The invention relates to the field of food compositions containing a microbial biomass, to a process for preparing same and also to fermentation activators or starters, and more particularly to the field of bread-making, the dairy industry and/or food supplements of “probiotic” type containing such compositions.
The present invention relates generally to an improved composition produced by means of a process for spraying a high level of microbial biomass, in particular of bacterial biomass, onto a substrate.
Said substrate of the composition according to the invention is in particular a substrate of granular type (granules or spherules, for example), specially capable of maintaining a high viability of the microbial biomass and good preservation of this viability over time (preservation/persistence of the viability). Said composition, which contains live microorganisms, in particular bacteria, sprayed onto said substrate, under the usual working conditions of the art, is generally used as a starter/leaven in dry powder form.
The technical field targeted in the present invention is in particular that of a composition dried according to an improved process suitable for the production of a live microbial biomass in dry form using a substrate of granular type capable of being evenly coated with a concentrated microbial biomass, it being possible for said biomass to represent from 10% to 30% by dry matter of the total dry matter of the coated substrate.
The two major techniques for preserving live bacterial biomass in dry form are lyophilization and spraying onto a substrate.
EP 0636692 A1 by the applicant describes a “Stable biomass based on yeast cells and lactic acid bacteria and process for its preparation”.
Lyophilization is a complex expensive technique and the drying yields are sometimes low depending on the strains and techniques used.
The spraying of bacteria onto a substrate is also known from EP 0 636 692 A1. However, these techniques remain limited with regard to the amount of biomass that can be deposited on the substrate [less than 0.5% DM W/W in the case of EP 0 636 692 A1; above this value, agglomeration (caking) of the powder and a loss of viability during storage are noted], which consequently limits the performance levels of the prior compositions thus produced.
The microbial biomasses sold today as starters for leavens are obtained either by spraying, or by mixing a large amount of lyophilisate and of yeast granules, or by mixing a large amount of lyophilisate with a diluent substrate, and they are stored in the absence of oxygen at −20° C., so as to have a lifetime of 2 years. In the absence of these storage conditions, the shelf life of the starters does not exceed 3 months.
The mixing operations, the need for an oxygen-free atmosphere, the use of a “quadriplex” leaktight packaging film and the method of storage are all parameters which still remain difficult to control, in certain countries in particular with regard to observation of the cold chain. This leads to problems of quality, without mentioning questions of industrial and environmental costs to be taken into account.
Another problem also arises, which is recurring and is linked to the current form of starters for leavens, namely that of the existence of a long lag time during the inoculation of the flour with the leaven, causing an extension of fermentation times, a variability of the duration of the leaven and a risk of development of the uncontrolled flora of the flour.
All of these problems limit the development of the application of starters/leavens in bread-making, although their use makes it possible to produce breads of high aromatic and nutritional quality.
More recently, it has also been possible to use live bacterial biomass as a probiotic, with the problems linked, on the one hand, to the need for a high concentration of live biomass and, on the other hand, to the survival of the microorganisms after passing through the stomach and its strongly acidic pH.
The inventors have, moreover, observed that:
The present invention intends to solve the problems mentioned above and to overcome the difficulties summarized here and encountered with the prior compositions.
The inventors have shown that there is in fact still the need for a composition of dry products based on a substrate which is capable of being coated and which allows a very high concentration of live bacteria to be sprayed thereon, it being possible for such a composition to be used in particular as a fermentation activator/starter or a probiotic.
Such a composition is improved in the sense that it must allow effective protection of the live bacteria sprayed onto said substrate with respect in particular to a series of “stresses” of the “temperature stress” type, the starter being stored at a positive temperature or even at ambient temperature —, of the “acid stress” type—in particular in the probiotic application, it corresponds to the resistance to the gastric pH—and of the “oxygen stress” type—during storage in air.
Thus, the present invention meets this longstanding need for a composition which has the qualities summarized above.
The subject of the present invention is therefore firstly a composition comprising a substrate capable of being evenly coated with a microbial biomass, which is preferably very highly concentrated, said biomass representing very high percentages of bacteria by dry matter of the total dry matter of the coated substrate.
The first subject of the invention is a composition comprising a substrate capable of being evenly coated with a microbial biomass, said biomass representing from 10% to 30% by dry matter of the total dry matter of the coated substrate.
