MXPA97002389A

MXPA97002389A - Streptococcus thermophilus stem, fermentation procedure using strain and productobten

Info

Publication number: MXPA97002389A
Application number: MXPA/A/1997/002389A
Authority: MX
Inventors: De Villeroche Jacques; Benbadis Laurent
Original assignee: Compagnie Gervais Danone
Priority date: 1994-09-30
Filing date: 1997-03-31
Publication date: 1997-06-01

Abstract

The present invention relates to a layer of S.thermophilus deposited in the CNCM (Coilection Nationale de Culture de Microorganisms) under the number I-1477 and its mutants which have characteristics of similar milk acidification

Description

CEPT OF 5TREPTQCOCCUS THERrlQPHILUS, FERMENTATION PROCEDURE USING SUCH STRAIN AND PRODUCT OBTAINED DESCRIPTIVE MEMORY The present invention relates to a strain of r? T reptococcus therrnoph 11 us, to the use of this strain for the production of fermented dairy products and to the products obtained using this strain. The choice of lactic acid bacteria for the production of the producer »fermented dairy products < With many criteria, especially the acidification activity and the formation of flavor components, the cubicles provide the organoleal properties of the product and the production of thickeners that play a role in texture and untuosity. The acidifying activity is essentially characterized? for three parameters: the kinetics of acidification, the acidity and the pH of final fermentation, which determine the organoleptic characteristics of the product and its quality of preservation, as well as the post-acidification, which develops during the preservation of the product A high acidification speed makes it possible to reduce the period during which the milk-based product is sensitive to con? animantes C pH > 4.7) and thus reduce the risk of bacterial contamination. An increase in the rate of acidification also improves the economy of the process by increasing the productivity and flexibility of the industrial material. 5 The post-acídication properties of the strains are particularly important for the preservation of the products. In fact, fresh fermented products are stored at temperatures between approximately 4 ° C and 8 ° C for a period not generally exceeding 4 weeks; but If the inetabolic activity of the bacteria is reduced by keeping it at low temperature, it is not blocked and causes the production of lactic acid from lactose, which results in a reduction in pH and an increase in acid taste. , which would give the organoleptic properties of the product. For the criteria retained for their contribution to the quality of the products, other elements more specifically linked to the procedure play a role in the choice of the strains, such as the temperature of fermentation, the ? 0 acidification speed and resistance to bundles. The resistance to the bundles is a very important criterion in the choice of strains to reduce the risk of incidents of fa or during production, which can block- for a longer period or so the production ? 5 complete for decontamination. It is not known until now. Thermophilus that exhibits a high acidification rate and a high degree of acidity combined with a post-acidification activity very low or practically zero. In fact, it is generally observed that S. ther ophilus cuHs having a reduced or reduced post-acy activity show normally an acidifying activity limited during fermentation, which does not It allows the desired degree of acidity to be oMenido in the products, Alemas, these strains commonly have a slow 1U growth and require high levels of inoculation and a longer incubation period which are incompatible with the economics of an industrial process. of the present invention is a strain of 5. he mophilus, which has an acidification kinetic quick to obtain a high degree of acidity and which does not add fresh fermented products during storage. Mae, in particular, the present invention relates to a strain DM- (101 116 of S. t ermophilus deposited in the 0 Collection Nationale de Cultures de Microorgam srnes (CNCM) under No. I-l < 77 and mutant.es of the same, which have similar characteristics of milk acidification. The < Ruinous strains that have similar loci performance characteristics similar to the deposited strain are , 'designed to designate' strains that can be obtained especially by mutation and selection of the reference strain and / or by genetic transformation with the help of vector-es. the acidification characteristics are a pH of incubation end of 4.6 in less than 4 hours and a variation of pH h at 28 days of less than 0.2 pH unit, preferably less than 0.1 unit. The mutant strains can be obtained from the reference strain, especially by means of mutation and selection according to their acidification properties. The mutation techniques are known, as well as the tests that make possible to control the acidification properties (especially "? Pmnier H. E ::, Corrieu G." Automatic method to quanti f and starter activity based on pH easurement ". of Dairy Research, 56 (1 89) 755-764); by Toissart H. and Luq? et F "M. 5 Edltion Lorica TSBN: 2-9507477-0-1.) E £ s < strains are more particular The present invention relates to a process for the preparation of fermented dairy or fermented milk products in which a milk substrate is fermented with at least one fermented milk product, which is advantageous for the preparation of all types of fermented milk products. strain of S. themophil S. It is also possible to provide, in this procedure, the use of a combination of one or more bacterial strains, especially with other lactic acid bacteria such as Lactobacillus lus bul yap cus, lactobacillus 11 acidophi lus , Lactobací lus caseí or Bi f i dobactepum.

