A postbiotic with low sodium, reduced salt and enhanced umami, and its preparation method and application

Abstract

The present invention belongs to the field of biomedical technology, and specifically discloses a postbiotic with low sodium, salt reduction and umami enhancement, its preparation method and application. The postbiotic with low sodium, salt reduction and umami enhancement according to the present invention comprises inactivated cells of Lactobacillus paracasei Probio-37 ( Lacticaseibacillus paracasei ) and metabolites of Lactobacillus paracasei Probio-37. The preparation method of the postbiotic of the present invention comprises: (1) activating the strain, and obtaining a seed liquid of Lactobacillus paracasei Probio-37 through enlarged culture; (2) inoculating the seed liquid in step (1) into a fermentation medium, fermenting and culturing until the pH reaches 4.5-4.6, stopping fermentation, and obtaining a fermentation broth; (3) inactivating the fermentation broth in step (2); (4) subjecting the inactivated fermentation broth to decolorization, concentration and spray drying to obtain the postbiotic. The snacks prepared from the postbiotic of the present invention not only achieve the effects of reducing salt without reducing umami and reducing sodium without reducing saltiness, but also can improve their own taste and smell, realizing the "scientific salt reduction" goal of "reducing sodium without reducing saltiness".

Description

Technical Field

[0001] The present invention belongs to the field of biological medicine technology, and particularly relates to a postbiotic with low sodium, salt reduction and umami enhancement, its preparation method and application. Background Art

[0002] Postbiotics refer to preparations of inanimate microorganisms and / or their components that are beneficial to the health of the host. Postbiotics are artificially inactivated microbial cells, which can be added with metabolites or cell components that have been proven to be beneficial to health, or not added. According to classification, postbiotics mainly include two major substances: metabolites and cell components. Metabolites include: organic acids, short-chain fatty acids, intracellular polysaccharides, vitamins, proteins, enzymes, lipids; cell components include: lipoteichoic acid, teichoic acid, peptidoglycan, cell surface proteins, polysaccharides, cell membrane proteins, extracellular polysaccharides. Postbiotics are more convenient to transport and store compared to probiotic powders. Moreover, the use of postbiotics can achieve similar probiotic-like health benefits while avoiding problems such as narrow application industries for live bacteria, low bioavailability, unstable effects, and easy transmission of drug resistance genes. Therefore, postbiotics are now widely used in industries such as health foods and food processing.

[0003] Lactobacillus paracasei is closely related to the life of humans and animals. It is a type of lactic acid bacterium commonly found in cream, meat, and many vegetables, fermented products, and feeds, and can play a beneficial role in the intestine. Currently, the reported application fields include food, feed, healthcare, cosmetics, beauty, aquaculture, probiotic preparations, etc. When a sufficient amount of bacteria is consumed, it may bring certain health benefits to the host. The prior art CN117179212B discloses a postbiotic composition for improving the storage quality of food, and the components of the postbiotic composition include inactivated cells and / or metabolites of a probiotic composition. The components of the probiotic composition include Lactobacillus paracasei ProSci-101 and Lactobacillus fermentum ProSci-602, and the postbiotic composition can effectively improve the storage quality of meat products such as cooked meat sausages. The prior art CN115886230B discloses a low-sodium, salt-reduced and umami-enhanced plant protein peptide, its preparation method and application. Using plant protein rich in amide substances as raw materials, based on the step-by-step hydrolysis of plant protein by double enzymes, after the hydrolysis by endonuclease, exopeptidase and glutaminase are simultaneously used for hydrolysis to de-bitter the hydrolysis solution and convert free amide substances, a plant protein peptide with enhanced umami is obtained. In order to achieve the goal of "scientific salt reduction" of "reducing sodium without reducing saltiness", new postbiotic compositions or protein peptides need to be developed. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a postbiotic with low sodium, salt reduction and umami enhancement, its preparation method and application. The specific technical solutions are as follows:

[0005] In a first aspect, the present invention provides a postbiotic for reducing sodium, decreasing salt, and enhancing umami, which comprises inactivated cells of Lactobacillus paracasei Probio-37 ( Lacticaseibacillus paracasei ) and metabolites of Lactobacillus paracasei Probio-37.

[0006] Among them, the Lactobacillus paracasei Probio-37 has been publicly deposited and described in CN111575211B.

