Active peptide anti-aging bread and processing method thereof

Abstract

The invention relates to active peptide anti-aging bread and a processing method thereof. The active peptide microfibril capsule is prepared by preparing active peptide from the red yeast rice dregs and performing surface deposition through electrostatic adsorption, the gastrointestinal tract tolerance of the active peptide is improved, the bitter taste of the active peptide is masked, and when the active peptide microfibril capsule is applied to preparation of bread, water migration in the cold storage process of the bread is reduced, recrystallization of starch particles is hindered, and the aging rate of the cold storage bread is reduced; the bread hardening rate is slowed down, the texture of the refrigerated bread is improved, meanwhile, the gastrointestinal tract tolerance of the active peptide is improved, and the health-care function of assisting in regulating and lowering blood pressure of fine food such as bread is improved.

Description

Technical Field

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

[0002] As an innovative bread category that combines bread dough with a variety of seasonings, vegetables and meat, prepared bread is very popular among consumers in Asian countries such as China and Japan, especially those that combine ingredients such as fruits, light cream, cheese and meat. However, in order to maintain the freshness of these added ingredients and extend the shelf life, prepared bread often needs to be refrigerated. Although this approach is effective, it inevitably sacrifices the taste of the bread. The low temperature in the refrigerated environment accelerates the aging process of the starch in the bread, causing the texture of the bread to become rough, dry and hard, significantly reducing the quality of the product. At the same time, with the vigorous development of the big health industry, consumers' demand for bread has shifted from a single color, fragrance and taste to a greater focus on nutritional value and functionality. In this context, how to improve the taste and quality of refrigerated bread has become a key issue that the industry needs to solve urgently.

[0003] Active peptides are considered as a potential ingredient for improving food quality due to their antibacterial and antifreeze physiological functions. However, the exposure of their hydrophobic residues will interact with taste cells and produce bitterness, which not only affects the flavor and taste of the active peptides themselves, but also greatly limits their application in the food field. Although antifreeze peptides have been successfully used in fish paste and dough products, the antifreeze peptides prepared by existing technologies often have the special flavor of the raw materials themselves, such as fishy smell, which limits their use to specific types of marine fishery products.

[0004] It is worth noting that some existing patents for the preparation of antifreeze peptides, such as CN114539387A, CN115505037A and CN116064709A, although each has its own innovations, still have obvious shortcomings. The antifreeze peptides prepared by the first two have a narrow scope of application due to the limitation of the flavor of the raw materials; and although the latter can improve the texture of the product, it does not consider the possible negative impact of the slightly bitter taste of the antifreeze peptide itself on the overall flavor of the product, which also limits its wide application. In addition, when the prior art applies antifreeze peptides to bread, yeast will directly use peptides as a nitrogen source during the fermentation process, resulting in a significant reduction in the antifreeze, anti-aging, and anti-ice crystal functional activities of the peptides. It is particularly regrettable that, to date, there has been no report on the use of antifreeze peptides in improving the quality of refrigerated bread products. Summary of the invention

[0005] In view of the above technical problems, the present invention provides an active peptide bread and a processing method thereof, in order to achieve the following purposes: 1) inhibiting the crystallization of bread during refrigeration and reducing the degree of aging; 2) maintaining the moisture content and taste of refrigerated bread and extending the quality period of bread; 3) effectively exerting the health care function of active peptide bread in assisting in regulating and lowering blood pressure.

[0006] To achieve the above object, in a first aspect, the present invention provides a method for processing active peptide bread, comprising the following steps:

[0007] preparing active peptides;

[0008] Preparation of acid-etched oat microfibrils;

[0009] The active peptide is acid-etched into oat microfibrils for surface deposition through electrostatic adsorption to prepare active peptide microfibril capsules; the active peptide microfibril capsules are added into bread dough and baked to prepare active peptide bread.

