

[0098] The crystallinity of starch is closely related to the degree of aging. High crystallinity provides a large number of ordered areas for starch molecules to form crystal cores, which promotes the molecular rearrangement during the aging process, leading to moisture loss in the heart of the cake, increased hardness, and cake crumbs. Therefore, the higher the crystallinity, the faster the aging rate and the worse the cake quality. Compared with the control, with the increase in the amount of active peptide microfibril capsules added, the crystallinity of starch in the core of the cake showed a downward trend. The above comparison shows that active peptide microfibril capsules can increase the viscosity of the cake, lock in moisture, and hinder the recrystallization of starch granules, thereby reducing the crystallinity of the cake during frozen storage and reducing the deterioration of cake quality.

[0099] Example 9 Analysis of peptide deposition rates of several different oat fibers / microfibrils

[0100] The oat dietary fiber used in Example 1 (referred to as oat fiber), the ultrafine oat dietary fiber obtained by low-temperature ultrafine grinding (referred to as oat microfibrils), and the acid-etched oat microfibrils obtained by ultrasonic-pressure heat treatment with citric acid solution and wet ball milling were respectively subjected to the above-mentioned method for calculating and analyzing the peptide deposition rate. The results are as follows: Figure 3 shown.

[0101] from Figure 3 The results show that the peptide deposition rate of oat fiber is 15.43%, the peptide deposition rate of oat microfibrils prepared by ultrafine processing can be increased to 28.42%, and the peptide deposition rate of acid-etched oat microfibrils is increased to 73.64%. It can be seen that the peptide deposition rate can be significantly improved by acid etching treatment. Compared with the initial oat fiber, the peptide deposition rate of acid-etched oat microfibrils is increased by 3.8 times.

[0102] Example 10 Texture Analysis

[0103] Freshly prepared cakes, frozen cakes without active peptide or active peptide microfibril capsules, and Examples 1-4 of the present invention were frozen at -18°C for 14 days. The frozen cakes after thawing were tested for hardness, elasticity, cohesion, chewiness, and resilience using the above texture analysis method. The test results are shown in Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 .

[0104] Cake hardness is negatively correlated with cake quality. Figure 4 It can be seen that compared with fresh cakes, the hardness of frozen cakes without additives increased significantly. The main reason is that the starch ages and recrystallizes, hydrogen bonds are formed between the ingredients, and water migrates, causing the cake core to harden. Active peptide microfibril capsules can significantly reduce the hardness of frozen cakes. There is no significant difference in the hardness of frozen cakes in the 1‰ and 2‰ groups compared with fresh cakes. Active peptides interact with starch to slow down starch aging. The porous structure of acid-etched oat dietary fibrils works together with active peptides to increase water holding capacity and inhibit ice crystal growth.

[0105] from Figure 5 It can be seen that there is no significant difference in elasticity between the fresh cake and different frozen cake test groups.

[0106] The greater the cohesion, the less likely the cake will break or crumble. Figure 6 It can be seen that compared with fresh cakes, the cohesion of frozen cakes without additives is significantly reduced. With the increase of the amount of active peptide microfibril capsules added, the cohesion of frozen cakes gradually increases. It can be seen that active peptide microfibril capsules can improve the internal texture structure of cakes and reduce the formation of ice crystals.

[0107] Chewiness is a parameter that depends on hardness and is analyzed by chewiness analysis ( Figure 7 ), the frozen cakes in the 2‰ group had lower chewiness, closer to fresh cakes. When the amount of active peptide microfibril capsules added continued to increase (4‰ and 6‰), the hardness and chewiness of the frozen cakes increased significantly, indicating that the effect of active peptide microfibril capsules on the hardness and chewiness of frozen cakes is closely related to the amount of addition.

[0108] See also Figure 8 As shown in the figure, compared with fresh cakes, the resilience of frozen cakes without additives increased significantly, and there was no significant difference between the resilience of frozen cakes in the 1‰ and 2‰ groups and fresh cakes, indicating that the active peptide microfibril capsules can enhance the interaction between the internal components of frozen cakes. When the amount of active peptide microfibril capsules added continued to increase (4‰ and 6‰), the resilience of frozen cakes increased significantly, which was due to the hardening of the cake core, resulting in reduced energy loss during compression.

