JPWO2017014290A1 - Fermented milk and method for producing the same - Google Patents

Abstract

The objective of this invention is providing the manufacturing method of fermented milk which can manufacture fermented milk which has sufficient hardness and smooth texture, without reducing the production efficiency of fermented milk. In the present invention, the raw material milk is sterilized at 115 ° C. to 150 ° C. before or after the step of homogenizing the raw material milk and the step of homogenizing the raw material milk so as to reduce the average particle diameter of the raw material milk. It is a manufacturing method of fermented milk including the process, the process of homogenizing raw material milk, and the process of sterilizing raw material milk, and the process of fermenting raw material milk.

Description

  The present invention relates to a production method for obtaining fermented milk having hardness (strength) that can withstand vibration during distribution and excellent in smoothness of texture, and fermented milk obtained by the production method.

  Fermented milk is made by fermenting milk or milk containing non-fat milk solids comparable to milk with lactic acid bacteria or yeast to make a paste, liquid, solid, or frozen these, It can be roughly divided into two types. One is a pre-fermentation type and the other is a post-fermentation type. In the former (pre-fermentation type), a predetermined amount of starter (lactic acid bacteria, etc.) is added to the raw milk, and the raw milk is used for a predetermined lactate acidity or a predetermined amount using a tank or the like before being packed in a single food container for distribution. After fermenting until it reaches pH, etc., and cooling, the obtained fermented milk is crushed and mixed with pulp and sweeteners (sugar solution, etc.) as necessary. Individual food containers (paper containers, plastic containers, glass containers, etc.) are filled. In the latter (post-fermentation type), a predetermined amount of starter is added to the raw milk, and this raw milk is filled in a distribution-use individual food container. Or fermented until reaching a predetermined pH or the like, solidified into a pudding, and then cooled. Pre-fermentation is often used for the production of soft type yogurt with pulp and drink type yogurt with sweetener. On the other hand, post-fermentation is often used for the production of so-called plain type yogurt such as hard type (set type) yogurt that does not contain pulp or sweeteners.

  Fermented milk is manufactured by adding a starter to sterilized raw material milk for fermentation. When raw milk is fermented by ultra-high temperature sterilization (UHT treatment, for example, heat treatment at 120 ° C or higher), the texture becomes very smooth and the palatability is significantly improved, but the hardness of the card is small (brittle) Fermented milk will be obtained. For this reason, in a set-type yogurt or the like, when trying to obtain a fermented milk having a high curd hardness (hard), generally, the raw milk is sterilized at a high temperature for a short time (HTST treatment, for example, heating at 85 to 95 ° C. Processed) and fermented. However, when raw milk is sterilized at high temperature for a short time and fermented, it is difficult to obtain fermented milk with a sufficiently smooth texture.

  As a method for producing fermented milk using high-temperature and short-time sterilization treatment, Patent Document 1 discloses that the dissolved oxygen concentration of raw material milk is reduced (5 ppm or less), and then raw milk is sterilized at high temperature and short- Describes a method for producing fermented milk with sufficient hardness, which is fermented at ˜37 ° C., excellent in smooth texture, and capable of maintaining the structure during distribution. Patent Document 2 describes a smooth food that reduces the dissolved oxygen concentration of raw material milk (5 ppm or less), then sterilizes raw material milk for a short time at high temperatures and then ferments at low temperatures (30-40 ° C). A method for producing fermented milk with excellent hardness and sufficient hardness that can maintain the structure in the distribution stage is described.

JP 2005-176603 A JP 2005-348703 A

In the methods for producing fermented milk of Patent Documents 1 and 2, an inert gas (nitrogen (N ₂ ), etc.) is injected in addition to the general production equipment for fermented milk in order to reduce the dissolved oxygen concentration of raw material milk Ancillary manufacturing equipment such as equipment, equipment for depressurization, equipment for defoaming is required. Moreover, since raw material milk is sterilized at a high temperature for a short time, it cannot be said that fermented milk having a sufficiently smooth texture can be obtained as compared with the case where raw material milk is sterilized at an ultrahigh temperature. That is, it is required to improve the texture of the past and improve the smoothness of the texture of the exhaled milk. When raw milk is sterilized at a high temperature for a short time, the sterilization time generally becomes longer, so it cannot be said that the production efficiency of fermented milk is good. That is, it is required to shorten the sterilization time than before and improve the production efficiency of fermented milk.

  In addition, when milk or milk beverages are distributed refrigerated, in order to sterilize heat-resistant spore bacteria and ensure bacterial quality, raw milk and raw milk are used in the production process of milk and milk beverages. Ultra high temperature sterilization is required.

  In other words, when raw milk or raw material milk is sterilized at high temperature and short time in the production process of fermented milk, it differs from the sterilization conditions in the production process of milk, milk drink, etc., so the production process of fermented milk, milk, milk drink, etc. If the same sterilization equipment is used in the manufacturing process, the sterilization conditions must be changed in each manufacturing process. Therefore, the production efficiency of various products has been reduced in the whole dairy factory. Moreover, when different sterilization facilities are used in the manufacturing process of fermented milk and the manufacturing processes of milk and milk beverages, the sterilization facilities must be installed in the respective manufacturing processes. Therefore, the number of production facilities for various products has been increased throughout the dairy factory.

  As described above, conventionally, in order to produce fermented milk having a sufficient hardness to maintain a structure during distribution and a smooth texture, the dissolved oxygen concentration of the raw milk can be reduced, or the raw milk can be converted into milk. It was necessary to sterilize at a temperature lower than the sterilization temperature of milk drinks or to add whey protein (α-lactalbumin, β-lactoglobulin, etc.) to raw milk. Therefore, the manufacturing cost of fermented milk is required, and the production efficiency of fermented milk is inevitably lowered.

  Then, the objective of this invention is providing the manufacturing method of fermented milk which can manufacture fermented milk with sufficient hardness and smooth texture, without reducing the production efficiency of fermented milk. It is in.

  As a result of intensive studies to solve the above problems, the present inventors have homogenized raw milk and reduced the average particle size of raw milk, thereby subjecting raw milk to ultra-high temperature sterilization treatment. However, it has been found that fermented milk having sufficient hardness can be produced, and the present invention has been completed.

  The present invention includes a step of homogenizing raw milk so as to reduce the average particle size of raw milk, and a step of sterilizing raw milk at 115 to 150 ° C. before or after the step of homogenizing raw milk. The process of fermenting the raw milk (including the meaning of the fermented milk base, which is the state after adding a starter of lactic acid bacteria to the raw milk) after the steps of homogenizing the raw milk and sterilizing the raw milk And a method for producing fermented milk.

  Moreover, this invention provides the manufacturing method of fermented milk which homogenizes raw material milk so that the average particle diameter of raw material milk may be 0.8 micrometer or less in the said homogenization process.

  Moreover, this invention provides the manufacturing method of fermented milk which further includes the process of reducing the dissolved oxygen concentration of raw material milk before the process of fermenting raw material milk in the said manufacturing method.

  Moreover, this invention provides the manufacturing method of fermented milk whose fermented milk is a set-type yogurt.

  The present invention also includes a step of homogenizing raw material milk, a step of sterilizing raw material milk at 115 ° C to 150 ° C before or after a step of homogenizing raw material milk, a step of homogenizing raw material milk, and a raw material A method for improving the hardness of fermented milk, comprising a step of fermenting raw material milk after a step of sterilizing milk.

  The present invention also includes a step of homogenizing raw material milk, a step of sterilizing raw material milk at 115 ° C to 150 ° C before or after a step of homogenizing raw material milk, a step of homogenizing raw material milk, and a raw material Provided is a method for improving the smoothness of the texture of fermented milk, including a step of fermenting raw material milk after the step of sterilizing milk.

  The present invention also includes a step of homogenizing raw material milk, a step of sterilizing raw material milk at 115 ° C to 150 ° C before or after a step of homogenizing raw material milk, a step of homogenizing raw material milk, and a raw material Provided is a method for improving the hardness of fermented milk and the smoothness of texture, including a step of fermenting raw material milk after a step of sterilizing milk.