[0010] Different from the existing technology, the above technical scheme adopts acid-etched oat dietary fiber to prepare a microfibril carbon-based skeleton support loaded with active peptides, and prepares active peptide microfibril capsules through electrostatic adsorption during the spray drying process, thereby improving the gastrointestinal tolerance of the active peptides and masking the bitterness of the active peptides. It is applied to the preparation of bread, which reduces the moisture migration during the refrigeration process of bread, hinders the recrystallization of starch particles, reduces the aging rate of refrigerated bread, slows down the hardening rate of bread, and improves the texture of refrigerated bread. At the same time, it improves the gastrointestinal tolerance of the active peptides in the bread, thereby enhancing the health care function of fine foods such as bread in assisting the regulation of lowering blood pressure.

[0011] In some embodiments, the active peptide is a red yeast rice active peptide, and the preparation steps include: weighing red yeast rice, adding water according to a mass ratio of red yeast rice: water = 1:10, adding papain for enzymolysis, the amount of papain added is 6000U / g, the time is 90min, the temperature is 45°C, the pH value is 5.7, and the supernatant is centrifuged after enzyme inactivation, ultrafiltration, and the dialyzed fraction with a molecular weight of less than 1kDa is collected to obtain 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.

[0012] In some embodiments, the steps of preparing the acid-etched oat microfibrils include the following:

[0013] The oat dietary fiber is ultra-finely crushed at low temperature to obtain ultra-fine oat dietary fiber;

[0014] The superfine oat dietary fiber is prepared into a superfine oat dietary fiber suspension by using citric acid with a molar concentration of 1 mol / L, and the mass concentration of the oat dietary fiber suspension is 10 g / L;

[0015] The ultrafine oat dietary fiber suspension is subjected to an ultrasonic-autoclave treatment, wherein the autoclave temperature of the ultrasonic-autoclave treatment is 120° C., the time is 50 min, and the ultrasonic power is 800 W. The suspension is further subjected to a wet ball milling treatment to obtain the acid-etched oat microfibrils.

[0016] 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 regulate the fiber pore structure, and wet ball milling further refines the fiber to make it easier to combine with active peptides. More preferably, the molar concentration of the citric acid solution is selected to be 1 mol / L. This concentration of citric acid can effectively etch oat dietary fiber and regulate the fiber pore structure.

[0017] In some embodiments, the material for wet ball milling is zirconium oxide, the grinding speed is 5000 r / min, and the time is 90 min. Zirconium oxide is used as a material for wet ball milling to grind oat dietary fiber filaments. Its high hardness and wear resistance can ensure long-term stable grinding, uniform grinding, and low wear, which can significantly improve the grinding efficiency. By setting the above grinding parameters, it 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 bread.

[0018] In some embodiments, 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, the inlet temperature of the spray drying is 180°C, the outlet temperature is 90°C, and the flow rate is 600mL / h. The mixing ratio of the active peptide and the acid-etched oat microfibril is 5:1, which can ensure the uniform distribution of the active peptide in the acid-etched oat microfibril, thereby improving its stability and bioavailability in bread. Acid-etched oat microfibril as a carrier helps to mask the bitterness of the active peptide, improve the digestion tolerance of the active peptide, and increase its dispersibility and stability in the dough, thereby improving the refrigeration quality of the bread. Adjusting the pH value of the mixture to 7.0 helps to maintain the biological activity of the active peptide and prevent it from denaturing or degrading in an acidic or alkaline environment. The inlet temperature is 170-180°C, and the flow rate is set to 600mL / h to ensure that the active peptide and oat microfibril can be dried quickly and evenly during the spray drying process. By adding active peptide microfibril capsules to bread, active peptide bread with higher nutritional value, better taste and texture, and more health benefits can be prepared.

[0019] Further preferably, the amount of the active peptide microfibril capsule added to the dough of the bread is 0.5% to 2% of the total weight of the dough. Through experimental comparison, it is found that within the above-mentioned addition amount range, the active peptide microfibril capsule increases the binding degree of starch, gluten protein and water through hydrogen bonds or electrostatic interactions, reduces the water loss rate, increases the binding capacity of water and bread components, inhibits the degree of starch aging during refrigerated storage of bread, and ensures that the bread maintains a good taste and texture without affecting the overall flavor of the bread.

