GB1560478A

GB1560478A - Compressed yeast compositions

Info

Publication number: GB1560478A
Application number: GB4639775A
Authority: GB
Original assignee: Gist Brocades NV
Current assignee: Gist Brocades NV
Priority date: 1975-11-10
Filing date: 1975-11-10
Publication date: 1980-02-06
Also published as: FR2330765A1; DE2651349A1; NL7612283A

Description

(54) COMPRESSED YEAST COMPOSITIONS (71) We, GIST-BROCADES N.V., a Dutch Body Corporate, of Wateringseweg 1, Delft, Holland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method for the manufacture of pulverous or fine granular compressed yeast, especially baker's yeast, and further relates to pulverous and fine granular sompressed yeast so produced.

Usually yeast is sold in blocks of compressed yeast in which the dry matter content of the yeast is 27 to 33%, and which has, for example, a butter-like consistency.

A sort of granular yeast, having an increased dry matter content, is known from, for example, British Patent Specification No.

1,135,418 which describes a method for its production starting from an aqueous suspension of yeast, which is concentrated until it is of a creamy consistency, whereafter an osmotic agent, such as sodium chloride, is added to a certain concentration, followed by separation of the yeast from the aqueous phase and washing the yeast before the cells are able to re-absorb all the water content they have lost by osmosis, until a dry matter content of 31 % or more by weight is obtained. The obtained product is sub-divided to give a granularlike product. The osmosis principle in connection with yeast is known from British Patent Specification No. 763,926 ("Salzverfahren").

In compressed yeast two kinds of water have to be considered: water present within the cells (intra-cellular water) and water present outside the cells (extra-cellular water). The consistency of the compressed yeast is dependent to a great extent on the amount of extra-cellular water present, and the lower the amount of extra-cellular water, the higher the consistency. By the "Salzverfahren" process mainly part of thn extra-cellular water is removed.

On the other hand, active dried bakers' yeasts have been developed, which are granular or pulverous products themselves.

however, in these yeasts water has been evaporated to such an extent that not only all the extra-cellular water has been removed but also the intra-cellular water to a certain extent. The yeast obtained has physical properties differing considerably from those of compressed yeast. Active dried bakers' yeast, based on dry matter content, is lessactive than compressed yeast because of the additional drying step.

It is an object of the invention to provide a compressed yeast composition of a higher consistency in the form of a pulverous product or a fine granular product which may easily be handled and has preferred freeflowing characteristics. Furthermore, it is an object of the invention to provide a compressed yeast composition which is easily dispersed in water or is smoothly distributed in flour when preparing a dough.

Thus the invention provides a yeast composition, especially a compressed bakers' yeast composition, which comprises 75 to 99.5% (preferably 90 to 99%) of compressed yeast having a dry matter content of 28 to 50% (preferably 33 to 40% and 0.5 to 25% (preferably 1 to 10%) of a C-om- patible solid highly water-absorbing agent (as hereinafter defined), said yeast composition being in a pulverous or a fine granular form. By the expression "compatible solid highly water-absorbing agent" as used in this specification and accompanying claims is meant a solid substance which does not, or does not substantially, affect the properties of the compressed yeast or other dough ingredients to which the yeast com-' position is later added and is physiologicallv inocuous to the animal organism in baked products and, moreover, is capable of absorbing at least part of the available extra-cellular water in a compressed yeast composition, viz. it is hydrophilic.

The yeast composition according to thein- vention is of a high consistency and possesses- good free-flowing characteristics either in the pulverous or in fine granular form.

Furthermore, the composition is easily dispersable in water and is smoothly distributable in flour during dough mixing. Additionally, the yeast composition has a better storage stability than compressed yeast in the untreated form.

The yeast composition may be prepared, according to a feature of this invention, by first preparing compressed yeast having a dry matter content of 28 to 50%, for ex are by using the osmosis principle as indicated above. It is preferred to prepare a compressed yeast having a dry matter content as high as possible by mechanical means, which may be done by applying the osmosis principle. Such a yeast still contains a considerable amount of extracellular water, and it is part of this water that is removed according to the present invention. This is done by adding a compatible solid highly water-absorbing agent to the thus obtained yeast, so that at least part of the available extra-cellular water is taken up by the water-absorbing agent, thus increasing the consistency of the yeast, so that the yeast may be transformed into a pulverous or a fine granular form.

The compatible solid highly water-absorbing agents are preferably in a form having a large surface area per unit of weight, e.g.

powders or granules. Silicas such as Aero sil (Trade Mark) or aluminium silicates such as Ketjensil (Trade Mark) are suitable waterabsorbing agents. Also water-absorbing emulsifiers and water-absorbing modified starches and celluloses are useful. Mixtures of two or more of those water-absorbing agents may also be used.

