Production method of fermented milk improved in preferred characteristics

Abstract

To provide a novel production method, etc. of fermented milk improved in preferred characteristics.SOLUTION: The disclosure is related to a production method of fermented milk improved in preferred characteristics, providing a method, etc. including a step of fermenting a milk material in the presence of 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) at least one genus of Lactobacillus other than 2), 4) Lacticaseibacillus, 5) at least one genus of Lactococcus, and 6) Bifidobacterium.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention broadly relates to a method for producing fermented milk with improved palatability, and the like.

Background Art

[0002] In the production of fermented milk such as yogurt, it is known that the coagulation time of milk is shorter when using a plurality of lactic acid bacteria than when using only a single lactic acid bacterium. Therefore, when using a plurality of lactic acid bacteria conventionally, the combination of bacteria is often selected with emphasis on their symbiotic relationship.

[0003] Due to the diversification of palatability and eating scenes, the flavors required for fermented milk such as yogurt products are diverse. For example, when eating yogurt like a sauce on pancakes, etc., a yogurt with a smooth texture, suppressed excessive sweetness, and a mild taste is required.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a method for producing fermented milk with improved palatability, and the like.

Means for Solving the Problems

[0006] Japanese Patent Application Laid-Open No. 2022-190134 discloses a method for producing fermented milk using at least two Lactococcus spp. bacteria, Lactococcus cremoris and Lactococcus lactis, and one or more selected from the group consisting of Lactobacillus spp., Streptococcus spp., and Bifidobacterium spp. However, the fermented milk disclosed herein solves the problem of providing a rich and complex flavor while suppressing acidity, and there is still room for improvement in the palatability of the fermented milk.

[0007] The present inventors have found that fermented milk with improved palatability can be obtained by performing fermentation in the presence of multiple bacterial species without using lactase, which is used in the production of fermented milk as a lactose-degrading enzyme, and have thus completed the present invention.

[0008] That is, the present invention encompasses the following inventions. [1] A method for producing fermented milk with improved palatability, comprising: in the absence of lactase, 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) one or more Lactobacillus spp. other than 2), and 4) Lactobacillus casei spp., and 5) one or more Lactococcus spp., and 6) Bifidobacterium spp., a step of fermenting a milk raw material in the presence thereof. [2] The one or more Lactobacillus spp. of 3) are one or more lactic acid bacteria selected from the group consisting of Lactobacillus helveticus and Lactobacillus acidophilus, the Lactobacillus casei spp. of 4) is Lactobacillus casei paracasei, the one or more Lactococcus spp. of 5) are Lactococcus cremoris and / or Lactococcus lactis, The Bifidobacterium bacterium in (6) is Bifidobacterium lactis, the method according to [1]. [3] The fermented milk contains less than 3.0% by mass of milk fat, the method according to [1] or [2]. [4] The fermented milk contains 8.0% by mass or more of non-fat milk solids, the method according to any one of [1] to [3]. [5] When compared with the case where only Streptococcus thermophilus and Lactobacillus bulgaricus are used as lactic acid bacteria, the amount of lactose and / or the types of peptides contained in the fermented milk are more, and / or the amount of glucose and / or the amount of lactic acid contained in the fermented milk are less, the method according to any one of [1] to [4]. [6] When compared with the case where only Streptococcus thermophilus and Lactobacillus bulgaricus are used as lactic acid bacteria, one or more selected from the group consisting of the lactose / glucose ratio, the (glucose + lactose) / lactic acid ratio, and the types of peptides in the fermented milk are increased, the method according to [5]. [7] The lactose / glucose ratio is 70 parts by mass or more of lactose with respect to 1 part by mass of glucose, the method according to [6]. [8] (The (glucose + lactose) / lactic acid ratio is 4 parts by mass or more of glucose + lactose with respect to 1 part by mass of lactic acid, the method according to [6]. [9] The number of types of peptides is 800 or more, the method according to [6].

[10] The palatability is one or more selected from the group consisting of smoothness, sweetness, the balance of sweetness and sourness, and mildness, the method according to any one of [1] to [9].

[11] Fermented milk having improved palatability, produced by the method according to any one of [1] to

[10] .