Another subject of the invention is a process for preparing a composition, comprising the following steps consisting in:
A subject of the invention is also a “Fermentation activator” or “Starter” containing the composition of the invention or as obtained according to the process of the invention, in particular of bread ferment type or of wine-making ferment type or else of milk ferment type.
Another subject of the invention is a “Probiotic” containing the composition of the invention or as obtained according to the process of the invention.
The first subject of the invention is a composition comprising a substrate capable of being evenly coated with a microbial biomass, said biomass representing from 10% to 30% by dry matter of the total dry matter of the coated substrate.
The inventors of the present invention have particularly endeavored to develop an improved composition which contains a biomass which is stable and effective, and have developed a specific process for preparing said composition such that it favorably meets the particularly discriminating and significant criteria in the fields of application targeted and mentioned above.
The performance levels of the compositions according to the invention are controlled by means of specific tests, some of which have been developed by the inventors, and which have been used by the inventors during their research.
These tests, hereinafter referred to as “evaluation tests” are centered around the viability and the acidifying performance levels of the compositions, in particular:
The time during which there is exposure to heat during the production of the composition of the invention is also a parameter which is taken into account.
The inventors have subsequently carried out measurements of the storage parameters for said composition after production thereof in accordance with the process of the present invention, thus defining percentages of preservation/persistence of the viability and acidifying performance levels.
A series of storage tests was thus carried out on the composition of the invention under various conditions, in particular temperature, air-exposure and duration. In particular, tests of the performance levels of said composition are carried out. These are in particular the following tests:
The following were also determined:
The composition of the invention has the following supplementary or alternative characteristics:
Advantageously, said yeasts are of the Saccharomyces genus comprising in particular the S. chevalieri species.
Preferably, said microbial biomass comprises at least bacteria chosen from the group consisting of bacteria belonging to one of the following genera: Lactobacillus, Pediococcus, Streptococcus, Leuconostoc, Lactococcus, Bifidobacterium, Propionibacterium and Bacillus.
Said bacteria are advantageously chosen from the group comprising: Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus sanfrancisco, Lactobacillus amylovorum, Lactobacillus kefir, Lactobacillus pentosaceus, Lactobacillus acidilactici, Lactobacillus rhamnosus, Leuconostoc oenos, Leuconostoc mesenteroides and Bacillus subtilis.
The coated substrate preferably also comprises a layer which consists of a cream yeast sprayed onto said substrate, preferably a cream of S. chevalieri, forming a protective layer. An improvement in the protection of the bacteria is then observed during the storage test under air.
The composition advantageously has a bacterial mortality rate of less than or equal to 0.5 Log CFU/g after storage for one year at a temperature of 20° C. under vacuum and/or after storage for one year at a temperature of 4° C. under air.
Preferably, the composition exhibits, after 1 year of storage at a positive temperature or even at ambient temperature, during the acidification test on medium comprising maltose, a decrease in pH from 6.5 to at least 5.7 after only 3 h.
Advantageously, the composition according to the invention, comprising a substrate which consists of active dry yeasts, also comprises at least on “drying” additive, or process aid, which is advantageously chosen from the group comprising modified fatty acid monoglycerides and diglycerides, fatty acid esters of sorbitan, such as sorbitan monostearate, fatty acid esters of glycerol, fatty acid esters of propylene glycol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose and/or a mixture of the latter.
A subject of the present invention is also a process for preparing a composition, comprising the following steps consisting in:
The mixer which is used in step (i) is advantageously a fluidized air bed (FAB) which allows simultaneous spraying and drying, consequently providing protection by coating. Moreover, this process promotes better storage of the composition according to the invention, which is more stable over time, from the viewpoint in particular of better preservation of the viability of the biomass, event at ambient temperature.
The process according to the invention also has the following supplementary or alternative characteristics:
The following are also subjects of the present invention:
In particular, the invention provides a composition with properties of interest that are particularly sought in the art.
Indeed, the research by the inventors has made it possible to develop a composition comprising a substrate which surprisingly makes it possible to increase the live microbial biomass which is sprayed onto said substrate so as to achieve a microbial, in particular bacterial, concentration never before achieved to date, said composition remaining stable over time. The inventors have also observed, surprisingly, a substantial improvement in the acidifying performance levels of said composition compared with the existing equivalent products, and also an excellent survival, even after 1 year of storage at ambient temperature or of storage under air.
