JPH0739370A - Instant dry yeast - Google Patents

Abstract

PURPOSE: To obtain a dry yeast composition, not losing activity even when rehydrated, excellent in preservability for a long period, and useful for bread products and the like by including a specific amount of water and a specified amount of one or more rehydration-controlling agents.

CONSTITUTION: This dry yeast composition contains (A) <8 wt.% of water and (B) 1.1-5 wt.% of one or more kinds of substances selected from fatty acid esters such as sorbitan esters, mono- and/or di-glyceride acid esters, gum arabic, xanthan gum, yeast extracts and sodium carboxymethyl cellulose(CMC).

COPYRIGHT: (C)1995,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to instant dry yeast compositions, a process for their preparation and their use in bread products and beverages.

[0002]

Yeast production starts with a small sample of pure culture. This sample is used to inoculate the first fermentation of a series of fermentations in a fermentor of increasing size. The first few fermentations are mildly aerated batch fermentations. Only the last two (sometimes three) steps are performed with good aeration and an increased molasses feed. These feed-fed batch fermentations are carried out in fermentors having a capacity of 100 m ³ or greater. Fermentation time is typically 12 to 20 hours, which results in about 10,000
0-30000 kg of compressed yeast is produced. Furthermore, the steps of separating yeast from the liquid medium by centrifugation and washing are included, and cream yeast (yeast cream) (17 to 23% by weight dry matter content) is obtained through them. The yeast cream is processed into compressed yeast (27
~ 33 wt% dry matter content) sold as is, or extruded and dried to produce active dry yeast (ADY) or instant dry yeast (IDY) with water contents of 6-8 wt% and 2-8 wt%, respectively. To do.

In the case of ADY, drying is usually done in a belt dryer or a rotating louver (drum) dryer. A fluidized bed drying method is commonly used for the production of IDY. Drying yeast at a level of about 20% moisture only evaporates free water. To further reduce moisture,
It is necessary to remove some of the bound water from the yeast,
This may damage the yeast cell membrane. U.S. Pat. No. 3,843,800 and U.S. Pat. No. 4,248,420 disclose saturated fatty acid esters of glycerol and / or fatty acids of propylene glycol to maintain the desired high direct fermentation activity of yeast during the drying process. Wetting agents such as esters are added. Dry yeast loses some of its fermentation activity during the drying process as well as during the rehydration operation. Dry yeast is still commonly used in the bakery market because of its long-term stability and because it does not require refrigeration. Dried yeast has been used in winemaking to obtain fast and reproducible fermentations, thereby minimizing the risk of failing natural fermentation. Furthermore, the yeast is readily available throughout the year.

Instant dry yeast (IDY) contains 19
It was the most recent type of bread yeast introduced in the early 70's (see, eg, US Pat. No. 3,843,800), and years later, instant dried wine yeast (IWY) was introduced. . This may be understood as a special type of instant dry yeast. High quality ID
In order to obtain Y, a relatively high protein content (42-60
% By weight) compressed yeast must be dried in a rapid drying process. The fermentative activity of IDY under utilization conditions is about 75-85% of that of compressed yeast, and the shelf life in vacuum sealed packaging is comparable to that of ADY. IDYs are typically provided in the form of very small rods that are highly porous and easy to rehydrate. On the one hand, this makes them ready for immediate use without prior rehydration. On the other hand, the high porosity facilitates access to water and oxygen (from air), which results in some rapid loss of activity when exposed to atmospheric conditions. IDY must be used within 3-5 days after opening for satisfactory results. Furthermore, the high porosity of IDY makes it extremely hypersensitive to rehydration conditions. IDY is usually 2 on a dry basis
It has a water content of ~ 8% by weight and a protein content of 42-60% by weight. As with ADY, some manufacturers add antioxidants (eg, BHA) to their products to improve stability. Ascorbic acid may be added to the IDY product to improve stability.