[0109] In summary, when the addition amount of active peptide microfibril capsules is 1‰ to 2‰, the texture quality of frozen cakes, such as hardness, elasticity, cohesion, chewiness and recovery, is better.

[0110] Example 10 Electron microscope observation

[0111] The control group and Examples 1-4 of the present invention were frozen at -18°C for 14 days, and the ice crystal structure was observed under an ultra-depth electron microscope. The results presented are as follows Fig. 9 , Fig.10 , Fig.11 , Fig.12 and Fig.13 shown.

[0112] from Fig. 9 , Fig.10 , Fig.11 , Fig.12 and Fig.13 The microscopic observation results shown in the figure show that the ice crystals of the frozen cake without additives are in an "explosive" state, that is, the ice crystals grow in an explosive manner. The active peptide microfibril capsule significantly inhibits the growth of ice crystals in the frozen cake. The active peptides in the microfibril capsule use their hydrophilicity to allow the free water in the cake to bind to the active peptides and attach to the evenly dispersed microfibril capsules. The ice crystals grow at the attachment points between the capsule protrusions, causing the surface of the ice crystals to bend, resulting in a larger local surface curvature, which has a significant inhibitory effect on the recrystallization of ice crystals. With the increase in the amount of active peptide microfibril capsules added, the formation and growth of ice crystals are further slowed down, thereby weakening the damage of ice crystals to the internal structure of the frozen cake, increasing the freeze-thaw stability of the frozen cake, and allowing the cake to maintain a good internal structure after thawing.

[0113] Example 11 Evaluation of in vitro digestion stability of active peptides and active peptide microfibril capsules

[0114] This example simulates an in vitro digestion system to evaluate the digestion stability of the active peptides and active peptide microfibril capsules prepared in Example 1.

[0115] 1) Prepare simulated gastric fluid: dissolve 2 g NaCl, 3.2 g pepsin, and 7.0 mL concentrated hydrochloric acid in distilled water to make up to 1000 mL, and adjust the pH to 2.0 ± 0.1 with 0.1 mol / L HCL.

[0116] 2) Simulated intestinal fluid: Take 6.8g KH2PO4, dissolve it in 250mL water, add 77mL 0.2 mol / L NaOH, 10g trypsin, add water to make up to 1000mL, and adjust the pH to 6.8±0.1 with 0.1 mol / L NaOH.

[0117] 3) The active peptide was dissolved in simulated gastric fluid at a concentration of 1 mg / mL. After fully dissolved, it was placed in a constant temperature shaking water bath at 200 r / min, simulated gastric digestion at 37℃ for 2h, adjusted to pH 6.8±0.1 with 1mol / L NaOH, centrifuged at 4℃ and 8000 r / min for 10 min, and the supernatant was collected. It was diluted by half with sterile water and stored at 4℃ as a gastric digestion test solution for use. The gastric digestion fluid and simulated intestinal fluid after pH adjustment were mixed thoroughly, placed in a constant temperature shaking water bath at 200 r / min, simulated intestinal digestion at 37℃ for 4h, and inactivated in a boiling water bath at 100℃ for 10min, cooled to room temperature, centrifuged at 4℃ and 8000r / min for 10 min, and the supernatant was collected and stored at 4℃ as an intestinal test solution for use.

[0118] 4) The ACE inhibition rates of the active peptides and active peptide microfibril capsules in a peptide solution with a concentration of 0.5 mg / mL, after baking, digested by gastric juice, and digested by gastrointestinal juice were tested to investigate the in vitro digestion stability of the active peptides and active peptide microfibril capsules. The test results are as follows: Fig.14 shown.