The present invention will now be described in detail in terms of its other characteristics and advantages by means of implementation examples given in a purely illustrative and nonlimiting manner and with reference to the appended tables and drawings.
A] Acidification Tests with Maltose
1) Material and Reagent:
If it is not used during the course of the day, this medium must be sterilized,
2) Procedure, Medium Maltose+Salts:
1) Material:
2) Technique:
3) Reading:
The very small loss of live bacterial population during storage for 1 year at 20° C. during storage under air and the absence of loss of live bacterial biomass during storage under vacuum are noted in table 1.a—the apparent increase in the biomass during storage is an artifact linked to the uncertainty of the analytical method used.
As illustrated in
As indicated in table 1.b, these results are particularly advantageous in comparison with those obtained with the control (Saf Levain LV1), under conditions of temperature stress (storage at 20° C.) or of oxidative stress (storage under air).
They demonstrate the advantage of spraying a high level of bacteria according to the process of the invention compared with the known processes, since it improves the preservation of the live bacterial biomass and of its acidifying capacity under conditions of temperature stress or of presence of oxygen. It should be noted that similar results were obtained with a durum semolina.
Preparation of an “oversprayed” composition according to the present invention comprising a coated substrate, namely a substrate and a superficial protective layer.
The cream of bacteria, obtained according to a procedure identical to that of step 1 of example 1, is sprayed onto the Instant Dry Yeast granular substrate and is dried in a stream of hot air. The resultant intermediate composition is then coated with a protective layer deposited by overspraying of a suspension (cream) of yeasts.
The composition to be oversprayed is obtained under the following conditions: 935 g of cream of bacteria at 20.6% of dry matter are deposited on 600 g of Saf-Instant substrate. The operation is carried out in a fluidized air bed under the same conditions as in example 1.
A “SPRAY_B” composition to be oversprayed which has a moisture content of 5.2% and the bacterial content of which is 25.2% dry matter/total dry matter is obtained.
Step 2: Overspraying with a Cream Yeast (SPRAY_C Composition)
500 g of the preceding “SPRAY_B” composition are introduced into the Glatt GPCG1.1 fluidized air bed, which is in the Wurster configuration and is equipped with a 0.8 mm two-fluid spray nozzle in the bottom position.
235 g of cream yeast (Saccharomyces cerevisiae) at 24% dry matter are oversprayed onto the “SPRAY_B” composition and the apparatus operating parameters (flow rate and temperature of the fluidization air, flow rate of the spraying suspension) are chosen such that the temperature of the product, at any time during the operation, is on average 39.0° C. The duration of this operation is 37 minutes.
A composition “SPRAY_C” protected by a layer of yeast, the moisture content of which is 4.3% and which contains 22.5% bacterial dry matter/total dry matter, is finally obtained.
The absence of significant loss of live bacterial population during storage for 1 year at 4° C. during storage under air and the absence of loss of live bacterial biomass during storage at 20° C. under vacuum are noted in table 2.a.
As illustrated in
As indicated in table 2.b, these results are particularly advantageous in comparison with those obtained with the control (Saf Levain LV1), either under conditions of temperature stress (storage at 20° C.) or under conditions of oxidative stress (storage under air). These results demonstrate the advantage of overspraying as protection of the biomass of interest.
Production of a leavened bread from the composition in accordance with the invention and described in example 1.
Two bread-making tests are carried out according to the formula and the process described below.
Test 1: Leavened bread produced with the Saf Levain LV1 control at 3 months of storage under vacuum at −20° C.
Test 2: Leavened bread produced with the composition of example 1 at 1 year of storage under vacuum at 20° C. (ambient temperature).
These two doughs, hereinafter referred to as “leaven” are left to ferment for 20 h at 30° C.
These results, judged to be similar both in analytical terms and in tasting terms, show the advantage of the composition of example 1 compared with a commercial control. Indeed, although stored for one year at ambient temperature and added at a dose 10 times lower than the control (test 1), the composition of example 1, in accordance with the invention, produces a bread with characteristics similar to those of a commercial starter stored for only 3 months under optimum conditions (−20° C. under vacuum).
Number | Date | Country | Kind |
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11/03902 | Dec 2011 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FR2012/052859 | 12/10/2012 | WO | 00 | 6/16/2014 |