Patent Application
20050123646
This invention relates to a method of manufacturing a cheese flavour ingredient and an ingredient so prepared. It is also relates to bacterial strains useful in the preparation of such an ingredient.
The expression “cheese flavour ingredient” means an ingredient from a protein source that is a component of a mixture of ingredients that have a cheese flavour. The cheese flavour ingredient may or may not itself have a cheese flavour.
Cheese is a biologically dynamic food in which flavour develops as a result of the activity of the enzymes and cultures that occur in the cheese. Flavour develops in the cheese as the enzymes and cultures trapped in the curd act on the milk substrates—caseins, fats, and residual lactose (Crow et al, 1993). The initial ripening reactions are hydrolytic, generating peptides and amino acids from milk caseins by the action of proteases and free fatty acids from milk fat by the action of esterases and lipases. The later reactions during cheese ripening are more complex. Amino acids, free fatty acids and lactate are the primary substrates and the flavour reactions involve, amongst other transformations, the dynamic interaction of deamination reactions, transferase reactions, and synthetic reactions (McSweeny et al, 2000).
Often cheese flavours take months and years to develop. Flavour development can be greatly accelerated using an enzyme modified cheese (EMC) process. In an EMC process, selected enzymes (proteases and lipases) are added to a cheese curd that is typically slurried with water. Intense flavours develop over a period of hours to days (Kilkawley et al, 1998). An EMC process is described in U.S. Pat. No. 3,765,905. EMC processes often involve both proteolysis of dairy proteins and lipolysis of dairy fats. Examples of such EMC processes are disclosed in international patent application WO 99/63834, U.S. Pat. No. 5,455,051 and European patent application EP 1 053 689.
However, often these flavour enhancing processes amplify particular groups of flavourful compounds, such as short chain fatty acids, and peptides of a particular molecular weight and as a consequence, the products of these EMC processes lack the balanced flavour profile of a cheese that has been ripened naturally.
It is an object of this invention to go some way towards overcoming this disadvantage or at least to offer the public a useful choice.
Accordingly, the invention may be said broadly to consist in a process for the manufacture of a cheese flavour ingredient which comprises the steps of,
Preferably, said protein comprises a dairy protein. More preferably, said dairy protein comprises casein. Preferably said mixture comprises a fat, protein and water emulsion In a preferred embodiment said mixture comprises cheese and water.
Alternatively, said mixture comprises on or more of cheese curd, ripened cheese, mature cheese, milk solids, reconstituted whole milk powder, milk protein concentrate, a casein, a milk protein or a non-dairy protein, milk fat or a non-dairy oil or fit.
Preferably said mixture comprises total solids in the range of 5% (w/w) to 50% (w/w) of the emulsion.
Preferably, said protease enzyme is a peptidase or a proteinase or a combination of a peptidase and a proteinase.
In one embodiment, said proteinase is protease A “Amano” (Amano Enzymes) and said peptidase is Neutrase (Novo Nordisk).
In another embodiment said proteinase is Flavorpro 192P (Biocatalysts) and said peptidase is Promod 215P (Biocatalysts).
In one embodiment the method comprises maintaining the emulsion at a temperature within the range of 20-60° C. to continue said proteolysis reaction before beginning step (c). Preferably, said proteolysis reaction is conducted at a temperature of from 40-50° C. Most preferably, said proteolysis reaction is conducted at a temperature of 43° C.
In one embodiment said proteolysis reaction is conducted for some 2 to 24 hours before beginning step (c). Most preferably, said proteolysis reaction is conducted for about 4 hours.
In one embodiment said proteolysis reaction is terminated by heating the reaction mixture to 80-100° C. for from 3 to 30 minutes before beginning step (c). Most preferably, said proteolysis reaction is terminated by raising the temperature of the reaction mixture to about 93° C. for about 15 minutes.
In one embodiment, said mixture is cooled after being heated to terminate said proteolysis reaction.
Preferably, further protease is added after said cooling step.
In one embodiment steps (b) and (c) are allowed to proceed at the same time.
In one embodiment, said bacterium is Enterococcus faecium B9642, AGAL accession number NM01/24754.
In another embodiment said bacterium is Enterococcus faecium B9645, AGAL accession number NM01/24755.