A problem encountered with ADY and IDY is that the yeast contents leak out of the cells during rehydration. This results in loss of gassing power or loss of ability to produce ethanol. The various methods of adding the yeast and mixing the dough vary from region to region. For more porous IDY's should be mixed with wheat flour before adding water, but dry yeast is often suspended in water with other soluble additives before adding wheat flour. Additives such as sugar, calcium propionate and salt affect yeast performance as water temperature does. When a warm climate region or baker uses a high speed mixer with exceptional heat input, the water is chilled to a suitable dough temperature, for example by adding ice after mixing. Under these conditions, the instant dry yeast comes into direct contact with the chilled water, thus significantly reducing the yeast's performance. In U.S. Pat. No. 4,764,472, 0.1-2
This problem has been partially solved by adding wt% locust bean gum, gatch gum or mixtures thereof. The addition of this can prevent loss of activity when adding water at about 20 ° C. However, in practice water at 15 ° C or lower, sometimes water /
Even ice mixtures are used and at such temperatures the activity after rehydration is extremely low.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dry yeast composition which does not lose its activity even when rehydrated at low temperature.

[0007]

Surprisingly, the present inventors have found that when 1.1 to 5% by weight (dry weight) of rehydration controlling agent is added to dry yeast, It was found that the yeast was very well protected against loss of activity due to rehydration of dry yeast at low temperatures. Accordingly, the present invention provides a dry yeast composition having a water content of 8% by weight, preferably 3-6% by weight and comprising 1.1-5% by weight of a rehydration regulator. The rehydration modifier is preferably 10
It has a moisture content of less than%. Upon addition, these materials often suspend in water to improve dispersion in yeast.
Rehydration modifiers control the rehydration (wetting) of IDY particles and individual yeast cells. This rehydration regulator functions as an exceptional barrier to the penetration of water into cells.
Preferably 1.5-3% by weight, more preferably 2-3% by weight of rehydration modifier is used. Preferably the rehydration modifier is at least 50% by weight, eg 55, 60, 6
It contains 5, 70 or 75% by weight of emulsifier.

Typical examples of rehydration regulators are: Esters of fatty acids such as fatty acid esters of sorbitan, for example monolauric acid esters, monopalmitic acid esters, monostearic acid esters or monooleic acid esters of sorbitan; of mono and / or diglycerides such as citric acid esters or diacetyl tartaric acid esters Acid ester; -fatty acid ester of glycerol or polyglycerol, such as glyceryl monostearate, glyceryl distearate or glyceryl monopalmitate; -fatty acid ester of propylene glycol, such as monostearic acid ester of propylene glycol; -gum arabic; Xanthan gum; -yeast extract; -CMC (sodium carboxymethylcellulose) -or a mixture of two or more of the compounds listed above.

The present inventors have found that the addition of the rehydration regulator according to the present invention results in a loss of activity even when water of 15 ° C. or even 10 ° C. or lower is added to the yeast. It has been found that the yeast is substantially protected. The rehydration modifier is added when the yeast is still wet prior to the final drying step. Thus, the yeast is protected during this drying step, thereby maintaining the desired high fermentation activity of the yeast. Mixing the yeast with flour does not affect the gassing power under standard conditions. Surprisingly, rehydration of the yeast in water greatly improves the performance of the instant yeast. The greatest improvement was obtained at the lowest temperature.
The present invention further provides a method for producing a dry yeast composition, comprising drying yeast in the presence of 1.1 to 5% by weight rehydration regulator. In addition, the present invention provides a method for producing bread, which comprises adding the composition according to any one of claims 1 to 7 to a dough and baking the dough. It will be appreciated that the dough contains, in addition to yeast, the ingredients commonly used in making dough. Surprisingly, the dough prepared with the yeast of the present invention increased the rate of gas production and substantially increased the bread capacity of the baked product. The amount of rehydration regulator present in yeast may vary according to different uses. All publications and patent documents cited herein are hereby incorporated by reference as if each individual publication or patent document was specifically and individually indicated and incorporated.