[0020] More preferably, the method further includes preparing the seed dough and the main dough before baking the bread, as well as the steps of shaping and proofing the bread.

[0021] The second aspect of the present invention provides an active peptide bread produced by the processing method described in the first aspect of the present invention.

[0022] Preferably, the bitterness response value of the active peptide bread measured by the electronic tongue is 1.43 to 1.67. However, the bitterness response value of bread prepared with active peptides in the prior art is between 4.67 and 5.27; the bitterness response value of bread prepared with the active peptide microfibril capsule of the present invention is between 1.43 and 1.67. It can be seen that the active peptide microfibril capsule significantly weakens the bitterness of the active peptide, and the bread product is basically bitter-free. The relative crystallinity of the refrigerated bread obtained by refrigerating the active peptide bread at 4°C for 2 days is 16.95 to 18.46, and the thermal enthalpy value ΔH of the refrigerated bread is 91.46 to 102.41.

[0023] 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

[0024] 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.

[0025] In the drawings of the specification:

[0026] Figure 1 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.

[0027] Figure 2The results of the in vitro digestion stability (ACE inhibition rate) evaluation of the active peptides and active peptide microfibril capsules according to the specific embodiments of the present invention are shown;

[0028] Figure 3 The bitter taste response value test results of the active peptides and active peptide microfibril capsules in the specific embodiments of the present invention;

[0029] Figure 4 The bitterness response value test results of bread made with active peptides and active peptide microfibril capsules according to the specific embodiment of the present invention;

[0030] Figure 5 The moisture distribution analysis results of the bread of Example 1 and the bread of the control group of Example 5 after 0, 1 and 2 days of refrigerated storage;

[0031] Figure 6 The moisture distribution analysis results of the bread of Example 2 and the bread of the control group of Example 5 after refrigerated storage for 0, 1 and 2 days;

[0032] Figure 7 The moisture distribution analysis results of the bread of Example 3 and the bread of the control group of Example 5 after 0, 1 and 2 days of refrigerated storage;

[0033] Figure 8 The moisture distribution analysis results of the bread of Example 4 and the bread of the control group of Example 5 after 0, 1 and 2 days of refrigerated storage;

[0034] Fig. 9 The results of microscopic observation of the bread slices of the control group of Example 5 stored in a refrigerator for 2 days;

[0035] Fig.10 The microscopic structural observation results of the bread slices of Example 1 were obtained by refrigerating for 2 days.

[0036] Fig.11 Microscopic observation results of the bread slices of Example 2 stored in cold storage for 2 days;

[0037] Fig.12 Microscopic observation results of the bread slices of Example 3 stored in cold storage for 2 days;

[0038] Fig.13 Microscopic observation results of the bread slices of Example 4 stored in a refrigerator for 2 days. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Unless otherwise specified, the raw materials used in the present invention, such as oats, citric acid, enzymes, flour, sugar, eggs, oil and other conventional raw materials for preparing bread, 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.

[0049] 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.

[0050] Red yeast rice is rich in various amino acids, peptide substances and metabolites of beneficial microorganisms, and has various physiological functions such as anti-oxidation and anti-fatigue. The red yeast rice used in the present invention is the lees which is a byproduct of brewing red yeast rice wine of Fujian specialty.

[0051] The relevant indicators and test methods involved in the present invention are introduced as follows:

[0052] Peptide deposition rate analysis: The degree of electrostatic adsorption of peptides by oat fiber was investigated by peptide deposition rate, where 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. The peptide content was determined in accordance with GB / T 22492-2008.

[0053] Determination of active peptide content: Determined in accordance with GB / T 22492-2008.

[0054] 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 active peptide bread was determined to evaluate the effect of the active peptide microfibril capsule on the taste of the bread.

[0055] Example 1 A kind of active peptide bread and its processing method

[0056] 1) Step 1: Preparation of active peptides

[0057] 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.