In another embodiment said bacterium is Enterococcus faecaelis B9509, AGAL accession number NM01/24757.
In another embodiment said bacterium is Enterococcus casseliflavus B9518, AGAL accession number NM01/24753.
In another embodiment said bacterium is Staphylococcus simulans B9646, AGAL accession number NM01/24756.
In another embodiment said bacterium is Pseudomonas putida B9647, AGAL accession number NM01/24752.
Preferably, said fermentation reaction is conducted at a temperature of from 30 to 45° C.
Most preferably, said fermentation reaction is conducted at a temperature of 40° C.
Preferably, said fermentation reaction is conducted at a pH of from 6.3 to 6.5.
Preferably, said fermentation reaction is conducted for from 30 to 72 hours.
More preferably, said fermentation reaction is conducted for between about 50 and about 65 hours. Most preferably, said fermentation reaction is conducted for about 53 hours or about 64 hours.
In one embodiment cheese and/or salt may be added during formation of the mixture, where required, to provide a desired solid contents and salt level in any final product. In another embodiment additional cheese and salt may be added immediately before said fermentation reaction is terminated. In another embodiment, cheese and/or salt may be added part way through said fermentation reaction.
Preferably, said fermentation reaction is terminated by heating to a range of 80° C. to 100° C. and holding for a time of 3 to 30 minutes.
Most preferably, said fermentation reaction is terminated by heating to a temperature of about 93° C. and holding for a time of about 15 minutes.
In one embodiment salt is added to said reaction mixture after said fermentation reaction has been terminated.
In another embodiment, cheese is added to said reaction mixture after said fermentation reaction has been terminated.
In one embodiment, the cheese flavour ingredient produced by said fermentation reaction is dried.
Preferably, said ingredient is dried by spray drying.
One embodiment of the invention comprises a cheese flavour ingredient produced by the method of the invention. Another embodiment of the invention comprises a food product comprising a cheese flavour ingredient of the invention. Preferably said food product comprises a product selected from the group comprising natural cheese, processed cheese, analogue cheese, foods comprising natural cheese, processed cheese or analogue cheese, sauces, dips, snacks, biscuits, soups, pizza, and cheese and savoury flavoured foods.
The invention may also be said broadly to consist in the bacterial strain Enterococcus faecium B9642, AGAL accession number NM01/24754.
Alternatively, the invention consists in the bacterial strain Enterococcus faecium B9645, AGAL accession number NM01/24755.
In another embodiment said bacterium is Enterococcus faecaelis B9509, AGAL accession number NM01/24757.
In another embodiment said bacterium is Enterococcus casseliflavus B9518, AGAL accession number NM01/24753.
In another embodiment said bacterium is Staphylococcus simulans B9646, AGAL accession number NM01/24756.
In another embodiment said bacterium is Pseudomonas putida B9647, AGAL accession number NM01/24752.
Another embodiment of the invention comprises a food product comprising a biologically pure culture of the invention.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
The invention may also be more fully understood by having reference to the accompanying drawing wherein:
In the preferred embodiment a protein in water mixture is prepared. Preferably, the protein is a dairy protein source such as cheese. Preferably a cheese, such as a Cheddar or Gouda, is shredded and water is added together with an emulsifying agent such as disodium phosphate (DSP) to form an emulsion. Preferably, the total solids in the mixture range between 5% (w/w) to 50% (w/w).
The preferred emulsifying salt is disodium phosphate (DSP). It is added until its concentration is up to 5% w/w. A preferred concentration is around 1.2% w/w. Other emulsifying food grade salts such as other phosphates and citrate salts may be used.
In addition, food grade emulsifying gums or other food grade emulsifying compounds may be used to assist in the formation of the emulsion.
If necessary, the pH of the mixture may be adjusted to within a range of pH 6.3 to 6.5 by adding a food grade base (alkali).
The reaction mixture is preferably heated to inactivate microbes in the mixture. A preferred temperature is about 93° C. for approximately 15 minutes. The total time elapsed from initiating the process to this first heating step is preferably about 60 minutes to ensure adequate mixing and pH stabilisation.
The mixture is preferably then cooled to about 40° C.