[12] A method for improving the palatability of fermented milk, in the absence of lactase, 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) one or more Lactobacillus bacteria other than 2), and 4) Lactobacillus casei, and 5) one or more Lactococcus bacteria, and 6) Bifidobacterium bacteria, A method comprising a step of fermenting milk raw materials in the presence of. Fermented milk with improved palatability.

Effect of the Invention

[0009] When lactase treatment is performed during the fermentation process, lactose contained in the raw material is decomposed into glucose and galactose, and the sweetness of the fermented milk increases. However, fermented milk prepared from a plurality of bacteria in the absence of lactase has an excellent balance of sweetness and sourness without undergoing lactase treatment.

[0010] By using a plurality of bacteria, palatability other than the balance of sweetness and sourness, such as smoothness, sweetness, and mildness, can also be improved.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments or modes of the present invention will be described in detail, but the present invention is not limited thereto, and various modifications are possible without departing from the gist thereof.

[0012] (Method for Producing Fermented Milk) In a first embodiment, a method for producing fermented milk with improved palatability, In the absence of lactase, 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) one or more Lactobacillus bacteria other than 2), and 4) Lactobacillus casei, and 5) one or more Lactococcus bacteria, and 6) Bifidobacterium bacteria, There is provided a method including a step of fermenting a milk raw material in the presence of .

[0013] It is said that there are several hundred types of bacteria (intestinal bacteria) in the human intestine, a total of about 100 trillion. These bacteria maintain a delicate relationship among good bacteria, bad bacteria, and intermediate bacteria, forming groups for each type, which is called the intestinal flora. Among the good bacteria, there are reports of effects such as improving the intestinal environment (such as improving bowel movements), infection prevention by enhancing immunity, cancer suppression, and improving allergic symptoms.

[0014] As used herein, the "improvement" of palatability means that the flavor and texture expected of fermented milk become preferable compared to the control. Examples of flavor include sweetness, the balance between sourness and sweetness, and mildness, and an example of texture is smoothness. The "balance between sourness and sweetness" is an index indicating whether both the sourness and sweetness of fermented milk can be felt well in balance. For example, when the sourness is extremely strong and the sweetness cannot be felt, the evaluation is low. Also, "mildness" is an index for evaluating the mildness and mellowness of sourness and sweetness. Even if the balance between sourness and sweetness is good (that is, even if both sweetness and sourness are felt), if the sweetness and sourness are extremely strong, the evaluation of "mildness" is low.

[0015] The improvement of sweetness means that when the fermented milk is held in the mouth, the sweetness is not too strong and is kept in a moderate state. Sweetness is improved by an increase in sugars such as lactose and glucose, but when the ratio of lactose / glucose increases, excessive sweetness can be suppressed.

[0016] The balance between sourness and sweetness can be adjusted by sour components and sweet components. For example, when the lactic acid concentration decreases, even if the absolute amount of the sweet component is the same, the balance between sourness and sweetness can be relatively improved. As an index for the balance between sourness and sweetness, there is the ratio of (lactose + glucose) / lactic acid. When this ratio increases, it can be judged that the balance between sourness and sweetness has improved.

[0017] Although mildness is a palatability related to the balance between sourness and sweetness, in addition to the sour and sweet components, the mildness varies depending on the variety of peptides produced during the fermentation process. For example, when the number of peptide varieties increases, excessive sourness and sweetness are suppressed by the actions of various peptides, and as a result, the mildness can be improved.

[0018] Improvement in smoothness means that when the fermented milk is held in the mouth, a hard texture is not felt and the smoothness of the mouthfeel is improved. Smoothness can be improved by an increase in components involved in viscosity, such as exopolysaccharides produced by bacteria.

[0019] In one embodiment, the improvement in palatability is one or more selected from the group consisting of smoothness, sweetness, the balance between sourness and sweetness, and mildness.

[0020] As used herein, "lactic acid bacteria" means bacteria that decompose sugars to produce lactic acid and that are the inoculum used in the production of fermented milk. Hereinafter, the lactic acid bacteria used in the production of fermented milk are also referred to as the inoculum. The lactic acid bacteria are preferably viable bacteria. The number of lactic acid bacteria species is 3 or more, preferably 5 or more. Particularly preferably, the number of species is 8.