[0058] 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.

[0059] 2) Step 2: Preparation of acid-etched oat microfibrils

[0060] 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.

[0061] 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.

[0062] 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. After the treatment, it was 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 fibers, i.e., acid-etched oat microfibrils.

[0063] 3) Step 3: Preparation of active peptide microfibril capsules

[0064] 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.

[0065] 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.

[0066] 4) Step 4: Preparation of active peptide bread

[0067] Noodle recipe: 260g wheat flour, 2.5g yeast, 40g fine sugar, 175g water.

[0068] Main dough recipe: 250g wheat flour, 40g fine sugar, 20g milk powder, 2.5g yeast, 75g water, 50g egg, 447.5g seed flour, 5g salt, 65g butter, the amount of active peptide microfibril capsule added is 0.5% of the total weight of the dough.

[0069] First, add the wheat flour, granulated sugar, yeast and salt in the seed dough formula into the mixing barrel in turn, and mix and stir evenly. Add water (water temperature is 22℃), stir slowly for 2min first, and then stir quickly for 2min. Set the proofing time to 2h, the proofing temperature is 35℃, and the humidity is 75%. The dough after proofing is the seed dough. Then add the main dough formula into the dough mixing cylinder, and then add water (water temperature is 18℃) according to the formula, and stir slowly for 3min first, and stir quickly for 2min. After the gluten is stirred to the full expansion stage (90%), switch to slow stirring. After stirring evenly, use a rubber scraper to divide the dough and remove from the cylinder; send it to the bread forming area for basic proofing for 30 minutes before dividing, and relax again for 10-15min. After preheating the oven, set the surface fire to 190℃~200℃, the bottom fire to 200℃~220℃, and the baking time to 10min. After baking, send it to the breeze cooling room to dissipate heat until no water vapor is generated, and then send it to the strong cooling room to room temperature.

[0070] The refrigerated bread was refrigerated at 4°C for 2 days before various tests.

[0071] Example 2 Adjusting the amount of active peptide microfibril capsule added

[0072] The steps of Example 1 were repeated, except that the amount of the active peptide microfibril capsule added to the dough was adjusted to 1% of the total weight of the dough, so as to investigate the effects of different addition amounts of the active peptide microfibril capsule on the quality of bread.

[0073] Example 3 Adjusting the amount of active peptide microfibril capsule added

[0074] The steps of Example 1 were repeated, except that the amount of the active peptide microfibril capsule added to the dough was adjusted to 1.5% of the total weight of the dough, so as to investigate the effects of different addition amounts of the active peptide microfibril capsule on the quality of bread.

[0075] Example 4 Adjusting the amount of active peptide microfibril capsule added

[0076] The steps of Example 1 were repeated, except that the amount of the active peptide microfibril capsule added to the dough was adjusted to 2% of the total weight of the dough, so as to investigate the effects of different addition amounts of the active peptide microfibril capsule on the quality of bread.

[0077] Example 5 Preparation of bread for the control group

[0078] Step 4 of Example 1 was repeated, except that the active peptide microfibril capsule was not added.

[0079] Example 6 Preparation of active peptide bread

[0080] Step 4 of Example 1 was repeated, except that the active peptide microfibril capsule was replaced with the active peptide.

[0081] Example 7 Electronic tongue detection of bitter taste response value

[0082] Sample preparation: Take the active peptide bread samples prepared at different addition amounts in Examples 1 to 4 respectively.

[0083] Electronic tongue test: The samples were tested using an electronic tongue device and the bitterness response values ​​were recorded.

[0084] Result analysis: According to the test results, it was determined that when the active peptide microfibril capsule was added at a dosage of 0.5-2%, the bitterness response value of bread ranged from 1.43 to 1.67, and the sensory evaluation showed that there was basically no bitterness.

[0085] Example 8 Analysis of peptide deposition rates of several different oat fibers / microfibrils

[0086] 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 1 shown.