  The present invention also provides fermented milk having a hardness of 26 g or more, a yogurt knife penetration angle of less than 60 degrees, and an average particle size after stirring of 43 μm or less.

Moreover, this invention provides fermented milk whose adhesive force is 0.0008 J / m < ² > or more in the said fermented milk.

  Moreover, this invention provides the fermented milk manufactured by the manufacturing method of the said fermented milk in the said fermented milk.

  Moreover, this invention provides the fermented milk packaged in the said fermented milk.

  Moreover, this invention provides the fermented milk which is a set type yogurt in the said fermented milk.

  Moreover, this invention sterilizes raw material milk at 115 to 150 degreeC before or after the process of homogenizing raw material milk, and the process of homogenizing raw material milk so that the average particle diameter of raw material milk may be made small. A process of filling fermented milk, including a step, a step of filling raw material milk into a container, a step of homogenizing raw material milk, a step of sterilizing raw material milk and a step of filling raw material milk, and fermenting raw material milk A set-type yogurt manufactured by the manufacturing method is provided.

  Moreover, this invention sterilizes raw material milk at 115 to 150 degreeC before or after the process of homogenizing raw material milk, and the process of homogenizing raw material milk so that the average particle diameter of raw material milk may be made small. A process, a process of fermenting raw milk to obtain fermented milk, a process of stirring fermented milk (crushing the card of fermented milk), and if necessary, pulp, vegetables, preparation, sauce, sugar solution, etc. A soft-type yogurt produced by a method for producing fermented milk, comprising a step of mixing and a step of filling fermented milk into a container.

  Moreover, this invention sterilizes raw material milk at 115 to 150 degreeC before or after the process of homogenizing raw material milk, and the process of homogenizing raw material milk so that the average particle diameter of raw material milk may be made small. A step of fermenting raw material milk to obtain fermented milk, a step of stirring fermented milk (crushing the card of fermented milk), and a step of homogenizing the fermented milk (refining the card of fermented milk) And, if necessary, a drink type produced by a method for producing fermented milk, comprising a step of mixing pulp, vegetables, preparation, sauce, sugar solution, etc., and a step of filling fermented milk into a container. Provide yogurt.

  In the method for producing fermented milk of the present invention, the main requirements are to homogenize the raw milk and sterilize the raw milk at 115 ° C. to 150 ° C. so as to reduce the average particle size of the raw milk. The fermented milk having sufficient hardness and smooth texture can be produced without reducing the production efficiency of fermented milk.

The graph which shows the hardness (card tension) of fermented milk of Example 1 and Comparative Example 1 of the present invention. The graph which shows the sensory evaluation of fermented milk of Example 2 and Comparative Example 2 of the present invention. The figure which shows the structure of the eating and swallowing measurement apparatus of this invention. The graph which shows the adhesive force of the fermented milk of the comparative example 4 and Example 13 of this invention.

  The present invention provides a method for producing fermented milk.

  In the present specification, “fermented milk” refers to dairy products and processed products obtained by fermenting milk or the like with lactic acid bacteria or yeast, etc., and “fermented milk” and “dairy lactic acid bacteria beverages” defined by a ministerial ordinance. And “lactic acid bacteria beverage”. The fermented milk produced according to the present invention may be yogurt, for example. Fermented milk produced according to the present invention is a pre-fermentation type yogurt in which raw milk is fermented in a tank or the like and then filled into a container, and a post-fermentation type yogurt in which fermented milk is fermented after being filled into a container Any of these may be used. The fermented milk produced by the present invention may be, for example, plain yogurt, set-type yogurt (solid fermented milk), soft yogurt (paste-like fermented milk), drink yogurt (liquid fermented milk), or the like. Since the manufacturing method of this invention can manufacture fermented milk which has sufficient hardness so that it may mention later, it can be utilized suitably for a set type yogurt.

  The production method of the present invention includes a step of homogenizing the raw milk so as to reduce the average particle diameter of the raw milk.

  As used herein, “raw milk” is milk, a milk component or a composition containing a milk component. Milk components include, for example, raw milk, cow milk, skim milk, whole milk powder, skim milk powder, whole fat concentrated milk, skim concentrated milk, sweetened condensed milk, sweetened skimmed condensed milk, sugar free condensed milk, sugar free skimmed condensed milk, whey , Whey powder, desalted whey, desalted whey powder, whey protein concentrate (WPC), whey protein isolate (WPI), α-lactalbumin, β-lactoglobulin, milk protein concentrate (MPC), casein, sodium Caseinate, calcium caseinate, cream, fermented cream, compound cream, cream powder, butter, fermented butter, buttermilk, buttermilk powder, butter oil and the like. The raw milk may contain two or more milk components. The raw material milk may further contain, for example, water, lipids, proteins, sugars, flavor components, fragrances, pigments, minerals (salts), vitamins and other food additives in addition to the milk components. The raw milk may also contain gelatin solution or the like that has been preheated and dissolved. The raw milk may be a known yogurt mix, for example.

  In the present specification, the “average particle diameter of raw material milk” is an average value of the particle diameter of particles composed of proteins and / or lipids (fat) contained in raw milk. The particles composed of protein and / or fat are, for example, casein micelles and / or fat globules. The average particle size of the raw milk may be evaluated by a laser diffraction type particle size distribution measuring device (for example, SALD-2200, Shimadzu Corporation).

In the present specification, “homogenizing raw material milk” refers to finely pulverizing (miniaturizing) particles composed of proteins and / or lipids contained in raw material milk. In the method for homogenizing the raw milk of the present invention, for example, a method of passing through a narrow gap while pressing and extruding raw milk, or a method of passing through a narrow gap while reducing and sucking raw milk is used. be able to. The pressure and flow rate (flow rate) for homogenizing the raw milk is such that the average particle diameter of the raw milk is 0.8 μm or less, preferably 0.77 μm or less, more preferably 0.75 μm or less, even more preferably 0.73 μm or less, and most preferably 0.7. Any pressure and flow rate that can be adjusted to μm or less can be used, and can be set as appropriate. At this time, the pressure for homogenizing the raw milk is preferably 180 kg / cm ² or more, more preferably 200 kg / cm ² or more, further preferably 220 kg / cm ² or more, and further preferably 240 kg / cm 2. ² or more, more preferably 260 kg / cm ² or more, further preferably 280 kg / cm ² or more, and more preferably 300 kg / cm ² or more. The pressure for homogenizing the raw milk is preferably 800 kg / cm ² or less, more preferably 700 kg / cm ² or less, further preferably 600 kg / cm ² or less, and further preferably 550 kg / cm ^2. It is as follows. Further, the flow rate for homogenizing the raw milk is preferably 100 to 30000 kg / h, more preferably 150 to 25000 kg / h, still more preferably 200 to 20000 kg / h, still more preferably 250 to 15000 kg / h. h. The method and equipment for homogenizing raw milk are not limited to the methods described above, and any known method and equipment can be used.