[0007] Specifically, the viable count of the inactivated cells of Lactobacillus paracasei Probio-37 is ≥ 1.86×10 11 CFU / g.

[0008] Specifically, the metabolites of Lactobacillus paracasei Probio-37 include flavor-active compounds, taste peptides, and taste amino acids.

[0009] More specifically, the flavor-active compounds include one or more of ketones, aldehydes, acids, alcohols, furans, pyrazines, thiazoles, and terpenes.

[0010] In some embodiments, ketone flavor-active substances such as 1-hydroxy-2-propanone and 4-hydroxy-2,5-dimethyl-3(2H)-furanone provide a roasted aroma, pyrazine flavor-active substances such as trimethylpyrazine provide a nutty flavor, furan flavor-active substances such as 2-methyl-5-methylthiofuran provide a meaty flavor, and aldehyde flavor-active substances such as 3-methylthiopropionaldehyde provide a boiled potato flavor.

[0011] In some embodiments, the total content of the taste amino acids is ≥ 2220 mg / L, and the content of umami amino acids in the taste amino acids is ≥ 1370 mg / L.

[0012] Specifically, the taste peptides include one or more of umami peptides, rich-taste peptides, salty peptides, and umami amino acids.

[0013] More specifically, the umami peptides include one or more of Gln-Leu, Pro-Glu-Thr, Ala-Pro-Ala, and His-Val.

[0014] More specifically, the salty peptides include one or more of Asp-Asp, Glu-Asp, Asp-Asp-Asp, Ser-Pro-Glu, and Phe-Ile.

[0015] In a second aspect, the present invention provides a method for preparing a postbiotic, comprising the following steps:

[0016] (1) Strain activation, through subculture, to obtain a seed solution of Lactobacillus paracasei Probio-37;

[0017] (2) Inoculate the seed liquid in step (1) into the fermentation medium, ferment and culture until the pH reaches 4.5 - 4.7, then stop fermentation to obtain the fermentation broth.

[0018] (3) Inactivate the fermentation broth in step (2).

[0019] (4) The inactivated fermentation broth is decolorized, concentrated and spray-dried to obtain postbiotics.

[0020] Among them, the liquid medium composition for strain activation in step (1) includes: peptone 10.0 g / L, beef extract 5.0 g / L, glucose 20.0 g / L, yeast powder 4.0 g / L, Tween-80 1.0 g / L, K2HPO4·7H2O 2.0 g / L, KH2PO4·7H2O 1.0 g / L, anhydrous sodium acetate 5.0 g / L, ammonium citrate 2.0 g / L, MgSO4·7H2O 0.2 g / L, MnSO4·H2O 0.04 g / L. The prepared medium is sterilized at 121 °C for 15 minutes.

[0021] Specifically, the inoculation amount of the seed liquid in step (2) is 1% - 5%, and the temperature for fermentation culture is 35 °C - 39 °C.

[0022] Among them, the inoculation amount refers to the ratio of the volume of the transferred seed liquid to the volume of the culture broth after inoculation. Here, the percentage of the inoculation amount refers to the volume fraction.

[0023] Specifically, the components of the fermentation medium in step (2) include: 1% defatted soybean powder, 8% skim milk powder and water.

[0024] Among them, the percentage of the components of the fermentation medium refers to the mass fraction.

[0025] Specifically, it includes mixing the components of the fermentation medium according to 1% defatted soybean powder, 8% skim milk powder and 91% water, then melting the materials at 58 °C (i.e., stirring at 150 rpm) for 15 min to obtain the material liquid; homogenizing the material liquid at 58 °C under the first-stage pressure of 19 Mpa and the second-stage pressure of 5.0 Mpa once to obtain the homogenized material liquid; sterilizing the homogenized material liquid at 93 °C for 30 min to obtain the sterilized material liquid; cooling the sterilized material liquid to 35 °C to obtain the fermentation medium.

[0026] Specifically, the inactivation method in step (3) is selected from any one of the heat inactivation method, chemical inactivation method and biological inactivation method.

[0027] In some embodiments, the heat inactivation method is used for inactivation.

[0028] Specifically, in step (4), the decolorization is carried out using a nanofiltration membrane with a membrane molecular weight of 200-300 Da.

[0029] Specifically, the conditions for concentration in step (4) include: a vacuum degree ≥ -0.07 MPa, a temperature of 65-75 °C, and the solid content of the inactivated fermentation broth reaching 55-65%.

