GB2544628A - Improvement relating to cheese making - Google Patents

Abstract

A curd cheese-making product comprises (i) a curd material; (ii) a chymosin-derived enzyme in the range 0.4 to 1.1 MIMCU per 20,000 25,000 litres of curd material; and (iii) a starter culture in the range 200-400 g per 20,000 25,000 litres of curd material. The chymosin-derived enzyme may be CH-MAXM. The starter culture may be a RSM starter culture. The cheese-making product may for making a hard cheese such as cheddar. Also disclosed is a method for delaying the proteolysis of casein in a curd material for cheese making comprising the steps of (a) adding a chymosin-derived enzyme in the range 0.4 to 1.1 MIMCU per 20,000 25,000 litres of curd material; and (b) adding a starter culture in the range 200-400 g per 20,000 25,000 litres of curd material.

Description

IMPROVEMENTS RELATING TO CHEESE MAKING

The present invention relates to a curd cheese making product with typical composition of a hard cheese such as Cheddar, a method of delaying the proteolysis of casein in a curd material for hard cheese making, and a cheese product obtained therefrom.

Cheese is a food derived from milk that is produced wholly or substantially by coagulation of the milk protein casein. The milk comes usually from cows, but also other animals such as buffalo, goats and sheep. Typically, the milk is acidified and then coagulated by the addition of rennet. Curd is the product obtained by the milk coagulation, and the process is sometimes called ‘curdling’. The solids formed in the curd are separated and pressed into a final form, and various differences in the timing, separating and pressing provide the varieties of the cheeses known.

Casein is the name for a family of related phosphoproteins, which typically make up 80% of the proteins in cow’s milk. Casein contains a high number of proline residues which do not interact, so that the casein can be held as a suspension in milk. The addition of an acid to the milk reduces the milk’s pH to allow the proteolysis of the casein to occur, typically catalysed by the addition of a suitable enzyme, which leads to the ‘de-suspension’ and formation of the solids in curd. The enzyme used in most cheese making is rennet, containing a proteolytic enzyme and typically obtained from the stomach of calves or other sources such as microbial.

Rennet is available in different ‘strengths’, one measurement of which is the ‘International Milk Clotting Unit, or ‘IMCU’ per millilitre. The common expression used for a thousand IMCUs is ‘MIMCU’.

Curd is typically made in ‘vats’. A conventional size of an industrial curd vat is 22.000 litres, although some variation is known, typically in the range 20,000 to 25.000 litres. For a 22,000 litre vat, starter culture is typically added in the range 500g to 1000g, and rennet typically added in the amount of 2 kg for the ‘standard IMCU/ml 600 strength rennet’, which equates to 1.2 MIMCU per vat. Changing the rennet strength down to e.g. 200 IMCU/ml or up to 1000 IMCU/ml naturally requires adjustment of the quantity used to achieve the same typical starter value of 1.2 MIMCU per vat used in the art.

Whilst variations in the curdling and subsequent cheese making provide the variety of known cheeses, a range of cheeses are know n as ‘hard’ cheeses, and a particularly major industrial and commercial product is ‘Cheddar cheese’, generally provided by reducing the level of moisture in the curd through the cheddaring’ technique or process. This generally involves repeatedly cutting or milling the curd a number of times to extract or push away moisture, in particular remaining whey.

However, once the milk is acidified and the rennet added, the casein proteolysis process, i.e. the cheddaring process, has begun. The producer wishing to make a cheese product out of fresh curd only has a limited window of time to obtain and use the curd to create the Cheddar cheese product. If the proteolysis process has already started to a significant degree, sometimes the product and process must be manipulated in a manner known in the art, which involves additional time and expense not desired on an industrial scale.

Currently, the commercial workable lifespan of curd is 5 days for providing a hard cheese product such as Cheddar cheese product, such that the curdling process or step is a significant focal point in the overall cheese making process, whose control and timing is critical in maintaining production of the cheese product from the curd at an industrial scale.

It is an object of the present invention to provide a cheese making product which is able to delay the proteolysis of casein in a curd material for making cheese products out of curd, typically for processed cheese products.

According to one aspect of the present invention, there is provided a curd cheesemaking product comprising; (i) a curd material; (ii) a chymosin-derived enzyme in the range 0.4 to 1.1 MIMCU per 20,000 - 25,000 litres of curd material; and (iii) a starter culture in the range 200 - 400 g per 20,000 - 25,000 litres of curd material.