[0010]

【Example】

Performance of yeast prepared according to the present invention. ─────────────────────────
────────── a. This test was performed under optimal instant yeast conditions. 300 mg of instant dry yeast was mixed with 62.5 g of flour. Solution 3 containing 1.25 g of NaCl
After the addition of 4.4 ml, the material was mixed into the dough for 6 minutes at 28 ° C and placed in a 28 ° C water bath. 10 to 10 after starting mixing
The volume of gas generated in 175 minutes is 28 ° C, 760 mmHg
Was measured in units of ml. b1. Same as (a) except that the yeast were moistened in a Erlenmeyer flask at 35 ° C. using a small funnel as monolayer particles on the surface of the water, thus exposing each particle directly to water. Therefore, this test was conducted under maximum rehydration conditions. b2. The same procedure as (b1) was carried out at a water temperature of 20 ° C. b3. The same procedure as (b1) was carried out at a water temperature of 10 ° C.

Example 1 Experiment 1 Fresh baker's yeast, strain 210 Ng, CBS 406.
The tests (Examples 1-5) were carried out using 87 common cultures. This product had a moisture content of about 68% and a protein content of about 50%. The block yeast was compressed to reduce the extracellular water content to 66%. The yeast was crushed and mixed with 0.25% (based on total dry weight) rehydration modifier Span-60 ™ (monostearate ester of sorbitan) using the following procedure: Span-60 65 Melt at ℃,
Suspended in water at 60 ° C. using a high shear laboratory mixer. This emulsion was added to pressed bread yeast to a content of 0.25% based on total dry weight. The formulation is then 0.8
Extruded three times with a screen having mm holes to form rod-shaped particles containing properly dispersed rehydration modifier. The product from this trial was finally pressed through a screen with 0.8 mm holes to again form rod-shaped particles.
The drying of this product was surrounded by a suitable screen to create a gentle fluidization pattern,
It was carried out in a laboratory scale fluidized bed dryer consisting of a conical crow tube mounted on an air supply system. The air supply system consisted of a two-way control valve that partially passed air through the heating section. This control valve maintained a constant outlet air temperature of 39 ° C during drying. The air flow was set at the bottom of the cone to a surface velocity of 1.6 m / s. The air flow was stopped as soon as the inlet air temperature reached 45 ° C. The product was collected and packaged under vacuum in a sachet for analysis.

Experiment 2 It was carried out as described in Test 1, except that Span-60, which accounted for 0.50% of the total dry matter, was used. Experiment 3 It was carried out as described in Test 1, except that Span-60, which accounted for 0.75% of the total dry matter, was used. Experiment 4 Performed as described in Test 1, but using span-60, which accounted for 1.0% of the total dry matter. Experiment 5 It was carried out as described in Test 1, except that Span-60, which accounted for 1.50% of the total dry matter, was used. Experiment 6 Performed as described in test 1, but using span-60, which accounted for 2.0% of the total dry matter. Experiment 7 Performed as described in test 1, but using span-60, which accounted for 3.0% of the total dry matter.

[0013]

[Table 1] Result of gas generating power of Example 1 ─────────────────────────────────── Result Result Test a Test b1 Test b2 Test b3 (ml) (ml) (ml) (ml) ───────────────────────────── ────── Span -60 0.25% 283 173 83 29 Span -60 0.5% 290 207 130 69 Span -60 0.75% 290 223 159 85 Span -60 1.0% 300 227 170 88 Span -60 1.5% 304 246 197 122 Span -60 2.0% 303 249 189 123 Span -60 3.0% 298 248 201 129 ─────────────────────────────── ───

Example 2 An experiment was conducted in the same manner as in Example 1 except that a commercially available citric acid ester of monostearic acid ester of glycerin (CGM) was used as a rehydration modifier.