[0030] In a third aspect, the present invention provides an application of the aforementioned postbiotic or the postbiotic prepared by the aforementioned preparation method in the preparation of food.

[0031] Specifically, the food includes one or more of convenience foods, biscuits, potatoes, puffed foods, sauces, roasted seeds and nuts, nut products, and meat products.

[0032] In a fourth aspect, the present invention provides a potato chip, which includes the aforementioned postbiotic and is prepared into a potato chip by baking according to conventional operations.

[0033] Compared with the prior art, the beneficial effects of the present application are reflected in:

[0034] The potato chips prepared by the present invention using low-sodium, salt-reducing, and umami-enhancing postbiotics have a 28.8% reduction in sodium content when the addition ratio of postbiotics is 5% compared with the all-salt scheme. The potato chips prepared by this technical solution have no significant impact on their state, texture, crispness, and flavor, and can endow the product with better umami and taste while reducing the sodium content. Adding low-sodium, salt-reducing, and umami-enhancing postbiotic products can eliminate chemical food additives, and while cleaning the label, can endow the product with a healthier concept. Description of the Drawings

[0035] Figure 1 It is the secondary mass spectrum of Glu-Ser;

[0036] Figure 2 It is the secondary mass spectrum of Asp-Glu-Thr;

[0037] Figure 3 It is the secondary mass spectrum of Ala-Leu-Ala;

[0038] Figure 4 It is the secondary mass spectrum of Glu-Gly;

[0039] Figure 5 It is the secondary mass spectrum of Asp-Asp;

[0040] Figure 6 It is the secondary mass spectrum of Glu-Asp;

[0041] Figure 7 It is the secondary mass spectrum of Asp-Asp-Asp;

[0042] Figure 8 The secondary mass spectrum of Ser-Glu;

[0043] Figure 9 The sensory evaluation radar chart of potato chips made by adding postbiotics;

[0044] Figure 10 The comparison of the appearance of potato chips made for 4 groups;

[0045] Figure 11 In it, A is the determination result of the electronic nose of potato chips, and B is the determination result of the electronic tongue of potato chips;

[0046] Figure 12 The determination result of the number of bacteria in potato chips made for 4 groups. Detailed implementation manners

[0047] The following combines specific embodiments to further elaborate on the present invention. The following embodiments are not used to limit the present invention, but only to illustrate the present invention. The experimental methods used in the following embodiments, unless otherwise specified, and the experimental methods without specific conditions indicated in the embodiments are usually in accordance with conventional conditions. The materials, reagents, etc. used in the following embodiments, unless otherwise specified, can all be obtained from commercial channels.

[0048] Experimental reagents / instruments: Lactobacillus paracasei Probio-37 (from naturally fermented yogurt whey in Yunnan), high performance liquid chromatography (purchased from Agilent Technologies, USA, model 1260), ultra-high performance liquid chromatography (ACQUITY UPLC, purchased from Waters Corporation, USA), inductively coupled plasma mass spectrometry (purchased from Agilent Technologies, USA), crystal violet solution (purchased from Beijing BioLabo Technology Co., Ltd.).

[0049] Example 1 A postbiotic with low sodium, salt reduction and umami enhancement

[0050] I. Preparation method

[0051] The single colony in the experiment is Lactobacillus paracasei ( Lacticaseibacillus paracasei ) Probio-37, and the specific steps are as follows:

[0052] (1) Activation of the strain and preparation of the seed solution:

[0053] Under sterile conditions, the activated single colony is inoculated into the liquid medium with an inoculation loop and cultured at 37°C for 8 - 10 h to obtain the primary seed solution;

[0054] Under sterile conditions, the primary seed solution is inoculated into the liquid medium at an inoculation amount of 2% and cultured at 37°C for 8 - 10 h to obtain the secondary seed solution;

[0055] Under aseptic conditions, the secondary seed liquid is inoculated into the liquid medium at an inoculation amount of 3%, and cultured at 37 °C for 8 - 10 h to obtain the tertiary seed liquid, with the stirring speed controlled at 50 - 70 revolutions per minute;

[0056] (2)Fermentation by Lactobacillus paracasei Probio-37:

[0057] The tertiary seed liquid obtained by activating in step (1) is transferred to the fermentation medium at an inoculation amount of 3% and stirred for 8 min, and fermented at 37 °C. Fermentation is stopped when the pH of the fermentation broth reaches 4.55 after 26 h of fermentation, and heat-inactivated at 115 - 120 °C for 10 min.