In this way, there is a significant reduction of starter culture, which helps control the manufacturing process. By addition of the enzyme in a surprisingly low and defined amount, along with a deliberately unusual lower enzyme amount, it has been found that there is a delay in the proteolysis of the casein in the curd material by up to 21 days without affecting the ability of the curd material to form the desired curd or standard cheese. This delay provides a significantly extended lifetime or ‘working window’ to use the curd for further processing.

The curd material is conventional, generally cow’s milk.

Optionally, the chymosin-derived enzyme is a bovine chymosin, more preferably a fermentation-produced or genetically engineered chymosin, such as CHY-MAX®, CHY-MAX®M, CHY-MAX®EXTRA or CHY-MAX®PLUS (available from Chr.Hansen, Hoersholm, Denmark).

Optionally, the chymosin-derived enzyme is provided in the range 0.5 to 1.0 MIMCU per vat or per 20,000 - 25,000 litres of curd material. More optionally, the chymosin-derived enzyme is used from one of a lower range of 0.5, 0.6, 0.7 or 0.8 MIMCU per vat, and from one of an upper range of 1.0, 0.9, 0.8 or 0.7 MIMCU per vat or 20,000 - 25,000 litres of curd materials.

Starter materials used in cheese making are generally based on mesophilic and/or thermophilic strains, often being blends thereof to take advantage of the scald temperature used in Cheddar manufacture, (which is normally greater than 38°C). This also increases the activity of the starter, enabling reduced inoculation rates.

One range of starter cultures known in the art are termed ‘RSF starter cultures’, and optionally the starter culture is a RSF 900 starter culture, such as RSF925, 940, 945, 950 and 960.

Optionally, the starter culture is used in the range 200g - 300g per 20,000 - 25,000 litres of curd materials. More optionally, the starter culture is used from one of a lower range of 21 Og, 220g, 230g, 240g, and 250g, and from one of an upper range of 290g, 280g, 270g, 260g, per 20,000-25,000 litres of curd materials.

Optionally, the enzyme and starter culture ranges defined herein relate to 22,000 litres of curd materials.

Optionally, the curd cheese-making product is for making a hard cheese.

Optionally, the curd cheese-making product is for making Cheddar cheese.

Other typical ingredients in the curd cheese-making product include: cheese, milk and salt.

The curd cheese-making product generally has:

In another aspect, the present invention provides a method of delaying the proteolysis of casein in a curd cheese-making product for cheese making comprising the steps of: (a) adding a chymosin-derived enzyme in the range 0.4 to 1.1 MIMCU per 20.000 - 25,000 litres of curd material; and (b) adding a starter culture in the range 200 - 400 g per 20,000 - 25,000 litres of curd material.

Optionally, the chymosin-derived enzyme is CHY-MAX®M, optionally M200 or M1000 product.

Optionally the chymosin-derived enzyme is added in the range 0.5 to 1.0 MIMCU per 20.000 - 25,000 litres of curd material. Other possible ranges are defined herein.

Optionally the starter culture is one of the RSF 900 starter cultures (also available from Chr.Hansen, Hoersholm, Denmark), such as mentioned above.

Optionally the starter culture is added in the range 200 - 300 g per 20,000 - 25,000 litres of curd material. Other possible ranges are defined herein.

Other process conditions controlled to replicate the recipe include scald time, pitch time, and total processing time.

According to one particular embodiment, the chymosin-derived enzyme is a CHY-MAX®M product, such as M200 or M1000, added to provide a MIMCU value per vat in the range 0.8 to 1, and the starter culture is one of the RSF 900 starter cultures added in the range 200-300g.

According to another aspect of the present invention, the process provides a cheese product obtained from the cheese making product as defined herein.

According to another aspect of the present invention, the present invention provides a process for making a cheese product comprising maturing a cheese making product as defined herein, such as a hard cheese such as Cheddar cheese.

Control examples and Example Recipe of the invention

The following table 1 shows a comparison of three curd cheese making products.

Control 1 recipe is based on a standard or conventional, curd recipe, using 500 g of a RSF600 starter culture, and 2kg of a CHY-MAX Extra rennet to provide a the standard conventional 1.2 MIMCU per vat.. (AFI).

Control 2 recipe was also prepared, based on using 500 g of the same RSF600 starter culture, and about 4.5kg of a CHY-MAX M rennet, to again provide the standard conventional 1.2 MIMCU per vat.

Example Recipe 1, an embodiment of the present invention, is based on using deliberately lower amounts of the same CHY-MAX M rennet as the Control 2, along with a only 250g of an RSF900 starter culture. The figures in Table 1 represent an average of three separate trials.