[0021] Lactic acid bacteria include not only Lactobacillus and Lactococcus in the sense of bacteria that decompose sugars to produce lactic acid, but also Bifidobacterium. Conventionally, the main lactic acid bacteria used in the production of fermented milk have been known to include Lactobacillus spp., Lactococcus spp., Streptococcus spp., Bifidobacterium spp., and the like.

[0022] Since Lactobacillus bacteria are systematically diverse, a reexamination of the classification was conducted at the genomic level in 2020, and as a result, Lactobacillus paracasei was reclassified into the genus Lacticaseibacillus spp.

[0023] In one embodiment, the starter culture is the following genus of bacteria: Streptococcus thermophilus as a Streptococcus bacterium; Lactobacillus bulgaricus as a Lactobacillus bacterium; Lacticaseibacillus spp.; and Bifidobacterium spp., and includes.

[0024] The starter culture may include Streptococcus bacteria other than Streptococcus thermophilus, but it is preferable to use only Streptococcus thermophilus as the starter culture among Streptococcus bacteria.

[0025] The inoculum contains Lactobacillus bulgaricus and one or more other Lactobacillus species. Examples of Lactobacillus species other than Lactobacillus bulgaricus include Lactobacillus helveticus, Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus reuteri, Lactobacillus rhamnosus, Lactobacillus plantarum, etc. However, as Lactobacillus species, a combination of Lactobacillus bulgaricus and Lactobacillus helveticus and / or Lactobacillus acidophilus is preferred.

[0026] The inoculum contains one or more Lacticaseibacillus species. Examples of Lacticaseibacillus species include Lacticaseibacillus paracasei, Lacticaseibacillus casei, etc. However, as Lacticaseibacillus species, Lacticaseibacillus paracasei is preferred.

[0027] The inoculum contains one or more Lactococcus species. Examples of Lactococcus species include Lactococcus cremoris, Lactococcus lactis, etc. However, as Lactococcus species, Lactococcus cremoris and / or Lactococcus lactis are preferred.

[0028] The inoculum contains one or more types of Bifidobacterium spp. Examples of Bifidobacterium spp. include Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium infantis, etc. However, as the Bifidobacterium spp., Bifidobacterium lactis is preferred.

[0029] As long as it has the effect of improving palatability, any strain belonging to the above-mentioned genus or species of bacteria can be used as the inoculum. The same applies to bacterial species with subspecies, and subspecies that have the effect of improving palatability can be used as the inoculum. Fermentation is carried out by a process of contacting the inoculum, a starter containing it or their culture with milk raw materials. The lactic acid bacteria used as the starter may be one or more bacterial species. As used in this specification, "starter" means a culture (a culture of lactic acid bacteria or non-lactic acid bacteria) that can cause fermentation from fresh milk.

[0030] In one embodiment, the lactic acid bacteria used as the starter are one or more selected from the group consisting of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus helveticus, Lactococcus lactis and Lactococcus cremoris.

[0031] The method of adding lactic acid bacteria to milk raw materials is not particularly limited, and it can be added in the state of bacterial powder or in the state of a culture (culture). Bacterial powder is a powdery product obtained by growing bacteria in an appropriate medium, separating them by centrifugation, mixing with a cryoprotectant for freeze-drying, then freeze-drying, pulverizing the dried product, and mixing with a diluent as needed. A culture is a liquid composition obtained by growing bacteria in an appropriate medium.

[0032] It is preferable to add lactic acid bacteria simultaneously, but they may also be added at separate timings for each bacterial species.

[0033] The total bacterial count of the inoculum when added to the milk raw material is not particularly limited as long as it meets the component specifications of the fermented milk and the final product has the effect of improving palatability. For example, those skilled in the art can appropriately adjust the total bacterial count within the range of 1×10 8 cfu / mL to 9×10 10 cfu / mL. Among lactic acid bacteria, for example, Bifidobacterium lactis, Lactobacillus casei paracasei, and Lactobacillus acidophilus have their bacterial counts regulated from the perspective of probiotics, and for other bacteria, the bacterial counts can be regulated with the taste balance being the top priority.