[0058] Among them, the components of the fermentation medium are 1% defatted soy flour, 8% skim milk powder and water. Specifically, after mixing the components of the fermentation medium in proportion, it is mashed at 58 °C (i.e., stirred at 150 rpm) for 15 min to obtain a slurry; the slurry is homogenized once at 58 °C under a primary pressure of 19 Mpa and a secondary pressure of 5.0 Mpa to obtain a homogenized slurry; the homogenized slurry is sterilized at 93 °C for 30 min to obtain a sterilized slurry; the sterilized slurry is cooled to 35 °C to obtain the fermentation medium.

[0059] (3)Decolorization and concentration:

[0060] The fermented broth after inactivation in step (2) is cooled to below 44 °C, and decolorized and preliminarily concentrated with a nanofiltration membrane with a membrane molecular weight of 200 - 300 Da. When the solid content of the inactivated fermented broth reaches 35 - 45%, the primary concentration is completed, and then transferred to double-effect vacuum concentration, with a vacuum degree ≥ -0.07 Mpa and a temperature of 65 - 75 °C. When the solid content of the inactivated fermented broth reaches 55 - 65%, the concentration is stopped, and the pH of the concentrated solution is adjusted to 4.5 - 4.8 (using sterilized calcium hydroxide) for standby.

[0061] (4)Powder preparation:

[0062] The inlet air temperature is automatically controlled between 120 - 150 °C, and the outlet air temperature is automatically controlled between 55 - 75 °C for spray drying; the postbiotic powder after spray drying is screened through a rotary oscillating sieve with 80 - 100 meshes. The postbiotic powder passing through the sieve is filled into a stainless steel storage tank, and the oversize material that cannot pass through the rotary oscillating sieve is ground by a grinder and then loaded into the storage tank.

[0063] (5)Packaging and inspection:

[0064] The postbiotic powder obtained in step (4) is automatically weighed at 1 kg per bag, heat-sealed, spray-coded, and then bagged and transferred to the finished product temporary storage room for sampling inspection. Among them, the appearance of the postbiotic is off-white or light yellow, without impurities, without peculiar smell, and the viable count ≥ 1.0×10 11CFU / g, no precipitation in the dispersion dissolution experiment, water content < 5%.

[0065] II. Detection of metabolites and cell count in postbiotics

[0066] 2.1 Detection of aroma-active compounds

[0067] Weigh 8 g of postbiotics and place them in a solid-phase microextraction vial; add 1 μL of 2-methyl-3-heptanone solution at 1.68 μg / μL as an internal standard, seal it; equilibrate in a water bath at 50 °C for 20 min; then insert the solid-phase microextraction needle into the vial and push the handle to make the fiber head in the headspace state for adsorption for 40 min.

[0068] Among them, the DB-WAX capillary column (30 m × 0.25 mm, 0.25 μm); the carrier gas is helium (purity > 99.99%); the constant flow rate is 1.2 mL / min, and the split ratio is 10:1; the inlet temperature is 250 °C; the column oven temperature program is: the initial temperature is 40 °C, hold for 3 min, increase the temperature to 200 °C at a rate of 5 °C / min, hold for 0 min, and then increase the temperature to 260 °C at a rate of 15 °C / min, hold for 3 min.

[0069] The measurement results are shown in Table 1. The mass concentration of 2-methyl-5-methylthiofuran is the highest and mainly provides a meaty flavor. 1-Hydroxy-2-propanone and 4-hydroxy-2,5-dimethyl-3(2H)-furanone provide a roasted flavor, trimethylpyrazine provides a nutty flavor, and 3-methylthiopropionaldehyde provides a boiled potato flavor. These aroma-active compounds are important factors in forming the overall aroma of postbiotics.

[0070] Table 1 Detection results of aroma-active compounds in low-sodium, salt-reduced, and flavor-enhanced postbiotics

[0071]

[0072] 2.2 Determination of taste amino acids

[0073] Transfer an appropriate amount of the postbiotics from Example 1 to an EP tube (2 mL), add 600 μL of 10% formic acid methanol solution-H2O (1:1, V / V) solution, vortex for 30 s, centrifuge at 12000 rpm at 4 °C for 5 min, take 10 μL of the supernatant, add 990 μL of 10% formic acid methanol solution-H2O (1:1, V / V) solution, vortex for 30 s, take 100 μL of the diluted sample, add 100 μL of the double-isotope internal standard with a concentration of 100 ppb, vortex for 30 s, filter the supernatant through a 0.22 μm membrane, and add the filtrate to the detection bottle for chromatograph detection.

