JPH1099019A - Hard yoghurt and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hard yoghurt containing peroxidase and having same hardness as that of a yoghurt containing no peroxidase, and to provide the production method of the hard yoghurt. SOLUTION: This hard yoghurt contains peroxidase and has 25 to 40g hardness and excellent hardness and shape holding property. This hard yoghurt is produced by compounding 1 to 50ppm peroxidase into a fermenting mix, controlling the amt. of oxygen dissolved to <=10ppm and fermenting the mixture. In order to control, the amt. of oxygen dissolved to <=10ppm, inert gas is injected or the yoghurt is processed under reduced pressure. The increase in acidity is suppressed by the effect of the peroxidase and the obtd. hard yoghurt has a hard structure with a good remaining rate of raw lactobacillaceae. The obtd. yoghurt does not cause fracture of the curd due to shocks during transportation or precipitation of fruits when fruits and the like are added to the yoghurt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hard yogurt which contains peroxidase (hereinafter referred to as PO) but has the same hardness as the case where no PO is contained and has good shape retention, and a method for producing the same. In addition, the hard yogurt of the present invention contains PO, whereby an increase in acidity during storage is suppressed and the survival of lactic acid bacteria is improved.

[0002]

2. Description of the Related Art There are roughly two methods for preparing hard yogurt. One method is to mix a raw milk with a lactic acid bacterium starter to prepare a fermentation mix. This is a method of manufacturing by filling and fermenting hard yogurt. The characteristics of the filled fermentation type hard yogurt are that the tissue is smooth, has an appropriate hardness, and has little whey separation (whey off) during storage or distribution. The other is a production method in which a fermented mix prepared by blending a lactic acid bacteria starter with raw milk is fermented in a tank, and the resulting curd is crushed and filled into individual food containers together with a gelling agent. It is a type of hard yogurt. The feature of this hard yogurt is that the fermented mix obtained by crushing the curd produced after fermentation in the tank is filled in an individual food container, so that various additives such as pulp, juice or flavor are easily added in the filling step. It is possible,
There is an advantage that a variety of flavors can be achieved. In addition, since a large amount of fermented mix is fermented in a tank at the same time during production, there is an advantage that the fermentation temperature can be easily controlled, that is, the fermentation can be easily controlled and the space can be saved.

[0003] However, the hard yogurt produced in this way has many problems to be solved because it contains lactic acid bacteria at a high concentration as viable bacteria. For example, during storage or distribution process, while maintaining a high concentration of lactic acid bacteria, suppress the increase in acidity, the problem that it is necessary to maintain the flavor immediately after production, to maintain a smooth tissue,
There is a problem that whey separation (whey off) must be suppressed as much as possible. From such a thing,
By adding PO to fermented milk, it is possible to increase the survival of lactic acid bacteria during storage or distribution process, or to suppress the increase in acidity,
Also, studies have been made to smooth the tissue and suppress whey separation. For example, in WO 92/13064,
By containing 1 mg / l or more of PO in the fermented milk product, excessive increase in acidity during distribution and storage of the product is suppressed,
It has been shown that an appropriate acidity is maintained throughout the expiration period, and JP-A-6-276933 discloses that a fermentation mix is mixed with PO and whey protein concentrate and / or whey protein isolate to produce a fermentation mixture. Thus, a fermented milk having a smooth tissue and reduced whey separation and a method for producing the same are described. Further, Japanese Patent Application Laid-Open No. Hei 5-41981 discloses that the fermented milk contains lactoperoxidase (hereinafter referred to as LPO) at a concentration of 10 ppm or more to improve the viability of viable Bifidobacteria and / or lactic acid bacteria. It has been shown to enhance.