  The step of homogenizing the raw material milk is performed so that the average particle size of the raw material milk reaches 0.8 μm or less immediately after the step of homogenizing the raw material milk and immediately before the step of fermenting the raw material milk. Also good. That is, the step of homogenizing raw milk is, for example, immediately after the step of homogenizing raw milk, before the step of sterilizing raw milk, after the step of sterilizing raw milk, or immediately before the step of fermenting raw milk. In addition, the raw material milk may have an average particle size of 0.8 μm or less. Here, the step of homogenizing the raw material milk may be performed before the step of sterilizing the raw material milk, after the step of sterilizing the raw material milk, or immediately before the step of fermenting the raw material milk. From the viewpoint of simplifying the production method (eg, easy handling of raw milk), the step of homogenizing the raw milk is preferably performed before (immediately before) the step of sterilizing the raw milk. The step of homogenizing the raw material milk may be performed once or may be performed twice or more, but from the viewpoint of simplifying the production method of the present invention, the raw material milk is homogenized. The process is preferably performed once. In the production method of the present invention, even when the raw material milk is processed at a high temperature of 115 ° C to 150 ° C by homogenizing the raw material milk under predetermined conditions and adjusting the average particle size of the raw material milk to be small, Fermented milk with sufficient hardness to withstand the vibrations of can be obtained. At this time, the average particle size of the raw material milk of the present invention is preferably 0.8 μm or less, more preferably 0.77 μm or less, further preferably 0.75 μm or less, more preferably 0.73 μm or less, The thickness is preferably 0.7 μm or less, more preferably 0.67 μm or less, and further preferably 0.65 μm or less. The average particle size of the raw material milk of the present invention is preferably 0.2 μm or more, more preferably 0.25 μm or more, further preferably 0.3 μm or more, further preferably 0.35 μm or more, and further preferably Is 0.4 μm or more. Further, the standard deviation of the particle size of the raw milk of the present invention is preferably 0.16 μm or less, more preferably 0.15 μm or less, further preferably 0.14 μm or less, and further preferably 0.13 μm or less. The standard deviation of the particle size of the raw material milk of the present invention is preferably 0.01 μm or more, more preferably 0.05 μm or more, further preferably 0.08 μm or more, and further preferably 0.1 μm or more.

  The production method of the present invention includes a step of sterilizing raw milk at 115 ° C to 150 ° C.

  The step of sterilizing the raw material milk may be performed before the step of homogenizing the raw material milk, or may be performed after the step of homogenizing the raw material milk. In the method of sterilizing raw milk, so-called “high temperature sterilization (HTST)” or “ultra high temperature sterilization (UHT)” can be used. The temperature and time for sterilizing the raw milk may be any temperature and time that can produce fermented milk having sufficient hardness and a smooth texture, and can be set as appropriate. At this time, the temperature at which the raw milk is sterilized is preferably 115 ° C. or higher, more preferably 116 ° C. or higher, further preferably 120 ° C. or higher, more preferably 125 ° C. or higher, and further preferably 130. It is above ℃. And the temperature which sterilizes raw material milk becomes like this. Preferably it is 150 degrees C or less, More preferably, it is 145 degrees C or less, More preferably, it is 140 degrees C or less. The time for sterilizing the raw milk is preferably 1 to 300 seconds, more preferably 1 to 120 seconds, still more preferably 1 to 60 seconds, still more preferably 1 to 30 seconds, Preferably it is 1 to 10 seconds, and most preferably 1 to 5 seconds. The method and equipment for sterilizing raw milk are not limited to the methods described above, and any known method and equipment can be used. In addition, fermented milk which improved the smoothness of food texture can be obtained by processing raw material milk at high temperature 115 to 150 degreeC.

  The production method of the present invention includes a step of fermenting raw milk (including the meaning of a fermented milk base material in a state after adding a lactic acid bacteria starter or the like to the raw milk).

  The step of fermenting the raw milk is performed after the step of homogenizing the raw milk and the step of sterilizing the raw milk. In the process of fermenting raw milk, after homogenizing raw milk and sterilizing raw milk, or after sterilizing raw milk and homogenizing raw milk, lactic acid bacteria and yeast starters, etc. Can be added (inoculated) to ferment raw material milk. Moreover, in the process of fermenting raw material milk, after sterilizing raw material milk, after adding lactic acid bacteria, a starter of yeast, etc. to raw material milk, raw material milk can be homogenized and raw material milk can be fermented. That is, the step of adding the starter to the raw milk is after the step of sterilizing the raw milk and before the step of fermenting the raw milk, before the step of homogenizing the raw milk and the raw milk The starter may be added to the raw milk from the viewpoint of simplifying the production method of the present invention (e.g. hygienically handling raw milk). The step of performing is preferably performed before (immediately before) the step of fermenting raw material milk. The step of adding the starter to the raw milk may be performed once or may be performed twice or more, but from the viewpoint of simplifying the production method of the present invention, the starter is added to the raw milk. The step of adding is preferably performed once.

  In the step of fermenting raw material milk or the step of adding a starter to raw material milk, any starter such as lactic acid bacteria, bifidobacteria and yeast can be used. Starters include, for example, Lactobacillus bulgaricus (Bulgaria, L. bulgaricus), Streptococcus thermophilus (S. thermophilus), Lactobacillus lactis (L. lactis), Lactobacillus gasseri (Gaseri, L. gasseri), Lactobacillus plantarum (L. plantarum), Lactobacillus casei (L. casei), L. acidophilus and Bifidobacteria One kind selected from lactic acid bacteria and yeast generally used in the production of fermented milk such as um (Bifidobacterium) can be used alone, or two or more kinds can be used in combination. The starter is preferably a starter based on a mixed starter of Bulgarian bacteria and Thermophilus bacteria from the viewpoint of being standardized as a yogurt starter in the Codex standard. Further, depending on the fermented milk to be actually obtained, gasseri, bifidobacteria, yeast and the like may be added while using a yogurt starter as a base. At this time, the added amount of the starter may be a quantity generally used in the production of fermented milk, and is, for example, 0.1 to 10% by weight, preferably 0.2 to 5% by weight, more preferably 0.5 to the raw material milk. -4% by weight, more preferably 1-3% by weight. The starter may be added by any method that is generally used in the production of fermented milk. For example, a method in which the starter is aseptically added in a state where the raw milk is stored in a tank or the like, In this state, the starter is added in-line while flowing in the pipe. The method and equipment for fermenting raw milk are not limited to the methods described above, and any known method and equipment can be used.

  The method of fermenting raw milk may be a method in which after adding a starter to raw milk, the raw milk is filled in a container and then held in the fermentation chamber, or after adding a starter to raw milk, A method may be used in which milk is filled in a tank or the like and then held in the tank or the like. And in the method of filling the raw milk into a tank or the like and holding it in the tank or the like, after the fermented milk is prepared in the tank or the like, the fermented milk is stirred (the card of fermented milk is crushed) If necessary, a soft type yogurt may be produced by adding a method of mixing pulp, vegetables, preparation, sauce, sugar solution and the like and filling the fermented milk into a container. Moreover, after filling raw material milk into a tank etc. and holding in a tank etc., after fermented milk is prepared in a tank etc., this fermented milk is stirred (the card | curd of fermented milk is crushed), After homogenizing fermented milk (miniaturized curd of fermented milk), add a method to mix the pulp, vegetables, preparation, sauce, sugar solution, etc. and fill this fermented milk into a container as necessary Thus, a drink-type yogurt may be manufactured.

  The conditions for fermenting the raw milk may be adjusted in consideration of the type and amount of lactic acid bacteria added to the raw milk, the flavor, texture and physical properties of the fermented milk to be actually obtained. The temperature and time for fermenting the raw material milk may be any temperature and time that can produce fermented milk having sufficient hardness and smooth texture, and can be set as appropriate. At this time, the temperature at which the raw milk is fermented (fermentation temperature) is preferably 30 ° C. or higher, more preferably 33 ° C. or higher, still more preferably 35 ° C. or higher, and most preferably 37 ° C. or higher. And the temperature which ferments raw material milk becomes like this. Preferably it is 50 degrees C or less, More preferably, it is 45 degrees C or less, More preferably, it is 43 degrees C or less. The time for fermenting the raw milk (fermentation time) is preferably 1 to 24 hours, more preferably 1 to 12 hours, further preferably 2 to 8 hours, and further preferably 2 to 6 hours. And more preferably 2 to 4 hours. When fermenting raw milk, the lactic acidity (acidity) varies depending on the composition, but if the non-fat milk solid content is about 8% by weight, it preferably reaches 0.5%, more preferably 0.6%. To reach. Further, the lactic acid acidity (acidity) preferably reaches 0.6%, more preferably 0.7% when the non-fat milk solid content is about 10% by weight. The lactic acid acidity (acidity) preferably reaches 0.7%, more preferably 0.8% when the non-fat milk solid content is about 12% by weight. The lactic acid acidity (acidity) preferably reaches 0.8% and more preferably reaches 1.0% when the non-fat milk solid content is about 14% by weight. The lactic acid acidity (acidity) preferably reaches 1.0%, more preferably 1.1% when the non-fat milk solid content is about 16% by weight. The lactic acid acidity (acidity) preferably reaches 1.1%, more preferably 1.3% when the non-fat milk solid content is about 18% by weight. Further, the lactic acid acidity (acidity) preferably reaches 1.2%, more preferably 1.4% when the non-fat milk solid content is about 20% by weight. The method and equipment for fermenting raw milk are not limited to the methods described above, and any known method and equipment can be used. In addition, the fermented milk which improved the smoothness of the texture can be obtained by fermenting raw material milk at low temperature 35 to 40 degreeC.