The mixing of the compatible solid highly water-absorbing agent with the compressed yeast is simple, and may be carried out by an ordinary mixer which is not deleterious for the yeast cells. For example, a hammer mill will do and, if desired, small amounts may be mixed in an ordinary electric coffee grinder. It is also possible to prepare a compressed yeast according to the known osmosis principle indicated above (Salzverfahren), and granulating it with the addition of an emulsifier. The compatible solid highly water-absorbing agent may be added to the granulate to obtain a free-flowing powder.

Although the invention is developed for bakers' yeast, it will be understood that the invention is also applicable to other kinds of yeast, e.g. beer yeast and wine yeast.

The invention is illustrated by the following Examples.

EXAMPLE I Compressed bakers' yeast, having a dry matter content of 29%, was crumbled by hand into pieces having a diameter of about 1 cm. The crumbled yeast was mixed with an amount of water-absorbing material (6 grams of "Aerosil 200" per 100 grams of compressed yeast) in a household coffee grinder for 15 seconds to give a pulverous product. The gas-producing ability of the pulverous product and the original compressed yeast was determined according to method B described in British Patent Specification No. 1,230,205. (The tests were performed in such a manner that both samples, original compressed yeast and pulsamples, original compressed yeast and the pulverous product derived therefrom, retained the same amount of yeast solids).

Both samples showed the same gas-producing ability when fresh. To ascertain the keeping quality the gas-producing ability was again determined after storage for four days at 300 C. The pulverous product showed a keeping quality 10% better than the original compressed yeast.

EXAMPLE 2 Compressed yeast with a dry matter content of 34%, obtained according to the "Salzverfahren" method, was mixed with a suspension of an emulsifying agent (1.5 g.

of sorbitan monostearate per 100 g. of yeast solids). The compressed yeast composition obtained was extruded through a perforated plate having orifices of 1.0 mm.

The granulate was treated with an amount of water-absorbing material by hand-mixing (3 g. of "Aerosil 200" per 100 g. of compressed yeast with emulsifying agent). The gas-producing ability of the original granulate and the granulate with the waterabsorbing agent was determined according to the method mentioned in Example 1.

Both samples showed the same gas-producing ability. After storage for four days at 30 C. the granulate with the water-absorbing material showed a keeping quality 25% better than the granulate as such.

EXAMPLE 3 The method of Example l was repeated with the exception that "Aerosil 200" was replaced by a modified starch (25 g. of "Remyline AC" per 100 g. of compressed yeast). The pulverous product obtained showed the same gas-producing ability as the original compressed yeast.

The percentages hereinbefore mentioned and in the following Claims are by weight.

WHAT WE CLAIM IS:- 1. A yeast composition which comprises 75 to 99.5% of compressed yeast having a dry matter content of 28 to 55%, and 0.5 to 25% of a compatible solid highly water-absorbing agent (as hereinbefore defined), said yeast composition being in a pulverous or a fine granular form.

2. A yeast composition according to

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Claims

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Furthermore, the composition is easily dispersable in water and is smoothly distributable in flour during dough mixing. Additionally, the yeast composition has a better storage stability than compressed yeast in the untreated form.

The yeast composition may be prepared, according to a feature of this invention, by first preparing compressed yeast having a dry matter content of 28 to 50%, for ex are by using the osmosis principle as indicated above. It is preferred to prepare a compressed yeast having a dry matter content as high as possible by mechanical means, which may be done by applying the osmosis principle. Such a yeast still contains a considerable amount of extracellular water, and it is part of this water that is removed according to the present invention. This is done by adding a compatible solid highly water-absorbing agent to the thus obtained yeast, so that at least part of the available extra-cellular water is taken up by the water-absorbing agent, thus increasing the consistency of the yeast, so that the yeast may be transformed into a pulverous or a fine granular form.

The compatible solid highly water-absorbing agents are preferably in a form having a large surface area per unit of weight, e.g.

powders or granules. Silicas such as Aero sil (Trade Mark) or aluminium silicates such as Ketjensil (Trade Mark) are suitable waterabsorbing agents. Also water-absorbing emulsifiers and water-absorbing modified starches and celluloses are useful. Mixtures of two or more of those water-absorbing agents may also be used.

The mixing of the compatible solid highly water-absorbing agent with the compressed yeast is simple, and may be carried out by an ordinary mixer which is not deleterious for the yeast cells. For example, a hammer mill will do and, if desired, small amounts may be mixed in an ordinary electric coffee grinder. It is also possible to prepare a compressed yeast according to the known osmosis principle indicated above (Salzverfahren), and granulating it with the addition of an emulsifier. The compatible solid highly water-absorbing agent may be added to the granulate to obtain a free-flowing powder.