[0004]

As described above, the addition of PO (including LPO) to fermented milk smoothes the tissue and suppresses whey separation and increase in acidity during storage and distribution. An excellent effect such as enhancing the survival of lactic acid bacteria can be expected. However, fermented milk,
In particular, when PO is added to hard yogurt, the hardness decreases and the tissue becomes soft, and the curd is crushed by the impact during transportation, and when solids such as pulp are added, the product sediments and becomes a non-uniform product. There is a problem that the value is reduced. From these facts, the inventors of the present invention have proposed a method of blending PO into hard yogurt to suppress the separation of whey and increase in acidity of PO and to improve the survivability of lactic acid bacteria, while reducing the hardness of hard yogurt. We studied obtaining yogurt. As a result, when PO is added and the dissolved oxygen amount is adjusted to a specific amount or less and fermentation is performed, whey separation and increase in acidity are suppressed, and not only the survival of lactic acid bacteria can be increased, but also the hardness decreases. And found that hard yogurt maintaining the same hardness as in the case of not containing PO can be obtained. The present invention
It has been completed based on such knowledge. That is, an object of the present invention is to provide a hard yogurt that contains PO and maintains the same hardness as a hard yogurt that does not contain PO, and a method for producing the same.

[0005]

Means for Solving the Problems The present invention has been made to achieve the above-mentioned object, and provides the following hard yogurt and a method for producing the same. That is, the present invention is a hard yogurt in which the hardness of yogurt containing peroxidase is the same as that of yogurt obtained under the same conditions except that no peroxidase is added to the fermentation mix. Such hardness in the present invention is 25 to 40 g. Further, the content of PO is desirably 1 to 50 ppm. The hardness in the present invention is 85 mm in diameter and 10 in height.
500 ml of hard yogurt is placed in a 0 mm container, and a stress (unit: g) is measured when a cylindrical plunger having a diameter of 16 mm is pressed from above at a speed of 5 mm / sec and penetrated 10 mm. As a specific hardness measuring device, a Leonard manufactured by Yamaden Corporation or the like can be used. Further, the method for producing a hard yogurt of the present invention comprises adding 1 PO to the fermented mix.
Fermentation is performed by adjusting the amount of dissolved oxygen to 10 ppm or less by adding 5050 ppm. In order to adjust the amount of dissolved oxygen in the fermentation mix as described above, it is preferable to blow an inert gas or perform a reduced pressure treatment. The dissolved oxygen content is preferably adjusted before the fermentation of the milk protein.

The PO in the present invention is not only PO extracted from horseradish and other plants, but also LPO separated from milk, and may be either of PO unless otherwise specified. . PO is an enzyme having a molecular weight of 80,000 to 90,000 widely present in plant or animal milk, and contains one molecule of iron (working group protohemin) in one molecule. PO is an enzyme that catalyzes the next reaction. H ₂ O ₂ + AH ₂ → 2H ₂ O + A (where A is an oxygen receptor) As a physiological function to microorganisms, PO is gram-negative like E. coli in the presence of thiocyanate ion and hydrogen peroxide. It is known to exhibit antibacterial properties against bacteria and bacteriostatic properties against Gram-positive bacteria such as lactic acid bacteria. It is said that part of the thiocyanate ion (SCN-) becomes hypothiocyanate ion (OSCN-) and damages the cell membrane, which is called the LP system. In the present invention, both PO extracted from horseradish and other plants and LPO isolated from milk can be used. But,
Preferably, LPO separated from milk is good. LP from milk
The method for separating and purifying O can be prepared, for example, in the process of separating lactoferrin from skim milk or whey as described in JP-A-3-109400.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the hard yogurt of the present invention, first, milk is used as a main component, and additives such as a sweetener, a stabilizer, and a flavor are blended as needed to prepare a raw material mix according to a conventional method. It is desirable to adjust the solid content of this raw material mix to be 8 to 15%. As the milk component, whole-fat milk, skim milk, or those obtained by adding milk fat such as butter and butter oil to these milks can be used. Alternatively, reconstituted milk in which whole milk or skim milk is dried and powdered once and dissolved in water or an aqueous medium such as raw milk may be used. The raw material mix thus prepared is sterilized or sterilized to obtain a culture medium. Next, 1 to 50 ppm of PO and 1 to 3% by weight of a lactic acid bacteria starter are added to this medium to prepare a fermentation mix. As lactic acid bacteria starters, for example, Lactobacillus bulgaricus ( L. bulgaricus ), Lactobacillus acidophilus ( L. acidophilus ) , Lactococcus lactis
( L.lactis ), Streptococcus thermophilus
Any lactic acid bacterium starter commonly used for preparing yogurt such as (S. thermophilus) can be used without any particular limitation.

