FR2459282A2 - PROCESS AND AGENT FOR THE FILTRATION OF FOOD LIQUIDS, IN PARTICULAR FERMENTED LIQUIDS - Google Patents

Abstract

THE SUBJECT OF THE INVENTION IS A PROCESS AND AN AGENT FOR THE FILTRATION OF FOOD LIQUIDS, IN PARTICULAR FERMENTED LIQUIDS. THE PROCESS IN ACCORDANCE WITH THE INVENTION CONSISTS OF USING AT LEAST ONE NATIVE STARCH, IN PARTICULAR TUBERS, AS A FILTRATION AGENT. IT APPLIES MORE PARTICULARLY TO THE FILTRATION OF BEER.

Description

PROCESS AND AGENT FOR FILTRATION OF FOOD LIQUIDS,
IN PARTICULAR FERMENTED LIQUIDS
The present French patent application No. 78 18640 relates to a process and an agent for the filtration of particularly fermented liquid foodstuffs and more particularly. for that of beer and cider.

 The main patent No. 78 18640 relates to a method for filtering liquid foods, especially fermented liquids, in which potato starch is used as a filtering agent, it also relates to the filter cake obtained at the outcome of the process.

 Continuing its research, the Applicant Company has found that, unexpectedly, not only potato starch but also native starches in general, especially those of tubers and, more particularly, those of cassava, are good filtering agents. food liquids; they also lead to non-polluting filtration residues because they can be used with advantage in animal feed, even human.

 The filtration process according to the invention, which is the subject of this certificate of addition, therefore consists in using, as filtering agents, native starches other than potato starch, in particular starches of tubers and , more particularly cassava, its starches may however be optionally mixed with potato starch.

 It is recalled that the native starches are those that have not undergone any chemical or physical modification whatever their origin.

 According to an advantageous embodiment of the aforesaid method. the filtration is carried out using a filter on which has been deposited a precoat constituted by at least 50%, preferably at least 70% of the aforesaid filtering agent according to the invention, the complement to 100% can between constituted by at least one filter aid chosen from among the group comprising Kieselguhr, the filtration grounds, the conventional filtration agents, the agent according to the invention on the one hand, and the filter aid, on the other hand, preferably being in the form of two superimposed layers of which the precursor sudite forms.

 According to another embodiment of the aforesaid process, the filtration is carried out by suspending in the liquid to be filtered the aforesaid filtering agent according to the invention in a sufficient quantity so that no clogging of the filter occurs.

According to yet another embodiment of the aforesaid process, the filter on which the precoat has been deposited is constituted by a leakproof filter avoiding the escape of the fermentation gases, in particular of the filterpress or candle filter type,
According to yet another advantageous embodiment of the aforesaid process, a quantity of filtering agent according to the invention is suspended in the liquor to be filtered, sufficient to ensure that no clogging of the filter takes place and depositing on the filter a precoat constituted by the same agent as that in suspension, ionéventuellement mixed with at least one of the aforementioned filtering auxiliaries.

 The filtering agent according to the invention consists of native starches, other than potato starch, in particular tuber starches, and more particularly cassava starch, these agents whose bacteriological quality must be compatible with their use in the filtration of food liquids which must in particular be free of yeasts and molds, which can be mixed with potato starch.

 The invention relates more particularly but not exclusively to the application of the above method and agent to the treatment of beer.

 It is also aimed at the filtration residue as a new industrial product because of its applicability to animal and human nutrition.

 And it can be well understood using the additional description which follows as well as the example, said additional description and example being more particularly relating to advantageous embodiments.

 Therefore, proposing to carry out the filtration step provided for in the industrial processes for manufacturing fermented liquid foods, at least one native starch other than potato starch is used as filtering agents. to a starch of tubers and more particularly of cassava, these starches possibly being mixed with potato starch, of bacteriological quality compatible with the normal requirements of the liquid food industry and free from yeasts and molds in particular normally be there.

 To achieve the desired bacteriological quality, it is sufficient to subject the starch to long-term storage, that is to say, at least six months at the end of which there are no longer living yeasts and molds, as it has been demonstrated in the main patent for potato starch.

 As already stated in the main patent for potato starch, it is also possible to sterilize the starch without altering more than in the previous process its granular structure i to do this, we can use for example to a treatment with ethylene oxide or propylene according to techniques well known to those skilled in the art and authorized in some countries or to a radio-pasteurization, that is to say sterilizing treatment including using gamma radiation.

The starch used is formed of egg-shaped granules with a moisture content of 18 to 20% in general: the particle size distribution in the case of cassava is given in Table I below alongside that of a
Kieselguhr conventionally used as a filtering agent.

 The constituent grains of the cassava starch are egg-shaped and its particle size spectrum is displaced with respect to that of the Kieselguhr as shown in the table below.