[0074] The detection results are shown in Table 2. The content of flavor-related amino acids in the postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment reached 2213.49 mg / L. The content of umami amino acids in the postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment is relatively high, so the umami taste is stronger. Ultrafiltration (UF), gel permeation chromatography (GPC), and high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF) were used to isolate and purify umami peptides, and four umami peptide segments, namely Glu-Ser, Asp-Glu-Thr, Ala-Leu-Ala, and Glu-Gly, were identified, which contributed significantly to improving its taste characteristics.

[0075] Table 2 Free amino acid content in postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment

[0076]

[0077] 2.3 Determination of salty peptides

[0078] High-performance liquid chromatography (Agilent 1260 II) equipped with a TSKgel chromatographic column (G2000 SWXL, 300 mm × 7.8 mm, 5 μm) was used to analyze the polypeptide distribution in the postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment. Standard curves were plotted using 2 mg / mL of aprotinin (Mr = 6512 Da), vitamin B12 (Mr = 1355 Da), glycine-tyrosine-arginine (Mr = 451 Da), glutathione (Mr = 307 Da), and glycine (Mr = 75 Da) as standards for external standard method analysis of the polypeptide distribution in the postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment. The abscissa was the retention time, and the ordinate was the logarithm of the relative molecular mass of the peptide standard (lg Mw). The molecular weight distribution range of the peptides could be obtained through the standard curve.

[0079] Table 3 shows the peptide distribution in the postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment. It can be seen that the peptides with a molecular weight < 1000 Da accounted for the highest proportion, reaching 71.8%. Some studies have proven that the peptide segments in the range of 300 - 2000 Da contribute to the rich taste by analyzing the correlation of non-volatile substances.

[0080] Table 3 Percentage of polypeptide distribution in postbiotics after low-sodium, salt-reducing, and freshness-enhancing treatment

[0081]

[0082] Take a certain amount of the components of the postbiotics and dilute them with ultrapure water. Use an Eclipse Plus C18 RRHD (2.1 mm×50 mm, 1.8 μm) high-performance separation chromatographic column to separate and identify the peptide sequences of salty peptides by Agilent 6530 UPLC-Q-TOF MS / MS. Use methanol and ultrapure water as the mobile phase, with a flow rate of 0.2 mL / min, an injection volume of 2 μL, and a column temperature of 35°C. The elution program is 3%-20% methanol for 0-20 min, hold for 1 min; 80%-100% methanol for 21-30 min; 100%-5% methanol for 30-32 min.

[0083] Among them, the mass spectrometry conditions are as follows:

[0084] Ion source: ESI positive ion mode; capillary voltage: 3500 V; nozzle voltage: 500 V; nebulization pressure: 35 psig, dryer temperature: 300°C; flow rate: 5 L / min; carrier gas: N2; temperature: 150°C; flow rate: 1 L / min; flow velocity: 0.2 mL / min; Fragmentor voltage: 135 V; collision energy: 100, 110, 120, 300 eV; ion scan range: 50-1000 m / z.

[0085] Such as Figure 1-8 The measurement results show that 4 salty peptides were detected in the postbiotics, including 3 dipeptides and 1 tripeptide. The amino acid sequences are Asp-Asp, Glu-Asp, Ser-Glu, Asp-Asp-Asp respectively, and the abundances of these four salty peptides in the postbiotics are quite high.

[0086] 2.4 Determination of the number of postbiotic bacteria

[0087] Weigh 1.0 g of the postbiotic sample and dissolve it in 9 mL of sterile 0.1% tween80 PBS buffer solution, shake and mix evenly; take 1 mL of the above diluted bacterial solution into a 2 mL EP tube, centrifuge at 12000 rpm for 8 minutes, collect the bacterial cell precipitate and then add 1 mL of PBS containing 0.1% tween80, shake and mix evenly; add 1 mL of 2% crystal violet solution, shake and mix evenly, and let it stand for staining at room temperature for 8-10 minutes; after staining, centrifuge at 13000 rpm for 3 minutes, remove the supernatant, and redissolve it with PBS containing 0.2% tween 80. Shake and mix evenly.