[0015]

[Table 2] Result of gas generating power of Example 2 ─────────────────────────────────── Result of addition Result Result Test a Test b1 Test b2 Test b3 (ml) (ml) (ml) (ml) ───────────────────────────── ────── CGM 0.25% 288 174 96 37 CGM 0.5% 290 193 128 54 CGM 0.75% 297 215 146 71 CGM 1.0% 300 225 165 93 CGM 1.5% 303 241 181 98 CGM 2.0% 307 233 189 109 CGM 3.0 % 310 249 199 121 ───────────────────────────────────

Example 3 Example 1 except that the rehydration modifier concentration was 1.0% for Span-60 and 2.0% for yeast extract powder. 1 was the same as Experiment 1. Example 4 Example 1 of Example 1 except that the rehydration modifier concentration was 1.0% for Span-60 and 1.4% for xanthan gum solution to give a final concentration of 1.4%. It was the same. Example 5 The experiment of Example 1 except that the rehydration modifier concentration was 1.0% for Span-60 and 1.0% for sodium carboxymethyl cellulose. It was the same as 1.

[0017]

[Table 3] Results of gas generating power of Examples 3 to 5 ─────────────────────────────────── Addition Result Result Result Result Test a Test b1 Test b2 Test b3 (ml) (ml) (ml) (ml) ─────────────────────────── ──────── Span -60 1.0% ＋ 298 244 229 133 Low salt yeast extract 2.0% (dm) Span -60 1.0% ＋ 308 282 246 157 Xanthan gum 1.4% (dm) Span -60 1.0% ＋ Sodium 299 261 213 151 Carboxymethyl cellulose 1.0% (dm) ───────────────────────────────────

Example 6 The strain used was 227 Ng, CBS155.91 (1991)
(Deposited on March 5, 2014) except that it was the same as Experiment 4 of Example 1. Example 7 Same as Example 6 except that CGM was selected as the rehydration modifier and its concentration was 2.5% final concentration. Example 8 Same as Example 6 except that the rehydration modifier was a blend of 1.0% Span-60 and 1.0% sodium carboxymethylcellulose. This sodium carboxymethyl cellulose was dissolved as a 5% aqueous solution and then mixed with the emulsion of Span-60.

[0019]

Table 4 Results of Examples 6, 7 and 8 ──────────────────────────── Addition Result Result Test a Test b3 (ml ) (ml) ──────────────────────────── Span -60 1.0% 325 87 CGM 2.5% 324 159 Span -60 1.0% + Sodium 319 146 Carboxymethylcellulose 1.0% (dm) ────────────────────────────

Example 9 237 Ng, wherein the strain used is a sugar-resistant type strain,
CBS158.86 (deposited on March 25, 1986)
Was the same as Experiment 4 of Example 1.
Contrary to Examples 1-8, the tests of gas generating capacity on the samples of Examples 9, 10 and 11 were carried out with the further addition of 10% sugar on flour basis. Example 10 Same as Example 9 except that CGM was selected as the rehydration regulator and its concentration was 2.5% final concentration. Example 11 Same as Example 9 except that the blend of Span-60 and sodium carboxymethyl cellulose in Example 8 was selected as the rehydration modifier.

[0021]

Table 5 Results of Examples 9, 10 and 11 ──────────────────────────── Addition Result Results Test a Test b3 (ml) ) (ml) ──────────────────────────── Span -60 1.0% 270 59 CGM 2.5% 268 89 Span -60 1.0% + Sodium 271 92 Carboxymethylcellulose 1.0% (dm) ─────────────────────────────