Preferably, the milk substrate is natural or reconstituted milk, skim or otherwise, or a milk-based medium or a medium based on products of dairy origin. This subst ato may consist of commonly used items for the preparation of milk desserts, solid items such as fruits, chocolate chips or cereals for example, but also sweetened products or liquid chocolates. I) In fact, the strain according to the invention has the advantage of being resistant to sugars, which makes it easier to prepare sweetened products containing specific substances. The present invention also relates to the fermented milk products obtained using this method, especially fresh fermented cheese and yoghurts, for example. The products obtained using this strain have a mild flavor and their organoleptic properties are preserved < -during the pavement. The cultivation of the strains according to the invention, pure or in combination with other strains, can also be used as a probiotic for human consumption or for animal feed and also as a ferment to be used in the conformity procedure. with the invention Other features and advantages of the present invention will be apparent by reading the following examples.

EXAMPLE 1 Comparison of acidification rate and post-acldification activity of different strains of s. thermophilus A reconstituted skim milk containing 12% dry matter and enriched with 0.1% yeast extract is heated for 15 minutes at 1? 1 ° C. An active crop of ci. thermophilus consisting of cells of 10 ^ _ per milliliter is used to inoculate this medium < -t 1% (p / p). The starter culture is obtained after approximately 4 hours of incubation at 44 ° C. This starter culture is used to ocular (1%? /?) 1 1 of reconstituted skim milk containing 12% dry matter, enriched with 0.1% yeast extract and previously pasteurized at 95 ° C for 30 minutes. The inoculated milk is shaken and subsequently incubated at 44 ° C. When the acidity reaches a pH of 4.6, the preparation is cooled for 16 hours at 4 ° 0. This fermented milk is subjected to a conservation test at 8 ° C for 28 days. The pH after 28 days of storage is compared to the different strains. The results are presented in table 1. Strain 1-1477 corresponds to strain DN-001 116. Only milk fermented with strain DN-001 116 of c.,. t ehermophi 1 us has practically zero post-acidification after 28 days of storage at 8 ° C. Strain DN-001 116 shows a fast acidification rate; a pH of 4.6 is reached in less than 4 hours of incubation at 44 ° C.

TABLE 1 Strain ofytigp Strain of imtwm'pn pHal final pH a Difference of incu28 days batch 1 DN-001 003 4 h 46 min 4.60 4.31 0.29 2 DN-0CI1 004 7 h 21 min 4.62 4.26 0.36 3 DN-001 013 7 h 18 mip 4.65 4.25 0.40 4 DN-0C1 015 6 h 16 min 4.65 4.30 0.35 5 DN-OCl 022 5 h 18 min 4.60 4.15 0.45 6 DN-OOl 023 3 h 55 min 4.59 4.19 0.40 7 DN-OOl 025 6 h 48 min 4.64 4.41 0.23 8 DN-OOl 031 5 h 43 min 4.60 4.40 0.20 9 DN-OOl 032 4 h 18 min 4.61 4.51 0.10, 0 DN-OOl 047 3 h 42 min 4.60 4.18 0.42 1 DN-OOl 054 4 h 19 min 4.60 4.16 0.44 2 DN-OOl 064 5 h 30 min 4.60 4.10 0.50 3 DN-OOl 067 4 h 09 min 4.60 4.10 0.50 4 DN-OOl 094 3 h 54 min 4.61 4.08 0.53 5 DN-OO: L 107 3 h 45 min 4.62 4.52 0.10 6 DN-OO :. 111 3 h 33 mip 4.60 4.11 0.49 7 DN-00;. 116 3 h 45 min 4.61 4.53 0.03 8 DN-OOl 138 4 h 15 min 4.60 4.12 0.48 9 DN-OOl 143 4 h 05 min 4.59 4.18 0.41 0 DN-OOl 145 3 h 40 min 4.60 4.17 0.43 1 DN-OOl 147 6 h 09 min 4.64 4.11 0.53 2 DN-OOl 156 4 h 24 min 4.60 4.12 0.48 3 DN-OOl 162 4 h 05 min 4.60 4.14 0.46 4 DN-OOl 171 5 h 30 min 4.58 4.08 0.50 5 DN-OOl 181 4 h 33 min 4.61 4.11 0.50 6 DN-OOl 223 5 h 30 min 4.60 4.21 0.39 7 DN-OOl 225 3 h 54 min 4.60 4.25 0.35 8 DN-OOl 228 4 h 35 min 4.61 4.16 0.45 9 DN-OOl 230 6 h 15 min 4.64 4.20 0.44 DN-OOl 236 5 h 30 min 4.63 4.10 0.53 1 DN-OOl 242 3 h 51 min 4.61 4.11 0.50 DN-OOl 276 5 h 25 min 4.60 4.18 0.42 DN-OOl 277 3 h 35 min 4.61 4.20 0.41 DN-OOl 280 6 h 00 min 4.62 4.10 0.52 DN-OOl 289 4 h 50 min 4.61 4.06 0.55 DN-OOi 342 5 h 30 min 4.60 4.53 DN-OOl 343 3 h 55 min 4.62 4.25 0.37 EXAMPLE 2 Comparison of post-acidification activity of the strain 001 116 of 5. thermophilus with other strains of S. thermophilus The starter culture is prepared as in example 1. This starter culture is used to inoculate (1% v / v) one liter of reconstituted skim milk containing 12% of dry matter, enriched with 0.1% yeast stratum and previously pasteurized for 30 minutes at 95 ° C. The inoculated milk is shaken and then incubated at 4 ° C. When the acidity reaches G0 ° O, the preparation is cooled for 16 hours at 4 ° C. This fermented milk is subjected to a conservation test at B ° 0 for 28 days. Table 2 presents the incubation time and the variation of pH and acidity of Dornic during storage at 8 ° C for 28 days » TABLE 2 The post-acid di fi cation by strain T25 is comparable with that of strain DN-001 116 but its rate of acidification is much slower. Strain JT44, which has a satisfactory rate of aci ification, shows a very high post-acidification.