[0088] The number of bacteria in the postbiotic sample calculated by the counting plate is: 1.86×10 11 CFU / g.

[0089] 2.5 Determination of sodium content

[0090] The sodium content was determined by inductively coupled plasma mass spectrometry (ICP-MS).

[0091] Weigh 1 g of the postbiotic sample and pour it into a tall beaker. Add 150 mL of deionized water and 10 mL of nitric acid. Heat it on a hot plate at 180 °C for 30 min. After cooling, pour it into a volumetric flask and make up to 500 mL with deionized water. Mix well and filter the sample solution, then pour it into a 50 mL beaker. Take 2.5 mL of the sample solution and pour it into a volumetric flask, make up to 25 mL with deionized water, and dilute this solution 10 times in the same way. After mixing evenly, load it onto the instrument. The sodium content in the low-sodium, salt-reduced, and flavor-enhanced postbiotic was determined to be 5350 mg / 100 g.

[0092] Example 2 A low-sodium, salt-reduced, and flavor-enhanced postbiotic

[0093] The preparation method is different from that of Example 1 as follows:

[0094] In step (2), the inoculum size of the tertiary seed liquor is 5% and it is transferred to the fermentation medium and stirred for 8 min, then fermented at 35 °C until the pH of the fermentation broth reaches 4.6. Stop fermentation and heat inactivate at 115 - 120 °C for 10 min.

[0095] In step (3), when the solid content of the inactivated fermentation broth reaches 65%, stop concentration.

[0096] The others are the same as in Example 1, and the metabolites and cell count in the postbiotic were detected.

[0097] The detection results of flavor-active compounds are shown in Table 4. Compared with the results in Table 1, the concentrations of flavor-active compounds have all increased, but the sour and roasted flavors are relatively strong.

[0098] Table 4 Detection results of flavor-active compounds in low-sodium, salt-reduced, and flavor-enhanced postbiotic

[0099]

[0100] The determination results of taste amino acids are shown in Table 5. The content of flavor-related amino acids in the low-sodium, salt-reduced, and flavor-enhanced postbiotic reaches 2291.61 mg / L, and the umami is more obvious, but the bitter flavor is also increased.

[0101] Table 5 Free amino acid content in low-sodium, salt-reduced, and flavor-enhanced postbiotic

[0102]

[0103] The determination results of salty peptides are shown in Table 6. Among them, the peptides with a molecular weight < 1000 Da still account for the highest proportion, the flavor is more intense, but the product cost is increased.

[0104] Table 6 Percentage distribution of polypeptides in postbiotics with low sodium, reduced salt and enhanced umami

[0105]

[0106] The number of postbiotic cells in the low-sodium, reduced-salt and enhanced-umami postbiotic sample was calculated using a counting chamber to be: 2.32×10 11 cells / g; the sodium content in the measured postbiotics was 5735 mg / 100 g.

[0107] Example 3 A postbiotic with low sodium, reduced salt and enhanced umami

[0108] The preparation method is different from that of Example 1 as follows:

[0109] In step (2), the inoculum amount of the tertiary seed liquor is 1% and it is transferred to the fermentation medium and stirred for 8 min, and fermented at 39 °C until the pH of the fermentation broth reaches 4.7, then the fermentation is stopped and heat-inactivated at 115 - 120 °C for 10 min.

[0110] In step (3), when the solid content of the inactivated fermentation broth reaches 55%, the concentration is stopped.

[0111] Others are the same as in Example 1, and the metabolites and cell numbers in the postbiotics are detected.

[0112] The determination results of flavor-active compounds are shown in Table 7. The content concentration of flavor-active compounds is relatively low and the overall flavor is not prominent.

[0113] Table 7 Detection results of flavor-active compounds in postbiotics with low sodium, reduced salt and enhanced umami

[0114]

[0115] The determination results of taste amino acids are shown in Table 8. The content of flavor-related amino acids in the low-sodium, reduced-salt and enhanced-umami postbiotics reaches 2104.68 mg / L, and the content is relatively low.

[0116] Table 8 Free amino acid content in postbiotics with low sodium, reduced salt and enhanced umami

[0117]

[0118] The determination results of salty peptides are shown in Table 9. The proportion of peptides with a molecular weight < 1000 Da is 66.33%, and the rich flavor is relatively light.