[0034] As used herein, "milk raw material" means the raw materials necessary for producing fermented milk. The milk raw material is not necessarily only animal-derived materials from the milk of mammals such as cows, goats, sheep, etc., but in addition to plant-derived milk from plants such as beans, nuts, grains, etc., it includes their processed products. The origin of the milk raw material is preferably a mammal, particularly preferably a cow. Processed products include, for example, adjusted-component milk, low-fat milk, non-fat milk, processed milk, or various dairy products manufactured using them. The milk raw material may include one or more of concentrated milk, skimmed concentrated milk, skim milk powder, cream, butter, whey protein concentrate, whey protein isolate, milk protein concentrate, whey powder, etc.

[0035] It is preferable that the milk raw material does not contain yeast, but it may be contained in the milk raw material if it is a yeast extract. The mixture of milk raw materials is preferably adjusted such that the non-fat milk solids fraction (Solids Not Fat; SNF) of the finally obtained fermented milk is 1.0 to 15.0% by mass, and more preferably adjusted such that the SNF is 8.0 to 14.0% by mass.

[0036] Non-fat milk solids play the role of fat in terms of the texture and flavor of fermented milk. The higher the SNF value, the lower the fat content can be. Also, increasing SNF increases the protein content, making the curd in fermented milk firmer and reducing whey separation. On the other hand, if SNF is excessively increased, saltiness and off-flavors derived from minerals are likely to occur, resulting in a powdery flavor. Therefore, from the perspective of flavor, SNF is preferably 12% by mass or less, and more preferably about 10% by mass.

[0037] The milk raw material is preferably subjected to a homogenization process and a sterilization process before inoculation with lactic acid bacteria. The sterilization treatment can be carried out by a conventional method. When sterilizing the fermented milk by heating, the temperature conditions can be appropriately determined by those skilled in the art. Although not intended to be limiting, the temperature in heat sterilization is 80°C or higher, 90°C or higher, 95°C or higher, or 100°C or higher. The heating time varies depending on the heating temperature, but in the case of heating at about 80°C, it is about 20 minutes to 40 minutes, preferably about 25 minutes to 35 minutes.

[0038] Known methods can be used in the heat sterilization process. For example, in the heat sterilization process, heat treatment can be carried out by a plate heat exchanger, a tube heat exchanger, a steam injection heating device, a steam infusion heating device, an electric heating device, etc., or heat treatment can also be carried out by a jacketed tank.

[0039] After heat sterilization, the milk raw material can be cooled before the fermentation process. The milk raw material can also be subjected to an additional process before moving to the fermentation process. For example, before the fermentation process, the components contained in the milk raw material may be passed through a process of decomposing using an enzyme other than lactase.

[0040] When the method for producing lactic acid bacteria includes a heat sterilization step and a decomposition step using an enzyme other than lactase, the heat sterilization step may be performed before or after the decomposition step. When the heat sterilization step is performed before the decomposition step, in the fermentation step described below, since the decomposition of the target component continues during the fermentation step, the concentration of the component in the fermented milk can be further reduced. Further, the addition of the enzyme to the raw material mixture is preferably performed by the timing when the lactic acid bacteria are added to the milk raw material, and optionally, the enzyme and the lactic acid bacteria may be added to the milk raw material at the same time.

[0041] By holding the raw material mixture added with an enzyme other than lactase in a temperature range of, for example, 5°C or higher and 50°C or lower, the decomposition of the target component by the degrading enzyme can be promoted. As described above, when the decomposition step is performed after the heat sterilization step, the decomposition of the target component by the enzyme other than lactase continues even after the lactic acid bacteria starter is added to the raw material mixture.

[0042] In one embodiment, a method for producing fermented milk with improved palatability comprises the following inoculum: 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) One or more Lactobacillus spp. other than 2), and 4) Lactobacillus casei spp., and 5) One or more Lactococcus spp., and 6) Bifidobacterium spp., and includes a step of fermenting the milk raw material in the presence thereof.

[0043] The fermentation conditions can be changed according to various factors such as the lactic acid bacteria used, the type of fermented milk desired, and lactic acid. For example, it is cultured at a temperature of room temperature or higher, preferably 35°C or higher, more preferably 40°C or higher for a predetermined time. From the perspective of preparing fermented milk with high palatability, it is preferable to carry out fermentation for about 3.5 to 10 hours at a temperature of about 40°C to about 43°C. However, the fermentation time can vary depending on the difference in the fermented fat-free milk solids and total solids. For example, when the fat-free milk solids are high, the fermentation time becomes longer, and when the raw materials contain sugar or the like and the total solids are high, the fermentation time becomes longer.