TABLE I

<tb><SEP> Kieselguhr <SEP> of <SEP> of <SEP> cassava
<tb><SEP>#en<SEP> II <SEP> of <SEP> cassava
<tb><SEP>:<SEP><SEP>:<SEP>
<tb><SEP>:<SEP> ~~ <SEP> ~~~~~~~~~~~~~~
<tb> Lower <SEP> particles <SEP> to
<tb><SEP> 5 <SEP> microns <SEP>. <SEP><SEP> 20 <SEP>. <SEP> 2,2 <SEP>
<tb> Particles <SEP> included <SEP> between
<tb> 5 <SEP> and <SEP> 9 <SEP> microns <SEP>: <SEP><SEP> 36 <SEP>: <SEP> 2.0
<tb> Particles <SEP> included <SEP> between
<tb><SEP> 9 <SEP> and <SEP> 15 <SEP> microns <SEP>: <SEP><SEP> 30 <SEP>: <SEP> 38
<tb> Particles <SEP> included <SEP> between
<tb><SEP> 15 <SEP> and <SEP> 25 <SEP> microns <SEP>: <SEP> 6 <SEP>: <SEP> 52
<tb> Particles <SEP> included <SEP> between
<tb> 25 <SEP> and <SEP> 40 <SEP> microns <SEP>: <SEP><SEP> 4 <SEP>: <SEP> 5.8
<tb> Higher <SEP> particles <SEP> to <SEP>: <SEP> - <SEP>: <SEP>
<tb><SEP> 40 <SEP> lower microns <SEP> and <SEP>
<tb> to <SEP> 100 <SEP> microns <SEP> approximately <SEP>: <SEP> 4 <SEP>: <SEP> O
<Tb>
It is understood that, if necessary, it is possible to use particular particle size fractions obtained, for example, by cycionage in air (turboseparation) or by cycloning within a liquid.

 Filtration is carried out using a filter-type filter press or candle filter type, this filter must in any case be sealed type, avoiding the escape of fermentation gases contained in the liquid.

 In general, a precoat is deposited on the filter, this precoat may consist of several superimposed layers of decreasing particle size starting from the filter, the constituent material of each layer being chosen from starches whose particle size spectrum corresponds to that required for individual layer envisaged.

 Thus, one can successively have a layer of potato starch and a layer of cassava starch.

 Between the layer of potato starch and the filter. a filter aid layer may be arranged as defined above.

 It is also possible to form the precoat with a mixture of filter aid and native starches, especially potato starch and / or cassava.

 The potato starch precoat mixed with at least one native starch or the native starch precoat can be prepared by first passing on said filter a potato starch suspension mixed with at least one native starch or a suspension of native starch in a liquid that may consist of water or the liquid to be filtered, the first quantities being recycled in the second case to undergo additional filtration after formation of the precoat.

 The precoat of filtration aid can be carried out in the same way.

 In general, the filtering agent according to the invention continues to be used during the entire filtration process in the liquid to be filtered, the quantity of suspended agent being chosen so that this agent is deposited sufficiently fast from the point of view of increasing the thickness of the layer so that there is no clogging of said layer, in particular yeast cells as well as retained colloidal substances.

 In practice, good results are obtained by producing a suspension of about 50 to 50 g, preferably 80 to 150 g, of filtering agent per hectolitre of liquid to be filtered.

 By the continuous deposition of the filtering agent according to the invention during the filtration, a filter cake is formed formed for example of starch and microorganisms, cake which advantageously finds its use both in animal feed human and therefore does not constitute a secondary product rejected and polluting.

 The proportion of filter aid that may be present in this cake is sufficiently small so as not to be detrimental to the aforementioned application.

As an indication, it is pointed out that when the
filtered liquid is beer and that the filtering agent is native starch, the content of the potato starch slurry in the beer for filtration is of the order of 100 g / hl and the Filtration residue is constituted by a starch mixture of yeast cells retained, the starch / cell ratio being generally between 1 / 0.2 and 1/3 depending on the fermentation process retained.

 Given the water content of about 20% for starch and about 75% for yeast, an average ratio of 1/1 equivalents, expressed as solids, to about 1 / 0.3.

 This product can be used in human nutrition, for example after a cell lysis treatment as a flavoring substance for soups and sauces in particular and, in animal feed, as a component of the diet, especially for pork.

 To illustrate the foregoing, two examples of implementation of the invention relating to an advantageous embodiment are described below.

EXAMPLE 1
This test relates to the filtration of a suspension of brewer's yeasts in water in which the filtering agent is a mixture of potato starch and cassava; the precoat was carried out by depositing on the filter a layer of potato starch. then a layer of cassava starch.

 The filtration was carried out with a pilot filtration station consisting of an alluvial frame filter, in this case that marketed by GASQUET under the identification "DC 50", and whose filter surface is 2.81 m2. Lambing is carried out by means of a variable flow metering pump.

 The liquid to be filtered consists of a suspension of brewery yeasts in water whose concentration is of the order of about 108 cells per liter.