[0119] Table 9 Percentage distribution of polypeptides in postbiotics with low sodium, reduced salt and enhanced umami

[0120]

[0121] The number of postbiotic cells in the low-sodium, reduced-salt and enhanced-umami postbiotic sample was calculated using a counting chamber to be: 1.32×10 11per g; the sodium content in the determined postbiotics was 4898 mg / 100 g.

[0122] Example 4 Application of low-sodium, salt-reduced and freshness-enhanced postbiotics in potato chip products

[0123] 4.1 Method for making potato chips

[0124] (1) Select potatoes of uniform size without pests and diseases. After washing them with clean water, draining, removing the epidermis, cut the potatoes into thin slices 1-2 mm thick, and then put them into clean water for soaking to wash away the starch on the surface of the potato chips. After fishing out and draining the water, put them into the oven for baking, divided into 4 groups. The set parameters of the oven are 190 °C and 45 min.

[0125] (2) Preparation of postbiotic samples

[0126] Dilute the postbiotic samples obtained in Example 1 with sterile maltodextrin in a certain proportion and then add them. According to the requirement of the standard T / CBFIA09001-2023 "Probiotic products - Lactic acid - Postbiotics" for the number of bacteria, dilute the postbiotics to 3×10 10 per g for addition.

[0127] (3) Preparation of postbiotic potato chips

[0128] When the potato chips are baked to 2 / 3 cooked (about 25 min), take out the potato chips, add seasonings on the surface. No. 1# represents the full-salt scheme with an addition amount of 5%; No. 2#, 3# and 4# represent the addition of 5% postbiotics, 5.5% postbiotics and 6.0% postbiotics respectively. Place them in the oven and continue baking. After baking, take them out and let them cool, and conduct relevant index detection.

[0129] 4.2 Determination of sodium content in potato chips

[0130] Refer to the experimental steps in 2.5 of Example 1, and the determination results are shown in Table 10.

[0131] Table 10 Determination results of sodium content in each group

[0132]

[0133] Compared with the full-salt scheme, when the addition ratio of postbiotics is 5%, the sodium content is reduced by 28.8%.

[0134] 4.3 Sensory evaluation of potato chips

[0135] The effects of adding probiotic metabolites Pbio-TNa on the original-flavor potato chips with 30% salt reduction were evaluated from five aspects: crispness, state, color, smell, and taste, with a total score of 100. The panelists consisted of 20 members engaged in food-related fields, with a male-to-female ratio of 1:1. The sensory evaluation criteria used refer to QB / T 2686-2005 and were revised according to the characteristics of this product, as shown in Table 11 below.

[0136] Table 11 Sensory evaluation form of probiotic metabolites Pbio-TNa in potato chips

[0137]

[0138] The evaluation results are as Figure 9 shown, and the comparison of the appearance of the potato chips is as Figure 10 shown. Figure 9-10 It can be concluded that compared with the full-salt formula, adding probiotic metabolites to potato chips has basically no significant effect on the surface state, crispness, and color of the product. Even when the sodium content is reduced, it still provides a good taste and enhances the fresh flavor of the product.

[0139] 4.4 Determination of electronic nose and electronic tongue of potato chips

[0140] The electronic nose and electronic tongue were used to measure the full-salt group 1# and the probiotic metabolite groups 2#, 3#, and 4# respectively. The results of the electronic nose and electronic tongue are shown in Figure 11 . The results of the electronic nose show that the response values of different sensors have little difference, indicating that the similarity of the smell among different addition amounts of probiotic metabolites in the salt reduction formula is very high, suggesting that the addition of different proportions of probiotic metabolites in the salt reduction formula has no significant effect on the change of the smell of potato chips. The results of the electronic tongue show that compared with the full-salt flavor of 1#, the saltiness of the potato chips added with probiotic metabolites 2#, 3#, and 4# is reduced, but the umami is increased, indicating that adding different proportions of probiotic metabolites can endow the product with better umami and taste while reducing the sodium content.

[0141] 4.5 Determination of the number of bacteria in potato chips

[0142] The number of bacteria in 4 groups of potato chip products was detected, and the detection results are shown in Figure 12 . The results show that the number of bacteria can be effectively detected in the potato chips with the application of probiotic metabolites, and the number of bacteria increases with the increase of the addition amount.