[0044] More specifically, in the case of fermented milk that does not contain solids other than fat-free milk solids, that is, does not contain milk fat, sugar, etc., when the fat-free milk solids ratio (SNF value) reaches 25% or more, fermentation does not proceed, and when it reaches 30% or more, almost no fermentation occurs. Therefore, from the perspective of making the fermentation time appropriate, the SNF value is preferably less than 25%, preferably 22% or less.

[0045] Also, the total solids value of fermented milk is usually about 8 to 25%. Within this range, acid production is within the normal range and fermentation is usually completed within the normal time. However, when the total solids value exceeds 50%, the acid production ability tends to be delayed, and as a result, the fermentation time becomes longer.

[0046] Taking an example of the fermentation conditions from the perspective of adjusting the lactic acid acidity, by carrying out fermentation at 40°C for about 4 hours, the lactic acid acidity becomes 0.6% to 0.8%. Note that due to the growth of lactic acid bacteria during fermentation, the lactic acid acidity that results in an appropriate flavor, sourness, physical properties, and number of lactic acid bacteria is usually 0.7% to 0.8%.

[0047] The pH at the end of fermentation is preferably in the acidic region, for example, 3.0 to 6.0, preferably 3.9 to 5.0, and more preferably 4.2 to 4.8.

[0048] In one embodiment, the fermentation temperature is 40°C and the fermentation time is 3.5 to 4.5 hours.

[0049] As used herein, "fermented milk" means a fermented product obtained by culturing lactic acid bacteria in a mixture containing milk raw materials. The type of fermented milk is not particularly limited, and it may be any of, for example, fermented milk defined by a ministerial ordinance such as milk, lactic acid bacteria beverage for dairy products, lactic acid bacteria beverage, etc. Yogurt is cited as an example of fermented milk, and the yogurt may be set-type yogurt, soft-type yogurt, or drink-type yogurt. Further, it is also possible to use the produced fermented milk as a material for frozen yogurt or cheese. Further, a fermented milk product is a product obtained by filling and packaging the above fermented milk as it is, or after subjecting it to processing such as dilution or addition of syrup into a container.

[0050] In one embodiment, the fermented milk is preferably adjusted so that the solids-not-fat (SNF) fraction is 1.0 to 15.0% by mass, more preferably adjusted so that the SNF is 8.0 to 14.0% by mass, and particularly preferably adjusted so that the SNF is 9.0 to 11.0% by mass.

[0051] Taking the case of preparing fermented milk from milk as an example, the solids-not-fat (components obtained by removing milk fat and water from milk) contains peptides; proteins; carbohydrates such as glucose (dextrose), lactose (milk sugar), rhamnose, galactose, glucose, fructose, sucrose, cellobiose, raffinose, stachyose, maltose, etc.; organic acids such as lactic acid, phosphoric acid, citric acid, formic acid, acetic acid, etc.; minerals; vitamins, etc.

[0052] In one embodiment, the amount of lactose contained in the fermented milk is preferably 6,000 to 11,000 mg / 100 g, more preferably 7,000 to 10,000 mg / 100 g, and particularly preferably 8,000 to 9,000 mg / 100 g.

[0053] In one embodiment, the amount of glucose contained in the fermented milk is preferably 10 to 60 mg / 100 g, more preferably 20 to 50 mg / 100 g, and particularly preferably 30 to 40 mg / 100 g.

[0054] In one embodiment, the amount of lactic acid contained in the fermented milk is preferably 800 to 1,400 g / 100 g, more preferably 900 to 1,300 mg / 100 mg / 100 g, and particularly preferably 1,000 to 1,200 mg / 100 g.

[0055] In one embodiment, the number of types of peptides contained in the fermented milk is preferably 800 to 1,400, more preferably 900 to 1,300, and particularly preferably 1,000 to 1,200.

[0056] In one embodiment, the ratio of lactose / glucose contained in the fermented milk is preferably 70 or more, more preferably 100 or more, and particularly preferably 150 or more.