In the present invention, hard yogurt is prepared by adjusting the amount of dissolved oxygen in the fermented mix prepared as described above to 10 ppm or less and then fermenting. Adjustment of dissolved oxygen amount
In the tank, it may be adjusted with a medium before adding PO or lactic acid bacteria starter, or may be adjusted with a fermentation mix to which PO or lactic acid bacteria starter is added. Furthermore, in the case of a filled fermentation type hard yogurt, it may be adjusted for each container immediately after filling the individual meal container. In each case, the adjustment is made before the milk protein is curd by fermentation. Specific method of adjusting the amount of dissolved oxygen, or an inert gas such as nitrogen gas or argon gas in the medium or fermentation mixture as described above, to replace the oxygen blown directly 0.1 to 10 kg / cm ² pressure of about Alternatively, the pressure is adjusted by reducing the pressure at a degree of vacuum of about 100 to 760 mmHg. In adjusting the amount of dissolved oxygen, it is desirable to set the conditions of the inert gas and the decompression treatment in consideration of the solid content of the fermentation mix, the tank capacity, the pressure resistance of the container, and the like.

As described above, the amount of dissolved oxygen in the fermentation mix is
After adjusting the fermented mixture to 10 ppm or less, the fermented mixture is maintained at a temperature suitable for the growth of lactic acid bacteria (depending on the lactic acid bacteria, but about 32 to 43 ° C. for the above lactic acid bacteria) for about 1 to 24 hours, preferably 2 to 4 hours. Fermented to a degree to make yogurt. The yoghurt obtained in this way is a product as it is if it is a filled fermentation type hard yogurt, and if it is a post-set type hard yogurt, the curd is crushed by means of stirring or the like to make it into a fluid state, which is necessary for this. According to the above, a gelling agent such as pectin or agar, a pulp or a flavor, etc. are added and mixed, and filled in an individual food container.

PO in hard yogurt originally exerts its effect in the presence of oxygen. However, even if fermentation is performed by adjusting the dissolved oxygen content to 10 ppm or less as in the present invention, the post-set hard yogurt In this case, stir after fermentation and fill the container, and in the case of filled fermentation type hard yogurt,
If a container or a lid material through which oxygen gradually permeates during storage is selected, the effect of PO is hardly affected. As such a container or lid in the present invention, a container or lid made of polystyrene, polyethylene, or the like is used. The hardness of the hard yoghurt thus prepared has a hardness of 25 to 40 g. The hardness here is 85mm in diameter and 1 in height
500 ml of hard yogurt is placed in a 00 mm container, and a cylindrical plunger with a diameter of 16 mm is pressed from above at a speed of 5 mm / sec, and the measured value is obtained by measuring the stress when 10 mm penetrates.
The hardness of the conventional hard yogurt containing PO differs depending on the type and amount of the gelling agent in the fermentation mix, the type of the lactic acid bacteria starter, or the nonfat milk solids content.
It is about 10 to 20 g. Therefore, the hard yogurt of the present invention has a remarkably improved hardness and good shape retention without being reduced in hardness unlike the conventional hard yogurt to which PO is added. Incidentally, the hardness of the hard yogurt containing no PO is about 25 to 40 g, so that the hard yogurt of the present invention has almost the same hardness. When fermentation is carried out with the above-mentioned dissolved oxygen content exceeding 10 ppm, the hardness is reduced and the desired hardness cannot be obtained. The amount of PO added is 1ppm
If it is less than 50 ppm, the PO will not function. On the other hand, if it exceeds 50 ppm, the effect in proportion to the blending amount cannot be expected and the cost will increase. Therefore, it is preferable to use the PO in the range of 1 to 50 ppm.