 The precoat is constituted by a first layer of potato starch, representing 50% by weight of the total precoat and a layer of manioc starch also representing 50% by weight of the precoat.

 The filtering agent consists of a mixture of potato starch, representing 75% by weight, and of cassava starch, representing 25% by weight.

 It was observed at the end of the test that the filtrate is clear, the efficiency is such that the filtrate contains 40 cells per liter.

 There was also a better mechanical strength of the filter cake during the removal of the filter, which facilitates its detachment.

EXAMPLE 2
This test relates to the filtration of a beer with 21 days of storage, carried out using a pilot filtration plant of the "FILTROX" type (manufactured by the company FILTROX WERK AG St. Gallon-Switzerland), including a alluvial frame filter known under the designation "VARIOX" whose dimensions are 40 x 40 cm and a filtering agent dispenser known under the designation "DOSIMAT" 55/130. The filtering surface of this installation is 4.22 m2. The precoat consists of a first layer of 580 g / m2 of a "medium" Kieselguhr (particle size between about 3 and about 30 microns), of equal permeability at about 200 millidarcy and a second layer of 1385 g / m2 of a mixture consisting of 60% cassava starch and 40% potato starch, which mixture has a permeability of about 33 millidarcy.

 The beer is filtered at a rate of 15 hl per hour.

During a 7-hour filtration cycle, the average hourly pressure drop measured is 21 cm of water per hour.

The brightness is measured using a device of the "HAZEMETER" type, calibrated in formazine unit EBC (European
Brewery Convention] and is between 0.45 and 0.55. Colloidal and bacteriological stability complies with conventional acceptance standards. These results demonstrate the excellent efficiency of the process and the filtering agent according to the invention.

 Following what, and whatever the embodiment adopted. a method and a filtering agent are thus available whose characteristics result from the foregoing and which have, in comparison with those which already exist, numerous advantages, in particular that of leading to a filtration residue not only non-polluting but, on the contrary, usable in food and feed, thus valued.

 It goes without saying and as it follows already from the foregoing, the invention is not limited to those of its embodiments which have been more specifically considered: it embraces, on the contrary, all variants.

Claims (14)

 1. A method for filtering food liquids, especially fermented liquids, characterized in that at least one native starch, other than potato starch, is used as filtering agent, in particular a starch of tubers. possibly mixed with potato starch.  2. Method according to claim 1, characterized in that the starch of tubers is cassava starch.  3. Method according to any one of claims 1 and 2, characterized in that ~ one carries out the filtration using a filter on which has been deposited a precoat constituted by at least 50%, preferably 70% of the filtering agent, the 100% complement may consist of at least one filter aid selected from the group comprising Kieselguhr, the filtering grounds, the conventional filtration agents, the filtering agent, a and the filter aid, on the other hand, being preferably arranged in the form of two superimposed layers, the whole of which forms the aforesaid layer.  4. Method according to any one of claims 1 to 3, characterized in that the filtration is carried out by suspending, in the liquid to be filtered, the filtering agent in a sufficient quantity so that it does not occur. produce no clogging of the filter.  5. Process according to any one of Claims 1 to 4, characterized in that the filter on which the precoat has been deposited is constituted by a leaktight filter avoiding the escape of the fermentation gases, in particular of the filter-press type or candle filter.  6. Process according to any one of Claims 3 to 5, characterized in that the filtering agent is suspended in the liquid to be filtered in an amount sufficient to prevent any clogging of the filter and that a precoat is deposited on the filter constituted by the same filtering agent as that suspended and optionally mixed with a filter aid.  7. Method according to any one of claims 3 to 6. characterized in that the precoat layer consists of several superimposed layers of decreasing particle size starting from the filter, the constituent material of each layer being selected from filtering agents whose particle size spectrum meets that required for the individual layer envisaged.  8. A method according to claim 7, characterized in that the precoat is constituted, starting from the filter, a layer of potato starch and a layer of cassava.  9. Process according to any one of claims 3 to 8, characterized in that between the filter and the first layer of starch, starting from the filter, is deposited a layer of at least one filter aid.  10. Method according to any one of claims 3 to 9, characterized in that the native starch, other than potato starch, optionally combined with potato starch, which is suspended is present therein at 50 to 500, preferably 80 to 150 g / hl.  11. Filtration agent for food liquids, especially fermented, characterized in that it consists of at least one native starch other than potato starch, in particular a tuber starch, optionally mixed with starch of starch. Potato bacteriological quality compatible with its use in the filtration of food liquids and especially free of yeast.  12. Filtration agent according to claim 11, characterized in that the native starch is a starch of tubers, including cassava starch.  13. Application of the method according to any one of claims 1 to 10 and the agent according to one of claims 11 and 12 to the filtration of beer.  14. New industrial product consisting of the filter cake obtained at the end of the process according to any one of claims 1 to 10.