Table 1

The accompanying Figure 1-10 comprises a series of side-by-side comparisons of three Polyacrylamide gel electrophoresis (PAGE) strips and developed graphical plots after 2, 4, 7, 9, 12, 14, 16, 19, 21 and 23 days of the Control 1 and 2 curds, and the Recipe 1 representative of the present invention.

Polyacrylamide gel electrophoresis is a well known method for separating and analysing proteins and their fragments to confirm the extent of protein breakdown, in particular casein breakdown. The PAGE graphical plots in Figures 1-10 show the breakdown of casein as a result of the proteolysis of the curd. The two starter peaks, and each developed peak thereafter, is emphasised by a square at the top of the graph for clarity.

Figures 1-10 show the breakdown of casein from the known initial ‘three main peaks’, into the increasing number of peaks, in particular the known ‘fourth peak’ that emerges only after the casein has broken down.

The PAGE plots for the Control curds 1 and 2 in the Figures show this breakdown occurring after 4 days, where the fourth peak emerges. In contrast, the same fourth peak only emerges after 21 days in the PAGE plots for the Example Recipe 1 of the present invention.

The skilled person in the art can see from these PAGE plots that the same calculation of reduced enzyme amount and reduced starter culture, working in the same or similar proportions or ratios per vat, can achieve the same breakdown delay. Thus the present invention can used any suitable enzyme able to provide MIMCU per vat in the range 0.4 to 1.1 not limited to those from CHY Hansen, and other starter cultures, as long as the correct ratio between them is achieved according to the present invention.

The present invention provides a curd cheese-making product that allows cheese manufacturers, in particular processed cheese manufacturers, with a significantly longer ‘working window’ to use the curd, whilst providing the same functional properties that processed cheese manufacturers need to make processed cheese, whether this be on day one after making the curd, or day 21. Thus, the present invention provides the cheese manufacturer with significantly less focus on the production around the use of curd before it is unusable to form cheese produced without significant cost, line speed reduction and product defects.

Claims (20)

1. A curd cheese-making product comprising; (i) a curd material; (ii) a chymosin-derived enzyme in the range 0.4 to 1.1 MIMCU per 20,000 - 25,000 litres of curd material; and (iii) a starter culture in the range 200-400 g per 20,000 - 25,000 litres of curd material.

2. A curd cheese-making product as claimed in claim 1 wherein the chymosin-derived enzyme is CHY-MAX®M.

3. A curd cheese-making product as claimed in claim 1 or claim 2 wherein the chymosin-derived enzyme is in the range 0.5 to 1.0 MIMCU per 20,000 - 25,000 litres of curd material.

4. A curd cheese-making product as claimed in any of the preceding claims wherein the starter culture is a RSF starter culture.

5. A curd cheese-making product as claimed in claim 4 wherein the starter culture is an RSF 900 starter culture.

6. A curd cheese-making product as claimed in claim 5 wherein the starter culture is an RSF 925, 940, 945, 950 or 960 starter culture.

7. A curd cheese-making product as claimed in any of the preceding claims wherein the starter culture is in the range 200 - 400 g per 20,000 - 25,000 litres of curd material.

8. A curd cheese-making product as claimed in any of the preceding claims for making a hard cheese.

9. A curd cheese-making product as claimed in claim 8 for making Cheddar cheese.

10 A cheese product obtained from the curd cheese-making product of any of claims 1 to 9.

11. A cheese product as claimed in claim 10 being a Cheddar cheese.

12. A method of delaying the proteolysis of casein in a curd material for cheese making comprising the steps of: (a) adding a chymosin-derived enzyme in the range 0.4 to 1.1 MIMCU per 20,000 - 25,000 litres of curd material; and (b) adding a starter culture in the range 200 - 400 g per 20,000 - 25,000 litres of curd material.

13. A method as claimed in claim 12 wherein the chymosin-derived enzyme is CHY-MAX®M.

14. A method as claimed in claim 12 or claim 13 wherein the chymosin-derived enzyme is added in the range 0.5 to 1.0 MIMCU per 20,000 - 25,000 litres of curd material.

15. A method as claimed in any of claims 12 to 14 wherein the starter culture is RSF starter culture.

16 A method as claimed in any of claims 12 to 15 wherein the starter culture is added in the range 200 - 400 g per 20,000 - 25,000 litres of curd material

17. A process for making a cheese product comprising maturing a curd cheesemaking product as claims in any one of 1 to 9.

18. A process for making a hard cheese product as claimed in claim 17

19. A process for making a Cheddar cheese product as claimed in claim 18.

20. A method of delaying the proteolysis of casein in a curd material for cheese making substantially as described herein and with reference to the accompanying drawings.