The hard yogurt of the present invention prepared as described above has a high survival rate of lactic acid bacteria during storage and during the distribution process. 27th, Ministry of Health and Welfare Ordinance No. 52) ”, which meets the fermented milk standard, suppresses acidity rise, maintains the flavor immediately after production for a long period of time, maintains a smooth structure, and separates whey (whey off). Is also suppressed. Moreover, when the hard yogurt of the present invention is used as a raw material of the post-set type hard yogurt, the hardness is higher than that of the conventional hard yogurt containing PO, so that the amount of the gelling agent is reduced. It also has good shape retention, improves flavor, and does not precipitate even when solids such as pulp are contained.

The following is a test example of hard yogurt prepared by changing the amount of LPO added and the amount of dissolved oxygen in the fermentation mix. 8810.0 g of warm water, 850 g of skim milk powder, 300 salt-free butter in a sample preparation tank
g, whey powder 5.0 g, and yeast extract 5 g were added and dissolved by stirring to obtain a raw material mix. The raw material mix is treated with a homogenizer and then sterilized. As a lactic acid bacteria starter, a mixed starter of Lactobacillus bulgaricus ( L. bulgaricus ) and Streptococcus thermophilus (S. thermophilus) 1.5% by weight and bifidobacterium longum
(B. longum) 1.5 wt% was added to prepare a fermentation mix. This fermentation mix was filled into a 500 ml polystyrene container, and LPO was adjusted to the amount of LPO shown below and the amount of dissolved oxygen was adjusted to the next amount of dissolved oxygen. To 0.8%, thereby obtaining hard yogurts of Samples A to D. In addition, the dissolved oxygen amount of each sample was measured by inserting a probe into each sample using a DO meter (manufactured by Shibata Kagaku). The sample with the dissolved oxygen amount adjusted was blown with nitrogen gas at a pressure of 1 kg / cm ^{2 at} a flow rate of 10 ml / sec for about 20 seconds.

LPO addition amount and dissolved oxygen amount Sample A-LPO addition amount 10 ppm. Adjust the dissolved oxygen content of the fermentation mix to 10 ppm by replacing with nitrogen gas. Sample B-no LPO added. Adjust the dissolved oxygen content of the fermentation mix to 10 ppm by replacing with nitrogen gas. Sample C-no LPO added. No nitrogen gas replacement.
The dissolved oxygen content of the fermentation mix is 20ppm. Sample D-10 ppm LPO added. No nitrogen gas replacement. The dissolved oxygen content of the fermentation mix is 20ppm.

With respect to the hard yogurt of each sample prepared as described above, the hardness immediately after production was measured using a Leonard manufactured by Yamaden Corporation, and the viscosity was measured using a B-type viscometer. The acidity increase during storage and the survival of lactic acid bacteria were measured. The results are shown in Table 1 for hardness and viscosity, Table 2 for lactic acidity, and Table 3 for lactic acid bacteria count.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