  In the production method of the present invention, as described in the examples described later, specifically, the fineness of the card structure, the mildness of the aftertaste, the creamy feeling of the flavor, the richness, the milky feeling of the aftertaste, the smoothness and the texture. Fermented milk that is excellent, has a good flavor, and has a smooth texture can be obtained.

  In the production method of the present invention, the dissolved oxygen concentration of the raw milk is determined before the step of fermenting raw milk (including the meaning of the fermented milk base material, which is the state after adding a starter of lactic acid bacteria to the raw milk). You may further include the process to reduce.

  The step of reducing the dissolved oxygen concentration of the raw material milk may be performed before the step of fermenting the raw material milk, for example, before the step of homogenizing the raw material milk, after the step of homogenizing the raw material milk, Before the step of sterilizing, after the step of sterilizing raw material milk, before the step of adding a starter to raw material milk, and after the step of adding a starter to raw material milk, it may be performed. The step of reducing the dissolved oxygen concentration of the raw milk may be performed once or may be performed twice or more, but from the viewpoint of simplifying the production method of the present invention, The step of reducing the dissolved oxygen concentration is preferably performed once or twice before the step of sterilizing the raw milk and before the step of fermenting the raw milk. At this time, the step of reducing the dissolved oxygen concentration of the raw milk is, for example, 5 ppm or less, preferably 4 ppm or less, more preferably 3 ppm or less, so that the dissolved oxygen concentration of the raw milk at the start of fermentation is lower than usual. The treatment is preferably performed to 2 ppm or less, more preferably 1 ppm or less. By reducing the dissolved oxygen concentration of the raw material milk at the start of fermentation, the lactic acid acidity reaches a predetermined value early, so that the fermentation time can be shortened and the production efficiency can be improved.

The method of reducing the dissolved oxygen concentration of the raw milk may be a method of injecting an inert gas into the raw milk and replacing the raw milk with an inert gas, or the raw milk is in a low-pressure or vacuum state Alternatively, the raw milk may be deaerated by depressurizing the raw milk to remove oxygen from the raw milk. The method and equipment for reducing the dissolved oxygen concentration of the raw material milk are not limited to the methods described above, and known methods and equipment can be used. For example, N ₂ may be used as the inert gas, or a rare gas such as helium, neon, argon, or xenon may be used. At this time, the method of reducing the dissolved oxygen concentration of the raw material milk may be a method of setting the retention time at the heating temperature to a predetermined value (somewhat longer) in the method of heating (sterilizing) the raw material milk, For example, when the heating temperature of the raw milk is 115 ° C. to 150 ° C., the holding time is preferably set to 5 to 60 seconds, more preferably 5 to 30 seconds, and further preferably 5 to 10 seconds. At this time, the step of reducing the dissolved oxygen concentration of the raw material milk can be performed simultaneously with the step of sterilizing the raw material milk.

  The production method of the present invention fills a container with raw milk before the step of fermenting raw milk (including the meaning of a fermented milk base, which is a state after adding a starter such as lactic acid bacteria to raw milk) You may further include the process to do.

  The step of filling the raw milk into the container may be performed before the step of fermenting the raw milk. For example, after the step of homogenizing the raw milk and the step of sterilizing the raw milk, a starter is added to the raw milk. It may be performed either before the step of performing and after the step of adding the starter to the raw material milk. The step of filling the raw milk into the container may be performed, for example, after homogenizing and sterilizing the raw milk and then adding the starter to the raw milk and then filling the raw milk into the container. In addition, what is necessary is just a container generally used in manufacture of fermented milk (dairy products), for example, a container made from plastic, glass, paper, etc. may be sufficient as a container.

  In the production method of the present invention, in the step of homogenizing the raw material milk, the average particle size of the raw material milk is reduced, and in the step of sterilizing the raw material milk, the treatment is performed at a high temperature of 115 ° C. It is possible to provide fermented milk that not only has sufficient hardness to withstand, but also has excellent texture. Moreover, in the manufacturing method of this invention, in the process of sterilizing raw material milk, the same sterilization conditions as products other than fermented milk, such as milk and a milk drink, can be set by processing at high temperature 115 degreeC or more. Therefore, in the production method of the present invention, in the process of sterilizing raw material milk, the same method and equipment as products other than fermented milk such as milk and milk drinks can be used, and the production of various products can be performed throughout the dairy factory. There is no reduction in efficiency, and there is no need to install new equipment for each type of product.

  Moreover, this invention provides fermented milk which has sufficient hardness and was excellent in the smoothness of food texture. The fermented milk of the present invention may have a hardness of 26 g or more. The fermented milk of the present invention may have a yogurt knife penetration angle (one of indices indicating smoothness) of less than 60 degrees. Further, the fermented milk of the present invention may have an average particle size after stirring (one of indices indicating smoothness) of 43 μm or less. Moreover, the fermented milk of this invention can be manufactured with the manufacturing method of fermented milk mentioned above. Moreover, the fermented milk of this invention can be adjusted to the physical property which has sufficient hardness and was excellent in the smoothness of food texture by being manufactured by the manufacturing method of fermented milk mentioned above.

  In this specification, “having sufficient hardness” means having a hardness (strength) that can withstand vibration during distribution and is not crushed by an impact during transportation. In this specification, “hardness” can be restated as strength and card tension. The “hardness” in the fermented milk of the present invention may be evaluated as a measured value of the breaking point of the yogurt knife in a card meter (for example, MAX ME-500, iTechno Engineering Co., Ltd.). The temperature may be 5-10 ° C., the load may be 100 g, and measured by the breaking point of the card meter. At this time, the fermented milk of the present invention only needs to have a hardness of 26 g or more, and is effectively suppressed from being crushed by an impact during transportation while stably maintaining the tissue during distribution. That is, the hardness of the fermented milk of the present invention is preferably 26 g or more, more preferably 28 g or more, still more preferably 30 g or more, and further preferably 32 g or more. And the hardness of the fermented milk of this invention becomes like this. Preferably it is 100 g or less, More preferably, it is 90 g or less, More preferably, it is 80 g or less, More preferably, it is 70 g or less.

  In this specification, “excellent in texture smoothness” means that the texture of the card is dense and the texture is not rough when placed in the oral cavity. The “smoothness of texture” in the fermented milk of the present invention may be evaluated as a measured value of the penetration angle of a yogurt knife in a card meter (for example, MAX ME-500, iTechno Engineering Co., Ltd.). The measurement temperature is 5-10 ° C, the load is 100 g, and the measurement curve of the card meter is measured by the angle between the tangent to the breaking point passing through the origin and the time-loading curve after the breaking point. It may be evaluated. When this angle is large, it is evaluated as fermented milk having a rough and rough texture, and when this angle is small, it is evaluated as fermented milk having a smooth texture. At this time, in the fermented milk of the present invention, the penetration angle of the yogurt knife may be less than 60 degrees, and the smoothness of the touch is effectively improved while stably maintaining the tissue during distribution. That is, the penetration angle of the fermented milk of the present invention into the yogurt knife is preferably less than 60 degrees, more preferably less than 56 degrees, still more preferably less than 52 degrees, and even more preferably less than 48 degrees. The penetration angle of the fermented milk of the present invention into the yogurt knife is preferably 10 degrees or more, more preferably 15 degrees or more, still more preferably 20 degrees or more, and further preferably 25 degrees or more.