The protease enzymes may be added before or after the heating step. In a preferred embodiment, about 0.1% (w/w) of the protease enzymes are added to the mixture. If the protease enzymes are added before the heating step then preferably the heating step also serves to terminate proteolysis.
The preferred protease enzymes which are added to the mixture are a blend of proteinase and peptidase enzymes. Protease A “Amano” (Amano Enzymes) and Neutrase (Novo Nordisk) are exemplary of a blend which can be employed. Another blend is Flavorpro 192P (Biocatalysts) protease and Promod 215P (Biocatalysts) peptidase.
In one embodiment, once the proteolytic enzymes are incorporated, the mixture is preferably held at a reaction temperature of about 20 to 60° C., preferably about 40° C, for about at least 10 minutes until the mixture is readily stirrable.
In another embodiment the proteolysis reaction and the fermentation reaction are allowed to proceed at the same time.
A bacterial culture of Enterococcus faecium B9642 (as defined below) is added to the mixture and cultured with minimal agitation, to minimise air entrapment. Strict anaerobic conditions are not required as the metabolic activity of the added enterococcal culture will ensure that dissolved oxygen levels are minimal during the course of the fermentation. However, the reaction is carried out under microaerophilic or anaerobic conditions.
A fermentation reaction is thereby established. The temperature is maintained at approximately 20 to 50° C., preferably about 40° C. If necessary the pH is maintained within a range of 6.3 to 6.5 by adding a food grade base. This may be done continuously or at intervals up to about 12 hours.
The fermentation reaction is continued for 20 to 100 hours until the desired ingredient has been produced. A preferred fermentation time is about 50 to 65 hours, about 50 to 54 hours or about 60 to 64 hours.
In some cases it is desirable to adjust the solids content of the fermentation mixture by adding additional starting material, such as grated cheese prior to terminating the fermentation. Salt may be added at the same time or at any other time during the fermentation.
The fermentation step is terminated by heating the mixture. In one embodiment the proteolysis reaction is also terminated at this point. A preferred temperature is 93° C. for approximately 15 minutes to inactivate the culture and its enzymes. Salt content is adjusted to give a final concentration of 5% in the aqueous phase. The solids content may be adjusted when desired by the addition of grated cheese.
The flavour ingredient is in the deactivated reaction mixture. This may be used directly or it may be dried by spray drying, for example, for further use.
The culture which is added to the ferment in the flow diagram of
The medium is then cooled to 30 to 45° C. prior to inoculation. A culture of the bacterium Enterococcus faecium B9642 is added under sterile inoculation conditions. The inoculated medium is incubated for 20 to 24 hours to allow for culture growth. During growth of the culture the pH is adjusted to maximise cell densities above 109/ml. The prepared culture may either be stored frozen at −20° C. or stored chilled at 5° C. until required, or added immediately to the fermentation vessel at typically 4% (w/w) inoculation level to initiate the fermentation. Other means known in the art of producing a culture are also useful herein.
The flavour ingredient recovered after completion of the fermentation has a concentrated mixture of flavours (derived chiefly from the products of amino acid fermentations). A panel comprising practitioners experienced in assessing the taste attributes of cheeses and cheese flavour concentrates was used to assess the product diluted in a bland white sauce. The white sauce was made from mixing and heating 125 g of sauce powder (5 g salt, 120 g standard white flour and 500 g cream powder) blended with 450 g of water. The ingredient was usually diluted in the range of 1 to 20%, typically at 10%, to produce strong flavours that enable batch-to-batch comparison. The flavour was described as having a strong smear flavour, often described as a dirty socks flavour. The other main flavours described were cooked, salty, savoury flavours with sulphury notes. The flavour of the ingredient was compared with two other commercial ingredient flavour concentrates in different dilutions in the white sauce. The ingredient was found to be comparable to, but to have a higher potency than the two commercial concentrates derived by the forced maturation of smear ripened cheese curd.