[0057] In one embodiment, the ratio of (glucose + lactose) / lactic acid is preferably 4 or more, more preferably 5 or more, and particularly preferably 6 or more.

[0058] In one embodiment, the number of types of peptides is preferably 800 or more, more preferably 900 or more, and particularly preferably 1,000 or more.

[0059] The fermented milk further contains components that affect the flavor, and an example thereof is milk fat. Milk fat also plays a role in stabilizing the shrinkage of the protein gel and preventing whey separation in the fermented milk. Whey separation can be prevented by increasing the milk fat content, but if the milk fat content is excessively increased, it will have a greasy flavor. Therefore, from the perspective of flavor, the milk fat content contained in the fermented milk is preferably less than 3% by mass, more preferably less than 2.8% by mass, and particularly preferably less than 2.5% by mass.

[0060] In one embodiment, the fermented milk contains 1.8 to 2.3% by mass, preferably about 1.9 to 2.1% by mass of milk fat.

[0061] Embodiments of the present invention will be specifically described by way of examples. The embodiments of the present invention are not limited to the following examples.

Examples

[0062] <Production of Fermented Milk> After mixing milk raw materials (530 g of raw milk, 7 g of cream, 52 g of skim milk powder, 6 g of whey protein concentrate, 6 g of whey powder) and 399 g of water to prepare a raw material mixture, it was heated to 80°C and held for 30 minutes. Next, the raw material mixture was cooled to 40°C, the lactic acid bacteria described in Table 1 were added so as to have the number of bacteria described in the same table, and cultured at 40°C for 4 hours. Thereafter, the mixture was cooled to 10°C or lower to obtain the fermented milk of the examples and comparative examples.

[0063] As a result of measuring the SNF (skim milk solid) of the obtained fermented milk, the SNF value was 10% by mass in both the examples and the comparative examples. In addition, SNF was measured by the quantification method described in the "Test Method for Component Standards of Milk etc." of the "Ordinance on Milk etc. (Ordinance on Component Standards etc. of Milk and Dairy Products)". The total solid content value was 12% by mass in both the examples and the comparative examples, and the milk fat content was 2.0% by mass in both the examples and the comparative examples.

[0064]

Table 1

[0065] Subsequently, the components contained in the fermented milk of the examples and comparative examples were evaluated.

[0066] <Measurement Method of Glucose and Lactose> Glucose and lactose are measured by high performance liquid chromatography (HPLC). The measurement conditions are as follows. Model: SCL-10Avp Detector: RI (Refractive Index Detector) Column for analysis: Prep-Sil Column temperature: 40 °C Mobile phase: Ultrapure water Flow rate: 0.5 ml / min

[0067] <Measurement method of lactic acid> Under the conditions shown below, the quantification of organic acids by high performance liquid chromatography (HPLC) was performed to determine the lactic acid content. Model: LC-20AD Detector: Conductivity meter CDD-10A vp Column for analysis: Shim-pack SCR-102H×2 Φ8.0nm×300nmh Column temperature: 45 °C Mobile phase: 5 nmol / L p-toluenesulfonic acid Reaction solution: 5 nmol / L p-toluenesulfonic acid containing 0.1 mmol / L EDTA and 20 mmol / L Bis-Tris

[0068] <Measurement method of the number of peptide types> Under the conditions shown below, the number of peptide types in fermented milk was determined. Column for analysis: Capillary column manufactured by Nisshin Techno Co., Ltd., packing material particle size 3um C18 (φ0.75mm, 25cm) Column conditions: Constant temperature at 50 °C, flow rate 0.1 mL / min Mobile phase: Water containing 5% formic acid and 80% acetonitrile 0.1% formic acid Sample injection volume: 1 μL Detection: Measured by the Data-Independent Acquisition (DIA) method using a mass spectrometer under the setting conditions of windowsize = 4.002 and resolution 50000 in the range of m / z 500 - 740.

[0069] <Test example: Sensory evaluation> For each fermented milk, three trained panelists conducted a sensory evaluation test. After culturing, for each sample cooled to 10°C or lower, the evaluation scores for the four items of <smoothness>, <sweetness>, <balance between sourness and sweetness>, and <mildness> were determined by the agreement of the three panelists based on the following evaluation criteria.

[0070] <Smoothness> 〇: It has a smooth texture. △: It has a firm texture.