  “Smoothness of texture” in the fermented milk of the present invention may be evaluated as a measured value of the average particle diameter after stirring of the fermented milk (final product, intermediate product), and the average particle diameter after stirring of the fermented milk. May be measured and evaluated by a laser diffraction type particle size distribution measuring apparatus (for example, SALD-2200, Shimadzu Corporation). When the particle size after stirring is large, it is evaluated as fermented milk having a rough and rough texture, and when the particle size after stirring is small, it is evaluated as fermented milk having a smooth texture. At this time, in the fermented milk of the present invention, the average particle size after stirring may be 43 μm or less, and the smoothness of the tongue is effectively improved while stably maintaining the circulating tissue. That is, the average particle diameter after stirring of the fermented milk of the present invention is preferably 43 μm or less, more preferably 42 μm or less, still more preferably 41 μm or less, and most preferably 40 μm or less.

  The fermented milk of the present invention may be yogurt, and may be any of pre-fermentation type yogurt and post-fermentation type yogurt, but is preferably post-fermentation type yogurt. The fermented milk of the present invention may be a plain type yogurt, a set type yogurt (solid fermented milk), a soft type yogurt (paste-like fermented milk) and a drink type yogurt (liquid fermented milk). Any of these may be used, but a plain type yogurt is preferable, and a set type yogurt is preferable.

  The fermented milk of the present invention may be packed in a container. In this specification, “packed in a container” means that the container (inside) is filled and sealed. The container should just be a container generally used in manufacture of fermented milk (dairy products), for example, may be plastic, glass, paper, etc. The fermented milk of the present invention is obtained by fermenting raw milk in a container after filling the container with raw milk (including the meaning of a fermented milk base material after adding a starter of lactic acid bacteria to the raw milk). Or after fermented milk in a tank before filling the container with fermented milk (fermented milk after fermenting the raw milk in the tank, etc.) In a container) (pre-fermentation type).

  In the present invention, the non-fat milk solid content of the raw milk and / or fermented milk (final product and / or intermediate product) is preferably 8% by weight or more, more preferably 8.2% by weight or more, and still more preferably 8.5%. % By weight or more, more preferably 8.7% by weight or more, and further preferably 9% by weight or more. The non-fat milk solid content of the raw milk and / or fermented milk is preferably 30% by weight or less, more preferably 25% by weight or less, further preferably 20% by weight or less, and further preferably 18% by weight. % Or less, more preferably 15% by weight or less, further preferably 13% by weight or less, more preferably 10% by weight or less, and further preferably less than 10% by weight. In the present invention, the fat (lipid) of raw milk and / or fermented milk is preferably 0.3% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, and further preferably Is 1.5% by weight or more, more preferably 2% by weight or more, further preferably 2.5% by weight or more, more preferably 3% by weight or more, and further preferably more than 3% by weight. The fat (lipid) of raw milk and / or fermented milk is preferably 8% by weight or less, more preferably 7% by weight or less, further preferably 6% by weight or less, and further preferably 5% by weight. Or less, more preferably 4.5% by weight or less, further preferably 4% by weight or less, and further preferably 3.5% by weight or less. In the present invention, the milk fat of the raw milk and / or fermented milk is preferably 0.3% by weight or more, more preferably 0.5% by weight or more, further preferably 1% by weight or more, and further preferably 1.5% by weight. % By weight or more, more preferably 2% by weight or more, further preferably 2.5% by weight or more, more preferably 3% by weight or more, and further preferably more than 3% by weight. The milk fat of the raw milk and / or fermented milk is preferably 8% by weight or less, more preferably 7% by weight or less, further preferably 6% by weight or less, and further preferably 5% by weight or less. More preferably, it is 4.5% by weight or less, more preferably 4% by weight or less, and further preferably 3.5% by weight or less. In the present invention, the carbohydrate of raw milk and / or fermented milk is preferably 3% by weight or more, more preferably 4% by weight or more, further preferably 5% by weight or more, and further preferably 5% by weight. More than%. The carbohydrate in the raw milk and / or fermented milk is preferably 15% by weight or less, more preferably 13% by weight or less, further preferably 10% by weight or less, and further preferably 8% by weight or less. More preferably, it is 6% by weight or less. In the present invention, the lactose of the raw milk and / or fermented milk is preferably 3% by weight or more, more preferably 4% by weight or more, further preferably 5% by weight or more, and further preferably 5% by weight. More than%. The lactose of the raw milk and / or fermented milk is preferably 15% by weight or less, more preferably 13% by weight or less, further preferably 10% by weight or less, and further preferably 8% by weight or less. More preferably, it is 6% by weight or less.

Further, the adhesive force of the fermented milk of the present invention may be 0.0008 J / m ² or more, preferably 0.0009 J / m ² or more. Further, adhesion of the fermented milk of the present invention may also be 0.0050J / m ² or less, preferably may be less than or equal to 0.0030J / m ^2. In the present specification, “adhesive force” represents energy consumption per unit area of an inclined surface when flowing down or sliding down on an inclined plate imitating the surface of a living body. The adhesive force can be measured using a measuring device as shown in Test 6 of an example described later. Since the fermented milk of this invention has high adhesive force compared with the conventional fermented milk as shown in the Example mentioned later, it can be set as rich fermented milk.

The fermented milk of the present invention may be fermented milk having a non-fat milk solid content of 8 to 30% by weight and a hardness of 26 g or more. The fermented milk of the present invention may be fermented milk having a non-fat milk solid content of 8 to 10% by weight and a hardness of 26 g or more. The fermented milk of the present invention may be fermented milk having a fat (lipid) of 0.3 to 8% by weight and a hardness of 26 g or more. Moreover, the fermented milk whose fat (lipid) is 0.1 to 4 weight% and whose hardness is 26g or more may be sufficient. The fermented milk of the present invention may be fermented milk having a milk fat of 0.3 to 8% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0050 J / m ² or less. The fermented milk of the present invention may be fermented milk having a milk fat content of 0.5 to 3.8% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0040 J / m ² or less. The fermented milk of the present invention may be fermented milk having a non-fat milk solid content of 8 to 30% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0040 J / m ² or less. The fermented milk of the present invention may be fermented milk having a non-fat milk solid content of 8 to 10% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0050 J / m ² or less. The fermented milk of the present invention may be fermented milk having a fat (lipid) of 0.3 to 8% by weight and an adhesive force of 0.0008 J / m ² or more. The fermented milk of the present invention may be fermented milk having a fat (lipid) of 0.3 to 3.8% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0050 J / m ² or less. The fermented milk of the present invention may be fermented milk having a milk fat content of 0.5 to 3.8% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0050 J / m ² or less. The fermented milk of the present invention may be fermented milk having a lactose content of 3 to 15% by weight and an adhesive force of 0.0008 J / m ² or more and 0.0050 J / m ² or less.

  In addition, the raw material labeling of the fermented milk of the present invention may be a combination of any one or more of milk, raw milk, dairy products and milk proteins and / or sugars (sugar, liquid sugar, oligosaccharide) and sweeteners. As a plain type, the raw material labeling of the fermented milk of the present invention is preferably only milk (raw milk) and dairy products or milk proteins, more preferably only milk (raw milk) and dairy products, and more preferably milk. (Raw milk) only. That is, the fermented milk of the present invention has a hardness (strength) that can withstand conventional transportation even if the raw material display is only milk (raw milk), specifically, the hardness is 26 g or more. .

  Moreover, this invention provides the improvement method of the hardness of fermented milk, and the improvement method of the smoothness of the texture of fermented milk. The method of the present invention (a method for improving the hardness of fermented milk and a method for improving the smoothness of the texture of fermented milk) includes a step of homogenizing raw material milk, a step of sterilizing raw material milk at 115 ° C to 150 ° C, And fermenting raw material milk. In the method of the present invention, a step of homogenizing raw material milk, a step of sterilizing raw material milk at 115 ° C. to 150 ° C., and a step of fermenting raw material milk are performed in the same manner as each step described above for the production method of the present invention. be able to.