[0087] from Figure 1 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 83.64%. 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 4.4 times.

[0088] Example 9 Evaluation of in vitro digestion stability (ACE inhibitory activity) of active peptides and active peptide microfibril capsules

[0089] This example simulates an in vitro digestion system to evaluate the digestion stability of active peptides and active peptide microfibril capsules.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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: Figure 2 shown.

[0094] from Figure 2 It 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.

[0095] Example 10 Determination of bitter taste response value of active peptides and active peptide microfibril capsules

[0096] The active peptide and the active peptide microfibril capsule were prepared into 0.5, 1, 1.5, and 2% concentrations, and the bitterness response values ​​of the active peptide and the active peptide microfibril capsule were measured by the bitterness response value determination method mentioned above. The results are as follows: Figure 3 shown.

[0097] from Figure 3 It can be seen that the bitter response value of the active peptide in the concentration range of 0.5-2% is between 5.67 and 6.76, while the bitter response value of the active peptide microfibril capsule in the corresponding concentration range is between 1.60 and 2.43, which are significantly lower than the bitter response value of the active peptide. This shows that the active peptide microfibril capsule can better mask the bitterness of the active peptide and can effectively improve the taste of the active peptide bread.

[0098] Example 11 Determination of the bitterness response value of bread prepared with active peptide and active peptide microfibril capsule

[0099] Take 100g bread sample, crush it and add 300mL pure water. After homogenization for 10min, centrifuge at 6000G / min for 15min. Take the supernatant and use the electronic tongue to test the bitterness. Take the last 3 sensor response values ​​as sample data for analysis. The results are as follows: Figure 4 shown.

[0100] from Figure 4It can be seen that the bitterness response value of the bread prepared with red yeast rice active peptides is between 4.67 and 5.27; while the bitterness response value of the bread prepared with active peptide microfibril capsules is between 1.43 and 1.67. Therefore, combined with the results of peptide deposition rate determination, it can be seen that the treated active peptide microfibril capsules greatly improved the peptide deposition rate and significantly reduced the bitterness of the active peptides, thereby enhancing the health function and good taste of the active peptide bread.

[0101] Example 12 Analysis of Bread Starch Retrogradation

[0102] (1) Crystallinity

[0103] The relative crystallinity of starch in bread was determined by X-ray diffractometer. The freeze-dried and ground powder of bread core 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.

[0104] Table 1 Relative crystallinity of starch in breads of Examples 1-4 of the present invention and the control group

[0105]

[0106] The crystallinity of starch is closely related to the degree of aging. High crystallinity provides a large number of ordered regions for starch molecules to form crystal cores, which promotes the molecular rearrangement of the aging process. Therefore, the higher the crystallinity, the faster the aging rate. From the results in Table 1, it can be seen that compared with the control, with the increase of the amount of active peptides or active peptide microfibril capsules added, the crystallinity of the starch in the bread core shows a downward trend. The relative crystallinity of the starch in the bread core of the active peptide microfibril capsules is lower than that of the corresponding amount of active peptides added. This is because during the bread fermentation process, yeast can use active peptides as carbon source nutrition, which reduces the content of active peptides to a certain extent and changes the structure of some active peptides, causing certain losses to their anti-ice crystal and anti-aging activities. The void structure of the microfibril capsule protects the active peptides, hinders the use of active peptides by yeast, and thus better maintains the anti-ice crystal and anti-aging activities of the active peptides. The above comparison shows that the active peptide microfibril capsule can increase the viscosity of the dough, lock in moisture, hinder the recrystallization of starch granules, reduce the crystallinity of bread storage, and thus reduce the degree of aging.

[0107] (2) Core aging enthalpy change after 2 days of storage

[0108] Retrogradation is the process in which the straight part of amylopectin and amylose tend to be arranged in an orderly parallel manner again from an amorphous state, and the structure changes to a crystalline state. The study of the thermodynamic properties of baked products can reflect the changes in starch, characterize the endothermic enthalpy change when the starch structure is broken, and calculate the enthalpy value of starch change through the DSC curve, indicating the recrystallization rate and the degree of retrogradation.