Example 12 In one type of baking test (method I) for making French Batar type bread, 3000 g of flour having a temperature of 20 ° C., 1.75% salt, 1% Unipan Plus ( Unipan Plus) (bread improver, Gist Brocades) and 0.45% instant dry yeast 227 Ng strain (CBS155.91) containing various contents of the rehydration regulator CGM were added to Pheb (Pheb).
us) Hand mixed in bowl of mixer. Then 32
Kneading was started by adding 56% water having a temperature of ° C (speed 1 for 1 minute and speed 2 for 18 minutes). The dough temperature was 27 ° C. First dough for 15 minutes at 30 ° C. and 85% relative humidity in a fermentation cabinet for the dough
The second fermentation was performed. Then, add 350 g of the dough to 12
Divided into pieces. Shape these small pieces at 30 ° C and 85
Intermediate fermentation was performed for 15 minutes at% relative humidity. After this step, the pieces were reshaped, molded and subjected to a final fermentation at 30 ° C. and 85% relative humidity for 110 minutes. Then, the fully fermented dough was placed in an oven and baked at 240 ° C for 25 minutes. In a second type of baking test (method II) for making French batard type bread, 3000 g of flour having a temperature of 42 ° C., 1.75
% Salt, 1% Unipan Plus® (bread improver, Gist Brocades) was placed in the bowl of a Febas mixer. Rehydration regulator CGM with various contents
0.45% instant dry yeast 227Ng containing
Strains were spread on the surface of this mixture. Then, 56% water having a temperature of 4 ° C. was poured onto the surface, mixing was started at speed 1 for 2 minutes, and mixed at speed 2 for 28 minutes until the temperature of the dough reached 27 ° C. The dough treatment, fermentation and baking operations were the same as above, except that the final fermentation time was varied. The final fermentation time was measured by placing 45 g of dough (after the first and second fermentation) in a standardized measuring cylinder and raising it to a fixed height of 10 cm.

In both methods, after cooling to room temperature, each bread volume was obtained by the rapeseed displacement method. The results are shown in the table below. Bread capacity is the average of four bread capacity measurements. From this table, there is an increase in bread capacity after addition of instant yeast containing more rehydration regulator in Method I with 20 ° C. flour and 32 ° C. water. This result is consistent with the gas generation result shown in Example 2. Making bread according to Method II resulted in shorter final fermentation times and resulted in somewhat higher bread volumes when using instant yeast with more rehydration regulator.

[0024]

Table 6 Bread capacity of Example 12 ────────────────────────────────── Addition Method I Method II Bread Volume (ml) Final fermentation time (min) Bread volume (ml) ────────────────────────────────── CGM 1.0% 1460 160 1336 CGM 1.5% 1472 150 1393 CGM 2.0% 1514 135 1419 CGM 3.0% 1563 135 1377 ──────────────────────────── ───────

Improved overall bread quality as a result of shorter final fermentation times. That is, the cracks and tears of the outer skin were better, and the texture of the contents was more delicate.

Claims (13)

[Claims] 1. A dry yeast composition having a water content of less than 8% by weight and comprising 1.1 to 5% by weight of a rehydration regulator. 2. Rehydration regulators are: -esters of fatty acids; -acid esters of mono and / or diglycerides; -gum arabic; -xanthan gum; -yeast extract; or-sodium carboxymethyl cellulose (CMC).
The composition of claim 1, comprising at least one of 3. The composition according to claim 1, wherein the ester of fatty acid is a polyglycerol ester of sorbitan ester, glycerol ester and propylene glycol ester. 4. The fatty acid ester is sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, glyceryl monostearate, glyceryl distearate, glyceryl monopalmitate. The composition according to claim 3, which is also a monostearic acid ester of propylene glycol. 5. The composition according to claim 2, wherein the acid ester of mono- and / or diglyceride is a citric acid ester or a diacetyl tartaric acid ester. 6. A composition according to claim 1, which comprises from 1.5 to 3% by weight, preferably from 2 to 3% by weight, of a rehydration modifier. 7. The composition according to claim 1, wherein the rehydration modifier comprises at least 50% by weight of emulsifier. 8. A method for producing a dry yeast composition, which comprises drying yeast in the presence of 1.1 to 5% by weight of a rehydration regulator. 9. The method according to claim 8, wherein the rehydration modifier is defined in any one of claims 2 to 7. 10. A method of preventing loss of yeast activity during rehydration comprising adding a rehydration regulator to the yeast during drying of the yeast. 11. A method for producing bread, which comprises adding the composition according to any one of claims 1 to 7 or 11 to a dough and baking the dough. 12. For protecting the yeast during hydration to produce a yeast having a water content of less than 8% by weight,
Use of the rehydration regulator defined in any one of claims 2-7. 13. Use of the composition according to any one of claims 2 to 7 for producing a dough using water at 0 to 15 ° C.