[0119] from Fig.14It can be seen that the red yeast rice active peptide prepared and used by the present invention has good ACE inhibitory activity. It can reduce hypertension by inhibiting the synthesis of angiotensin II or promoting the release of bradykinin, but the active peptide has poor digestion tolerance to gastrointestinal fluid. After the active peptide was digested by gastrointestinal fluid, the ACE inhibition rate decreased from 74.38% to 43.32%, and the ACE inhibition activity retention rate was 58.94%. However, the active peptide microfibril capsule prepared by acid etching oat microfibril, after digestion by gastrointestinal fluid, the ACE inhibition rate decreased from 73.45% to 65.41%, and the ACE inhibition activity retention rate could still reach 89.05%. Therefore, the active peptide microfibril capsule can significantly improve the gastrointestinal tolerance of the active peptide, maintain the ACE inhibitory activity, and has a certain blood pressure lowering auxiliary regulation function.

[0120] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A method for processing an active peptide antifreeze cake, characterized in that: The following steps are involved: preparing active peptides; Preparation of acid-etched oat microfibrils; The active peptide is adsorbed on the acid-etched oat microfibril by electrostatic adsorption to deposit on the surface to prepare an active peptide microfibril capsule; The active peptide microfibril capsules are added into cake batter and baked to obtain active peptide antifreeze cakes.

2. The processing method according to claim 1, characterized in that: The active peptide is red yeast rice active peptide, and the processing method thereof comprises the following steps: weighing red yeast rice, adding water according to the mass fraction of wine lees: water = 1:8-1:12 and mixing evenly; adding papain for enzymolysis, wherein the addition amount of papain is 5000-7000 U / g, the enzymolysis time is 1.5-2h, the enzymolysis temperature is 45-50°C, and the pH value is 5.5-6; after inactivating the enzyme, centrifuging and collecting the supernatant, ultrafiltrating, collecting the dialyzed component with a molecular weight less than 1 kDa, and obtaining the active peptide.

3. The processing method according to claim 1, characterized in that: The steps of preparing the acid-etched oat microfibrils include: the following: The oat dietary fiber is ultra-finely crushed at low temperature to obtain ultra-fine oat dietary fiber; The superfine oat dietary fiber is prepared into a superfine oat dietary fiber suspension with a mass concentration of 8-12 g / L by using citric acid; The ultrafine oat dietary fiber suspension is subjected to an ultrasonic-autoclave treatment, wherein the autoclave temperature is 120° C., the time is 50-60 min, and the ultrasonic power is 800 W, and further subjected to a wet ball milling treatment to obtain the acid-etched oat microfibrils.

4. The processing method according to claim 3, characterized in that: The molar concentration of the citric acid is 1-1.2 mol / L.

5. The processing method according to claim 3, characterized in that: The grinding speed during the wet ball milling treatment is 5000 r / min and the time is 90-100 min.

6. The processing method according to claim 1, characterized in that: In the preparation step of the active peptide microfibril capsule, the mass ratio of the active peptide to the acid-etched oat microfibril is 5:1, the pH is adjusted to 7.0, the inlet temperature during spray drying is 180° C., the outlet temperature is 90° C., and the flow rate is 600 mL / h.

7. The processing method according to claim 1, characterized in that: When the active peptide microfibril capsule is added to the cake batter, the added amount of the active peptide microfibril capsule is 1‰ to 2‰ of the total weight of the cake batter.

8. The processing method according to claim 1, characterized in that: The baking step comprises: Pour the batter of the active peptide antifreeze cake into the mold and shake out the bubbles; Put it in the preheated oven, top fire 200℃, bottom fire 150℃, bake for 16 minutes; After taking it out, turn it upside down and let it cool before demoulding.

9. An active peptide antifreeze cake obtained by the processing method according to any one of claims 1 to 8.

10. The active peptide antifreeze cake according to claim 9, characterized in that: The bitterness response value of the active peptide antifreeze cake is 1.12 to 1.76, and the relative crystallinity of the starch in the frozen cake is less than 15%. Preferably, after the active peptide antifreeze cake is frozen at -18°C for 14 days, the hardness, elasticity, cohesion, chewiness and recovery after thawing are close to those of the fresh active peptide antifreeze cake.

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