The flavour ingredient can be used in a range of food applications either on its own or in combination with other flavouring agents. In general terms the ingredient is diluted sufficiently so that the smear flavour note is not detected but rather the ingredient provides flavour balance and enhances the impact of other flavour components. In most applications the flavour ingredient is used in the range of 0.1% to 2%. It may be used to enhance the flavour of natural cheese, processed cheese and analogue cheese foods. It can be used in sauces and dips, for example in a fondue recipe (14% Cheddar cheese, 23% cream, 47% milk, 9% butter, 4% flour, 2% other flavours) the 1% addition of the flavour ingredient improves the savoury and cheesy taste. It can be used in other foods requiring a cheese like flavour component such as snacks, biscuits, soups, pizza or other cheese or savoury flavoured food.
The bacterium used in the fermentation step according to the invention is of one of the genera Enterococcus, Staphylococcus and Pseudomonas.
Enterococcus is the preferred genus for this fermentation. The genus Enterococcus was proposed originally for gram positive diplococci of intestinal origin (Schleifer and Kilpper-Balz, 1984). The genus can be distinguished from other gram-positive, catalase-negative cocci by their ability to grow between 10° C. and 45° C., in 6.5% NaCl, at high pH (pH 9.6) (Hardie et al, 1997). While some strains of Enterococcus have been associated with opportunistic secondary infections in humans (Franz et. al., 1999), these are of a type not found in foods. In fact, several strains are used as probiotics to confer health benefits when they are consumed and many strains are used for the positive contribution they make to food fermentations that include cheeses and other fermented milk products (Franz et al, 1999).
Enterococci occur in a number of cheese varieties but are particularly associated with the cheese produced in southern Europe. They may occur in numbers ranging from 104-106 CFU/g in some ripened cheeses, including Emmental. The predominant enterococcal isolates from cheese are E. faecalis and E. faecium. The beneficial contribution of Enterococci to flavour in cheese has been attributed to the metabolic activity of the cultures, particularly the spectrum of proteolytic enzymes (Centeno et al, 1996) and esterase enzymes (Tsakalidou et al, 1993) and the wide ranging aromatic flavour compounds produced by the cultures.
Enterococcus faecium B9642 is a preferred bacterial strain. It is stored in the culture collection of the Dairy Research Institute, Palmerston North, New Zealand as culture number B9642. It is also deposited in the culture collection of the Australian Government Analytical Laboratory (AGAL), 1 Suakin Street, Pymbal, NSW 2073, Australia as accession number NM01/24754.
Enterococci are Gram-positive, catalase negative cocci mostly in pairs or chains. They produce lactic acid as the major end product of fermentation and do not form gas. Enterococci can be distinguished from other streptococci by their ability to grow at 10 and 45° C., grow in 6.5% sodium chloride, grow at pH 9.6 and to survive heating at 60° C. for 30 minutes. They posses group D antigen (Lancefield serological typing scheme).
Further characteristics of the Enterococcus strains used in this invention are set out below in Table 1.
*nd = not determined
A culture of Staphylococcus has also been used in this invention. Staphylococci are Gram-positive, catalase positive, facultative anaerobic, non-motile cocci, 0.5-1.0 μm in diameter, dividing in more than one plane to form pairs and clusters. Staphylococci can be distinguished from other micrococcaceae by their ability to grow anaerobically and being oxidase negative. The major end product of fermentation anaerobically is lactate. Characteristics of the S. simulans B9646 strain are set out in Table 2 below.
A culture of Pseudomonas has also been used in this invention. Pseudomonads are Gram-negative, catalase positive, usually oxidase positive, straight or curved rods motile by polar flagella. Their metabolism is respiratory, never fermentative, using oxygen as the terminal electron acceptor. Species in the genus Pseudomonas can be distinguished from other members of the pseudomonadaceae family because they do not require growth factors, do not grow at pH 3.6, do not form flocks with dendritic outgrowths and do not produce xanthomonadins. The characteristics of P. putida 9647 are set out in Table 3 below.
The deposit details for the strains in each of Tables 1 to 3 are set out in Table 4.
The invention consists in the foregoing and also envisages constructions of which the following gives examples.
A protein in water mixture comprising a cheddar cheese was formed and then incubated with protease enzymes in a first incubation and then incubated with protease enzymes and a culture of Enterococcus faecium B9642 in a second incubation.