[0109] DSC was used to measure the thermodynamic properties of bread. The bread core was freeze-dried and ground. The DSC scanning temperature range was 30℃~200℃, and the heating rate was 5℃ / min. The initial gelatinization temperature T0 and the peak temperature T p , gelatinization termination temperature T C and thermal enthalpy ΔH. The analysis results are shown in Table 2.

[0110] Table 2 Thermodynamic properties of breads of Examples 1-4 of the present invention and the control group

[0111]

[0112] From the results in Table 2, it can be seen that compared with the control, with the increase in the amount of active peptide microfibril capsule added, the thermal enthalpy value gradually decreased, indicating that the degree of damage or loss of the double helix structure in the amylopectin microcrystals was reduced, and the starch recrystallization rate was reduced. This shows that during the storage of bread, active peptide microfibril capsules are beneficial to inhibit starch aging.

[0113] Example 13 Moisture Distribution in Bread

[0114] A low-field nuclear magnetic resonance imaging analyzer equipped with a 25 mm diameter NMR probe was used to measure the spin-spin relaxation time T2 of water molecules at 25°C. About 1.0 g of sample was taken from the bread crumbs of Example 1, Example 2, Example 3, Example 4 and the control group and placed in a nuclear magnetic tube for testing. The parameters were set as follows: the duration (TW) between consecutive scans was 500 ms, the echo time (TE) was 0.25 ms, the number of scan repetitions (NS) was 8 times, and the number of echoes (NECH) was 2000. The test results were inverted using the Newmai NMR analysis application software V4.0.

[0115] The relaxation time of the bread of Example 1 and the control group after refrigerated storage for 0, 1 and 2 days is as follows: Figure 5 shown.

[0116] The relaxation time of the bread in Example 2 and the control group after refrigerated storage for 0, 1 and 2 days is as follows: Figure 6 shown.

[0117] The relaxation time of the bread of Example 3 and the control group after refrigerated storage for 0, 1 and 2 days is as follows: Figure 7 shown.

[0118] The relaxation time of the bread of Example 4 and the control group after refrigerated storage for 0, 1 and 2 days is as follows: Figure 8 shown.

[0119] The three transverse relaxation times correspond to 1 The three fractions of HT2 are divided into T 21 (0.01ms~2ms), T 22 (2ms~25ms) and T 23 (25ms~400ms), representing the bound water tightly bound to starch and gluten protein through hydrogen bonds or electrostatic interactions, the weakly bound water not tightly bound to macromolecules but located near the hydrophilic groups, and the most mobile free water. 1 HT2T 22 The peak areas of the fractions were all larger than those of the control group bread, T 21 and T 23 There is no significant difference in the peak area of ​​the fractions. This shows that the active peptide microfibril capsule can increase weakly bound water. After storage for 1d and 2d, the peak areas of the three fractions of the control bread all decreased rapidly, indicating that water molecules continuously migrated from the bread core to the bread crust and evaporated outward. At the same time, the starch aged, and the water bound to the amorphous starch quickly migrated to the re-formed crystalline area. Compared with the control, the peak areas of the three fractions of the active peptide bread with different addition amounts slowly decreased after storage for 1d and 2d, but were all higher than the control bread of the same day. With the increase in the addition amount, the peak areas of the three fractions of the active peptide bread after storage for 1d and 2d also increased accordingly. This shows that the complex formed by the active peptide microfibril capsule and starch increases the binding degree of starch and water, reduces the water loss rate, and increases the moisture content of the bread. It can also be seen from this that the active peptide microfibril capsule mainly increases the moisture content of bread by enhancing the combination of starch and water, so that the bread still has a high moisture content after storage, keeping it moist and soft; at the same time, it reduces the moisture migration of bread, resulting in insufficient moisture demand for starch recrystallization, inhibiting the formation of crystal structure, thereby reducing the aging rate of bread and slowing down the hardening rate of bread.