[0071] <Sweetness> 〇: The sweetness is suppressed. △: The sweetness is strongly felt.

[0072] <Balance between sourness and sweetness> 〇: The balance between sourness and sweetness is good. △: Either sourness or sweetness is prominent.

[0073] <Mildness> 〇: It has a mild taste (sourness and sweetness). △: The assertion of sweetness and sourness is strong.

[0074] The measurement results and the sensory evaluation results are shown in the following table.

[0075]

Table 2

[0076]

Table 3

[0077] As a result of the sensory evaluation, in terms of <smoothness>, <sweetness>, <balance between sourness and sweetness>, and <mildness>, the multi-strain (Example) was better than the two-strain (Comparative Example). Although not intended to be restricted by theory, the relationship between the above results and the use of multi-strains, etc. is considered as follows.

[0078] Regarding <smoothness>, it is considered that in the fermented milk fermented with multiple strains (Examples), many components involved in viscosity such as exopolysaccharides were produced.

[0079] Regarding <sweetness>, it is considered that in the fermented milk fermented with multiple strains (Examples), the ratio of lactose / glucose increased, suppressing excessive sweetness.

[0080] Regarding <the balance between sourness and sweetness>, it is considered that in the fermented milk fermented with multiple strains (Examples), the lactic acid concentration that causes excessive sourness decreased, and the ratio of (lactose + glucose) / lactic acid increased.

[0081] Regarding <mildness>, it is considered that in the fermented milk fermented with multiple strains (Examples), the number of types of peptides produced during the fermentation process increased, and the actions of various peptides suppressed excessive sourness and sweetness.

Claims

1. A method for producing fermented milk with improved palatability, comprising the step of fermenting a milk raw material in the absence of lactase and in the presence of: 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) one or more Lactobacillus species other than 2), and 4) Lactobacillus casei species, and 5) one or more Lactococcus species, and 6) Bifidobacterium species.

2. The method according to claim 1, wherein the one or more Lactobacillus species in 3) are one or more lactic acid bacteria selected from the group consisting of Lactobacillus helveticus and Lactobacillus acidophilus, the Lactobacillus casei species in 4) is Lactobacillus paracasei, the one or more Lactococcus species in 5) are Lactococcus cremoris and / or Lactococcus lactis, and the Bifidobacterium species in 6) is Bifidobacterium lactis.

3. The method according to claim 1 or 2, wherein the fermented milk contains less than 3.0% by mass of milk fat.

4. The method according to claim 3, wherein the fermented milk contains 8.0% by mass or more of non-fat milk solids.

5. The method according to claim 1 or 2, wherein the amount of lactose and / or the types of peptides contained in the fermented milk are greater, and / or the amount of glucose and / or the amount of lactic acid contained in the fermented milk are less, compared to the case where only Streptococcus thermophilus and Lactobacillus bulgaricus are used as lactic acid bacteria.

6. The method according to claim 5, wherein one or more selected from the group consisting of the lactose / glucose ratio, the (glucose + lactose) / lactic acid ratio, and the types of peptides in the fermented milk are increased compared to the case where only Streptococcus thermophilus and Lactobacillus bulgaricus are used as lactic acid bacteria.

7. The method according to claim 6, wherein the lactose / glucose ratio is 70 parts by mass or more of lactose per 1 part by mass of glucose.

8. The method according to claim 6, wherein the (glucose + lactose) / lactic acid ratio is 4 parts by mass or more of glucose + lactose per 1 part by mass of lactic acid.

9. The method according to claim 6, wherein the number of types of peptides is 800 or more.

10. The method according to claim 1 or 2, wherein the palatability is one or more selected from the group consisting of smoothness, sweetness, balance of sourness and sweetness, and mildness.

11. ​ ​ ​ ​ ​ ​ Fermented milk with improved palatability, produced by the method according to claim 1 or 2.

12. A method for improving the palatability of fermented milk, in the absence of lactase, 1) Streptococcus thermophilus, 2) Lactobacillus bulgaricus, 3) one or more Lactobacillus species other than 2), and 4) Lactobacillus casei, and 5) one or more Lactococcus species, and 6) Bifidobacterium species, comprising the step of fermenting a milk raw material in the presence of. Fermented milk with improved palatability.

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