[0143] The application of probiotic metabolites with low-sodium, salt-reducing, and umami-enhancing formula in potato chips has no significant effect on its state, texture, crispness, and flavor. It can endow the product with better umami and taste while reducing the sodium content. Adding products with low-sodium, salt-reducing, and umami-enhancing probiotic metabolites can eliminate chemical food additives, clean the label, and endow the product with a healthier concept.

[0144] Obviously, the above embodiments are only a detailed description of the present invention, rather than a limitation on the implementation manner. For those skilled in the art, other different forms of changes or variations can be made based on the above description. The changes or variations made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A low-sodium, salt-reducing and freshness-enhancing postbiotic, characterized in that: The postbiotics include Lactobacillus paracasei ( Lacticaseibacillus paracasei ) inactivated bacteria of Probio-37 and metabolites of Lactobacillus paracasei Probio-37; the preparation method of the postbiotics comprises the following steps: S1, activating the strain, and expanding the culture to obtain the seed liquid of Lactobacillus paracasei Probio-37; S2, inoculating the seed solution in step S1 into the fermentation medium, fermenting and culturing until the pH is 4.5-4.7, stopping the fermentation, and obtaining the fermentation liquid; S3, inactivating the fermentation broth in step S2; S4, the inactivated fermentation broth is decolorized, concentrated and spray-dried to obtain postbiotics; The components of the fermentation medium include 1% defatted soy flour, 8% defatted milk powder and water; The deposit number of the Lactobacillus paracasei Probio-37 is CGMCC No. 18638.

2. The postbiotic according to claim 1, characterized in that The metabolites of Lactobacillus paracasei Probio-37 include flavor-active compounds.

3. The postbiotic according to claim 1, characterized in that The metabolites of Lactobacillus paracasei Probio-37 include flavor peptides and flavor amino acids.

4. The postbiotic according to claim 3, characterized in that The total content of the flavor amino acids is ≥ 2220 mg / L, and the content of umami amino acids in the flavor amino acids is ≥ 1370 mg / L.

5. The postbiotic according to claim 3, characterized in that The flavor peptides include one or more of umami peptides, kokumi peptides and salty peptides.

6. The postbiotic according to claim 5, characterized in that The umami peptide includes one or more of Gln-Leu, Pro-Glu-Thr, Ala-Pro-Ala and His-Val.

7. The postbiotic according to claim 5, characterized in that The salty peptides include one or more of Asp-Asp, Glu-Asp, Asp-Asp-Asp, Ser-Pro-Glu and Phe-Ile.

8. The method for preparing the postbiotics according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) activating the strain and expanding the culture to obtain the seed solution of Lactobacillus paracasei Probio-37; (2) inoculating the seed solution in step (1) into a fermentation medium, fermenting and culturing until the pH reaches 4.5-4.7, and stopping the fermentation to obtain a fermentation liquid; (3) inactivating the fermentation broth in step (2); (4) The inactivated fermentation broth is decolorized, concentrated and spray-dried to obtain postbiotics; The components of the fermentation medium include: 1% defatted soybean powder, 8% defatted milk powder and water.

9. The preparation method according to claim 8, characterized in that: The inoculation amount of the seed liquid in step (2) is 1%-5%, and the temperature of the fermentation culture is 35°C-39°C.

10. The preparation method according to claim 8, characterized in that: The inactivation method in step (3) is selected from any one of thermal inactivation, chemical inactivation and biological inactivation.

11. The preparation method according to claim 8, characterized in that: The concentration conditions in step (4) include: vacuum degree ≥ -0.07 MPa, temperature 65-75°C, and solid content of the inactivated fermentation broth reaching 55-65%.

12. Use of the postbiotic according to any one of claims 1 to 7 or the postbiotic prepared by the preparation method according to any one of claims 8 to 11 in preparing food.

13. The use according to claim 12, characterized in that: The food includes convenience food.

14. The use according to claim 12, characterized in that: The food comprises one or more of biscuits, potatoes, puffed foods, sauces, roasted seeds and nuts foods, nut products and meat products.

15. A potato chip, characterized in that: The method comprises adding the postbiotics described in any one of claims 1 to 7 or the postbiotics prepared by the preparation method described in any one of claims 8 to 11, and baking according to conventional operations to prepare potato chips.

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