[0120] Example 14 Observation of the microstructure of bread

[0121] The breads of the control group, Example 1, Example 2, Example 3 and Example 4 which had been stored in the refrigerator for 2 days were sliced, and the central cross-section was taken and observed under an electron microscope with a magnification of 4 times. The results are as follows: Fig. 9 , Fig.10 , Fig.11 , Fig.12 and Fig.13 As shown. Figure 9-13By comparison, after 2 days of refrigerated storage, the three-dimensional network structure of the bread in the control group was weak, the surface of the gel showed a rough velvety structure, and a small amount of fragments appeared. With the increase in the amount of active peptide microfibril capsules added, the pore wall of the gel surface was significantly thickened and the roughness decreased, indicating that the active peptide microfibril capsules can inhibit the phase separation during starch aging, thereby better maintaining the microstructure of the gel.

[0122] In summary, the present invention prepares active peptide microfibril capsules by combining common active peptides with acid-etched oat microfibrils, and uses them in the preparation of active peptide bread, thereby improving the gastrointestinal tolerance of active peptides, masking the bitterness of active peptides, and enhancing the health care function of fine foods such as bread in assisting in regulating and lowering blood pressure. Through testing, it was found that the bread of the present invention reduces water migration during refrigeration and hinders the recrystallization of starch particles; the pore wall of the gel surface is significantly thickened, the roughness is reduced, and the phase separation during starch aging is well inhibited, the aging rate of bread is reduced, the hardening rate of bread is slowed down, and the refrigerated storage quality of bread is improved.

[0123] 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 active peptide anti-aging bread, characterized in that: The following steps are involved: preparing active peptides; Preparation of acid-etched oat microfibrils; The active peptide is acid-etched on oat microfibrils to deposit on the surface through electrostatic adsorption to prepare active peptide microfibril capsules; The active peptide microfibril capsules are added into bread dough and baked to prepare active peptide anti-aging bread.

2. The processing method according to claim 1, characterized in that: The active peptide is red yeast rice active peptide, and its preparation steps include: weighing red yeast rice, adding water according to a mass ratio of red yeast rice: water = 1:10, adding papain for enzymolysis, the addition amount of papain is 6000U / g, the time is 90min, the temperature is 45°C, the pH value is 5.7, after inactivating the enzyme, centrifuging to obtain the supernatant, ultrafiltration, collecting the dialyzed component with a molecular weight less than 1kDa, 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 by using citric acid with a molar concentration of 1 mol / L, and the mass concentration of the oat dietary fiber suspension is 10 g / L; The ultrafine oat dietary fiber suspension is subjected to an ultrasonic-autoclave treatment, wherein the autoclave temperature of the ultrasonic-autoclave treatment is 120° C., the time is 50 min, and the ultrasonic power is 800 W. The suspension is 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 material for the wet ball milling is zirconium oxide, the grinding speed is 5000 r / min, and the time is 90 min.

5. The processing method according to claim 1, characterized in that: 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, the inlet temperature of the spray drying is 180° C., the outlet temperature is 90° C., and the flow rate is 600 mL / h.

6. The processing method according to claim 1, characterized in that: The ACE inhibitory activity retention rate of the active peptide microfibril capsule is greater than or equal to 89.05%.

7. The processing method according to claim 1, characterized in that: The amount of the active peptide microfibril capsule added to the bread dough is 0.5% to 2% of the total weight of the dough.

8. The processing method according to any one of claims 1 to 7, characterized in that: The method also includes the steps of preparing the seed dough and the main dough before baking the bread, as well as the steps of shaping and proofing the bread.

9. An active peptide bread prepared by the processing method according to any one of claims 1 to 8.

10. The active peptide bread according to claim 9, characterized in that: The bitter response values ​​measured by the electronic tongue ranged from 1.43 to 1.67; the relative crystallinity of refrigerated bread ranged from 16.95 to 18.46, and the thermal enthalpy value ΔH of refrigerated bread ranged from 91.46 to 102.41.

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