Ingredients for the first incubation: 500 kg of grated commercial New Zealand Cheddar cheese; 12 kg of food grade disodium phosphate dissolved in 50 L hot water; 600 g proteolytic enzymes (protease A “Amano” and Neutrase in equal amounts) dissolved in 10 L water at 43° C.; 250 L water at 43 to 45° C.; 50% (w/w) solution of food grade NaOH.
Ingredients for the second incubation: 400 kg grated Cheddar cheese; 600 g proteolytic enzymes (protease A “Amano” and Neutrase in equal amounts) dissolved in 5 L sterile water; 26 kg of Enterococcus faecium B9642 culture; 50% (w/w) solution of food grade NaOH; 19.5 kg cheese salt.
First Incubation:
1. The water was placed in a tank at a temperature of about 53° C. so addition of the cold cheese would bring it down to about 43° C. The dissolved disodium phosphate was added and mixed into the water. Approximately half the grated cheese was added while stirring over about 15 to 20 minutes.
2. Freshly made protease solution was added, the mixture was stirred for about 5 minutes and then the remaining grated cheese added over about 10 minutes. The temperature was set to 43° C. and the mixture incubated for about 4 hours. After about 3.5 hours NaOH (2.4 L) was added to take the pH to 6.5.
3. After 4 hours incubation at 43° C., the solution was heated to about 93° C. and held for 15 minutes before cooling to about 40° C.
Second Incubation:
4. A further 600 mL NaOH solution was added to the mixture to take the pH to about 6.4-6.6. The proteolytic enzyme solution and 26 kg of the B9642 culture was added. The reaction mixture was held at 40° C. with gentle stirring for about 53 hours. The pH was checked and adjusted to 6.4 to 6.6 if necessary.
5. At the end of the 53 hour incubation the grated cheese and cheese salt was added with mixing and the mixture heated to 93° C. and held for 15 minutes.
6. The ingredient was packed at 85° C. in 20 L pails with plastic liners.
A protein in water mixture comprising a Gouda cheese source was formed in a first incubation then incubated with protease enzymes and a culture of Enterococcus faecium B9642 in a second incubation.
Ingredients for the first incubation: 440 kg of grated brine salted commercial New Zealand Gouda cheese; 10.5 kg disodium phosphate dissolved in 75 L hot water; 3 kg of cheese salt; 325 L water at 43 to 45° C.; 50% (w/w) solution of NaOH.
Ingredients for the second incubation; 760 kg grated Cheddar cheese; 1320 g proteolytic enzymes (protease A “Amano” and Neutrase in equal amounts) dissolved in 5 L sterile water; 26 kg of B9642 culture; 50% (w/w) solution of NaOH; 37 kg cheese salt.
First Incubation
1. The water was placed in a tank at about 53° C. so the cold cheese would bring it down to about 43° C. The dissolved disodium phosphate was added with stirring following by approximately half the grated cheese over about 15 to 20 minutes. The mixture was stirred throughout the process.
2. The remaining grated cheese was added over 10 minutes. The temperature was set to about 43° C. and the mixture incubated for 30 minutes. During this incubation, the cheese salt and 3.5 L NaOH (pH stable at 6.4-6.6) were added.
3. The solution was heated up to about 93° C. and held for about 15 mins before cooling to about 37° C.
Second Incubation
4. The pH was adjusted to pH 6.4-6.6 if necessary and the temperature set to about 40° C. The proteolytic enzyme solution was added and the mixture stirred for about 10 minutes. Then 26 kg of B9642 was added and the mixture held at about 40° C. with intermittent stirring for 64 hours. At end of the 64 hour incubation the grated cheese and cheese salt was added with mixing. Then the reaction mixture was heated to 93° C. and held for 15 minutes.
5. The ingredient was packed in 20 L pails with plastic liners at 85° C.
The final flavour ingredient from each example had the same sensory profile described above (a strong smear flavour, often described as a dirty socks flavour; other main flavours described were cooked, salty, savoury flavours with sulphury notes) when evaluated in a white sauce application as described above.
The above describes some preferred embodiments of the present invention and indicates several possible modifications but it will be appreciated by those skilled in the art that other modifications can be made without departing from the scope of the invention.
References
| Number | Date | Country | Kind |
|---|---|---|---|
| 515881 | Dec 2001 | NZ | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NZ02/00266 | 12/2/2002 | WO |