Although the invention is developed for bakers' yeast, it will be understood that the invention is also applicable to other kinds of yeast, e.g. beer yeast and wine yeast.

The invention is illustrated by the following Examples.

EXAMPLE I Compressed bakers' yeast, having a dry matter content of 29%, was crumbled by hand into pieces having a diameter of about 1 cm. The crumbled yeast was mixed with an amount of water-absorbing material (6 grams of "Aerosil 200" per 100 grams of compressed yeast) in a household coffee grinder for 15 seconds to give a pulverous product. The gas-producing ability of the pulverous product and the original compressed yeast was determined according to method B described in British Patent Specification No. 1,230,205. (The tests were performed in such a manner that both samples, original compressed yeast and pulsamples, original compressed yeast and the pulverous product derived therefrom, retained the same amount of yeast solids).

Both samples showed the same gas-producing ability when fresh. To ascertain the keeping quality the gas-producing ability was again determined after storage for four days at 300 C. The pulverous product showed a keeping quality 10% better than the original compressed yeast.

EXAMPLE 2 Compressed yeast with a dry matter content of 34%, obtained according to the "Salzverfahren" method, was mixed with a suspension of an emulsifying agent (1.5 g.

of sorbitan monostearate per 100 g. of yeast solids). The compressed yeast composition obtained was extruded through a perforated plate having orifices of 1.0 mm.

The granulate was treated with an amount of water-absorbing material by hand-mixing (3 g. of "Aerosil 200" per 100 g. of compressed yeast with emulsifying agent). The gas-producing ability of the original granulate and the granulate with the waterabsorbing agent was determined according to the method mentioned in Example 1.

Both samples showed the same gas-producing ability. After storage for four days at 30 C. the granulate with the water-absorbing material showed a keeping quality 25% better than the granulate as such.

EXAMPLE 3 The method of Example l was repeated with the exception that "Aerosil 200" was replaced by a modified starch (25 g. of "Remyline AC" per 100 g. of compressed yeast). The pulverous product obtained showed the same gas-producing ability as the original compressed yeast.

The percentages hereinbefore mentioned and in the following Claims are by weight.

WHAT WE CLAIM IS:- 1. A yeast composition which comprises 75 to 99.5% of compressed yeast having a dry matter content of 28 to 55%, and 0.5 to 25% of a compatible solid highly water-absorbing agent (as hereinbefore defined), said yeast composition being in a pulverous or a fine granular form.
2. A yeast composition according to

claim 1 in which the compressed yeast is a compressed bakers' yeast.
3. A yeast composition according to claim 1 or 2 which comprises 90 to 99OÓ of compressed yeast.
4. A yeast composition according to claim 1, 2 or 3 in which the dry matter content of the compressed yeast is 33 to 40%.
5. A yeast composition according to any one of the preceding claims in which the amount of the compatible solid highly water-absorbing agent present in the composition is 1 to 10%.
6. A yeast composition according to any one of the preceding claims in which the compatible solid highly water-absorbing agent is a silica.
7. A yeast composition according to any one of claims 1 to 6 in which the compatible solid highly water-absorbing agent is an aluminium silicate.
8. A yeast composition according to any one of claims 1 to 7 in which the compatible highly water-absorbing agent included in the composition is a water-absorbing emulsifying agent or a water-absorbing modified starch or cellulose.
9. A yeast composition according to any one of claims 1 to 5 in which the compatible solid highly water-absorbing agent is a mixture of two or more silicas, aluminium silicates, water-absorbing emulsifying agents and water-absorbing modified starches or celluloses.
10. A yeast composition according to any one of claims 1 to 9 in which the compatible solid highly water-absorbing agent included in the composition is in powder or granular form.
11. A yeast composition according to any one of the preceding claims in which the compressed yeast is a beer or wine yeast.
12. Process for the preparation of a yeast composition as claimed in any one of claims 1 to 11 which comprises the steps of preparing a compressed yeast having a dry matter content of 28 to 50%, mixing with it a compatible solid highly waterabsorbing agent (as hereinbefore defined) so that at least part of the available extracellular water is taken up by the waterabsorbing agent thus increasing the consistency of the yeast, and transforming the yeast composition so obtained into a pulverous or a fine granular form.
13. Process for the preparation of a yeast composition as claimed in claim 1 substantially as hereinbefore described.
14. Process for the preparation of a yeast composition as claimed in claim 1 substantially as hereinbefore described in Example 1, 2 or 3.
15. A yeast composition as claimed in claim 1 when prepared by the process claimed in claim 12, 13 or 14.
16. Use of a yeast composition as claimed in any one of claims 1 to 11 and 15 in the making of baked products, beer or wine.