EXAMPLE 3 Stability of a fermented ultrafiltered milk prepared with strain DN 001 116 e prepares a mixture composed of a retentate milk containing 6% protein (NT-NPN x F? .38) and cream that contains Lene 40% of fat. The proportion of each of the two constituents is 82% of retained material and 18% of cream. and adds n.03% (? /?) of casein hydro lysate. The content of the mixture is 5.3% protein and 7.2% fat. The preparation is subjected to a pre-heating ion at 75 ° C, homogenization at 75 ° C and 200 bars, and then pasteurization at 95 ° C for 8 minutes before cooling to 40 ° C. The mixture is then inoculated with a frozen concentrated preparation of strain DN-001 116 in an amount of 30 g / 100 1 of a starter culture at 9x10 9 CFU / g. The inoculated mixture is incubated at 40 ° C until a pH of about 4.7 is obtained. After the curd is allowed to settle and after the curd has been discarded, a soft paste is formed in a suitable valve before cooling to 20 ° C in a plate exchanger. The softened and cooled product is then packed in l k containers. These containers, after palletizing, pass inside a cold air tunnel to cool the product at 4 ° C. The product is then subjected to a conservation test at 4 ° C and at 10 ° C. The results are presented in table 3.

TABLE 3 (n +) good, very soft. (* - <) good, smooth These results confirm that strain DN-001 116 of S. therrnophilus has a very reduced post-acidification at 4 ° C and at 10 ° C.

EXAMPLE 4 Character of resistance to bundles of the strain DN-001 116 of S. thermophilus 60 bundles of. The mopnilus were isolated after 10 years of production and in factories in different geographical areas. The analysis of their host spectrum made it possible to classify them into 7 subgroups. The resistance of strain DN-001 116 was tested for representative bundles of these 7 subgroups (015, 057, 047, 77 076, 029, 065), the title of the bundles exceeded 107 < The shape of plate / inl units (The underlined bundles have been described in the publication Biochinie (1990) 72, f'55,862). The strain DN-001 116 is resistant to all tested bundles.

EXAMPLE 5 Resistance to sugars The procedure is carried out as in the example 3, but adding to a medium to be varied fermented amounts of sucrose. The time of the p > The objective to be obtained is measured: - medium containing 9% sucrose: pH 4.7 620 rnin - medium containing 13% sucrose: pH 4.7 920 min The strain of C? reptococc? s thermophilus has been deposited in Collection Nationale de Cul tur-es de Microorganisms (CNCM) under number T-L477 on September 22, 1994.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A strain of treptococcus therrnophilus deposited in the Colecté Nationale de Cultures de Microorganismos (CNCM) under number 1-1477 and mutant.es of the same that have similar characteristics of milk acidification. 2.- A strain of S. thermophilus according to claim 1, corresponding to strain number T-1477. 3. A strain of S. therrnophi lus according to any of claims 1 and 2, further characterized because the rn.4tant.es are obtained by mutation and selection of their scidifying properties. . - A procedure for the preparation of products Fermented dairy products in which a milk substrate is fermented with at least one strain of r- > . th rrnophilus according to one of claims 1 to 3. 5. A method according to claim 4, further characterized in that the fermentation is carried out in the presence of at least one other strain of bacteria. 6. A method according to claim 5, further characterized in that the other strain of bacteria is a lactic acid bacteria. 7. A method according to claim 6, further characterized in that the Lactic Acid bacterium is selected from: Lactobacillus bulgaricus, Lactobacillus acidophi lus, Lactobacillus casei and Bi idobacteri u. 8. A process according to one of claims 4 to 7, further characterized in that the milk substrate is milk. 9. A process according to one of claims 4 to 8 further characterized in that the substrate contains solid artLcuLs. 10. A process according to claim 9, further characterized in that the solid articles are routes, chocolate products or cereals 11. Fermented products obtained using the method according to one of claims 4 to 10.