  In the method of the present invention, the step of homogenizing raw material milk achieves an average particle size of raw material milk of 0.8 μm or less immediately after the step of homogenizing raw material milk and immediately before the step of fermenting raw material milk. It may be done as follows. At this time, from the viewpoint of further improving the hardness of the fermented milk and further improving the smoothness of the texture of the fermented milk, the average particle diameter of the raw milk of the present invention is preferably 0.77 μm or less, more preferably It is 0.75 μm or less, more preferably 0.73 μm or less, and most preferably 0.7 μm or less.

  The method of this invention may further include the process of reducing the dissolved oxygen concentration of raw material milk. In the method of the present invention, the step of reducing the dissolved oxygen concentration of the raw material milk can be performed in the same manner as the step of reducing the dissolved oxygen concentration of the raw material milk described above for the production method of the present invention.

  In the method of the present invention, even when the raw material milk is processed at a high temperature of 115 ° C to 150 ° C by homogenizing the raw material milk under predetermined conditions and adjusting the average particle size of the raw material milk to be small, Fermented milk with sufficient hardness that can withstand vibration can be obtained. Moreover, the fermented milk which improved the smoothness of food texture can be obtained by processing raw material milk at high temperature 115 to 150 degreeC. In other words, in the method of the present invention, in the step of homogenizing the raw milk, the average particle size of the raw milk is reduced, and in the step of sterilizing the raw milk, the treatment is performed at a high temperature of 115 ° C. It is possible to provide fermented milk that not only has sufficient hardness to withstand vibration but also has an excellent texture.

  In the method of the present invention, as described in the examples below, specifically, it is excellent in the denseness of the card structure, the mildness of the aftertaste, the creamy feeling of the flavor, the richness, the milky feeling of the aftertaste, the smoothness and the texture. And fermented milk with a good flavor and a smooth texture.

  Hereinafter, examples will be shown and the embodiment of the present invention will be described in more detail. However, the present invention is not limited to the following examples.

[Measurement method of average particle diameter]
In this example, the average particle size and standard deviation of raw milk were measured using a laser diffraction particle size distribution analyzer SALD-2200 (Shimadzu Corporation). Specifically, raw milk was diluted with ion-exchanged water and adjusted so that the maximum value of the diffraction / scattering light intensity distribution was 35 to 75% (absolute value: 700 to 1500). Then, using the software WingSALD II for the particle size distribution measuring device, the light intensity distribution was analyzed, and the average particle size ± standard deviation was obtained.

[Method of measuring hardness of fermented milk]
In this example, the hardness (strength or card tension) of fermented milk was measured using a card meter MAX ME-500 (I Techno Engineering). Specifically, a yoghurt knife with a weight of 100 g is placed on the top of the fermented milk, and the fermented milk is continuously raised and weighted at about 2 g / sec. Thus, the measured value of the weight was expressed by a curve. At this time, the elapsed time (seconds) of this weighting is represented by the vertical axis, the measurement value of this weighting is represented by the horizontal axis, and 10 g on the vertical axis and 4 seconds on the horizontal axis are represented as the same distance. When the fermented milk breaks, the yogurt knife enters from the top of the fermented milk, resulting in an inflection point (breaking point) in this time-load curve. It was set as the index of (g).

[Evaluation method for smoothness of fermented milk]
In this example, the smoothness of the texture of the fermented milk was evaluated by measuring the penetration angle of the yogurt knife and the average particle size after stirring. Here, in the method for measuring the hardness of fermented milk described above, the angle between the tangent line passing through the origin to the breaking point and the time-loading curve after the breaking point in the measurement curve of the card meter is measured, and the yogurt The penetration angle of the knife was evaluated. In addition, fermented milk (sample) is stirred for about 100 revolutions using a propeller-type stirring blade or medicine basket, and the card is broken, and then a laser diffraction particle size distribution analyzer SALD-2200 (Shimadzu Corporation) is used. Then, the average particle size of the fermented milk after stirring was measured.

[Test 1]
(Example 1)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1 wt%, nonfat milk solids: 9.70 wt%), and the raw milk is heated (about 80 ° C) to be homogeneous (400 kg / cm ² ), ultra-high temperature sterilization (UHT; 130 ° C., 2 seconds), and then cooling (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw material milk was 0.52 ± 0.13 μm.

After heating the raw milk (about 43 ° C), N ₂ was injected, the dissolved oxygen concentration (DO) of the raw milk was reduced to 5 ppm, and then the lactic acid bacteria starter (Meiji Bulgaria Yogurt LB81 (Meiji Corporation) Was added (inoculated) at 3% by weight.

  After filling the cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C) and let it stand until the lactic acid acidity reaches 0.70% (about 3 hours). The set-type yogurt (Example 1) was produced.

(Comparative Example 1)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1% by weight, non-fat milk solid content: 9.7% by weight), and the raw milk is heated (about 80 ° C) to be homogeneous (150 kg / cm ² ), ultra-high temperature sterilization (UHT; 130 ° C., 2 seconds), and then cooling (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw milk was 1.38 ± 0.13 μm.

After warming the raw milk (about 43 ° C), injecting N ₂ and reducing the dissolved oxygen concentration (DO) of the raw milk to 5 ppm, the lactic acid bacteria starter (Meiji Bulgaria Yogurt LB81 (Meiji Co., Ltd.) Was added (inoculated) at 3% by weight.

  After filling into a cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C) and let it stand until the lactic acid acidity reaches 0.7% (about 3 hours). The set type yogurt (Comparative Example 1) was manufactured.

(Hardness of fermented milk)
The hardness (card tension) of the yogurt of Example 1 and Comparative Example 1 was measured. FIG. 1 is a graph showing the hardness of yogurt of Example 1 and Comparative Example 1. Here, if the hardness is 26 g or more, it can be said that it is fermented milk capable of maintaining the structure during distribution.

  As shown in Fig. 1, the yogurt of Comparative Example 1 (average particle diameter of raw milk: 1.38 ± 0.13μm) has a hardness of 25g and less than 26g, and the hardness is insufficient, maintaining the structure during distribution It was shown that it is not possible. On the other hand, the yogurt of Example 1 (average particle diameter of raw milk: 0.52 ± 0.13 μm) has a hardness of 51 g and 26 g or more, indicating that the hardness is sufficient and the structure can be maintained during distribution. It was done. From the above results, when raw milk is sterilized by ultra-high temperature without sufficiently reducing the average particle size of raw milk, fermented milk with sufficient hardness to withstand vibration during distribution cannot be obtained. It could be confirmed. On the other hand, when the average particle diameter of raw material milk was made small, it was confirmed that fermented milk having sufficient hardness that can withstand vibration during distribution can be obtained even when raw milk is subjected to ultrahigh temperature sterilization.

[Test 2]
(Example 2)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1% by weight, non-fat milk solid content: 9.7% by weight), and the raw milk is heated (about 80 ° C) to be homogeneous (400 kg / cm ² ), ultra-high temperature sterilization (UHT; 130 ° C., 2 seconds), and then cooling (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw material milk was 0.52 ± 0.13 μm.

After the raw milk is heated (about 39 ° C), nitrogen (N ₂ ) is injected, the dissolved oxygen concentration (DO) of the raw milk is reduced to 5 ppm, and then a starter for lactic acid bacteria (Meiji Bulgaria Yogurt LB81 ( Was added (inoculated) at 3% by weight.

  After filling the cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C), let it stand until the lactic acid acidity reaches 0.7% (about 3 hours), and then store it in the refrigerator ( A set-type yogurt (Example 2) was produced.

  The yogurt of Example 2 (average particle diameter of raw material milk: 0.52 ± 0.13 μm) had a hardness of 49 g and 26 g or more, indicating that the structure can be maintained during distribution. The penetration angle of the yogurt knife was 47 degrees, the average particle size after stirring was 27 μm, and it was shown that the texture was excellent in smoothness. From the above results, when the raw material milk was ultra-high temperature sterilized by reducing the average particle size of the raw milk, it had sufficient hardness to withstand vibration during distribution and excellent texture It was confirmed that fermented milk could be obtained.