As is clear from Tables 1 to 3, the yogurt of Sample A prepared using a fermentation mix in which LPO was added to adjust the dissolved oxygen content to 10 ppm or less according to the method of the present invention, had a hardness and viscosity of the sample. It is about the same as yogurt of C (prepared according to the conventional method of preparing hard yogurt without addition of PO), but the acidity increase suppressing effect and the survival of lactic acid bacteria are much improved. On the other hand, the yogurt of Sample B was prepared using a fermentation mix in which only nitrogen substitution was performed without adding LPO, and thus the hardness, viscosity and acidity increase were the same as those of Sample C. Even so, the survival of lactic acid bacteria is poor. The yogurt of sample D is L
Since PO was added but a fermentation mix without nitrogen substitution was used, the effect of suppressing the increase in acidity and the survival of lactic acid bacteria had almost the same tendency as the yogurt of sample A obtained according to the method of the present invention. As shown, the hardness and viscosity were low, the card was crushed by the impact during transportation, and when solids such as pulp were added as a post-set type hard yogurt, precipitation of these solids occurred . As shown in Table 1, it was found that the viscosity had a positive correlation with the hardness.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 8965.5 g of warm water, 900 g of skim milk powder, 100 g of unsalted butter, 4.0 g of gelatin and 0.5 g of pectin were put in a tank and dissolved by stirring to obtain a raw material mix. This raw material mix is treated with a homogenizer and then sterilized. Lactobacillus bulgaricus ( L. bulgaricus ) and Streptococcus thermophilus (S. thermophilus) are used as lactic acid bacteria starters.
A 3% mixed lactic acid bacteria starter was added to prepare a fermentation mix. After adding 5 ppm of LPO to the fermentation mix, the tank was sealed and depressurized. The pressure was reduced under a reduced pressure of 300 to 600 mmHg for about 30 minutes while stirring the mix gently and paying attention to bumping. The dissolved oxygen content of the fermented mix after the reduced pressure treatment was 5 ppm. next,
This fermented mix is fermented at 41 ° C for 2 hours 30 minutes, acidity 0.8
I got a hard yogurt. The hardness of the obtained hard yogurt was 38 g.

[0020]

Example 2 8810.0 g of warm water, 850 g of skim milk powder, 300 g of salt-free butter, 5.0 g of whey powder, and 5 g of yeast extract were put into a tank and dissolved by stirring to obtain a raw material mix. The raw material mix is treated with a homogenizer and then sterilized. Lactobacillus bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus) are used as lactic acid bacteria starters.
A 1.5% mixed starter and 1.5% Bifidobacterium longum were added to prepare a fermentation mix. After filling this fermentation mix in a 500 ml polystyrene container, adding 10 ppm of LPO and stirring, nitrogen gas was blown in at a pressure of 1 kg / cm ² at a flow rate of 10 ml / sec for 1 minute, and replaced until the dissolved oxygen content became 5 ppm. did. Next, the container was sealed with a top lid, and the fermented mix was fermented at 41 ° C for 2 hours and 15 minutes.
A hard yogurt of 0.8 was obtained. The hardness of the obtained hard yogurt was 35 g.

[0021]

The effect of adding PO to yogurt conventionally has the effects of smoothing the tissue, suppressing whey separation and increase in acidity during storage and distribution, and enhancing the survival of lactic acid bacteria. Was known. However, when PO is added to hard yogurt, the hardness decreases and the tissue becomes soft, and the curd is crushed by the impact during transportation, and when solids such as pulp are added, the sedimentation results in an uneven product. There was a problem. In the present invention,
Since fermentation is performed after adjusting the dissolved oxygen content of the fermentation mix containing PO to 10 ppm or less, the obtained hard yogurt has a hardness as high as that of a hard yogurt containing PO but not containing PO. It has good shape retention and has the advantage of PO-containing hard yogurt, that is, the increase in acidity during storage is suppressed, the survival of lactic acid bacteria is good, or the tissue is smooth and whey separation is improved. It has the effect of being small.

Claims (5)

[Claims] 1. A composition containing peroxidase and having a hardness of 25 to
40g hard yogurt that maintains the same hardness as without peroxidase. The hardness is 85
500 ml of hard yogurt is placed in a container 100 mm in height and 100 mm in height.
It is expressed by the measured value of the stress when 10 mm is penetrated by pressing at the speed of c (the same applies hereinafter). 2. A peroxidase content of 1 to 50 ppm.
The hard yogurt according to claim 1, wherein 3. The method of claim 1, wherein peroxidase is added to the fermentation mix.
A hardener that contains peroxidase, has a hardness of 25 to 40 g, and maintains the same hardness as when no peroxidase is contained. Manufacturing method of yogurt. 4. The method according to claim 3, wherein the amount of dissolved oxygen is adjusted by blowing an inert gas or reducing the pressure.
A method for producing the hard yogurt according to the above. 5. The method for producing a hard yogurt according to claim 3, wherein the amount of dissolved oxygen is adjusted before the milk protein is converted into a curd by fermentation.