(Comparative Example 2)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1 wt%, nonfat milk solids: 9.70 wt%), and the raw milk is heated (about 80 ° C) to be homogeneous (150 kg / cm ² ), then sterilized at a high temperature for a short time (HTST; 95 ° C., pasteurized at a high temperature) and then cooled (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw milk was 1.40 ± 0.15 μm.

After heating the raw milk (about 39 ° C), N ₂ was injected and the dissolved oxygen concentration (DO) of the raw milk was reduced to 5 ppm, and then the lactic acid bacteria starter (Meiji Bulgaria Yogurt LB81 (Meiji Corporation) Was added (inoculated) at 3% by weight.

  After filling the cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C), let it stand until the lactic acid acidity reaches 0.7% (about 3 hours), and then store it in the refrigerator ( A set-type yogurt (Comparative Example 2) was produced.

  The yogurt of Comparative Example 2 (average particle diameter of raw milk: 1.40 ± 0.15 μm) had a hardness of 55 g and 26 g or more, indicating that the structure can be maintained during distribution. However, the penetration angle of the yogurt knife was 91 degrees, and the average particle size after stirring was 45 μm, indicating that the texture was poor.

(sensory evaluation)
Sensory evaluation of the yogurt of Example 2 and Comparative Example 2 was performed. In the sensory evaluation, six days after the production of yogurt, a two-point comparison method was performed by 17 professional panelists based on a seven-stage scale (−3 to +3). It was evaluated that there was a significant difference (expressed by “**”) with a risk rate of 1%. FIG. 2 is a diagram showing the results of sensory evaluation of yogurt in Example 2 and Comparative Example 2.

  In the yogurt of Example 2 (average particle size of raw milk: 0.52 ± 0.13 μm, sterilization: UHT), compared to the yogurt of Comparative Example 2 (average particle size of raw material milk: 1.40 ± 0.15 μm, sterilization: HTST), The fineness of the texture (of the card), the mildness of the aftertaste, the creamy feeling of the flavor, the richness, the milky feeling of the aftertaste, the smoothness, the texture, and the overall evaluation were significantly superior. That is, it was confirmed that there was a statistically significant difference between Example 2 and Comparative Example 2 in each of these items. Therefore, when the raw milk is homogenized, the average particle size of the raw milk is adjusted to be small, and the pasteurization treatment is performed at a high temperature, the structure is dense, mellow, creamy, rich, and aftertaste milk. It was confirmed that fermented milk excellent in feeling, smoothness and texture could be obtained. That is, by homogenizing raw material milk, adjusting the average particle size of raw material milk to a small value, and subjecting it to ultra-high temperature sterilization treatment, fermented milk with good flavor and smooth texture can be obtained. It could be confirmed.

[Test 3]
(Example 3)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1 wt%, nonfat milk solids: 9.70 wt%), and the raw milk is heated (about 80 ° C) to be homogeneous (400 kg / cm ² ), sterilized by ultra-high temperature (130 ° C., 2 seconds), and then cooled (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw material milk was 0.52 ± 0.13 μm.

After heating the raw milk (about 43 ° C), N ₂ was injected, the dissolved oxygen concentration (DO) of the raw milk was reduced to 5 ppm, and then the lactic acid bacteria starter (Meiji Bulgaria Yogurt LB81 (Meiji Corporation) Was added (inoculated) at 3% by weight.

  After filling into a cup container (capacity: 100 g, made of plastic), store it in a fermentation room (43 ° C) and let it stand until the lactic acid acidity reaches 0.7%, 2 hours 50 minutes (about 3 hours) After that, it was stored in a refrigerator (10 ° C. or lower) to produce a set-type yogurt (Example 3).

(Example 4)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1% by weight, non-fat milk solid content: 9.7% by weight), and the raw milk is heated (about 80 ° C) to be homogeneous (400 kg / cm ² ), sterilized by ultra-high temperature (130 ° C., 2 seconds), and then cooled (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw material milk was 0.52 ± 0.13 μm.

  3 wt. Of lactic acid bacteria starter (separated from Meiji Bulgaria Yogurt LB81 (Meiji Co., Ltd.)) without adjusting the dissolved oxygen concentration (DO) of raw milk after heating the raw milk (about 43 ° C) % Added (inoculated).

  After filling into a cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C) and let it stand until the lactic acid acidity reaches 0.7%, 3 hours 50 minutes (about 4 hours) After that, it was stored in a refrigerator (10 ° C. or lower) to produce a set-type yogurt (Example 4).

(Fermentation time)
The fermentation time of the yogurt of Examples 3 and 4 (time until the lactic acid acidity reached 0.7%) was measured and shown in Table 1. As shown in Table 1, in the yogurt of Example 3 (deoxygenation treatment before fermentation: yes), the fermentation time is greatly shortened compared to the yogurt of Example 4 (deoxygenation treatment before fermentation: no). It was shown that. From the above results, fermented milk production can be achieved by deoxidizing before fermentation and reducing the dissolved oxygen concentration in the raw milk, because the fermentation time can be shortened and the time required to produce fermented milk can be shortened. It was confirmed that the efficiency could be improved.

[Test 4]
(Examples 5 to 8 and Comparative Example 3)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1% by weight, non-fat milk solid content: 9.7% by weight), and the raw milk is heated (about 80 ° C) to be homogeneous Then, it was cooled (about 10 ° C.) after ultra high temperature sterilization (130 ° C., 2 seconds).

  At this time, the raw material milk was prepared by adjusting the condition (pressure) for homogenizing the raw material milk to variously change the average particle size. And in the yogurts of Examples 5 to 8 and Comparative Example 3, the average particle diameter after homogenization of the raw milk is shown in Table 2.

After heating the raw milk (about 43 ° C), N ₂ was injected, the dissolved oxygen concentration (DO) of the raw milk was reduced to 5 ppm, and then the lactic acid bacteria starter (Meiji Bulgaria Yogurt LB81 (Meiji Corporation) Was added (inoculated) at 3% by weight.

  After filling the cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C), let it stand until the lactic acid acidity reaches 0.7% (about 3 hours), and then store it in the refrigerator ( Set type yogurt (Examples 5 to 8 and Comparative Example 3) was produced.

(Hardness of fermented milk)
The hardness of the yogurts of Examples 5 to 8 and Comparative Example 3 was measured and shown in Table 2. As shown in Table 2, the yogurt of Comparative Example 3 (average particle size of raw milk: 1.30 μm) has a hardness of 20 g and less than 26 g, and the hardness is insufficient, and the structure cannot be maintained during distribution. It has been shown. In contrast, in the yogurts of Examples 5 to 8 (average particle diameter of raw milk: 0.40 to 0.73 μm, 0.73 μm or less, homogenization pressure of raw milk: 250 to 400 kg / cm ² ), the hardness is 34 to 59 g. It was shown that the hardness was sufficient and the structure could be maintained during distribution. Based on the above results, we set the pressure to homogenize the raw milk to 150 kg / cm ² (150 kg / cm ² or less), and sterilized the raw milk with ultra-high temperature without reducing the average particle size of the raw milk to 1 μm or less. When it was processed, it was confirmed that fermented milk with sufficient hardness to withstand vibration during distribution could not be obtained. On the other hand, if the pressure for homogenizing the raw milk is set to 250 to 400 kg / cm ² (180 kg / cm ² or higher) and the average particle size of the raw milk is reduced to 1 μm or lower (0.8 μm or lower), It has been confirmed that fermented milk having sufficient hardness to withstand vibration during distribution can be obtained even when the milk is subjected to ultrahigh temperature sterilization treatment.

[Test 5]
(Examples 9 to 12)
The raw milk was warmed (about 80 ° C.) and homogenized (400 kg / cm ² ), then sterilized by ultra-high temperature (holding time: 2 seconds) and then cooled (about 10 ° C.).

  At this time, by adjusting the conditions (temperature) for sterilizing the raw material milk, the heat history was variously changed to prepare the raw material milk. Table 3 shows the average particle diameters after homogenization of the raw milk in the yogurts of Examples 9 to 12.

After the above raw milk is heated (about 43 ° C), nitrogen (N ₂ ) is injected, the dissolved oxygen concentration (DO) of the raw milk is reduced to 5 ppm, and then the lactic acid bacteria starter (Meiji Bulgaria Yogurt LB81 ( Was added (inoculated) at 3% by weight.

  After filling into a cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C), leave it until the lactic acid acidity reaches 0.7% (about 3 hours), and then store it in the refrigerator. A set-type yogurt (Examples 9 to 12) was produced by storage at 10 ° C. or lower.

(Hardness of fermented milk)
The hardness of the yogurts of Examples 9 to 12 was measured and shown in Table 3. As shown in Table 3, in the yogurts of Examples 9-12 (average particle diameter of raw milk: 0.45-0.57 μm (0.57 μm or less), pasteurization temperature of raw milk: 130-144 ° C.), the hardness is 50-60 g It was 26 g or more, and the hardness was sufficient, indicating that the structure could be maintained during distribution. From the above results, when the average particle size of the raw milk is reduced to 1 μm or less (0.8 μm or less), the temperature for sterilizing the raw milk is set to about 130 to 144 ° C. (115 ° C. or higher), and the raw milk is made extremely hot. Even when sterilized, it was confirmed that fermented milk with sufficient hardness to withstand vibration during distribution could be obtained.

[Test 6]
(Example 13)
Raw milk, skim milk powder and water are mixed to prepare raw milk (yogurt mix; fat: 3.1% by weight, non-fat milk solid content: 9.7% by weight), and the raw milk is heated (about 80 ° C) to be homogeneous (250 kg / cm ² +50 kg / cm ² ), ultra-high temperature sterilization (130 ° C., 2 seconds), and then cooling (about 10 ° C.).

  At this time, the average particle size ± standard deviation of the raw material milk was 0.5 ± 0.13 μm.

After the cooled raw material milk is heated to about 43 ° C., nitrogen (N ₂ ) is injected, the dissolved oxygen concentration (DO) of the raw material milk is reduced to 5 ppm, and then a lactic acid bacteria starter (Meiji Bulgaria yogurt LB81 ( Was added (inoculated) at 3% by weight.

  After filling the cup container (capacity: 100 g, made of plastic), store it in the fermentation room (43 ° C), let it stand for about 3 hours until the lactic acid acidity reaches 0.7%, and then store it in the refrigerator room (10 ° C The set-type yogurt (Example 13) was manufactured.

(Evaluation of adhesion)
Using a device for measuring the characteristics of eating and swallowing (hereinafter referred to as a device for measuring eating and swallowing), fermented milk of Example 13, and Meiji Bulgaria Yogurt LB81 (Meiji Corporation; Comparative Example 4), which is a conventional set type yogurt, The difference in flavor characteristics (mainly texture during eating and swallowing) was evaluated.

  The configuration of the eating and swallowing measurement device used is shown in FIG. The eating and swallowing measurement device includes an inclined plate to which a material imitating the surface of a living body (produced by mixing water, hydrophilic polyvinyl alcohol and dimethylsulfosudide) is attached. When a predetermined amount of sample (liquid, solid, semi-solid, jelly, etc.) is supplied to the inclined plate, the sample flows or slides on the inclined plate, thereby imitating the phenomenon of eating and swallowing. The eating and swallowing measurement device simulates the phenomenon of eating and swallowing by numerically analyzing and measuring the behavior of a sample flowing down or sliding down on an inclined plate with multiple sensors and multiple cameras. It is a measuring device to quantify.

  Specifically, as shown in FIG. 3, the eating and swallowing measurement device includes an inclined plate having an inclined surface, a supply unit (high-precision quantitative supply piston pump) that provides a sample on the inclined surface, and a supply unit. A supply sensor (discharge confirmation sensor) for detecting a sample supplied onto the inclined surface, an arrival sensor (upper arrival confirmation sensor and lower arrival confirmation sensor) for detecting a sample flowing down a predetermined point on the inclined surface, A data logger that records the output of the sensor, a top camera that captures the sample flowing down on the inclined surface from above the inclined surface and generates a top image, and a sample that flows down on the inclined surface from the side of the inclined surface A side camera that generates a side image, and a calculation unit that uses at least one of the output of the data logger, the side image, and the top image to calculate the state parameter of the sample flowing down on the inclined surface.

  The eating and swallowing measurement device defines the behavior of a bolus that flows down or slides down on an inclined plate as a pseudo swallowing phenomenon, and the speed, acceleration, pressure, force, shear rate, wall shear stress, wall shear stress, wall surface To determine the shear force, energy consumed on the wall, dynamic contact angle, flow area, sliding area, flow path, sliding path, center thickness at the time of sample flow, center thickness at the time of sliding down, and adhesion force Is possible. Here, the adhesion force means energy consumed by the inclined surface per unit area of the inclined surface. By using a measuring device for eating and swallowing, it is possible to evaluate the difference in physical quantities that occur during eating and swallowing for bolus samples with different physical properties and characteristics, so that the physical properties of the bolus change to the behavior during swallowing. It will be possible to evaluate the impacts.

Each physical quantity can be calculated by the following formula. Here, it is expressed as shear rate γ, thickness δ, viscosity μ, shear stress τ, force F, area S, length L (distance between sensors), work amount W, and adhesion force fs [J / m ² ]. The viscosity is measured by, for example, a rheometer (dynamic viscoelasticity measuring device).

  Using the above-described eating and swallowing measurement apparatus, each physical quantity at the time of flowing down or sliding down the fermented milk of Meiji Bulgaria Yogurt LB81 (Meiji Corporation; Comparative Example 4) and Example 13 was measured four times. Table 4 shows the results of the measured physical quantities. FIG. 4 is a graph showing the adhesion force between Comparative Example 4 and Example 13.

As shown in Table 4 and FIG. 4, compared with the conventional fermented milk (Meiji Bulgaria yogurt LB81), it was shown that the fermented milk of Example 13 has high adhesive force. The adhesion of the fermented milk of Example 13 was 0.0008 [J / m ² ] or more, which was about 1.3 times that of the conventional fermented milk. In addition, the fermented milk of the present invention was prepared only with “milk” on the display, but it was shown that it can maintain the same hardness as the conventional set type yogurt (such as Meiji Bulgaria yogurt LB81). .

  The present invention can be used for the production of fermented milk such as yogurt, and can be particularly suitably used for the production of a set-type yogurt.

Claims (11)

Homogenizing the raw milk so as to reduce the average particle size of the raw milk;
Before or after the step of homogenizing, sterilizing the raw milk at 115 ° C. to 150 ° C .;
A method for producing fermented milk, comprising a step of fermenting the raw milk after the step of homogenizing and the step of sterilizing.   2. The method for producing fermented milk according to claim 1, wherein in the homogenizing step, the raw milk is homogenized so that an average particle size of the raw milk is 0.8 μm or less.   3. The method for producing fermented milk according to claim 1, further comprising a step of reducing a dissolved oxygen concentration of the raw material milk before the step of fermenting.   The method for producing fermented milk according to any one of claims 1 to 3, wherein the fermented milk is a set-type yogurt. Homogenizing raw milk,
Before or after the step of homogenizing, sterilizing the raw milk at 115 ° C. to 150 ° C .;
A method for improving the hardness of fermented milk, comprising a step of fermenting the raw material milk after the step of homogenizing and the step of sterilizing. Homogenizing raw milk,
Before or after the step of homogenizing, sterilizing the raw milk at 115 ° C. to 150 ° C .;
A method for improving the smoothness of the texture of fermented milk, comprising a step of fermenting the raw milk after the step of homogenizing and the step of sterilizing.   Fermented milk having a hardness of 26 g or more, a penetration angle of a yogurt knife of less than 60 degrees, and an average particle diameter after stirring of 43 μm or less. The fermented milk according to claim 7, wherein the adhesive force is 0.0008 J / m ² or more.   The fermented milk according to claim 7 or 8, produced by the production method according to any one of claims 1 to 4.   The fermented milk according to any one of claims 7 to 9, which is packed in a container. The fermented milk according to any one of claims 7 to 10, wherein the fermented milk is a set-type yogurt.